! UNIVERSITY OF B.C. LIBRARY STORAGE ITE ; i i-pl-i>i2c U.B.C. LIBRARY ■*«mwM»waMMi*MMiBiwiiiimii»iiMi ■■* Gwm tsf I of i{ic^\\ii\un\\i{\j tit c 7-4*4-7 Digitized by the Internet Archive in 2010 with funding from University of British Columbia Library http://www.archive.org/details/soilshowtohandlOOflet SOILS HOW TO HANDLE AND IMPROVE THEM THE FARM LIBRARY FARM ANIMALS . . . ByE.V. Wilcox COTTON . By C. W. Burkett and Clarence H. Poe SOILS By S.W. Fletcher Zhc Jfarm Xibrar^ SOILS How to Handle and Improve Them By S. W. FLETCHER Professor of Horticulture in the Michigan Agricultural College Illustrated from photographs by the author NEW YORK Doubleday, Page & Company 1908 Copyright, 1907, by Doubleday, Page & Company Published, January, 1907 All rights reserved, including that of translation into foreign languages including the Scandinavian ACKNOWLEDGMENTS The illustrations are by the author except No. 24, from Rollins and Linn, Lookout Mountain, Tenn.; No. 78, from "Irrigation," by Newell; and Nos. 80, 81, 83, and 84, which are from the Office of Irrigation and Drainage Investigations, United States Department of Agriculture. Perhaps the most valuable feature of the book is the lists of crop rotations in the Appendix, which were contributed by authorities on this subject in the several states, as noted in connection with the lists. These courtesies are gratefully acknowl- edged. THE INFLUENCE OF Hofin flfll. fepencet, JFarttur HAS GIVEN GREATER SIMPLICITY AND FORCE TO AGRICULTURAL TEACHING FOREWORD Many of the early books on farming were written in a technical style. They smacked of the lecture room and the library rather than of the soil. They were scholarly rather than practical. A spirit of directness and simplicity . is be- ginning to dominate agricultural literature. The modern type of farm books is born of actual contact with the soil and a desire to be of service to the men who are getting a living from the soil. They are democratic; they discuss common things in a plain way. The long and tedious tables of figures in the old books are giving place to crisp summaries. The technical lecture-room phrases are replaced by words in common use on farms. The idea is not to present less science — for nothing is so practical as sound science — but to present science in a simple and practical way. This new spirit is contemporaneous with the farmers' in- stitute, the farmer's reading-course, Nature-study, elementary agriculture in the public schools and other efforts to serve the man who tills the soil. It is an expression of a general movement which aims to democracise agricultural teaching. This book is an attempt to set forth the impor- tant facts about the soil in a plain and untechnical manner. It is not a contribution to agricultural science, but an interpretation of it — a new presen- tation of what is already known. S. W. Fletcher. Agricultural College, Michigan, October 30, 1906. CONTENTS - Chapter I. SOIL BUILDERS The weathering of rocks .... Mountains and stones becoming smaller Soils being changed into rock Changes in temperature crack rocks Plants as soil builders The work of lichens and mosses Soils built mostly by plants Stems and roots split rocks Plants as soil binders How ice has made soil Animals as soil builders The remains of all animals are returned to the soil The service of ants, moles, gophers, beavers, etc. How angleworms improve soil The action of moving water .... In wearing away a soil and carrying it elsewhere The origin of alluvial soils In dissolving rocks ..... Soils built wholly or partly by the wind The soil teems with life . Chapter II. THE NATURE OF SOILS The fineness of the soil .... All soils are becoming finer The number of particles in different soils Fineness is richness The weight of soils .... The mineral contents of the soil The rocks from which soil is made Elements, compounds and plant food The water in the soil Free or ground water Film water .... Water absorbed from the air PAQB 3 3 5 5 7 7 8 9 10 11 12 12 13 14 15 16 17 17 18 20 23 23 23 25 26 26 27 28 29 29 30 31 Xll CONTENTS The temperature of the soil .... How warm the soil must be for various crops The comparative temperature of different soils Drainage promotes warmth Influence of the exposure on the warmth of soils Dark colored soils absorb more heat The influence of tillage on soil temperature The ventilation of the soil .... The necessity for air in the soil Methods of improving the ventilation of soil Electricity in the soil .... Germ life in the soil ..... The beneficial work of nitrogen-fixing germs Conditions essential to the life of these germs Germs that waste nitrogen A multitude of other soil bacteria Chemical changes in the soil .... PAG9 31 31 32 83 34 34 36 37 37 37 39 40 40 42 42 43 44 Chapter III. THE KINDS OF SOILS AND HOW TO MANAGE THEM Sedentary soils Transported soils 46 47 Alluvial soils 47 Drift soils 48 Wind-built soils 50 The composition of soils The basis of separation The characteristics of sand 51 51 51 The characteristics of clay 52 The characteristics of silt . , 52 The characteristics of humus 53 The leading types of farm soils Sandy soils .... Sandy loams . Clay soils 53 54 55 56 Clay loams Loams 58 59 Gravelly and stony loams Peat and muck 59 60 Loess soils . 62 Adobe soils . 63 Salt marsh soils 64 CONTENTS Xlll The problem of alkali soils What causes alkali The effect of alkali Treatment for alkali The subsoil What it is Its fertility Different types Analysing the soil at home Weighing the humus Separating the sand, silt, and clay PAGE 65 65 66 67 69 69 70 70 71 72 73 Chapter P7. SOIL WATER The amount of water needed by plants How plants drink ..... Rainfall insufficient or unevenly distributed The capacity of different soils to hold water Influence of the subsoil on water-holding capacity Height of the water table .... How to increase the water-holding capacity of soils The influence of forests upon the water supply The loss of soil water by seepage The extent of the loss .... Plant food lost in seepage water . How to prevent loss by seepage . The movement of film water How film water creeps from grain to grain Capillary action ..... How to prevent the loss of film water by evaporation The function of a mulch .... The soil mulch ..... The water-moving ability of different soils How to test the water-holding capacity of soils How to test the water-moving ability of soils . — Chapter V. THE BENEFITS OF TILLAGE The present emphasis on good tillage Tillage to prepare the seed bed The competition between plants in the wild Culture an improvement on nature The reward of thoroughness 76 77 78 80 83 84 84 85 85 87 87 87 89 90 91 91 92 93 95 97 98 98 99 100 XIV CONTENTS Tillage to kill weeds What a weed is The tirade against weeds Friendly words for weeds A spur to the sluggard Tillage to save water The amount lost by evaporation The efficiency of the soil mulch Increasing the water-holding capacity of soils Dry farming . • Its growing importance in the West Conditions under which it is necessary Methods of handling the soil Crops under dry farming Caution necessary .... Tillage to promote fertility . Nature's method of promoting fertility How tillage increases fertility Tillage the poor man's manure The alchemy that follows the plow PAGB 101 101 101 102 103 104 104 104 105 105 106 106 107 108 109 110 110 110 111 112 — Chapter VI. THE OBJECTS AND METHODS OF PLOWING The evolution of the plow Primitive plows Early American plows The modern plow The objects of plowing To destroy wild plants and bury herbage To pulverise the soil To prepare the seed bed To promote fertility To deepen the soil reservoir To drain the soil To establish a mulch The depth to plow is influenced by: The nature of the soil The time of year The nature of the subsoil The value of deep-plowing and sub-soiling 114 114 115 116 117 117 118 120 120 121 122 122 122 123 123 124 126 CONTENTS xv The draft and power in plowing Heavy teams do better work Horse, mule, and ox power The power for plowing Steam and electric power Greater power needed Essentials of a good plow The beam The mouldboard The coulter The jointer The beam-wheel The share The clevis When to plow The benefits of and the occasions for fall plowing The critical time for spring plowing When plowing is dispensed with The usefulness of the different kinds of plows The landside plow The swivel plow The sulky plow The gang plow The disk plow Adjusting the plow in the field — Chapter VII. HARROWING AND CULTIVATING The tillage of preparation .... The objects of harrowing Better harrowing needed . The kinds of harrows and the influences of each Each kind best for specific purpose The spike-tooth harrow . The spring-tooth harrow The Acme harrow Rolling harrows— disk, cutaway, and spading When the soil is ready to harrow The kinds of cultivators and the usefulness of each The difference between a harrow and a cultivator Shovel-tooth or coulter cultivator Spike-tooth cultivator Spring-tooth cultivators Sulky cultivators Weeders PAGB 127 128 129 129 129 130 131 131 131 132 132 133 133 133 134 134 135 136 137 137 137 138 138 139 140 142 142 143 144 144 145 147 148 149 151 152 152 153 153 154 155 156 XVI CONTENTS Cultivating to kill weeds Weeds steal plant food Weeds steal water .... The best time to kill weeds When weeds get a start Weed collection .... The prevalence of weeds in sown crops Cultivation to save water Sometimes needed when there are no weeds Signs of the need of cultivation How often to cultivate for making a mulch How deep to cultivate .... The advantages of level culture Preventing the loss of soil water from sod land PAGB 157 157 158 159 160 162 163 163 164 164 165 166 168 170 Chapter VIII. ROLLING, PLANKING AND HOEING Rolling to assist germination by supplying more moisture How accomplished When practicable Making a mulch after rolling Other illustrations of the principle of rolling Other benefits of rolling To crush lumps To warm the soil Incidental benefits The kinds of rollers Planking The construction of a planker When to use it and what it does Hoeing .... Of less importance than formerly Hoeing to make a mulch Hoeing to kill weeds Good and poor hoeing Different styles of blades Miscellaneous hand tools . Their decreasing importance Hand cultivators Scuffle hoes Selecting farm tools Too many tools means tied-up capital A variety necessary . 171 172 172 173 174 175 175 176 176 177 178 178 178 179 179 180 180 181 182 183 183 184 184 185 186 186 CONTENTS xvn — Chapter IX. THE DRAINAGE OF FARM SOILS Drainage mainly a problem east of the Mississippi When drainage is needed To dry out a wet soil To deepen a shallow soil To improve texture Many soils are well drained naturally When it will pay to drain land How drainage affects the soil It makes the soil warmer It ventilates the soil Draining a soil makes it more moist Practical results from draining land What kind of drains to use Surface drains Underdrains When ditches are practicable How to dig a drainage ditch The grade The distance apart Surface drainage by plowing into lands The action of underdrains Planning a system of underdrains The necessity for a plan The outlet .... The grade .... Simple devices for establishing the grade The number and direction of the drains Distance between drains The depth to lay the drains The kinds of tiles The size of tiles Digging the ditch Placing the tiles Filling the ditch Obstructions in tile drains The cost of putting in tile drains Other kinds of underdrains Draining pot holes Draining large swamps and marshes The large area of reclaimable swamp and marsh land PAGE 189 190 191 192 192 194 195 196 198 197 197 199 200 200 200 201 202 203 204 204 205 207 207 209 210 212 216 218 219 221 222 224 225 226 227 228 229 230 231 231 XV111 CONTENTS Chapter X. FARM IRRIGATION PAGB The present extent of irrigation ..... 233 In foreign countries ...... 233 In the United States 233 The area in the United States that can be irrigated . . 234 The objects of irrigation . . . . . .236 To remedy a deficiency in rainfall . . . .236 To enrich the land 237 To correct alkali and improve texture .... 237 How far the natural water supply will go depends upon . 237 The minimum amount of rainfall needed . . . 238 The season when it falls ...... 238 The retentiveness of the soil ..... 238 Irrigation in humid regions ...... 239 Used to supplement deficiency in summer rainfall . 239 Under what conditions it will pay . . . 240 Better tillage may obviate the necessity for irrigation . 241 The supply of water for irrigation .... 243 From streams ....... 243 From ponds and lakes . . . . . 24 3 From springs and wells ...... 244 Hydrant water 244 The construction of small earth reservoirs . . . . 245 Pumping water for irrigation . . . . .246 With windmills 247 With steam and gasoline engines .... 248 With water wheels 249 With hydraulic rams ...... 250 The sluice gate 250 Building distributing ditches . . . . . .251 The use of flumes and pipes ...... 252 Cement-lined ditches ....... 252 Methods of applying water ...... 253 A local and personal problem ..... 253 Check flooding 254 Wild flooding 256 Irrigation by furrows ....... 257 Sub-irrigation ........ 260 Methods of measuring water ...... 262 The divisor 262 The module 263 By apportionment ....... 263 Units in measuring water ...... 263 CONTENTS xix PAGE The duty of water 264 The character of the soil . . 265 The kind of crop . 265 The amount of rainfall . 266 The frequency and time of irrigation . 267 Indications in the soil and crop . 268 The folly of over-irrigation . 268 The time of day to irrigate . 269 Directing the flow . 269 Tillage after irrigation . 270 Methods of irrigating important crops . 271 Meadows .... . 271 Fruits . 271 Potatoes .... . 273 Garden vegetables . 274 The cost of irrigation . . 274 National aid in irrigation . 275 The Reformation Act of 1902 . . 276 Windbreaks . ... . 278 — Chapter XI. MAINTAINING THE FERTILITY OF THE SOIL What fertility is 280 Many views 281 The native richness of soils 281 The soil a storehouse of plant food 282 Plant food locked up 282 Soils exhausted of plant food 283 The loss of fertility by erosion . 284 An insidious leak 286 Erosion in the South 287 Methods of checking erosion 287 Preserve forests and wooded stri] )S 288 Re-forestation . 288 Directing water. 289 Terracing 291 Side-hill ditches 291 Soil-binding crops 291 Breaks .... 292 Deep-plowing and humus . 294 Tillage operations 295 XX CONTENTS The relation of fallowing to soil fertility An ancient practice . Fallowing to store water Fallowing to set free plant food Fallowing to destroy weeds The methods of fallowing . Rotation of crops Nature's rotations Why a rotation is beneficial It affects the relative supply of plant foods The different rooting habits of crops Rotations and weediness Injurious insects and diseases lessened Keep the soil busy Economy of labour . Choosing crops for a rotation . Typical systems of rotations Single-crop farming Selling fertility A bank account with the soil of farming Loss of plant food in different systems Advantages of diversified farming Keeping live-stock to maintain fertility The excretory theory of soil fertility . PAGE 296 296 297 297 298 298 299 300 300 301 301 302 303 304 304 305 307 310 311 312 312 315 316 318 Chapter XII. GREEN-MANURING AND WORN-OUT SOILS What is meant by "good texture" How Nature secures good texture How humus benefits the soil By improving its texture . By increasing its power to hold water . By enriching it . The kinds of green-manures Leguminous ..... Non-leguminous .... When a green-manuring crop may be grown In a rotation ..... Catch crops and cover crops The fertilising value of roots and stubble . Green-manures not complete fertilisers 322 323 327 327 S28 328 329 329 330 330 331 331 332 332 CONTENTS xxi Inoculating the soil With old soil With artificial cultures Each crop has different bacteria Plowing under a green-manure . Leguminous crops for green-manuring Non-leguminous crops for green manuring The renovation of worn-out soils How soils have become worn out How to build up worn-out soils . - Chapter XIII. FARM MANURES Manuring the oldest means of maintaining fertility How manure benefits the soil .... Its value as plant food. .... The chemist's valuations not the farmer's Its influence on soil texture Bacteria in manure ..... Comparative plant-food value of different manures The quality of manure. ..... How manure is wasted ..... Throwing it away ..... Loss from leaching ..... Loss from fermentation .... Loss in liquid portions .... How to care for manure ..... Covered barn-yards ..... Manure pits, sheds and cellars . Preventing fermentation The use of bedding ..... Mineral absorbents ..... The amount of manure made on the farm When to apply manure ..... How much to use ...... How to apply ....... Chapter XIV. COMMERCIAL FERTILISERS PAGE 333 334 334 335 337 338 341 342 343 344 346 346 347 347 347 348 349 350 351 351 352 353 354 354 355 355 356 357 357 358 360 361 363 Rapid growth of fertiliser trade What commercial fertilisers are made of State supervision of the fertiliser trade 364 366 367 XX11 CONTENTS Studying fertiliser tag3 Some guarantees misleading Repetitions in guarantees The forms of phosphoric acid . Calculating the value of a fertiliser Low-grade fertiliser expensive . The advantages of home mixing Sources of nitrogen Sources of phosphoric acid Bone fertiliser . Rock phosphates Phosphate slag . Superphosphates Sources of potash Mixing the raw materials What kinds of fertiliser to use Soil analyses as a guide to fertilising Questioning the soil . The needs of different crops The relative importance of the three plant When to apply fertilisers . The solubility of the fertiliser The needs of the crop How to apply fertilisers . When it will pay to use fertilisers Indirect fertilisers . The benefits of liming Lime a plant food Improves texture Unlocks potash Sweetens sour soils The soils that need liming Tests for sour soils . Land plaster, marl and other amendments foods PAGE 363 368 369 370 373 375 376 377 379 379 381 381 382 384 386 388 389 390 392 394 395 395 396 396 398 399 399 399 399 400 400 400 401 402 APPENDIX I. Crop rotations in the different states. II. Analyses of soils . III. Native plant food in farm soils. 405 417 419 CONTENTS xxin IV. Plant food drawn from the soil by average yields of crops ........ 420 V. Analyses of commercial fertilising materials . .421 VI. Analyses of farm manures ..... 422 VII. Fertilising materials in farm products . . 423 VIII. Schedule for the valuation of fertilisers . . . 426 INDEX 427 LIST OF ILLUSTRATIONS "The Farmer" L. H. Bailey Frontispiece FACING PAGE 1. Taughannock Falls, Ithaca, N. Y 4 2. Soil and Stones Brought Down by a Stream .... 4 3. Rock Split by the Growth of a Tree which Happened to Find Lodgment in a Crevice 5 4. Ledge Being Torn Apart by the Growth of Tree Roots in the Crevices 5 5. Erosion of a Mountain in Montana 6 6. Niagara Falls, Canadian Side 6 7. The Beginning of a Soil 6,000 Feet High, on Grand- father Mountain, North Carolina 7 8. Mosses and Other Humble Plants on Ledges ... 7 9. A Pond Fitting Up, Plants Encroach Upon It More Every Year Until Finally It is Completely Filled .... 10 10. A Pond Completely Filled by Plants 10 11. The Humble Beginnings of a Soil 11 12. The Great Usefulness of Plants as Soil Builders ... 11 13. Mangrove Swamp in Florida 12 14. Cocoanut Trees on the Coast of Florida 12 15. Castings of Earthworms on Surface 13 16. Ant-hill 13 17. Pieces of Rock Split Off by Frost 13 18. Lichens on Rock 13 19. How Water Moves Through the Soil 18 20. The Difference Between Surface Soil and Subsoil . . 19 21. How Plants Eat 19 22. A Sedentary Soil of North Georgia 20 23. A Transported Soil— The "Palouse Country" of Oregon and Washington 20 24. An Alluvial or Water-made Soil — The Moccasin Bend of the Tennessee River, From Lookout Mountain, Near Chattanooga, Tenn 21 26. A Small Brook Doing Exactly the Same Work as the River Above 21 XXV xxvi LIST OF ILLUSTRATIONS PACING PAGE 26. Sand Dunes Near Lake Michigan — A Wind-formed Soil that is Valueless 28 27. The Everglades of Florida — A Soil Built Largely by the Decay of Plants 28 28. A Unique "Soil" 29 29. The "Particles" of the Above Soil 29 30. The Three Chief Ingredients of Soils: Humus or De- caying Vegetation, Clay, and Sand 30 31. A Clay Soil Cracking 30 32. How Film Water is Prevented from Evaporating by a Soil Mulch 31 33. Corn Leaves Curling in a Drought 31 34. Tilling the Soil — The Most Common, and the Most Im- portant Operation on the Farm 102 35. Potatoes in Dire Need of Tillage 103 36. Potatoes Luxuriating Under a Mulch of Loose, Dry Soil 103 37. Water Held by a Coarse and by a Fine Soil . . . . 106 38. A Lumpy Soil 106 39. A Perfect Soil Mulch 107 40. Where Troublesome Weeds are Wont to Congregate and to Multiply 107 41. Plowing the Corn Field . 116 42. Flat-furrow Plowing — The Slice Completely Inverted . 117 43. Clay Soil Plowed When Too Wet 117 44. Ideal Plowing 124 45. An Ideal Plow for Ordinary Work 125 46. A Cheap and Rather Ineffective Wooden-beam Plow . 125 47. Shiftless Plowing in North Florida 128 48. Turning Under Thick Herbage with the Aid of a Chain 128 49. The Appearance of Land After Fall Plowing . . 129 50. The Appearance of the Same Land the Following Spring 129 51. The Work of the Acme Harrow 144 52. A Home-made Spike-tooth Harrow, in Two Sections . 145 53. A Sulky Harrow 145 54. A Spring-tooth Harrow 146 55. The Work of a Spring-tooth Harrow 146 56. "Sweeps" Attached to a Plow-stock, for "Laying By" Corn 147 57. The Effect of Using the Above Tool for Cultivating a Cotton Field 147 58. The Most Common Type of Deep-working Coulter-tooth Cultivator 158 LIST OF ILLUSTRATIONS xxvii FACING PAGE 59. Young Corn in Need of a Cultivation 158 60. A Cultivator that is Really a Plow 159 61. Cultivating at a Disadvantage 159 62. Rolling Wheat Seeding in a Dry September .... 182 63. A Cloddy Soil that would be Benefited by Rolling . . 183 64. A Four-section Iron Roller Weighted 183 65. A Three-section Iron Roller 186 66. A Home-made, Three-section Wooden Roller . . . 186 67. A Serviceable Home-made Planker or "Float" . . . 187 68. Corn "Drowned Out" 198 69. Meadow on which Less Water Has Been Standing . . 198 70. A Soil Well-drained Naturally by a Gravelly Subsoil . 199 71. Surface Drainage by " Plowing into Lands " .... 199 72. Draining Wet Lands with an Open Ditch 202 73. An Open Ditch with Grassed Sides on an Easy Slope, so They do not Wash 202 74. Laying a Tile Drain 203 75. A Tile that Has Been Clogged by Tree Roots ... 203 76. The Plow may be Used to Facilitate the Removal of Surface Soil for Drains 228 77. Outlet of a Tile Drain Clogged by Soil so that the Drain Does not Work. 228 78. A Typical Eastern Swamp that can Easily be made into Farming Land 229 79. Map of the Mean Annual Rainfall in Different Parts of the United States (After Newell) 236 80. Irrigating Olives, Fresno, California, by Check System . 237 81. The Intake of the Sunnyside Canal, Yakima Valley, Washington 237 82. Irrigating a Garden from a Hydrant in a Semi-arid Region (Pullman, Wash.) 274 83. Irrigating Strawberries by Pumping from Cache Creek, California. 274 84. Irrigating Alfalfa by Furrow System, Yakima Valley, Washington 275 85. A Barnyard in the Shenandoah Valley, Virginia . . . 286 86. The Ohio River Flooding its Meadows 287 87. Pasturing with Cattle 287 88. Sheep at Pasture 287 89. Harrowing the Summer Fallow 320 90. Hay that Will Soon be Baled and Shipped to the City . 321 91. Clover Following Wheat — One of the Commonest Ro- tations in this Country 321 xxviii LIST OF ILLUSTRATIONS FACING PAGE 92. Loss of Fertility by Erosion 324 93. A Georgia Field that Once Produced a Bale of Cotton per Acre, now Ruined Beyond Redemption by Gully- ing 324 94. Richness Running off in the Bottom of the Deep Furrow Made by Ridging this Cotton 325 95. A "Break" of Corn Stalks Used to Check Gullying . 325 96. A Fifteen Years' Growth of Long-leaf and Jersey Scrub Pines on a Southern Hillside Farm 332 97. A Hillside that Gullied Badly Until Covered with Ber- muda Grass and Lespedeza 333 98. The Dense Turf of Bermuda Grass 333 99. Soil in Poor Texture 336 100. Clod of Clay Soil; Decaying Stems and Leaves, which Become Humus 336 101. Nodules, or Tubercles, on the Roots of Soy Bean . . 337 102. Cowpeas on "Worn Out" Cotton Field 337 103. A Field of Cowpeas Grown to Improve the Soil . . 340 104. A Single Cowpea Vine, Twelve Feet Long, on a North Georgia Farm 340 105. Velvet Beans Grown for a Green Manure in Florida . 341 106. The Right Place for a Cover Crop— To Protect the Bare Ground of the Corn Field Over Winter .... 341 107. A Common, and an Extremely Wasteful Method of Storing Farm Manures 348 108. The Essence of the Manure 348 109. Pond Covered with "Duck Meat" through Manure Draining into it 349 110. Manure Wagon 349 111. Manure Pile in the Field, to be Spread Later ... 362 112. Spreading Manure from the Wagon on Corn Stubble . 362 113. Buying in Sacks 363 114. A Fertiliser Tag Taken from a Sack, Showing the Guaranteed Analysis of the Fertiliser 363 SOILS HOW TO HANDLE AND IMPROVE THEM CHAPTER I SOIL BUILDERS MANY people who till the soil, either as a business or as a recreation, look upon it merely as dirt — cold, inert, lifeless, change- less. I have met farmers in New England who took it for granted that the land they till to-day is about the same as it was two hundred years ago, when their forefathers cleared it, except for being less fer- tile. They had not noticed, or at least had not interpreted, the soil-building and soil-changing agencies at work all about them — wearing away the uplands, enriching the meadows, reducing the rocks, filling the swamps ; changing from year to year the contour of their farms and their agricultural value. THE WEATHERING OF ROCKS Every farm soil is a complex material and has an interesting history. Most soils are a mixture of ground rock, decayed plants and the remains of insects and animals. Some soils, as the sands, are almost entirely particles of rocks; others, as peat and muck land, are made almost entirely of de- cayed plants. Neither of these extremes makes a a good farm soil, as a rule. The majority of the soils in which plants are cultivated are made mostly of ground rock, with the addition of a greater or less amount of decayed plants. Rock has been, and is still being, ground by weathering — the action of air, rain, snow, frost, 8 4 SOILS heat and ice. Ever since the surface of the earth cooled, making a crust of rock, these agencies have been constantly at work, breaking up this crust, wearing away fragments of rock and carrying them to lower levels. They are Nature's plows. All mountains and hills are slowly wearing away. We can no longer regard them as "firm and ever- lasting." "Whole mountain chains of geologic yesterday have disappeared from view," says Merrill, "and we read their history only in their ruins." The Appalachian Mountains have al- ready lost by weathering and erosion as much material as now remains. Even within the mem- ory of one man, a hill may become noticeably lower. The whole earth is being levelled — very slowly, yet quite perceptibly. The face of every rock is roughened and chipped by the elements. Drops of rain wear away particles of it; water freezes m the crevices, expands, and chips off fragments. The air searches these crevices and corrodes them, as it does iron. Everywhere cliffs are lower, rocks are smaller and soils are finer than they used to be. The big rock that the farmer has plowed around for thirty years is smaller now than it was when he first "rode horse" for his father. The stones on the gravelly knoll pass between the cultivator teeth easier than they used to. All about us, in the wild and on the farm, are indisputable evidences that soil is being made by the weathering of rocks. Most farm soils are still incomplete — they contain rocks and stones that are slowly being made into soil. A few, as the clays and alluvial soils, are changing less; but even the finest clay soil is af- fected by weathering to some extent. The reducing and fining process is universal and ceaseless. 1. TAUGHANNOCK FALLS, ITHACA, N. Y. How many centuries has it taken this stream to wear the deep gap in the cliff ? 2. SOIL AND STONES BROUGHT DOWN BY STREAM Much of it was worn away from rocks and cliffs like the above. Some day it will be used for farming ROCK SPLIT BY THE GROWTH OF A TREE, WHICH HAPPENED TO FIND LODGMENT IN A CREVICE "Half-way stone," Lansing. Michigan LEDGE BEING TORN APART BY THE GROWTH OF TREE ROOTS IN THE CREVICES Plants aid in soil building by the pressure of growth of stem or root SOIL BUILDERS 5 An interesting example of soil formation by weathering is the heaving of stones to the surface, especially in the clay soils of northern states. A vivid recollection of my boyhood is the thankless task of picking up stones from rocky New England fields. This had to be done every fall and every spring. Though we might pick up and cart off in the fall every stone to be seen, there would always be many on top of the ground by the time for spring plowing. These stones were heaved up. The clay soil in which they were embedded became wet, froze and expanded, throwing the stones upon the sur- face, there being the least resistance in that di- rection. So many of our small fields of a few acres had immense piles of stones in each of the four corners, the accumulation of many years. When these stones are not picked up they lie upon the surface and are slowly reduced to soil. Soil Becoming Rock. — The reverse process, of changing soil into rocks, is also taking place. Many of the common rocks and stones that we may pick up in our fields were once soil. Sand- stone, whicn is now sought for trimming buildings, is sand that has been hardened into stone. "Pud- ding" stones, or conglomerates, are made of gravel. Sometimes these rocks may be broken up, by weathering or erosion, and the soil in them again become available for plant growth. Thus the materials of the earth's surface may be worked over and over during countless cycles of time. The soil that nourishes plants to-day may be the build- ing stones of a future generation. The soil of every farm has an antiquity of ao ordinary character. Extreme Changes in Temperature Crack Rocks. — Weathering from changes in temperature is as 6 SOILS effective, though often not as noticeable, as weather- ing from other causes. The changes of temperature from summer to winter, and even from the heat of mid-day to evening, are sufficient to tear rocks to pieces. Rocks are made of several or many dif- ferent minerals, each of which expands and con- tracts differently when subjected to heat or cold. The result is that the rocks are cracked and split from being pulled many ways. There are few parts of the world where surface temperatures are uniform for any length of time; hence nearly all surface rocks, even the smallest stones, and espe- cially those in the North, are being slowly pushed and pulled to pieces by alternate expansion and contraction. According to Shaler, a change of temperature of 150° F., which is common in the North between the extremes of summer and winter, makes a granite rock 100 feet in diameter expand one inch. In regions having great extremes of temperature daily, particularly in Texas, Montana, Arizona, and other parts of the West where rocks are sparsely protected by vegetation, the splitting of rocks is quite noticeable and is sometimes attended with gun-like reports and cracking sounds loud enough to be heard many rods. Livingstone states that in South Africa blocks of stone weighing 200 pounds are frequently split off during the night by the con- traction due to the rapid fall of temperature. Many people have noticed how pieces are chipped off from the foundation stones of a building that has burned. In most parts of eastern United States, where the rocks are more or less protected by vegetation, the cracking of rocks from this cause is less noticeable; but it is certain that all rocks everywhere are being affected more or 5. EROSION OF A MOUNTAIN IN MONTANA The soil made on the mountain by weathering has been mostly washed away to make the fertile valley below 6. NIAGARA FALLS, CANADIAN SIDE The Falls are moving backward towards Lake Erie at the rate of 4 feet a year. The rock par- ticles worn away by the cataract are deposited as soil many miles down stream THE BEGINNING OF A SOIL 6,000 FEET HIGH, ON GRANDFATHER MOUNTAIN, NORTH CAROLINA The mountains are being worn away and deposited in the valleys as soil MOSSES AND OTHER HUMBLE PLANTS ON LEDGE They will help prepare the way for the growth of higher plants SOIL BUILDERS 7 less. The simile — "immovable as a rock," is not perfect. Even the rock, our common symbol of stability, is subject to the universal law of change; it is broken down, re-created and broken down again, over and over, while it fills its place in the working out of the Great Design. PLANTS AS SOIL BUILDERS Broken rock alone, however, does not make a fertile soil, as the farmer defines fertility. There are plants that thrive on bare rock, but the plants that are grown as farm crops are of a higher order and cannot rough it like this. A fertile soil — one that will grow large crops of the higher plants, either wild or cultivated — must contain a con- siderable amount of humus, which is chiefly de- cayed vegetation. A soil made of rock alone may contain all the mineral plant food that farm crops need, but it is apt to lack nitrogen and has not the right texture. The Evolution of a Soil. — Nothing in nature is more interesting than the gradual evolution of a fertile soil from a barren rock, and nothing is more significant of the illimitable wisdom of the Creator. The history of soil building reads something like this: In the beginning is a lofty cliff, mute witness of the eruptions and disturbances through which the earth passed in cooling. It is bare and deso- late. No living thing finds nourishment upon it. For centuries the storms beat against it; ice, rain and sudden changes in temperature pry off great boulders, which crash into the valleys. In the course of time there come to be upon these boulders, and upon the rocks and stones split off from them, lichens and other humble plants that are able to 8 SOILS send their minute root structures into the crevices and live upon the slight substances that are formed on the surface by weathering, together with what they can get from the air. These lichens are very acid and are able to etch the rocks. They die and decay, leaving the beginning of a fertile soil in the crevices and upon the ledges. The growth of higher plants is thus made possible; perhaps the mosses gain a foothold. These in turn elaborate more of the rock for their own use and in turn die, enriching the soil with themselves. Now there is a pocket of soil upon the ledge which may be able to support such humble plants as ferns or saxifrage. Thus the process goes on from decade to decade and from century to century, the lower plants being succeeded by larger and more highly organised plants, as the rocks are made finer by weathering and are enriched by the decay of the plants that they nourish. Finally the soil can support mulleins, honeysuckles, or fir trees. Many years later it may be able to support a crop of corn, timothy, or apples. A fertile farm soil is the product of many agencies working through thousands of years. How Plants are Making Soil To-day. — Plants are helping to make fertile soil to-day as they have for centuries. Each year the forest floor receives a fresh carpet of leaves, and the older generations of trees fall to the ground and slowly pass into mold. Each year the grass in the meadows and the weeds by the roadside add their substance to the soil from which they have sprung, thereby enabling it to nurture other and lustier plants in succeeding years. Lichens spread their thin substance over rocks, and mosses take up the battle where the lichens leave off, just as of old. SOIL BUILDERS 9 Swamp lands and meadows are the most con- spicuous examples of soils built mostly of plants. Lakes, ponds, streams and swamps are being filled in, not only with soil washed from surround- ing higher land, but also with plants. The little pond that I skated upon as a boy is reduced to a mere mudhole now; the lilies, sedges, reeds, cat- tails and other aquatic and semi-aquatic plants have encroached upon it from the edges year by year, until now hay is cut where I used to catch bullheads. Most of the rich valleys and meadows of northern United States were once water-courses or glacial lakes. The weedy water's edge of to- day may be a sphagnum bog a century hence and a cabbage field in another hundred years. The mangrove swamp of this century, reaching trunk- like roots into the sea, may be the tilled land of a future generation. Stems and Roots Split Rocks. — Plants also aid in soil building, to a considerable extent, by the pressure they exert upon rocks. The roots of trees often follow the crevices of rocks to a consider- able depth, and by the force of growth help to widen them. Even on top of the ground one may see many examples of rocks that have been rent by the growth of trees. Among greenhouse plants it is quite common to find pots that have been split apart by the growth of roots. But in many of the cases where rocks are split apart, and a tree is growing in the crevice, the rock was was first split open by weathering and the tree then widened the crevice. The acids secreted by the roots of plants dissolve a small portion of plant food from the rocks that the roots embrace. Rocks that have been etched by root acids may be found in almost any tree-covered ledge. In these various 10 SOILS ways plants are contributing to the upbuilding of our agricultural soils. The peculiar value of certain plants as soil binders must not be forgotten. One of the most efficient and certainly the most notorious of soil binders is "quack-grass," and its counterparts variously known as " Johnson-grass," "witch- grass," "couch-grass," and other aliases. The evil reputation of this grass is due to the fact that it is extremely difficult to kill, because the long underground stems may root at any point. The smaller the pieces into which the roots are chopped by the irate husbandman, the more widely and thoroughly is the pest scattered. This is just the reason why "quack" is such an excellent soil binder; the tough, white root -stalks thread the soil in every direction, soon making a network of fibres, which prevent light soils from washing badly. Steep banks or slopes are sometimes held by establishing quack grass upon them ; the under- ground stems are chopped into small pieces and these are sown thickly. Several other grasses, notably Bermuda grass, are particularly service- able in such cases. In some sections, notably in Oregon, Eastern Massachusetts and Western Michigan, drifting sands are held by planting them with sedges or "beachgrass." In Holland the dikes are planted with rushes to bind the soil. Willows and osiers planted on the banks of turbulent streams are effectual in preventing them from eating away their banks. Morning-glories and related plants are called bind-weeds, because the vines root at the joints and hold the soil tenaciously. A few horse- tails planted in a wet place soon make a dense mat of roots which grasp the soil so firmly that it cannot 9. A POND FILLING UP Plants encroach upon it more every year until finally it is completely filled. Sometime this land may be used for farming 10. A POND COMPLETELY FILLED BY PLANTS Ten years ago this was a sphagnum bog. The water-loving alders and viburnums around the edges will enlarge their area every year }# - ;4— j^ 11. THE HUMBLE BEGINNINGS OF A SOIL Upon the pieces of rock chipped from the ledge several plants have gained a foothold. When they die their substance is added to the rocks and other plants thrive thereon 12. THE GREAT USEFULNESS OF PLANTS AS SOIL BUILDERS Leaves, stems, roots — all parts of all plants — eventually return to the soil, adding to it and enriching it SOIL BUILDERS 11 wash away. These are only a few examples of plants that are particularly valuable for this pur- pose. All plants are soil binders to some extent, as well as soil makers ; they not only enrich it with their herbage, but also hold it with their roots and, if they lie close to the ground, with their herbage also. In hilly sections some plants may be used to great advantage in checking erosion. This problem is discussed in Chapter XL HOW ICE HA.S MADE SOIL Once the northern part of North America was covered with a great sheet of ice, reaching as far south as Cape Cod, northern Pennsylvania, Ohio and westward to the Rockies. Geologists tell us that this immense glacier must have been several hundreds, and in some places several thousands of feet thick. It slowly bore down from the north, moving only a few inches to a few feet an hour, scraping the surface of the earth and carrying great quantities of rocks, stones and soil to the southward. According to some authorities certain parts of the glacier must have exerted a pressure of at least two undred thousand pounds per square inch upon parts of the surface over which it passed. The bottom of the ice sheet became studded with huge boulders, which acted like teeth, tearing and grind- ing the rocks over which the ponderous mass passed. Some of these boulders, scratched and worn, may be still seen in the hillside pastures of New England and other parts of the glaciated region. Some exposed ledges of rock still show the deep grooves that were cut in them by these boulder teeth. When the ice melted a mass of soil material was 12 SOILS dropped, perhaps many hundreds of miles away from the place where it was picked up. Rocks that could have come only from the mouth of Lake Huron are found in the drift or glacial soils in Ohio. Rocks from Ontario are found as far south as Kentucky. Great masses of ice were stranded here and there over the land. The streams of water resulting from the melting of the ice still further mixed the rocks, and the soils that the glacier had ground from the rocks. The result of this ice sheet is the endless variety of soils that are found in the North. Most of the soils of that part of the northern United States that was covered by the great glacier were made by this agency. They are technically known as ' 'drift" soils. Where parts of the ice sheet settled and melted away there were formed "morains" or "drumlins," the long, rounded knolls so common in northeastern United States. Since the time when this ice sheet covered our land, moving water has still further shifted and mixed soils, rounded the knolls and deepened the gullies. But most of the great variety of soil and diversity of contour in this region is due to the scouring, crushing, mold- ing, transporting and distributing power of the great glacier. Small glaciers, performing exactly the same work, may be seen to-day in the Alps, Alaska, and other frigid regions. ANIMALS AS SOIL BUILDERS Animal life contributes much more to the build- ing of soils than seems possible at first thought. Eventually every animal and insect returns to the soil, from which it came. The addition of animal matter to the soil is not nearly so evident as the 13. MANGROVE SWAMP IN FLORIDA The branches take root, causing the plant to spread so rapidly that large areas of salt marsh land are reclaimed from the sea. Some day this land will be cropped 14. COCOANTT TREES ON THE COAST OF FLORIDA They hold the soil and carry it farther out into the sea f> y^SB $£E&£te&£$M m^l tv/^S 5- «. s-*> N i xEl'%* «2L " h**,^^rt^ ^r^^^ ■ ° "cl ™ o Z * d X O rt U *E n If SOIL BUILDERS 13 addition of vegetable matter from decaying plants; yet, when we reflect upon it, the excrements and the remains of all creatures upon the earth must aggregate a considerable amount. Of no small importance also, are the burrows, channels, holes, etc., in which animals live or by which they feed. Ants, moles, gophers, wood- chucks, and the like are insignificant soil builders as individuals, but in the aggregate they have great influence. Ants are abundant on many of the lighter soils and often exercise a profound in- fluence on their structure and agricultural value. Shaler has calculated that ants bring to the surface of a four-acre field, in Cambridge, Massachusetts, enough sand and fine soil to cover the entire area one-fifth inch deep each year. This is probably a larger amount of material than ants move in most places, although those of us who have had to fight ants in lawns are quite willing to accept these figures ; but they call our attention to the insidious and far-reaching influence that these tiny creatures may exert. Since the material brought to the surface by the smaller ants is mostly fine sand and smaller particles of soil, they being unable to move the larger particles, it is evident that the texture of the surface soil must be greatly modified by their industry. The mounds built by the large black and brown hill-building ants are often two feet in height and four feet in diameter. They are composed mostly of soil brought from below, mixed with bits of leaves and bark. They are being washed down constantly by rains and added to the surface soil. These ants usually build a new mound each year. Furthermore, the subterranean burrows and chan- nels of ants, penetrating as they do from several 14 SOILS inches to many feet, have a pronounced effect upon the texture of the soil, and upon its aeration. The burying beetle, crayfish, woodchuck, chip- munk, mole, gopher, prairie dog, ground squirrel, badger, and other burrowing animals and insects, all contribute largely, in the aggregate, to the move- ment and aeration of soils, the latter four being especially abundant west of the Mississippi. Go- phers have honeycombed millions of acres, and prairie dogs and ground scjuirrels have been no less industrious. However injurious these animals may be otherwise, and however difficult may be the task of exterminating them so that crops can be grown, they certainly serve a useful purpose in mixing the subsoil with the surface soil and pro- moting better drainage and aeration. Thousands of acres of land in the United States have been submerged by the erection of beaver dams and their value for agricultural purposes has been pro- foundly influenced thereby. The beaver is no longer an important factor in soil building with us, but he has contributed very largely in the past. The Important Service of Angleworms. — The most important soil builder among animals is the angleworm or earthworm. Of these there are many kinds, from the big, snaky "night walker,'* that the fisherman with a torch finds crawling along the ground at night, to the tiny red ones beneath the pile of old manure. In South Africa some earthworms are two feet long. All of them are most industrious soil workers. After a rainy night, especially in early spring, the ground may be thickly strewn with their castings. On digging down in most moist soils a labyrinth of angleworm channels will be found. These burrows go more than five or six feet below the surface. SOIL BUILDERS 15 Angleworms benefit farm soils in several ways. The channels that they make loosen, aerate and drain the soil to a considerable depth, far deeper than the subsoil plow works. The small roots and rootlets that reach deep into the subsoil usually follow the worm burrows, This is particularly true of tenacious soils, in which angleworms most frequently work. They are rarely numerous in very light, sandy soils because these do not contain a sufficient quantity of vegetable matter upon which they may feed. Again, the soil is fined by being passed through the worms. In making these channels the worm swallows the soil for the pur- pose of using as food the decaying vegetable matter it contains. As it passes out through the worm this soil is ground, as grain is ground in a chicken's gizzard. Charles Darwin estimated that the angle- worms in English soils passed through their bodies and ground over ten tons of soil per acre each year; that is, they deposited about one-fifth of an inch of castings over the entire surface each year. This is the richest kind of top-dressing. He estimated that there are about 50,000 earth worms in each acre of English garden land, and about 25,000 in each acre of meadow land. Our American soils are as full of " bait worms" as the English soils, and their influence on our agriculture must be fully as pronounced as that assigned to them by the great scientist. THE ACTION OF MOVING WATER ON SOIL No soil is ever at rest. It is constantly receiving and constantly losing. The additions come mostly from the weathering of rocks and the decay of plants and animals. The losses are mostly due 16 SOILS to the action of moving water. Moving water has been given the gigantic task of world levelling, and is working at it industriously and successfully. The mountains, hills and knolls are worn away; water carries the particles down the valleys and deposits them as soil. Lakes and ponds are being filled with soil washed from higher land. The flat lands about the lakes and streams are made mostly of soil worn away from the surrounding highlands. The streams carry great quantities of soil and deposit it in the shallows and bends. The coarser and heavier materials, as gravel and sand, are deposited first and the finer material, as clay, is deposited only when the current becomes sluggish. At the mouths of streams, where the current is sluggish, a "delta" is often formed by the accumulation of soil carried down by the streams. It has been estimated that the amount of soil carried to the Gulf of Mexico every year by the Mississippi River would cover a square mile of territory 268 feet deep. At this rate, the American continent might be reduced to sea-level in four and one-half million years. This is but a small pro- portion, however, of the total amount of soil that these rivers carry, for most of it is left along their banks. According to reliable measurements, England is 550 square miles smaller now than at the time of the Norman Conquest, owing to the soft chalk and clay shores being crumbled away by waves. Every stream is constantly changing its course; many a valley farmer has had the river take away a large slice of his farm and give it to his neighbour down stream. Brooks states that within a genera- tion the Connecticut River has gradually taken several hundred acres of rich meadow land from SOIL BUILDERS 17 the town of Hadley and bestowed it upon the town of Hatfield. Smaller streams, even the tiniest rills, are transporting and building soil in a similar manner. Sometimes this action of water is bene- ficial, but usually it is injurious. The loss of farm soil by erosion is discussed in Chapter XL Alluvial Soils. — The flat lands near streams are often flooded each year and receive a top-dressing of rich mud that keeps them extremely fertile. The Nile is a noted example, but many of our own rivers, including the Ohio and Mississippi, fertilise their meadows in the same way, much to the profit of man. The fertile plains of Egypt, once the " granary of the world, ' are not made of native soils, but of soil washed down from the mountains of Abyssinia, many hundreds of miles away. All the rich rice and cotton fields of southern Louisiana were built by the Mississippi River, of soil brought from the mountains three thousand miles away. In some places this soil is three hundred feet deep. These various kinds of alluvial or water-built soils are among the most valuable for agricultural purposes. In any hilly country one can ob- serve this kind of soil building going on at a rapid rate. Besides transporting soil from place to place, water also assists in soil building by wearing away the rock over which it passes. It would seem hardly possible that water should be capable of wearing away so rapidly the hardest of rocks, were it not that we can see the action going on all around us. Even a single drop, falling continuously year after year, will eat a deep hole in the hardest rock. When a volume of water is in motion, and especially when it is carrying along with it particles of soil, its grinding and filing effect is much more 18 SOILS pronounced. The stones on the bottom of the brook at home are rounder and smaller now than when we first watched the tadpoles there. The spring that slaked our thirst twenty years ago has worn a deeper channel in the rock over which it flows. Each year the apex of the Horseshoe Falls of Niag- ara is four feet nearer Lake Erie. The Colo- rado River, which has already worn a channel half a mile deep in the solid rock of the Grand Caiion, is cutting deeper every year. All water, even the purest spring water, has some minerals and gases dissolved in it, and these help it to dissolve the rock. Rain water contains small quantities of carbonic acid gas and other gases, which increase its power to dissolve rocks. SOILS BUILT WHOLLY OR PARTLY BY THE WIND Soils built wholly or in part by wind are not un- common. In arid regions, along the sea coast and near the shores of the Great Lakes, the drifting sands often cover and ruin valuable soils. Some of the most productive farm soils in this country were made, and are still being made, by wind. A noted example is the Palouse region of eastern Washington, eastern Oregon and northern Idaho. Here the land is a succession of rounded knolls and hills, which are sometimes several hundred feet high and are a rich, black, basaltic ash to the bot- tom. The native Indians account for the hills in a legend. They say that at one time all this region was a level prairie of marvellous fertility. Wonder- ful crops of maize were raised upon it by the red men. One evil day they heard that the white men were coming. Knowing by repute the white man's greed, the Indians went to work to gather the 19. HOW WATER MOVES THROUGH THE SOIL It creeps from grain to grain by suction. The finer grained a soil is the higher it can pull up water by " capillary action." Compare the height to which the water in the pan has climbed in the clay soil on the left, with the coarse-grained sand on the right 20. THE DIFFERENCE BETWEEN THE SURFACE SOIL AND THE SUBSOIL The former is usually darker, having more humus, and usually richer. The subsoil, however, is potential plant food; it gradually becomes surface soil 21. HOW PLANTS EAT The fringe of delicate root hairs may be seen on many of these rootlets. The root ha rs feed on the outside of particles of soil. Hence the finer a soil is the more feeding area it has SOIL BUILDERS 19 precious soil into huge heaps, preparatory to carry- ing it away into the mountains, beyond trie grasp of the avaricious whites. But the white men came before the soil could be carried away, took it for their grain fields, and it has been in heaps ever since. The more prosaic geologist, however, says that these fertile hills were made almost entirely by wind, assisted by erosion. In parts of Cali- fornia, Oregon, Washington, and Wyoming, the clayless "dust soil" becomes cracked and loosened in dry weather and is carried away by the wind in dense clouds, banking up like snow behind rocks and bushes. Recall, also, the stories of caravans in the desert being overwhelmed by sandstorms. There are numerous records of large quantities of soil being carried over a thousand miles by wind. Even where the soil has been made mostly by other agencies, wind contributes something to it. Fine soil, leaves, chaff and dust are swept over the hill crest and deposited on the leeward slope. The amount of soil that is made and transported by wind, in the form of dust, must amount to an appreciable quantity in the course of a year. The slope opposite to that of the prevailing wind is usually less abrupt than the other, because so much soil material has been deposited there by the wind. Still another way in which wind assists in making soil is by blowing fine particles of sharp sand and dust against the rocks and so wearing them away. At first thought it would seem that the result of this would be very insignificant, but in reality it is often quite important. In arid parts of the United States and elsewhere, the millions and millions of soil grains blown against cliffs and rocks leave a 20 SOILS striking testimony to their abrasive power. In a surprisingly short time rough corners are worn smooth, great boulders are undermined, hollows are scoured out, and sometimes large, erect rocks are completely filed off near the base, where the wind-blown sand is thickest, and fall over. The " Mushroom Rocks" of Wyoming are a notable ex- ample. In humid sections, the filing of rocks by blown sand is less conspicuous, except near the sea-coast. The windows of houses near the coast are roughened and sometimes eaten through by the natural sandblast. THE SOIL TEEMS WITH LIFE There are other soil builders, more minute but not less active or influential than those that have been mentioned. The old idea was that the soil is dead; the fact is, it teems with life. It contains germs of decay, bacteria that influence in some mysterious way the palatability of plant foods, ferments of many kinds, moulds of diverse sorts — a fertile soil fairly hums with activity. Countless tiny organ- isms, visible only to the eye behind a micro- scope, are constantly at work, changing, break- ing down, building up. Some are beneficial, some are harmful, some are harmless. How many kinds there are, and what part each plays in the complex operation of soil building, no- body knows, for the science of bacteriology is yet at its beginning. Every farm presents many phases of soil building and soil wasting. The farmer should observe the various agencies at work upon his land, and turn them to his own profit. He should remember that the soil is not dead, but alive; that it is constantly 22. A SEDENTARY SOIL OF NORTH GEORGIA It is made by the surface weathering of the underlying rock — the red shale here shown coming to the surface 3. A TRANSPORTED SOIL— THE "PALOUSE COUNTRY" OF OREGON AND WASHINGTON It was laid down in these low hills mostly by wind. This soil often is several hundred feet deep and is very rich 24. AN ALLUVIAL OR WATER-MADE SOIL— THE MOCCASIN BEND OF THE TENNESSEE RIVER, FROM LOOKOUT MOUNTAIN, NEAR CHATTANOOGA, TENN. There are several thousand acres below the " ankle." Sometime the river will cut through at that point. Alluvial soils are usually deep and rich A SMALL BROOK DOING EXACTLY THE SAME WORK AS THE RIVER ABOVE Note how it is cutting into the bank on one side, and building up soil on the other. Moving water is levelling the world SOIL BUILDERS 21 swept by winds, worn and transported by- waters, broken and refined by frost and air, loosened and enriched by plants and animals, and all the while creeping nearer and nearer to a level. CHAPTER II THE NATURE OF SOIL IF WE take up a handful of mellow soil and look at it closely, we can see only a crumbling mass of particles, intermixed with black bits of de- cayed and decaying vegetation. There seems to be no life in it. Put a bit of this soil on a glass slide and look at it under a powerful mi- croscope; a scene of constant activity is now revealed. Moulds, ferments, decays, bacteria, and other organisms are constantly at work, destroying, creating, changing the structure and the agricultural value of this soil. Currents of water pass through it; waves of heat quicken it. The tiny particles of rock are ground and worn smaller each year, and the plant foods are changed from one form to another. The soil has a flora and a fauna scarcely less complex than that which clings to its surface. Little is now known about the soil as compared with other agricultural subjects; it is remarkable that the soil, the foundation of agriculture and the be- ginning of all wealth, should have received so little minute study. We may expect the present deep interest in soil physics and soil bacteri- ology to greatly increase our knowledge of this most important factor in successful farm- ing. Some of the significant facts about the nature of the soil, according to present knowl- edge, are considered in the following para- graphs. 22 THE NATURE OF SOIL 23 THE FINENESS OF SOIL It was stated in Chapter I that the basis of most farm soils is rock, ground into "rock-meal" by Nature's millstones, the air, water, frost, ice and other elemental forces. At first the soil particles are very large, mere fragments of rock at the base of a cliff, but upon these wild morning-glories or mulleins may be able to grow. Some hundreds of years later these small rocks will be finer; perhaps they will average less than one-quarter"inch in dia- meter, and they will be mixed with humus. The fin- ing process goes on a few generations or centuries more, until the pieces of rock have been broken into such small particles that farm crops thrive upon them. Nearly every soil is constantly becoming finer. All soils that contain small rocks or pebbles receive from them each year many particles of soil by weathering, and the size of the rocks and pebbles is reduced that much. Even the rich prairie loam or alluvial clay, which is apparently all soil and contains no rocks or pebbles at all, is becoming finer. Weathering is much less active on such soil, however, than on gravelly and stony soils. The number of individual particles in a fertile soil is astonishing to those who have not tried to count them under a microscope. A good corn soil has about 280,000,000,000 particles in an ounce, while the clay loams that are preferred for grass often have 400,000,000,000 particles in an ounce. These particles are of varying sizes and shapes, even in the same soil. Sometimes they are uniform and rounded, and pack together poorly, leaving large spaces between them, like marbles piled together. Sometimes they are 24 SOILS uneven and jagged, packing together tightly, like the crushed rock of a macadamized road. The spaces between the soil particles differ in size and shape, according to the size and shape of the grains. I have met a farmer who could not quite see how a soil could contain air at a depth of four feet, yet he admitted that there must be air at the bottom of his wheat bin. The trouble was he looked upon the soil as a solid mass, since he could not see the spaces between the grains with his naked eye as he could in wheat. If he would think of his soil as a bin of wheat, with the kernels about one-millionth as large, he could see how it is that air and water pass freely through all' ordinary soils, and to a great depth. It is of practical as well as of scientific interest to know about the size of the grains of a soil, and the size of the spaces between them. The value of a soil for certain crops depends quite largely upon just such factors. With the refinement of soil surveys and methods, soil experts assure us that they will be able to tell us with a fair degree of certainty that soils containing, for example, from 250,000,000,000 to 350,000,000,000 particles per ounce are adapted for potatoes; soils containing 350,000,000,000 to 450,000,000,000, for onions, and so on. At present we classify soils and judge their adaptability for certain crops in grosser terms ; we say potatoes do best on a sandy loam, and that an alluvial clay loam is excellent for onions. There are limits to the practical value of this informa- tion, for the fineness of the soil is but one of many factors that determine the adaptibility of a cer- tain soil for a certain crop; yet this one point is extremely valuable to know when selecting land for special crop farming. THE NATURE OF SOIL 25 Fineness is Richness. — The fineness of the soil has a very important bearing upon its fertility. Other things being equal, the finer a soil is, the richer it is, because it contains more surface for the roots to feed upon. The rootlets of plants do not suck up particles of soil, as Jethro Tull supposed, in his now famous "Horse-hoeing Husbandry." They feed upon the film water upon the outside of the soil grains. This contains much plant food dis- solved from the grains. The natural agencies that dissolve plant food from the soil — water, air, etc., act only on the outside of the particles. Hence the more surface there is to the grains, the greater is the "pasturage," or feeding area for the rootlets, and the more rapid is the weathering. If a small stone is broken into six pieces, the pieces have several times more surface, in the aggregate, than the unbroken stone. It has been calculated that if every particle in one cubic foot of mellow soil could have all its surface spread out flat, the ag- gregate surfaces of all these grains would cover about one acre. The presence of small stones and pebbles in a soil is beneficial, making it lighter, more porous, and warmer. It would be a great calamity if all soils contained no pebbles and larger pieces of rocks. These are a store of plant food which is added to the soil from year to year. Yet the farmer should remember that, in general, fineness means richness. If a soil is lumpy, because of lack of humus or excessive moisture, its available feeding area is greatly reduced. This matter is considered more fully in succeeding chapters, where practical methods of making a soil fine and mellow are de- scribed. 26 SOILS THE WEIGHT OF SOILS This depends upon their composition and com- pactness. It is of interest to the farmer chiefly as an indication of the amount of vegetable matter that a soil contains, because this influences its value for cropping. The coarser the grains, the heavier the soil; humus makes a soil lighter. A heavy soil — one weighing over 80 lbs. per cubic foot — is likely to be benefited by the addition of humus. As the term is commonly used, however, a heavy soil is one that is tenacious, and refers to texture, not to weight. Schubler gives the average weight of a cubic foot of dry soil as follows : Sand 100 lbs. Garden Soil rich in humus 70 lbs. Peat Soil 30—50 lbs. The weight of the soil on an acre of land is so great that if a very small percentage of it is plant food this may amount to a very large quantity per acre. An acre of clay loam, nine inches deep, weighs about 3,000,000 to 3,500,000 lbs. Suppose this soil contains only one-tenth of one per cent, of nitrogen, which is an average amount of that plant food; the acre would contain, in the first nine inches only, 3,000 to 3,500 lbs. of nitrogen. Com- pared with this amount, the 30 to 75 lbs. of nitrogen that we apply as a fertiliser to an acre of impoverished land is a mere bagatelle. THE MINERAL CONTENTS OF THE SOIL The basis of most farm soils is rock that has been ground into very fine particles by frost, air, water. THE NATURE OF SOIL 27 etc., and mixed with the remains of plants and animals. The value of decayed vegetation, or humus, in a soil is so great, and the farm practices resting upon this fact are so important, that this matter is treated in a separate chapter (XII) . The mineral contents of a soil depend upon the kind of rock from which it has been made. These rocks are of many kinds; the nature of a soil may often be determined by seeing specimens of the rocks it contains, provided the soil is south of the region that was covered by the great soil mixers, the glaciers. There is no mineral in any soil that cannot be found in the rock from which it came; there is no mineral in any plant that is not in the soil from which it sprang. Soil is being made from many kinds of rocks, f>rincipally quartz, feldspar, mica, apatite, zeo- ites, hornblende; and various combinations of these, as granite, which is made of quartz, feldspar, and mica. Quartz and feldspar form the largest proportion of most soils. The chief constituent of all soils that have been made from rocks is silica (pure sand), which is the principal ingredient of quartz. This is because silica is the hardest kind of rock material and hence it is not dissolved and lost as rapidly. The rocks of the earth, and the soils made from them, contain from 65 to 70 so-called "elements," the simple ingredients; as iron, carbon, oxygen. These elements, however, unite with one another to make innumerable "compounds," or combinations of several elements. This might be illustrated by saying that eggs, salt and milk are the elements or ingredients of a compound — omelet. It is the great number and the intricacy of these compounds that make geology and chemistry so complex. 28 SOILS No one kind of rock contains all the elements, but all of the rocks from which fertile soil is made contain at least seven of them — nitrogen, potassium, phosphorus, calcium, iron, magnesium, sulphur. No plant can grow unless these seven are present in the soil; they are the "plant foods," and con- stitute from 80 to 90 per cent of most fertile soils. The first four of these seven are much needed by plants and so the soil is most likely to be exhausted of them by continuous cropping; while the latter three are usually so abundant that the farmer is never concerned about how he may add them to his soil. The nature and sources of these four essential plant foods, nitrogen, potash, phosphorus, and calcium, which are the necessary constituents of fertilisers, are discussed in Chapters XI to XIV. Besides these seven elements in the soil which are absolutely necessary for the growth of plants, a number of others are frequently absorbed by the roots of plants and used by them. Of these the most common are chlorine, silicon, aluminum, and manganese. Numerous experiments have shown that plants thrive as well without these as with them, so they must be considered as accidental or unnecessary elements. * In considering the mineral contents of the soil as a supply of food for the growth of plants, we must not forget that the soil furnishes but a small part of the material out of which plants are made. We are so actively engaged in trying to keep up the fertility of our soils by checking their wastes, and by adding to them fresh supplies of the min- erals that our crops have taken from them, that we are apt to think tnat the plant comes from the soil alone. Yet over 90 per cent, of the crops that we 26. SAND DUNES NEAR LAKE MICHIGAN— A WIND-FORMED SOIL THAT IS VALUELESS Sometimes drifting sand covers valuable farm soils 27. THE EVERGLADES OF FLORIDA— A SOIL BUILT LARGELY BY THE DECAY OF PLANTS Some day these glades will be drained and will become rich farming land 28. A UNIQUE "SOIL" These pineapples are growing thriftily upon coral rocks on Elliott's Key, Florida. There are no fine particles, as in ordinary soils, but some humus and guano are mixed with the rocks 29. THE " PARTICLES " OF THE ABOVE SOIL The roots follow the crevices. Compare with Fig. 22 THE NATURE OF SOIL 29 remove from a soil comes from the air. The air, not the soil, is the greatest storehouse of fertility. From the air plants get, through their leaves, three other foods — oxygen, hydrogen and carbon. These are all gases, the latter being combined with oxy- gen in the form of carbonic acid gas. The supply of these plant foods is, so far as we know, in- exhaustible. A friend once remarked, "That is mighty lucky. I have a hard enough time now, trying to supply my worn-out soil with enough potash, phosphoric acid and nitrogen to grow profitable crops; yet you say these are only side dishes of a plant's dinner. If I had to supply it with the main dishes, or fillers, as you might call these foods that it now gets from the air, I don't believe I could have raised my family of six on these forty rocky acres of New England soil." HOW WATER IS HELD IN THE SOIL All fertile soils contain many tons of water, which is present in the soil in several forms. First, and most conspicuous, is what is variously called free water, ground water, standing water or bottom water. This fills all the spaces between the particles up to a certain height, which varies with different soils, and even different parts of the same field. Free water is supplied by rainfall; it frequently comes to the surface as springs and is often the source of supply of wells. If a hole is dug in any soil water will stand in it up to a certain point, which may be several inches or many feet below the surface. This point is called the "water table." The height of the water table may be judged in a general way by the depth of surface wells, but this evidence is not always reliable. It may vary at different 30 SOILS times during the year, according to the dryness of the season. We must consider, then, that beneath all farm soils, at some depth, is standing water; that we plow and harrow above subterranean lakes, which are no less lakes because the water is not entirely free but merely fills the spaces between the particles of soil. The importance of this fact lies in its in- fluences upon the production of a crop. If it is only two or three feet from the top of the soil to the surface of the lake, there is not enough dry soil on top for roots to grow in and the plants drown. Such soils are said to be shallow; they are of little value for ordinary farm crops until ditched or under-drained and the level of the underground lake lowered thereby. The draining of land is considered in detail in Chapter IX. Film Water. — Water is also present in all farm soils as film moisture. Above the water table is the soil in which the roots of farm crops forage. This soil must be moist, else plants would not grow in it ; but water does not fill all the spaces between the soil grains, as it does below the water table. If we look at a handful of this soil we cannot see water standing in it, but it feels moist. The water is sticking to the soil grains, covering them with a very thin film, as when small stones are dipped in water. It is held close to the grains by surface tension, or adhesion. If this soil were put in an oven and heated, the film water would be driven off as water vapour, and the soil would be left per- fectly dry. There is always a large amount of film water clinging to the grains of every soil, even in the dry est season. The dry est road dust has some film water clinging to it. The amount of water that can ■«■■■■ ). THE THREE CHIEF INGREDIENTS OF SOILS; ON LEFT, HUMUS OR DECAYING VEGETATION; ON RIGHT, A LUMP OF CLAY; IN MIDDLE, SAND These three are combined in nearly all farm soils in varying proportions 31. A CLAY SOIL CRACKING The soil may be cracked for some distance below the surface. Much soil water is escaping through the cracks 32. HOW FILM WATER IS PREVENTED FROM EVAPORATING BY A SOIL MULCH The water drawn up from the pan by this soil has been stopped by the shallow layer of loose soil on top. Thus it is in the field illustrated below :«. CORN LEAVES CURLING IN A DROUGHT A soil mulch has been made. How to furnish crops with an adequate and equable supply of water is one of the greatest problems of the farm THE NATURE OF SOIL 31 adhere to a single grain of soil is, of course, in- finitely small, but the amount of water that can cling to all the soil grains of a field is enormous, especially when we consider the vast surface area of the grains, in the aggregate. A good farm soil often holds more than one-half its weight of film water. Film water is far more important in farming operations than free or bottom water, for it is the direct supply of plants. No common farm crops can thrive in free water, but all must have a large area of soil that is moist with film water. Much of this supply of film water, however, is drawn from the natural reservoir of free water below. Water absorbed from the air. — Under certain conditions the soil absorbs a small amount of water from the air. The air that fills the spaces between the particles of soil usually contains much water vapour; if the soil becomes very dry it may absorb some of this. The surface soil may also absorb water vapour from the air, especially when there are heavy fogs. This "hydroscopic" water, how- ever, is not of much importance as a means of supplying plants with water, except in a time of great drought. THE TEMPERATURE OF THE SOIL The soil must be warm in order to produce crops. Most farm soils of the United States are not likely to become too warm for ordinary crops; there is far greater likelihood that they may be too cold. This is especially true in the Northern States, where the season is short, and it is very often desirable to make the soil warmer, particularly in early spring. The seeds of most cultivated plants will decay 32 SOILS before they have had time to germinate if the temperature of the soil is below 45° ; the colder the soil, the slower the seeds germinate. Only after the soil has reached a temperature of 65° to 70° do most crops grow well in it. The soil temperature that is considered most favourable for the germination of barley has been determined by experiment to be 61° to 70° F.; of clover, 77° to 100° F.; of pumpkins, 100° F.; of tomatoes, 100° F. The growth of a crop after germination is in- fluenced fully as much by the temperature of the soil as is the sprouting of the seeds. The farmer knows that certain crops, as onions, barley, turnips, parsnips, peas and potatoes, are "cool plants"; they can be sown early when the ground is cold, and thrive in the coolness of spring. Others, as corn, tomatoes, melons and squashes, are "hot plants"; seeds of these do not sprout well if sown very early, and the plants do not begin to grow satisfactorily until there have been summer days to warm the soil thoroughly and deeply. The Temperature of Different Soils. — The tem- perature of a soil depends upon many factors, most of which are beyond the control of the farmer, but some of them he can regulate by comparatively simple means. The temperature of every soil varies widely with the season, and from day to night. The surface soil becomes warm on a hot day and cools several degrees at night, but this fluctuation rarely extends below two and one- half feet. At a depth of thirty feet the soil tem- perature changes little if any throughout the year, even in the Northern States. Much also depends upon the materials of which the soil is composed. The coarser it is, the warmer it gets, and the better it holds the heat; hence gravelly and sandy THE NATURE OF SOIL 33 loams are among the earliest and warmest of soils. In Europe, gardeners sometimes put loose gravel around grape vines to keep them warm during the night. But a soil in which the particles are very small, as in clay, warms much faster than sand because the particles lie so close together that the heat passes more readily from grain to grain than in sand where the grains lie loosely. For the same reason a clay soil loses more heat by radiation than a sandy soil. Moreover, a clay soil holds more water than a sandy soil and so loses more heat be- cause of the larger amount of evaporation. Hence, fine-grained soils, though they absorb more heat than coarse-grained soils, are colder. Sandy soils are "warm," clay soils are "cold." Draining a Soil Warms it. — The warmth of a soil comes chiefly from the sun and incidentally from the fermentation and decay of the vegetable matter and other refuse that it contains. The temperature of a soil is modified most by the amount of water it contains. Wet soils are cold. The wetter a soil is the colder it is, at least during the summer, when warmth is needed most. It is the coolness as much as the excess of moisture and lack of air that makes corn with "wet feet" grow poorly. The chief reason for this is that it takes a large amount of heat to evaporate the excess water from a soil, and also much heat to warm the wet soil that remains, water being a poor con- ductor of heat, the evaporation of one pound of water from a cubic foot of clay soil makes it 10 degrees cooler. There may be a difference of 7° to 10° in the temperature of a well-drained loam and a poorly drained soil of the same character. There is one exception to the state- ment that the wetter a soil is the cooler it is. 34 SOILS In early spring we frequently have warm rains that raise the temperature of the surface soil several degrees. It is after these rains that "things just jump." Fortunately the means of controlling this factor is largely in the hands of the farmer. The excess water may be removed, and the soil warmed by draining it. The draining of land by deep plowing, ditching, tiling and other methods is considered in Chapter IX. Influence of Exposure on Warmth of Soil. — The "lay of the land" with reference to the compass, and the steepness of the slope, have an important in- fluence on the warmth of the soil. The soil on a northern slope — which receives about one-third less sunshine than a southern slope, depending upon its steepness — may average 7° to 10° cooler in summer than the soil on a southern slope. The soil of a gentle southern or western slope may be 3° to 5° warmer than the same kind of soil is on a level. In the northern part of the United States the sun is always more or less in the south, so that its rays never strike level soil squarely. It is farthest in the south when the need of greater soil warmth is most likely to be felt. In early spring a slope of 12 to 15 feet in a hundred will catch the largest number of the sun's rays, being most nearly at right angles to them. Many of the rays glance off from the level land because they strike it obliquely. The practical conclusion is that a moderate slope to the south or southwest is the best site for a crop when earliness is desired; which is what hus- bandmen, especially fruit growers and gardeners, have known and practised for centuries. Dark-coloured Soils Absorb More Heat. — The colour of a soil is often some index to its agricul- THE NATURE OF SOIL 35 tural value and has an important influence on its temperature. A dark-coloured soil is usually warmer and earlier than a light-coloured soil. All dark substances absorb more of the sun's rays than light substances. That is why we wear light- coloured clothes in summer, and partly why snow melts faster on the dark-coloured, plowed ground than on the meadow. In Switzerland farmers some- times hasten the disappearance of the snow by strew- ing it with black, powdered slate. Gardeners some- times sprinkle a light-coloured soil with peat, charcoal and bog mould; these are called "sun traps." Melons are ripened in Saxony with the aid of a layer of coal dust. But although colour has an important influence on the power of a soil to absorb heat, it has not ability to retain heat. Schub- ler states that, other things being equal, a dark- coloured soil is about 8° warmer near the surface than a light-coloured soil. This difference in the temperature of soils, due to colour, may have a marked influence upon the growth of a crop, especially on its germination. When earliness is a prime consideration, as it is with most market-garden crops, the colour of a soil may become very important. Dark, sandy loams, rich in humus, are preferred by market gardeners. Light-coloured soils may be made dark by filling them with humus. Two or three green-manuring crops plowed under will darken a light-coloured soil quite noticeably. I have a neighbour who, in three years, has transformed a poor, yellow soil into a black, retentive and pro- ductive loam by plowing under four inches of com- posted manure every fall. Another neighbour, under similar circumstances, has accomplished nearly as good results by plowing under muck 36 SOILS drawn from a near-by swamp. The chief reason for adding humus to a soil is to improve its texture, but another benefit, and one that is often quite important, is to improve its colour. The buff yellow and yellowish-brown colours of soils are usually due to the presence of iron oxides. These soils are most common south of the glaciated part of the United States, particularly in the south- ern Appalachian states. The Influence of Tillage on Soil Temperature. — The way in which a soil is handled has much to do with its warmth. Uneven, ridged soil, like that left by fall plowing, loses more heat than smooth, level soil. However, ridging may warm the soil by drying it, and this usually more than counter- balances the loss of heat because of the greater surface exposed. Rolling land in fair and warm weather makes it warmer, but rolling it in cloudy and cold weather, especially if it is wet, makes it colder. Deep plowing makes the soil cooler, because loose soil is a poor conductor of heat. The decay and fermentation of farm manure plowed into a soil may raise its temperature several de- grees; it produces as much heat in the soil as it would if burned in the open air. Manured soil is usually about 2° warmer in spring than unma- nured soil. Thorough tillage, especially in the preparation of a seed bed, lias a marked influ- ence on soil temperature; it prevents the evap- oration of soil moisture and hence keeps in the soil the large amount of heat that it takes to evaporate water. Good tillage saves heat, then, as well as water, especially in early spring. This means that the soil for early crops should be plowed early and tilled often. THE NATURE OF SOIL 37 THE VENTILATION OF THE SOIL The spaces between the soil grains are filled either with water, or air, or both. This soil air is somewhat different from the free air above the sur- face, containing less oxygen, more carbonic acid gas and more ammonia gas. Part of its oxygen is used by the plant roots; the other gases are absorbed from the vegetable matter decaying in the soil. Practically all of our farm crops need a well ventilated soil. The roots of plants, except certain bog, marsh and water plants, must have air to breathe. If it is denied them, because the inter- spaces of the soil are filled with water, the plants will die. Corn is "drowned out" in low, wet places, chiefly because the roots cannot breathe. Furthermore, air is needed in the soil to make more plant food. The air penetrates deeply into the soil and its oxygen, carbonic acid and ammonia dissolve the minerals and make the soil more fertile. The nitrogen of this air may be used as a food by certain plants (See Chapter XII), The oxygen of the soil air combines with the nitric acid produced by the decay of plants, making it a nitrate, which is a plant food. Manure which is piled loosely, so that air penetrates it readily, heats quicker and stronger than tightly packed manure; likewise a soil that is well drained and open, so that air passes into it freely, has more life, fermentation and fertility in it than a close-grained, air-tight soil. Air may penetrate the soil to a depth of many feet, depending upon its openness. Soil air changes in temperature like surface air, and continually passes up and down in currents. Methods of Improving the Ventilation of Soil. — Any kind of tillage which stirs and loosens the soil, 38 SOILS like plowing and harrowing, promotes a better aera- tion, or ventilation, of the soil. Plowing under farm manure, green manure or stubble also has the same desirable effect, since the humus thus produced separates the particles of soil and renders it more porous, hence more open to the downward passage of air. Under-draining, however, is the chief means of ventilating a heavy soil. Remove the water and the air will rush in. When the water table is lowered two or three feet, as it may be by under-draining, the roots of plants grow deeper; when they decay, they leave little channels in the soil and through these air penetrates. Earthworms and ants still further deepen and aerate the soil by following these channels. When land is tile-drained, the tiles themselves provide a system of underground ventilation of far reaching influence. The soil of a tile-drained field is ventilated much more thoroughly than the soil of another field of the same character in which the water table stands naturally at the same height. The air in tile drains is largely surface air. The roots of most farm crops deepen and aerate the soil, but the roots of leguminous plants, espe- cially of clover and alfalfa, are particularly useful in soil ventilation. This is partly because clover roots are large and bore straight down into the sub- soil for several feet, leaving much larger and more effective channels for the passage of air and water than the roots of grains ; and also, in a very slight measure, because these plants absorb nitrogen from the soil air, thus making it necessary for more surface air to be forced into the soil to replace that which is lost. Fortunately for the farmer, most soils are able to absorb various gases, notably ammonia, which THE NATURE OF SOIL 39 is very valuable for the nitrogen which it contains. Advantage is taken of this fact when decaying animal matter is buried to remove the offensive smell, and when sandy loam is used behind cows in the stable. The soil acts much like a charcoal filter which is used to remove objectionable odors from water. THE ELECTRICITY OF THE SOIL Weak currents of electricity continually pass through the soil and through the plants it nour- ishes. In recent years the effect of soil electricity on plant growth has been studied quite thoroughly. The practical value of passing moderate currents of electricity over and through the soil by means of wires has been demonstrated in several European and American fields. For this specific purpose Messrs. R. &B. Bomford, near Evesham, England, have 19 acres of land with wires suspended 16 feet above the ground so as not to interfere with steam plowing. The current discharged from the wires is generated by a dynamo. This treatment is said to increase the yields of barley and wheat 25 per cent, and give a still larger increase of straw. It makes the plants germinate quicker and grow lustier. The current is turned on morning and evening until harvest. In our own country, several small fields and greenhouse soils have been treated with electricity from wires sunk in the soil, with decidedly beneficial results. The U. S. Department of Agriculture is making a special study of this matter. Most of the beneficial effect of electricity is probably due to the fact that it makes some of the plant foods more soluble; perhaps, also, it enables 40 SOILS the plants to take some nitrogen from the air. Only weak currents can be used; a strong current kills the plants. It is quite doubtful whether the benefit derived from the use of a weak current will make it profitable to use electricity in general crop production, for the expense of wiring a field is large; but it may be useful in greenhouses. GERM LIFE IN THE SOIL No soil has exactly the same composition from year to year, or even from month to month. It is constantly receiving additions of new soil from the weathering of rocks, from the decay of plants, the deposits of winds and other sources. It is constantly losing by leaching, by erosion and by the demands of plant growth. It also has numer- ous activities within itself that exert a most potent influence on its fertility. Some of these activities are physical, some are chemical and some are due to germ life. A few are already known and under- stood, but only the merest beginning has been made in the study of soil life. Nitrogen-Fixing Germs. — One of the most interesting phases of soil life is the process called "nitrification," due to the activity of very minute germs or bacteria, and sometimes called the "nitric acid ferment." This is somewhat like the ferment that sours milk, and the bacteria in yeast that raise bread by their growth. Although the air contains vast amounts of nitrogen, this is not used by any plants, so far as is known, except to some extent by the "legumes," of which clovers, alfalfa and vetch are examples. (See Chapter XII.) Most farm crops get their nitrogen, which they need in considerable quantities, solely from THE NATURE OF SOIL 41 the soil. This nitrogen enters into their structure, and is returned to the soil when the plants decay, but not in the same form. It enters the plant as a salt of nitrogen — a nitrate; it returns to the soil in combination with many other substances, and is called by the chemist "organic nitrogen." The important point about this is that plants cannot use organic nitrogen, because it will not dissolve in water, and all the food that plants get from the soil must be taken in liquid form. It must first be separated from its partners in the compound, and then changed into a nitrate before the soil water can dissolve it, and the roots of plants absorb it. The work of transforming valueless organic nitrogen into valuable nitrates, which are plant food, is performed by our tiny helpers, the "nitro- gen-fixing germs." They are found in all fertile soil in inconceivable numbers, busily engaged in making plant food out of all vegetation that is re- turned to the soil, provided the conditions are right. One essential condition is that they have plenty of food. All these ferments may be con- sidered very minute plants; they must have food like other plants. One food of the nitrogen fixing germs is phosphoric acid, which is also one of the most important foods of ordinary farm crops. If a soil has very little phosphoric acid in it, the transformation of humus into plant food is apt to take place very slowly. The principal food of the germs, however, is humus itself. This they can use only after the leaves, stems, or other vegetation has been thoroughly incorporated with the soil and is rotted. These minute plants need moisture and a medium temperature in order to thrive and do their work, as the yeast ferment needs moisture and 42 SOILS a certain temperature in order to multiply and as a corn plant needs water and hot weather in order to bring forth its increase. The growth of these microscopic soil plants is checked in very dry weather as much as the growth of the larger plants above ground. Furthermore, they do not thrive in a very wet soil. The temperatures most favour- able for their growth have been found to be 54° to 99° F. In the Southern States they grow the year around. Another essential condition is a plenteous supply of oxygen, such as would be had if the soil were well drained and hence well ventilated. It will be seen, therefore, that the conditions that favour the growth of these useful workers are those that are most necessary for the growth of farm crops — a moist, well-drained soil and thor- ough tillage. Given these conditions, a multitude of the germs attack the rotten leaves, stems or stubble lying in the soil, or the clover, rye or cow- peas that have been plowed under, and soon change the useless organic nitrogen into a nitrate. In order to do this, however, the soil must contain a sufficient quantity of some "base," as lime, to combine with the nitrogen and so make it a nitrate. If the soil is at all acid, or sour, (see Chapter XIV), the germs cannot complete their work. Germs That Waste Nitrogen. — It is interesting to know that there are also at work in some soils bacteria that accomplish a result exactly opposite to that of the nitrogen-fixing germs. The process is sometimes spoken of as "de-nitrification, " and the germs may be called "nitrogen-wasting" germs. They feed upon the nitrates, and set free the nitro- gen gas, which may then escape into the air and so be lost to the soil. These germs are abundant in wet soils; under-draining benefits the soil in more THE NATURE OF SOIL 43 ways than by merely removing water. Thus these two, the nitrogen-saving and the nitrogen-wasting bacteria, are pitted against each other; the one is a blessing to the soil, the other may be a detriment. It is wise farming to encourage the growth of the former by providing the conditions most favourable for them — thorough tillage and excellent drainage. Other Soil Bacteria. — These two kinds of bac- teria are but a very small part of the germ life of the soil. Adametz has calculated that there are 50,000 germs of various kinds in a single gram of fertile soil. Many are beneficial, most of them are harmless, some are injurious. When the roots and stubble of a certain crop decay in the soil, a certain kind of " ferment," which is bacterial growth, is produced. If the crop is grown for several years on the same soil, after a while the soil may become crowded with the particular kind of ferment that the decay of the crop produces. The result may be that eventually the soil will no longer produce satisfactory crops of this plant, but it will produce larger crops of some other. This is the explanation, in many cases, of "clover-sick" and "flax-sick" soils and other soils that fail to respond as they used to. The practice of inoculating soils with certain beneficial bacteria is discussed in Chapter XII , with particular reference to legumi- nous crops. The limits of the practical value of soil bacteriol- ogy can only be surmised at this time ; but it seems not improbable that the farmers of some future generation may be able to inoculate their soils with different beneficial bacteria and secure spe- cific and valuable results, much as the butter maker of to-day secures certain flavours with certain cultures. . The field of study opened before us by 44 SOILS recent investigations in soil bacteriology is ex- tremely interesting and it may yield extremely important results. CHEMICAL CHANGES IN THE SOIL The chemical changes that are constantly taking place in every farm soil are no less numerous and no less important than the changes resulting from the work of bacteria. The elements of which the soil is composed are always shifting and changing. The compounds, which are merely combinations of several elements, are continually dissolving partnership and the elements join themselves to- gether in new bonds, according to affinity. The nitrogen released from a nitrate by the nitrogen- wasting germs may be instantly seized by some near-by hydrogen to make ammonia. The am- monia may then be attacked by the nitrogen-saving germs and made into nitrous acid; which, in turn, may soon become a nitrate, or it may escape into the air and be lost to the soil, until brought down by rain. The phosphoric acid that the farmer applies in superphosphate or bone meal is at once seized by hungry elements and enters into several partnerships. Some of it is readily soluble in water and might leach away were there not some lime or sodium handy to catch it. That part of it which is not used by plants the first year or two may get locked up so strongly in partnerships with other elements that it becomes valueless to plants. When a potash fertiliser, as ashes, is applied to the soil, the plant food it contains would mostly dissolve in the soil water and wash away were it not that it unites with some of the "bases" of the soil and becomes "fixed." In fact, the THE NATURE OF SOIL 45 plant food in most fertilisers applied to soils would be quickly leached or washed away, if these chem- ical changes did not occur and hold it until the roots of plants can use it. Plants feed, not upon the materials that we apply to the soil — ashes, bones, phosphates, guano, and the like — but upon the chemical compounds formed in the soil by them. These and other chemical changes that all fer- tilisers pass through before they are absorbed by the roots of the plants illustrate what takes place with each and every constituent of the soil, whether it is essential to the growth of the plant or not. The soil is a great chemical laboratory. Numberless reactions, or new adjustments of the partnerships between the elements, occur every hour. No chemist holds the beaker or fires the great retort; the changes take place in obedience to natural laws, quietly and methodically, yet with results so far reaching that we can hardly grasp their signifi- cance. It is the business of the chemist and the bacteriologist to explore this laboratory and report how its chemical changes are effected by the dif- ferent methods of handling the soil. It is the business of the farmer to keep the soil laboratory in excellent working order, by a wise and varied husbandry; and especially by giving careful atten- tion to those principles of good farming that we already know make it run smoothly — thorough tillage, excellent drainage, and a rotation of crops. CHAPTER III KINDS OF SOILS AND HOW TO MANAGE THEM SOILS may be classified according to their origin or according to their composition. With respect to origin all soils are either transported or sedentary; that is, they are composed of materials that have been moved by some natural agency, as wind, water, or ice, as discussed in Chapter I, or they have been made by the weather- ing of rocks or the decay of plants in the places where they now are. In one sense all soils are both sedentary and transported, since they have all received more or less material from other sources ; but these terms are meant to apply in a broad sense. SEDENTARY SOILS In a general way the soils in that part of Northern United States which was covered by the great glacier are mostly transported, while the soils farther south, and east of the Mississippi River, are mostly sedentary. Sedentary soils are usually not deep, because the mother rock beneath weathers very slowly, being largely protected by the soil above it. The red clay soils of Tennessee, Georgia and other parts of the South, and the famous "blue grass soil" of Kentucky, derived from limestone, are excellent illustrations of a sedentary soil. They are usually very fertile. Other examples of a sedentary soil are muck and 46 KINDS OF SOIL 47 peat, which are made almost entirely by the decay of plants, together with the little mineral material that is blown in. The plant that accomplishes the most in this direction is sphagnum moss. It is a semi-aquatic plant and grows with great luxuriance, making a thick carpet over the water. Eventually the whole surface of a shallow pond may be covered with sphagnum. Other plants get a foothold upon this—rushes, sedges, cat-tails, cranberries, and the like. "Float- ing" cranberry bogs are quite common on the fresh- water marshes of Cape Cod. Finally the covering of plants is solid enough and has decayed suffi- ciently for small water-loving shrubs, as huckle- berries and alders, to get established. The float- ing carpet gets thicker and heavier from the decay of plants; finally it either breaks and sinks at once to the bottom of the stream or lake, or sinks into it gradually and is covered with water. Then begins the formation of peat. This process of pond, swamp, and stream filling is going on in all parts of the United States, mostly on a small scale but sometimes on large areas. One million acres of soil in the Kissimmee Valley of Florida have been made in this way. The Great Dismal Swamp of Virginia is another illustration. When drained these swamps may be very fertile. TRANSPORTED SOILS Transported soils are more numerous. Among the most important of these are the alluvial or water-made soils. These are rarely stony, are usually level, fine-grained and often very deep. Water usually leaves the soil it carries in more or less distinct layers; this "stratification" can often 48 SOILS be seen in alluvial soils. The largest area of alluvial soil in the country is the flood plain or delta of the lower Mississippi. It reaches from the mouth of the Ohio southward for 1,100 miles. The whole area is flooded periodically and receives each time a deposit of the mud that gives the Missouri its Indian name, meaning "Big Muddy." It is exactly such conditions as this that have en- abled the valley of the Nile to produce bountiful crops for 4,000 years without artificial fertilisation. The same process is responsible for thousands of meadows, swales, and swamps in northern United States, and it may be seen in action on the banks and at the mouth of every stream. Alluvial soils are made mostly of very fine sand, and silt and clay. They vary greatly in chemical composition, but are usually very rich. Drift Soils. — Of even greater agricultural im- portance are "drift" soils, those that were formed by the action of the great ice sheet of the geologic past. They are distinguished from all others by having many rounded rocks or boulders, which were worn smooth and rounded by glacial action. Some drift soils are assorted or in layers, having been laid down by successive streams of water issuing from the ice; others are not in layers, having been deposited directly by the ice. The deposits of drift soil are not always spread evenly over the land. Sometimes the underlying rock comes to the surface, making patches of sedentary soil; sometimes drift soil is heaped into broad rounded knolls, from several feet to 300 feet high. These "morains" or "drumlins" are a distinctive feature in the farm landscape from eastern Massachusetts to North Dakota and north into British Columbia. The average depth of drift soils is about 30 to 50 KINDS OF SOIL 49 feet, but in some places it is 300 to 500 feet deep, and often it is merely a skim coat of seven or eight inches over the surface. As would be expected, the distribution of drift soils is very erratic. An acre may contain several wholly distinct kinds. There is a field of one acre near Lan- sing, Mich., in which about one-half of the soil is a stiff clay, one-fourth is gravelly loam and the balance, which was formerly a swamp, is muck. Who would try to advise the owner how to treat this field as regards tillage, fertilising, and draining ? iVll the variations in soils that affect the production of crops are not apparent on the surface; the char- acter of the subsoil has a very important influence on the fertility of the surface soil. The subsoils of drift or glacial soils are extremely varied. The diver- sity of many of the soils of northeastern United States may be judged from a report of James Geikie on the different kinds of soils that he found in a cut 355 feet deep, working from the surface downward : Sandy clay 5 feet Brown clay and stones .... 17 " Mud 15 " Sandy mud 31 " Sand and gravel 28 " Sandy clay and gravel 17 " Sand 5 " Mud 6 " Gravel 30 " Brown sandy clay and stones . . 30 " Hard red gravel 4 " 6 inches Light mud and sand 1 " 8 " Light clay and stones 6 " 6 " Light clay and thin block ... 26 " Fine sandy mud 36 " Brown clay, gravel, and stones . . 14 " 4 " Dark clay and stones 68 " 355 feet 50 SOILS This is probably more varied than most drift soils, but it shows the extent to which the ice, and streams of water produced by the melting of ice, have assorted and mixed the soils and soil ma- terials of the Northeast. The value of drift soils for cropping is very variable, depending upon the material of which they are composed, and the way in which they are laid down. As a rule, however, they are fertile be- cause they are composed of materials that have been brought together from several sources, and there is therefore greater likelihood that the essen- tial plant foods will be present in abundance. They are apt to contain more sand or gravel and less clay than sedentary soils; hence they are usually of good texture and easily worked. But a drift clay or muck is not more valuable or manage- able than a sedentary clay or muck. Those con- taining a fair percentage of clay are more valuable than those that consist chiefly of gravel. Wind-built Soils. — Still another type of trans- ported soils — those built mostly by wind — is some- times very valuable for cropping. The wind- formed soils of Washington and Oregon are com- posed of fine basaltic ash. The loess and adobe soils discussed further on have been made partly by wind. More frequently, however, wind-formed soils are of little or no value, being composed mostly of fine sand ; and moreover, they may cover and ruin other soils that are valuable. On the southeast shores of Lake Michigan sand dunes 100 to 200 feet high have buried large areas of forest. The sand hills of Wyoming cover about 20,000 square miles of territory on both sides of the Niobrara River. These are a part of the "Bad Lands," a dreary waste of naked, rounded hills, KINDS OF SOIL 51 composed chiefly of yellowish or grayish sand, or sandy clays blown by the wind, and extending over portions of Nebraska, Colorado, Wyoming, and Utah. The "Pine Barrens" of Michigan and of the Atlantic Coast are other illustrations of drift soils worthless for agricultural purposes. COMPOSITION OF SOILS With respect to composition, all soils are made of four ingredients — sand, silt, clay and humus. No one of these ingredients alone makes a valuable soil, nor is it possible to find any soil composed entirely of a single grade. The most valuable soils — the loams — are a mixture of the four ingredients. The basis upon which the four ingredients of soils are separated is the size of the grains, and here an arbitrary division is made. This is called a "mechanical" analysis" of the soil as distinguished from a chemical analysis, described in Chapter XI. The coarser materials are screened from the soil by passing it through several sieves, with meshes of different sizes. Fine sand, silt, and clay are separated by allowing them to settle in water, the fine sand settling first, then the silt and finally the clay. The approximate size of the different ingredients is: Coarse sand . -^ to -r?r of an inch in diameter Medium sand Fine sand . Very fine sand Silt . . . Fine silt. . Clay . . . Sand is made chiefly of particles of quartz, and 1 "2T to l FIT 1 ■3T to TOT THU to 1 T5T YTTT to tttg" "5"0"er cent, of clay as a heavy clay loam. A clay oam usually has 25 to 35 per cent, of sand, and a heavy clay loam 10 to 25 per cent, of sand. The fair proportion of sand mixed with the clay in this type of soils makes them easier to handle than clay soils, and more porous. They are apt to be rich, especially in potash, not only because of the store of native plant food, but also because they are very retentive soils. The plant food in fertilisers that may be applied to them is not quickly leached away, as it is on sandy soils, but is held very tenaciously by this more compact soil. Crops upon clay loams are not likely to suffer from drought as badly as on clay soils, because water KINDS OF SOIL 59 moves through them more freely. Some clay loams, however, are cold and wet. These soils more than any other type, are benefited by under- drainage. The clay loams are suitable for a larger range of cropping than any other soils, except the loams themselves. They are especially valuable for grass, wheat and corn. In handling clay loams attention should be given to the details of manage- ment that are beneficial to clay soils, and espe- cially to underdrainage, judicious plowing and the incorporation of humus. LOAM SOILS These are the most useful "all around" soils; they combine the lightness and earliness of the sands, with the strength and retentiveness of the clays. Loams contain from 40 to 60 per cent, of sand, and 15 to 25 per cent, of clay. They "work up" easily, do not crust or crack, are well supplied with plant food, and, what is chiefly important, water moves through them freely and still they are not leachy. Practically all farm crops grow satis- factorily on a loam. It is especially suitable for potatoes, corn, market-gardening crops, and small fruits; but grasses, cereals, clover, alfalfa, and cotton, find it congenial. It requires no special treatment, except such attention to good tillage, drainage, and the addition of humus as is a neces- sary part of the best farm practice everywhere. GRAVELLY AND STONY LOAMS These are sandy loams, clay loams, or loams with an admixture of gravel or stones ; all pieces of 60 SOILS rock from 1-25 of an inch in diameter up to two or three inches are gravel — larger pieces are stones, Gravelly and stony loams are most common in the North, especially in the Northeastern states, where they were formed by the work of glaciers. Most of the pieces of rock are worn smooth. The presence of a large quantity of small stones in a soil makes it warmer, for rock absorbs heat more freely than soil, and loses it more slowly, thus keeping the soil warmer at night. If the stones are numerous and large, however, the increased difficulty of tillage may more than offset the advantage of earliness. For this reason a gravelly loam is usually more valuable than a stony loam. A gravelly or stony sandy loam is sought when extreme earliness is desired. Some of the most profitable strawberry plantations in New York are on this type of soils. As a rule they are better adapted for fruits, especially small fruits, than for staple farm crops. PEAT AND MUCK SOILS Peat and muck are the black soils produced when a luxuriant growth of plants decays slowly under water for many years. When the plants are but partially decayed, so that the soil is very spongy and fibrous, it is called peat. When decay has progressed further, and especially when the soil is alternately submerged and exposed to the air, becoming finer, blacker and no longer fibrous, it is called muck. Muck is an advanced stage of peat. Both are passing through the same process by which coal has been formed. Peat and muck swamps and bogs are found all over the eastern United States, and in many parts KINDS OF SOIL 61 of the West except in the arid regions. Most of our fresh water marshes are muck or peat. They are not so numerous here, however, as in many parts of Europe, especially in Ireland, one-tenth of which is said to be peat bogs. These soils are being made to-day, where shallow lakes, ponds, streams, and swamps are being filled by the growth of plants, especially the sphagnum moss; but less peat is being made now than during a period in the earth's history when rainfall was more abundant. The Value of Peat and Muck Soils. — The value of peat and muck soils for farming depends chiefly upon the amount of mineral matter they contain and upon their drainage. Some of these soils are nearly 100 per cent, humus, others are but 30 per cent, humus. Considerable fine rock or mineral soil may be blown upon peat or muck land; the more of this the better. Muck, being further ad- vanced in decay than peat, is more apt to become serviceable as a farm soil than peat; it is, moreover, more compact and usually contains more mineral soil, having been above water longer. Many muck and some peat soils need only to be drained in order to become valuable for cropping. Thousands of acres of land, especially fresh marsh land, have been reclaimed in this way. In Michi- gan and Ohio reclaimed swamp lands are largely used for growing celery and onions. Open ditches are most commonly used for this purpose, these soils being so loose that tile drainage is usually impracticable at first, except for the most earthy mucks. The result of drainage is to lower the water table so that air can penetrate the soil. Many peats, and some mucks in which the decay has not progressed far, do not make good farm land, even 62 SOILS after they are drained; they become very dry and chalky, having scarcely more power to draw up the free water beneath by capillary action than a pile of chips. Not until several years after drainage, when the fibrous matter has been broken down and made into fine soil, are some peat and muck soils able to grow profitable crops. When well drained and sufficiently fined to per- mit the free movement of water upward, these soils are especially suitable for cabbage, cauliflower, celery and peppermint. On the finest of mucks the grasses and a variety of vegetables are successful. In southwestern Massachusetts, and in New Jersey, Wisconsin, Michigan and some other sections, peat and muck bogs are ditched, the surface covered with 3 to 6 inches of sand, and then planted with cranberries. In handling muck and peat soils one must remember that they are largely humus and always contain a large per cent, of nitrogen, the chief fer- tilising element produced by the decay of vegeta- tion. In fact, muck often contains as much ni- trogen as barn manure, although but little of this is in available form, being in the form of organic nitrogen. These soils usually need fertilising with the mineral plant foods — potash, phosphoric acid, and lime. Wood ashes are espe- cially beneficial to muck soils. As a rule they do not respond to manuring as satisfactorily as soils that contain more mineral matter. LOESS SOILS The name "loess" is applied chiefly to large areas of soils that have been carried to their present resting places by water or wind, and which KINDS OF SOIL 63 show no layers, being of the same nature through- out. The largest deposit of loess soils in the United States is the alluvial loess of the great Mississippi Valley, including thousands of square miles of the "prairie" soil of the central states. They are found in southern Michigan, Ohio, Illinois, Indiana, Iowa, Kansas, Oklahoma, Tennessee, Arkansas, Missouri, Kentucky, Alabama, Mis- sissippi, Louisiana. Smaller areas of alluvial loess soils are found in the valleys of the Connecticut, Ohio, and other rivers; while wind-formed loess soils are found in California, Washington, Oregon and many other western states. There are large deposits in the valley of the Rhine, the famous steppes of Russia and the inland plains of China. Loess soils are noted for their great depth and remarkable fertility. In China they have pro- duced bountiful crops for over three thousand years, with little apparent diminution of fer- tility. The richness of our own loess lands in the central West is well known. There the soil is from 5 to 150 feet deep. Although loess soils may differ very widely chemically, they are all about the same physically — a fine silt or clay, possessing great tenacity. Most of the loess soil of the West contains from 55 to 15 per cent, of silt and from 6 to 15 per cent, of clay. ADOBE SOILS These peculiar soils are found only in the arid West, especially in Utah, Arizona, southern California, New Mexico, western Texas, and in the elevated valleys of Colorado and New Mexico. They consist very largely of clay and silt, partly worn down from surrounding high land 64 SOILS and partly blown there from elsewhere. They are exceedingly sticky when wet and bake very hard when dry, so that they are used for building purposes. This makes them very hard to work; in short, they are aggravated clay soils. When they are wet enough they are remarkably pro- ductive, as they are unusually rich in plant food. Some adobe soils are very deep — those in some of the valleys of the arid regions being over 2,000 feet deep. Adobe soils are usually light buff or gray, ex- cept when they contain a considerable quantity of humus, which makes them darker. They are very fine grained; no grit is felt when adobe is rubbed between the fingers. The depth, fineness and virginal fertility of adobe soils, since they have lost very little from leaching, makes them wonderfully productive. These soils are quite similar to the loess soils of the Central West. SALT MARSH SOILS All along the Atlantic Coast, and especially in New England, are thousands of acres of marsh land that some day will be used for farm crops. They are made largely from soil that has been worn by the sea from the rocks on the coast. Each wave that curls its crest over the "stern and rock- bound coast" wears it away to some extent, as is witnessed by the honeycombed rocks at Marble- head and elsewhere. The headlands that project into the sea are worn down and strewn upon the beach as sand. Each wave that comes tumbling in grinds these rock particles a little finer — we can hear them rustle and grind against each other in the undertow. After a while the coarse sand of the KINDS OF SOIL 65 beach becomes fine sand or mud; it may then be carried out to sea by the undertow or deposited along the inlets and bays by coastwise currents. The latter case marks the beginning of a salt marsh soil. As soon as it gets fairly well started, though still covered with water, the soil is occupied with a dense growth of eel-grass. This accumulates more soil; sea weed, dead fish and other refuse collect and the soil thickens rapidly. Finally it is raised above the tides and the eel-grass gives place to other grasses which slowly extend to the beach over the mud flats. In the course of time farmers cut from these flats ''salt hay," which is much relished by cattle. All salt marshes are likely to be overflowed occasionally. It is necessary to drain them thor- oughly and to prevent the overflow of salt water by diking before they can be used for ordinary farm crops, which object to so much salt in the soil. It is stated that there are over 200,000 acres of very rich salt marsh land between New York City and Portland, Me., which would be worth $20,000,000 if reclaimed; and that there are 3,000,000 acres on the entire Atlantic Coast that could be reclaimed. The cost of diking and draining these lands should not be over $50 per acre. A considerable area of salt marsh soils has already been reclaimed. Salt marsh soils are particularly valuable for growing grass, onions, cabbage, celery; where they contain a large amount of muck cranberries are successful. THE PROBLEM OF ALKALI SOILS Between the Missouri River and the Rocky Mountains, in parts of California, and in a few 66 SOILS other parts of the West, are large areas of alkali soils. They are found almost entirely in arid or semi-arid regions. These soils produce an insignifi- cant growth of a few native plants and are wholly unfit for cropping until properly treated. They are called alkali soils because they contain large quantities of various salts, mostly common salt and carbonate of soda, which is ordinary washing soda. Otherwise they are normal. Thousands of acres of once valuable land have been made too alkaline for crops by seepage waters. The surface of alkali soils is often covered with crystals of the salts, making it look whitish. This is caused by the evaporation of water from the soil, leaving behind on the sur- face the salt that was dissolved in it. Over-irri- gation, especially on heavy lands, often makes them alkaline and may ruin them. But all soils that are white on the surface are not alkali. Excellent limestone soils have sometimes been mistaken for alkali, because they had a coating of carbonate of lime on the surface. Quite frequently there are alkali spots in an otherwise fertile field, the spots varying from several feet to several acres in extent. There are two common types of alkali soils, "black alkali" and "white alkali." The former contains chiefly carbonate of soda, which de- composes the humus in the soil and makes it very black; while the latter is a mixture of several salts, chiefly common salt and sulphate of soda. Black alkali is much more injurious to plants than white. The effect of alkali upon plants depends chiefly upon the kind of plant and upon the amount of salt in the first foot or two of soil. Some plants -cannot stand alkali at all, some are tolerant of it, a very few prefer it. The plants that tolerate it are mostly native salt bushes and grasses. Of KINDS OF SOIL 67 cultivated plants, sugar beets, alfalfa and sweet clover are most tolerant, especially sugar beets, j The grains are impatient of it, but rye and barley appear to stand it better than the other cereals. Practically all the common farm crops will not thrive in alkali soils, but after the salts are removed from these soils they are found to be remarkably fertile and produce very large crops. How to Treat Alkali Soils. — There are two methods of improving alkali soils; the alkali may be removed, or it may be changed into another form. The most common and most efficient way of removing alkali, whenever non-alkaline water can be had in abundance, is to irrigate the land and drain it. If persisted in, irrigation and drainage usually effect a permanent cure. Irrigation washes the salt out of the soil and drainage carries it off. The waters of some streams and wells, however, contain much alkali and are not suitable for irri- gation. Irrigation without drainage may make a soil more alkaline, by bringing more of the salts to the surface. Under-drainage alone is usually ef- fective, especially for small areas that can be drained at slight expense, but it is too expensive to be prac- ticable except for land having a high valuation. In irrigating alkali land the entire surface of the soil should be flooded to remove the salts. In experiments by the Bureau of Soils in Utah a 40-acre tract of waste land containing 2 1-2 per cent, of salt, or 6,650 tons to a depth of 4 feet, was flooded with 57 inches of water per year. Of this amount 45 inches were recovered as drainage, and this drainage water contained 2,401 tons of salt. In other words one-third of the alkali was removed in one year. The cost of this work is from $16 to $30 per acre. 68 SOILS The injurious salt may be changed into another material that is less harmful by dressing the soil with gypsum, or land plaster. An application of four to six hundred pounds per acre is considered sufficient. This treatment is valuable only for black alkali. When a quarter or more of the salt is on or near the surface, as is often the case, it is sometimes practicable to scrape the surface and cast the scrapings elsewhere. Certain plants, notably greasewood and the Australian Salt-bush, thrive on alkali soils and take large quantities of salts from them. Occa- sionally it is practicable to crop soils that are very alkaline with these plants for several years, to remove part of the salts. The plants should not be burned on the land, however; ashes of all kinds and especially these, make the soil more alkaline. A crop of Australian salt bushes produces 15 to 20 tons of excellent green forage per acre, or 3 to 5 tons of dry forage. This plant grows well upon black alkali. Some soils that are very badly alkaline may not be worth the attempt to reclaim; those that are only mildly alkaline it will certainly pay to reclaim, providing they possess the other requisites of a fertile soil. Usually it takes several years to com- pletely remove the objectionable salts, but if the soil is under-drained a fair crop can be grown upon it the second season. Deep plowing should be given to all soils that are more or less alkaline. Thorough tillage lessens the evaporation of water and hence lessens the amount of salt deposited upon the surface. Hilgard says, "When the alkali is not very abundant nor very noxious, frequent and deep tillage may afford all the relief needed. More than half the alkaline land in this state (California) KINDS OF SOIL 69 that the people are afraid to touch requires no more remedy than thorough, deep tillage, maintained at all times." Liberal dressings of manure, espe- cially horse manure, are very beneficial. Alkali soils are apt to be deficient in nitrogen, because the nitrogen-fixing germs are not able to do their work when there is much alkali present. It is stated by Snyder that if a • few loads of soil from fertile land are sprinkled on alkali spots the beneficial germs will be introduced and much good will result. After steps have been taken to remove the excess of salts the land should be cropped first with plants that are not very impatient of alkali. Oats is considered one of the best crops for this purpose. Practically all farm soils contain some alkali, but wherever rainfall is plentiful the salts are washed away before they accumulate sufficiently to injure plants. A very little alkali in a soil is beneficial. In fact, it is necessary to apply lime to some acid soils in order to make them sufficiently alkaline to be most productive, as is noted in Chapter XIV THE SUBSOIL The soil immediately beneath the richest part of the surface soil is called the subsoil. It may be of any depth, and extends to the underlying rock. The distinction between the soil and the subsoil, as the two names are commonly used, lies almost entirely in the colour and texture, due to the greater amount of humus near the surface. In cultivated land there is usually a more or less dis- tinct line between the rich, black surface soil and the poorer and lighter-coloured subsoil. In most 70 SOILS soils, especially in the East, this line marks the depth of plowing. The depth at which the vege- tation that gives the surface soil its black colour and looser texture has been buried is about nine inches. Many soils, especially those made by wind or built by water, and peat and muck soils, show very little if any difference in colour or texture be- tween the first nine inches of soil and that below. In nearly all cases the subsoil contains less available plant food than the soil above because it is not affected as much by weathering, being pro- tected, and because it is less affected by acids re- sulting from the decay of vegetation, since it con- tains less humus. We might call the subsoil rotting rock, and the soil rotted subsoil. This is a providential arrangement. If the plant food in all the soil, down to bed-rock, were as easy to lose as that in the first nine inches of soil our fields would become unproductive much sooner than they do now. The subsoil is a store of plant food that is held in reserve. We should look upon the rocks, stones, pebbles and subsoil of our fields as so much po- tential plant food. It is being doled out to us from year to year as fast as it can be used to advantage. As the surface soil slowly wears away and is carried off in crops, the subsoil gradually becomes surface soil. The roots of deep-feeding plants, as clover and alfalfa, bring up plant food that they secure below the roots of ordinary crops. When these crops are cut, and the stubble and roots plowed under, a part of the plant food that the sub- soil has contributed to their growth is returned to the surface soil, enriching it. Earthworms bring to the surface subsoil that has never seen the light of day and this adds richness. A plowing some- what deeper than usual may mix an inch or more of KINDS OF SOIL 71 light subsoil with the surface soil. This may re- duce the crop for a year or two, or until the raw plant food in the subsoil has been acted upon by air, water, and soil acids, but eventually the surface soil is enriched by the fresh material. It is advantageous for a sandy soil to rest upon an impervious clay subsoil, and for a clay soil to be underlaid with a sand or gravel subsoil; both sub- soils help to correct the defects of the soil above them. A deep gravel or sandy subsoil, however, is usually a disadvantage, as it allows plant food to leach down beyond the roots of plants. ANALYSING THE SOIL AT HOME The determination of the relative proportions of sand, silt, clay, and humus in a soil is called a "mechanical analysis," as compared with a "chem- ical analysis," in which the kinds and the amounts of the different plant foods are determined. It is not always possible to have the soil analysed by a chemist, but it is always practicable for a farmer to determine himself, roughly, the relative amounts of the four ingredients that his soil con- tains. A mechanical analysis should point out the deficiencies of the soil much better than simply viewing it on the surface. A close examination of a handful of the soil will reveal much concerning its composition, especially if a miscroscope or even a pocket lens is used. Note the colour, whether dark or light ; look closely for the tiny black particles of humus that are likely to be the cause of the dark colour, and are a sign of good texture and large water-holding capacity. Rub the soil gently between the thumb and fore- finger to determine the size of the particles. Are 72 SOILS they mostly coarse or fine? If the soil feels dis- tinctly gritty it probably contains a considerable amount of sand ; if it feels quite smooth and makes a very smooth, sticky paste when water is added to it, it contains a large percentage of clay or silt. Take a handful of moist — not wet — soil and squeeze it hard. If the ball of soil crumbles quickly and freely when the pressure is removed the soil contains sufficient humus or sand and is likely to prove of good texture and easy to work. If, however, the ball of moist soil retains its shape to a considerable extent, remaining hard and compact, it indicates that clay and silt predom- inate and that the soil will need to be handled carefully. A more accurate test for clay, silt, sand and humus may be made in the following manner. Take a small sample of moist soil, as it is found in the field, say a quart; screen out all except fine par- ticles, and weigh it very carefully. Spread it thinly on a pan and set it in a very moderate oven or on the back of the stove, where it will dry slowly, but not burn. When it is perfectly dry weigh it again. The difference shows the amount of water that the soil contains, all of which has been driven off as vapour of water. Place this dry soil upon a coal-shovel above hot coals, or on a pan placed in a very hot oven. The humus in it will begin to smoke. If the soil is kept very hot for two or three hours practically all of the humus will burn, leaving only the "ash" or mineral part of the soil. A fairly reliable meas- ure of the amount of humus that the soil contains is secured by comparing the weights before and after burning. All soils that have a fair proportion of humus and are therefore most valuable for farming, KINDS OF SOIL 73 should shrink considerably in bulk and in weight by burning. Separating the Sand, Silt and Clay. — After the humus is burned out of this soil the sand, silt and clay remain. These being pieces of rocks, or mineral matter, they will not burn like humus, which is vegetable matter. A simple way to separate the three ingredients is to put the soil into a tall, wide-mouthed bottle; one holding two quarts will answer, but a larger one is better. Fill this full of water and shake it violently until all the soil is mixed with water. Stand it on the table and watch the soil settle. If the soil contains coarse sand this will settle almost immediately, being largest and heaviest. Medium sand and fine sand will settle more slowly. Part of the silt and clay will remain suspended in the water for many hours. After several days, or when the water is clear, all the soil will be deposited in the bottom of the jar; the sands on the bottom, then silt, and clay on top. These ingredients may not be deposited in well- defined layers, because sand, silt and clay are ar- bitrary terms, used to designate soil grains of cer- tain abitrary sizes, for the sake of convenience in describing them. In some cases the sand may grade into the silt and the silt into clay impercep- tibly; in other cases ill-defined layers can be seen. In any case a close scrutiny of the way in which the soil settles and of its appearance after it settles will enable one to estimate roughly the proportions of sand, silt, and clay that it contains. It will pay a farmer to test the different types of soil on his farm in this way, and especially to test several different soils at the same time and com- pare them. The results of these simple experi- ments will bear out and emphasise field observa- 74 SOILS tions on the agricultural value of these soils, or they may indicate a weakness where none is sus- pected. It is well to take a dozen or more samples of soil from different parts of a field in which the soil is all approximately similar, to mix them and to take from the combined lot the sample of soil that is tested. This makes it quite certain that the re- sults obtained represent the field fairly. The Bureau of Soils of the United States De- partment of Agriculture is making a "soil survey." The types of soils in all the important agricultural sections of the country are being studied. About 100,000 square miles of land in different states have already been studied and reports issued. These reports should be very useful to the farmers in these sections. They may be obtained of the Division of Publications, Washington, D. C. CHAPTER IV SOIL WATER PROBABLY no other phase of modern farming, except the ever pressing problem of how to keep up the fertility of the soil, is now receiving more attention than the problem of how to maintain an adequate supply of soil water. The farmers of our vast arid regions, both in the irrigation and in the dry-farming sections, pay scarcely more atten- tion to it than the farmers in the states east of the Mississippi, where the rainfall is supposed to be sufficient for ordinary crops. It is frequently stated that the lack of sufficient water at the right time does more to reduce the yields of farm crops in the United States than the lack of available plant food. This does not refer particularly to the great droughts, which may reduce the corn crop of the whole Mississippi valley 50 per cent. ; nor even to the local droughts, which sere the meadows and shrivel the gardens in scattered localities. The greatest losses from lack of water are not from noticeable droughts, but from the unnoticed dryness which merely lessens the crops year after year, reducing the average and lowering the standard. There are a few restricted sections of the country where the problem of soil water is not pressing; but in most parts of the United States a paramount problem in crop production is how to supply moisture at the right time and in adequate quantity. If a man handles his soil in such a way that it is in the best condition 75 76 SOILS to receive and hold a limited rainfall, he has taken the most important step in solving the coordinate problem of now to maintain its fertility. THE AMOUNT OF WATER NEEDED BY PLANTS It takes a very large quantity of water to mature even an ordinary crop. Irrigation farmers appre- ciate this much more than farmers in humid re- gions, because they can see it in bulk. Hellriegel has determined the amount of water necessary for the growth of average crops of the following plants : clover, 400 tons per acre; potatoes, 400 tons; wheat, 350 tons; oats, 375 tons; corn, 300 tons; grapes, 375 tons. This does not take into account water that is constantly being evaporated from the soil in which the crop is growing; it considers only the water used by the plants themselves. At the Iowa Agricultural Experiment Station it was found that the loss of water in growing a ton of clover hay, including what was used by the plants and what evaporated from the soil, was about 1560 tons, or enough to cover an acre 13.7 inches deep. The loss of water in growing one ton of air-dried corn fodder was 570 tons, or five inches per acre; of one ton of oats, 1200 tons of water, or 11 inches per acre; of 200 bushels of potatoes, 582 tons of water, or 5.6 inches per acre. The loss of water in grow- ing one acre of pasturage was 3223 tons, which is equivalent to a rainfall of 28 inches per acre. These interesting figures emphasise what every good farmer already knows: that an abundant supply of water is even more essential to a large crop than an abundance of plant food, and that some crops make larger demands upon the soil reservoir than others. SOIL WATER 77 How Plants Drink. — It is not easy to see how it can take from 200 to 375 pounds of water to make one pound of dry plants unless one knows something of the way in which plants drink. Only a small amount of this water becomes a part of the structure of the plant. Some plants are very succulent; 94 per cent, of the strawberry fruit is sweet- ened water, 90 per cent, of the entire corn plant is water, and 86 per cent, of the entire potato plant is water. Even if the crop were 99 per cent, water this would account for only a small portion of the amount that is actually lost from the soil during its growth. Most of this enormous amount of water is lost by evaporation through the leaves. Contrary to the old notion, plants do not feed by sucking up tiny particles of soil. The plant food in the soil is first dissolved in soil water, as salt dissolves in water; this is then drawn up through the roots by a peculiar process of absorption called "osmosis." The soil water drawn up by the roots contains very little plant food; it is so weak that we consider it pure water, and we drink it as it comes from tile drains or wells. Therefore the plant has to draw up a very large quantity of water in order to get sufficient food. After the plant has used the food in this very weak fertiliser solution, the pure water is exhaled through the pores of the leaves. Put a geranium, or other potted plant, under a glass jar and note how soon the inside of the jar becomes clouded with the moisture given off by the leaves. The soil in the pot may be covered with oil-cloth or 78 SOILS coated with hot wax to prevent evaporation from it. A plant, then, is a pump; there is a cloud of in- visible water vapour rising from every grass blade and every cotton leaf. The value of some plants as pumps compares quite favourably with the pumps we buy. Eucalyptus trees are sometimes used for draining malarial swamps; willows planted at the mouth of the sink drain keep the soil from getting soggy. RAINFALL INSUFFICIENT OR UNEVENLY DISTRIBUTED With these figures on the actual amount of water that a soil may lose in producing certain crops, and with this explanation of where so much of it goes, the farmer may now get from the nearest Weather Bureau a statement of the average amount of water that falls upon his soil each year or he may consult the general rainfall map on another page. Then compare the two sets of figures. At first sight, it may look as though there ought to be no difficulty in watering the crop; the rainfall may be thirty inches and the crop may use but thirteen. But how much of this rainfall comes during the months when the crop is growing ? How much of the rain- fall previous to the planting of the crop can be saved in the soil ? These two questions must be answered. The weather man will answer the first; only the farmer can answer the second, for it depends entirely upon the kind of soil he cultivates and upon the way he handles it. A comparison between the average rainfall dur- ing the growing season, say from April 1st to Sep- tember 15th, and the amount of water needed by SOIL WATER 79 the crop, may reveal an interesting situation. It may show, for instance, that the rainfall in those months is equal to or greater than the water used in producing the crop. This would be all right were it not for two facts; quite frequently there are years that fall much below the average in sum- mer rainfall, perhaps considerably below the amount needed by the crop; it is the average of wet years and dry years that gives the ''normal" rainfall. Then, again, not all the rain that falls becomes available for plant growth. Some of it runs off as surface water and nils the creek; some of it passes down through the soil; some of it evaporates. Very often not half of the summer rainfall can be utilised by crops. The comparison of figures may show that the total amount of water that falls during the growing season is only about one- third as much as the crop needs. In nearly all sections of the country the situation is that not enough rain falls during the growing season to water the crops after that lost by surface drainage, evaporation and seepage is deducted. The total rainfall may be adequate, but it is unevenly distributed. The problem, then, is to store the abundant rains of winter and early spring against the dryness of summer; this is one of the most important problems in farming. The water may be stored in reservoirs and used for irrigation or it may be stored in the soil itself; the former is a Western, the latter an Eastern method. Soil storage is more common and re- quires more skill. The man who has learned to store water in the soil effectively ha« mastered one of the most important problems la crop husbandry. 80 SOILS CAPACITY OF DIFFERENT SOILS TO HOLD WATER The different forms in which water is found in the soil have been mentioned in Chapter II. The water that is most valuable to the plant is that which is held by the grains as film moisture, although a large part of this may be drawn from the reser- voir of free or standing water below. Soils vary widely in their ability to hold film water. In judging the value of a piece of land for cropping, it is fully as important to consider its water-holding capacity as its rich- ness in plant food; a soil may be exceedingly rich in the essential plant foods, yet if it does not hold enough water to dissolve that food and carry it to the plants, it will produce no more than a very poor soil. Fertility consists as much in an abundance of soil water as in an abundance of plant food. The capacity of a soil to hold water depends upon its composition and upon its texture. The lighter a soil is, or the more sand it contains, the less water it will hold. The smaller the grains, the more water the soil holds, since there is more surface for it to cling to and less likelihood that it will leach through. Each soil grain is surrounded by a film of moisture ; if there are over 168,000,- 000,000 grains in an ounce of soil, as in some alluvial soils, the amount of surface for the water to cling to is much greater than if there are but 56,000,000,000 grains in an ounce, as in some truck soils. The more humus a soil contains the greater is its water-holding capacity, for humus is vegetable sponge. If small quantities of several SOIL WATER 81 kinds of soil are completely dried in an oven, and water is then added to them, it will be found that they will hold about the following amounts : Sharp sand 25% Clay soil (60% clay) 40% Heavy clay (80% clay) 61% Loam 51% Garden mould 89% Humus 181%, The same soils do not hold as much water as this in the field, because a large part of it drains off, as it must in order to make the soil congenial for plants. It is far more important to know how much water a soil will hold under its natural con- ditions in the field, after the excess water that fills the spaces has drained away and only film moisture remains. The amount of film water held by dif- ferent soils is about as follows: A coarse sand holds but 12 to 15 per cent, by weight of film moisture; a sandy loam from 20 to 30 per cent.; a clay loam from 30 to 40 per cent. ; a heavy clay, or a soil very rich in humus, may hold 40 to 50 per cent, of film moisture. This means that a mellow loam with a retentive subsoil holds four to five inches of water in the first foot of soil. Although a sandy soil holds less water than a clayey soil this disadvantage is partially offset by the fact that the lighter soils give up to the plants a larger percentage of the water they do contain than the heavier and wetter soils. A light soil may hold 30 per cent, of water and a heavy soil 55 per cent., yet the lighter soil may give nearly three-fourths of its water to the crop while the plants could secure scarcely one-half of the water held by the heavy soil. 82 SOILS Influence of Subsoil on the Water-holding Ca- pacity of Soils. — The amount of water held by a soil depends not only upon the character of the upper two or three feet of surface soil, in which the roots of most farm plants chiefly feed, but also upon the character of the subsoil and upon the distance to the water table. Some subsoils are retentive, others are leachy. A layer of gravel or sand three or four feet below the surface may provide perfect natural drainage, thereby increasing the amount of film water that the upper soil can hold. A hard- pan of impervious clay, or of rock close to the sur- face, will greatly reduce the water-holding capacity of the soil, strange as it may seem. One might think that if the water could pass down only three or four feet before it strikes hardpan, the soil above would be wetter than if the water could pass down through many feet of soil. But the fact is that the shallow soils are dry est; because, in times of abundant rains, the water soon fills the soil, and then flows off as surface drainage; whereas it sinks down into the deep soil for many feet and is stored there for the future use of the crop. The first five feet of a strong loam may contain enough water to make a layer ten to twenty inches deep over the field. Height of Water Table. — The distance below the surface at which free water is found has an im- portant influence on the amount of film water held by the soil above it. Generally speaking the nearer the water table is to the area in which the roots of cultivated plants forage, the larger will be the amount of film water held by this soil; for a large part of this film water is drawn directly from the free water, and the nearer this is, the more abun- dant and equable will be the supply. The roots SOIL WATER 83 of most cultivated crops rarely go more than five feet deep, hence a soil in which the water table is from four to six feet below the surface is apt to be most abundantly supplied with film water. When wet land is tile drained, the level of the water table is reduced from four to six feet deep, depending upon the depth at which the drains are laid below the surface. The chief reason why wet lands are so valuable after being under-drained is that the water table is lowered only to the point where it can most easily supply the soil above with film moisture; while in lands that need no under-drainage the water table may be thirty feet deep instead of six. HOW TO INCREASE THE WATER-HOLDING CAPACITY OF SOILS Fortunately for the farmer he can do much to in- crease the amount of film water that some soils can hold, and thereby increase their productiveness. The farmer who irrigates should be interested in the sub- ject as much as the farmer who depends upon natural rainfall to supply his crops with water; it is tedious and expensive to irrigate frequently, and he should know how to increase the capacity of his soil to hold water so that fewer irrigations will be needed. Under-drainage is the most efficient means of im- proving a soil in which the water table is always so close to the surface that the soil is too wet for farm crops; or which is very wet in winter and very dry in summer. Deep plowing, harrowing, cultivating and other tillage operations also do much to deepen the soil and enlarge the reservoir, because the more a soil is pulverised the more water it will hold. The addition of humus to a soil in the form of farm manure, muck or a green manure, has a very 84 SOILS marked influence on its ability to hold water. Fur- thermore, if the surface of the soil is softened, rains sink into it better. Fall plowing will leave the soil loose so that it will absorb the winter rains: if the surface is hard and compact, much of the water runs off. All of these operations are so funda- mental to successful farming that each one is dis- cussed at length in subsequent chapters. Influence of Forests on Water Supply. — The influence of forests upon the water supply should not be overlooked. When forests near streams are removed, the soil of the adjoining farm land is made dryer, and there is increased danger of floods. The large body of humus beneath forest trees holds an immense amount of water, like a sponge — nearly twice as much as its own weight when dry. In times of drought, this water is given off gradually to adjoining dryer land. Moreover, the air near large forests contains more moisture than the air of cleared areas because the trees give off large quantities of water through their leaves: hence farm soils in deforested areas lose water more rapidly, because the air above them is dryer. There are thousands of acres of land in this country which have been cleared of timber to use for farming, but which are nearly valueless for that purpose and should revert to forest; to say nothing of the wholesale destruction of forests for timber alone. Policy, as well as sentiment, should induce every man to |leave as much of his farm in woodland as is practicable. LOSS OF WATER BY SEEPAGE The free water of all soils is continually passing downward in obedience to the law of gravitation. SOIL WATER 85 Near the surface it seeps down slowly, but as it goes deeper it gathers volume and power. If the soil is shallow, it soon strikes hardpan and over- flows as surface drainage. If the soil is deep, it may sink down many hundreds of feet until it comes to some kind of a check or channel; per- haps a stratum of rock, perhaps a layer of coarse gravel. Down this it passes, joining forces with other underground currents, as the rill joins the brook and the brook joins the creek. This channel may lead it many miles away to where the stratum of rock or gravel comes to the surface. Then it gushes forth as a spring near the base of some hill, or on the bottom of some lake. Or it may not come to the surface but seek a lower level and there seep upward through the soil because of the pres- sure of other water behind it. Just as surface water flows down hillsides and collects in valleys, so underground water may sink through the soil of the mountain, hill, knoll or ridge, until it reaches the levels, where it may be pushed up towards the surface again by the pressure of water behind it. Many thousands of acres of farm lands are thus sub-irrigated, or watered from below, by water that has seeped down from higher land, perhaps many miles away. When drained, these soils become very productive, not only because of the equable supply of water that they receive from below, but also because this water, having perhaps travelled a long dis- tance in seeking its level, has dissolved much plant food from the soil through which it has passed. Loss of Plant Food in Seepage Water. — This latter phase of the seepage of soil water has a very important bearing upon the fertility of the land. 86 SOILS The water in the soil, both free and film, is not pure but has in it various salts and elements that it has dissolved from the soil. Some of these are plant foods. The nitrates, containing that most ex- pensive of plant foods, nitrogen, are most likely to be carried off in this way; also the phosphates and the potash salts to some extent. Most any kind of farm plant will grow very well in the water caught from a drain tile, and nothing else, showing that this water contains as much plant food as that which the plants in the soil draw up through their roots. The coarser a soil is, and the less humus it con- tains, the less able is it to retain the rain that falls upon it. It takes longer for water to seep down through clay soils, in which the spaces between the particles are very small, than through a sandy soil, in which the spaces between the grains are much larger. This is why sandy soils are leachy. The loss of water from clayey soils, through seep- age, is much facilitated by the burrows of earth- worms and the decay of roots, both of which open channels; also, to a considerable extent, by the numerous cracks that appear in all clay soils as they dry. These cracks are often very large on the surface; smaller though less numerous cracks are found for several feet below. With the exception of very sandy soils, the loss of water by seepage is not likely to occur during the growing season. In most parts of the country the upper soil becomes so dry during the summer that the summer rainfall is mostly taken up or evapo- rated before it is lost by seepage. It is during the season when vegetation is dormant or inactive, which is usually when the precipitation is largest, that the loss of water by seepage, and the loss of SOIL WATER 87 the plant food dissolved in this water, is likely to be largest. The loss of soil water by seepage can be prevented, in part, by judicious farm practice. If a leachy soil is filled with humus, either from manure or from decaying vegetation, the large spaces between the grains are clogged and water sinks through the soil less rapidly. An open, porous soil may also be compacted by rolling, which reduces the size of the spaces by crushing the grains together. Liming a sandy soil may have a slight effect in the same direction. If the soil is not left bare during the winter when a crop is not growing upon it, but is kept covered with a catch crop, as rye, the roots and herbage of this crop hold much of the water that otherwise would be lost. These operations are discussed at length in succeeding chapters. THE MOVEMENT OF FILM WATER In Chapter II it was stated that by far the most important kind of water in the soil is that which surrounds the soil grains like a film; because it is this, not free water, which the roots of plants use. This water is held to the surface of the soil grains by tension or adhesion, as a film of water adheres to a pebble dipped into the brook. There is also more or less water in the spaces between the grains. These films of water are not all of the same thick- ness. Some grains have more water on them than others; therefore parts of the soil are dryer than others. The dryness of some parts of the soil may be due to the fact that they have received less water from rainfall. It may also be caused by the roots of thirsty plants. The movement of film water takes place in this 88 SOILS way : The minute root hairs are always absorbing water, together with the plant food that is dissolved in it; not free water, but the film water clinging to the grains of soil. The soil grains which thus pay tribute to the plants become dry. But*they touch grains that are not in direct contact with the plant pump; part of the film moisture clinging to these is passed along to the dry grains, so that both be- come equally moist. Now the grains a little further off have more moisture than these which have given a part of theirs to the dry grains in the grasp of the root hairs. These, likewise, give of their abun- dance to the soil grains less favoured. So it comes about that there is always a steady current of film water passing to every root hair of every thirsty, growing plant; not flowing through the soil, but creeping from particle to particle, and space to space. In exactly the same way there is always a cur- rent of film water passing upward on every summer day to replace the water that the upper- most soil grains have lost by evaporation. The amount of water lost from common farm soils by evaporation may be as much as five inches a month during the summer. There must be in- equalities in the dryness of the soil that are due to other causes, as difference in texture or com- position; but for the most part we may think of this great volume of film water, equal to a layer of water over fifteen inches deep in the first five feet of some soils, as settling strongly in two currents — toward the surface, to replace the loss of water by evaporation, and toward the roots of plants. These invisible currents are not affected by the law of gravitation; they travel up, down, or sidewise in the endeavour to make the soil equally moist SOIL WATER 89 throughout its bulk. But this result is never brought to pass; it is prevented by the frequent downward passage of water, constant evaporation from the surface and continued absorption by roots. We are not concerned about checking the current of film moisture toward the roots, except to in- crease it. Usually the larger the loss of film water in this way, the greater the gain to the farmer. But we are greatly concerned about the current of film water that is passing upward to the surface of the soil and is then lost in the air as water vapour. We cannot afford to lose this water; and we can- not afford to lose, even temporarily, the plant food that is dissolved in it. When the water evaporates, this is left upon the surface of the soil where it is useless to plants, until washed down into the root- feeding area. We would rather have the water evaporate, not from the soil, but through the leaves of crops, after it has given to the plants the food that it contains. The sun is the mightiest of pumps. The amount of water that is evaporated from the soil in one summer day is astonishing even to those who have observed how quickly the soil becomes dry in midsummer after a heavy rain. King found that each square foot of an ordinary farm soil lost 1.3 pounds of water daily by evaporation from the surface. Capillary Action. — The movement of film water in the soil is frequently called "capillary action." The soil being made of millions of tiny grains, there are likewise millions of tiny spaces between the grains, as in a pile of wheat; so it follows that there is a more or less continuous passage from one space to another, making many small and very 90 SOILS crooked tubes — hence the term "capillary/' hair- like. Film water passes up, down and sidewise through these tubes, but mostly upward, for there is where the soil is most likely to become dry. For the purpose of illustration, then, we may conceive that every farm soil is permeated with very fine hair-like tubes which reach deep into the subsoil; that it is, we will say, something like a bundle of wheat straw. The lower ends of the tubes rest upon the water table — which may be two, six or thirty feet below the surface, according to the depth at which free water is found. The upper ends of the tubes open upon the surface. Water is drawn up through these tubes, from the water table to the surface, by a kind of suction called "capillary ac- tion." Capillary action is something like the pro- cess by which oil is drawn up through a wick; the flame that burns the oil is like the sun that evaporates the water; as oil creeps up through the strands of the wick, so soil water creeps up through tiny pores of the soil. Whenever the sun is hot, or a drying wind hugs the ground, water is drawn up through these tubes. In reality the tubes are as crooked and irregular as the holes in a piece of cheese, yet the principle and the results are the same. How to Prevent the Loss of Film Water. — How can this great loss of water — sometimes amounting to over one and one-half inches of rain in a single week — be checked ? Obviously there is but one way to do it — by stopping the mouths of the tubes. One need not travel far to find illustrations of how this may be done. Turn over a board or stone lying on the ground; the soil beneath is more moist than the adjacent soil; the pores of the earth have been closed, and the current of water SOIL WATER 91 passing upward has been stopped. That is why fishermen hunt for earthworms beneath stones, when the weather is very dry. A layer of small flat rocks scattered over the surface of the ground would prevent a large part of the film water from escaping, were it practicable. The woodpile offers another illustration, for the soil is always moist beneath the layer of chips, showing that evap- oration has been checked. But a layer of straw does just as well and is easier to apply. Any material that is spread upon the soil to stop up the mouths of the water tubes and shade the surface from the sun, thus preventing the loss of soil water, is called a mulch. The most effective and practicable mulches are coarse hay, straw, and farm manures ; not only because they are easy to apply, but also because they benefit the soil in other ways, chiefly through the humus that they add. Occasionally other materials are used to mulch the soil, as leaves, straw waste, coal ashes, sea-weed. Mulching to save soil water is rarely practised in growing common farm crops. Small fruits, espe- cially the strawberry, currant and gooseberry and also, to a slight extent, the tree fruits, are frequently mulched with these materials. The Soil Mulch. — The most practicable mulch in general farming is made of loose, dry soil. This is obtained by stirring the surface of the soil with the implements of tillage, as the plow, harrow and cultivator. Stirring the soil makes it much looser. The pores are broken. Water can creep from one soil grain to another only when the grains are close together — when the soil is compact. Stirring the soil spreads the grains so far apart that water can- not pass from one grain to another, or but very slowly. So it comes no further than the mouths 92 SOILS of the tubes, which are now not on the surface but eight inches, six inches or three inches below the surface, according to the depth to which the soil has been loosened. The practical application of this fact, and other benefits of tillage, are fully described in Chapter V. THE WATER-MOVING ABILITY OF DIFFERENT SOILS Since soils are so variable in composition and in texture they naturally vary a great deal in their " capillarity," or their ability to move film water. This point is worth considering when selecting a farm; a soil through which water moves slowly is not apt to be very productive. The coarser a soil is, the less water it can draw up. Fill one lamp chimney with coarse sand and another with clay loam, both packed hard. Set both of them in a pan of water and note the difference in the amount of water that they draw up and the time it takes them to do it. For a while water will rise rapidly through sand, but it will not be drawn very high, because the spaces or tubes are so large. In the finer soils, especially those containing some clay, water rises more slowly, but it is drawn up very much farther. Humus increases the water- drawing power of a soil. The importance of securing a soil with high capillary power lies in the relation this has to the water supply of crops. Film water, on which plants feed, is drawn largely from the reservoir of free water below. It is important that a soil be able to draw water freely and rapidly in order to keep the roots constantly bathed in the life giving fluid. A large crop makes a tremendous drain upon the water in the upper part of the soil during SOIL WATER 93 a single day. If the sun is very hot, the amount of water lost by evaporation is large; even thorough tillage cannot entirely prevent the escape of water. This means that the supply of film water in the surface soil must be quickly replenished from be- low, else the plants will suffer. In some soils the water table is many feet below the soil in which the roots of plants feed; in such cases there is especial need that the water be able to move rapidly through the soil. Very sandy soils not only do not hold much water, but also have little power to transport it by capillary action. Very stiff clay soils, on the other hand, while they hold a large amount of water, regain water very slowly after having be- come dry, so that they frequently suffer much in a drought. When a clay soil dries it shrinks, and cracks appear not merely on the surface, but also to a depth of several feet. These cracks let in air which still further dries the soil ; the roots of plants may also be torn apart and exposed, All kinds of loams have excellent water-carrying power; this fact, together with their mellowness and fer- tility, makes them among the most valuable of farm soils. How to Test the Water-holding Capacity of Farm Soils. — The points that have been brought out in the preceding paragraphs will be made more concrete to the reader if he will try a few simple experiments. Get a quart each of stiff clay, sand, and the black, spongy humus beneath forest trees. Put the three samples into a slow oven and dry them for two or three hours, or until they appear perfectly dry. Stand three lamp chimneys in pans and fill one with the dry humus, one with the dry sand and one with the dry clay. 94 SOILS Pack each very tightly. Fill three quart jars with water and pour water slowly from one of them into the top of the chimney of humus; water the chim- neys of sand and clay likewise from the other two jars. Pour in only a very little water at a time so as to allow it to settle slowly and wet all the soil thoroughly. Stop pouring water when the soil is wet to the bottom, and water begins to seep from the bottom of the chimney. Note first, how quickly water passes through sand and how little water it holds — it is leachy. Observe that the humus also absorbs the water quite readily, but holds much more of it. The clay takes up the water very slowly but holds a large quantity of it. The water left in each of the three jars shows the relative water-holding capacity of the soils. The chimneys of soil represent actual conditions in the field ; the water held by the soil in the chim- neys is film or capillary water, while the water that seeps out at the bottom of the chimney is free or standing water. The same results may be secured in anotner way by filling several flower pots with different soils and drying them in an oven. After weighing each pot of soil separately, add water to it very slowly until it seeps out at the bottom. Set the pots away to drain. When no more water seeps out, weigh them again. The difference in weight is the amount of film water that the soil can hold. The several types of soil on the farm may now be tested in the same way. Compare the water- holding capacity of a sandy loam with a clay loam. If you have a stiff clay soil, fill one chimney with this, another with a sample of the same soil which has had some humus mixed with it, and a third chimney with another sample of the same SOIL WATER 95 soil which has had some sand mixed with it. A comparison of these three samples should point a profitable lesson. If you have a very sandy soil find the influence of adding humus to it in like manner. If accurate measurements are desired, weigh the dry soil and the same soil after it is thoroughly saturated. A good soil should be able to absorb at least one-half its own weight of water; humus often holds almost twice its own weight of water, and sand from 15 to 25 per cent. Testing the Water-moving Ability of Soils. — The ability of a soil to move water by capillary action, and to draw upon the free water to supply the needs of plants, may be determined with a fair degree of accuracy in the following manner. Take chimneys of fire-dried and well-packed clay, sand and humus, as in the previous test, and stand them in a pan. Cover the bottom of the pan with half an inch of water. Note the water creep up into the chimney by capillary attraction. It rises very rapidly in the sand at first, but is carried only three or four inches high and then stops — the spaces between the grains are too large for it to be drawn higher. Humus takes the water up more slowly but eventually the soil at the top of the chimney is wet with the film water drawn up from below. The clay absorbs water even more slowly than humus, but the surface soil of the chimney of clay is wet in a few hours. Now test in a similar manner the farm soils which you have to handle. See what effect mixing a little sand or humus with the clay has upon its water-drawing power, and what influence mixing a little humus with the sand has upon its capillary power. Compare the capillary power of sand when it is put into the chimney loosely, and when it is packed 96 SOILS i into the chimney very firmly; it may suggest the value of rolling. The chimney of soil is a field in miniature; all fertile soils draw up water from the water table by capillary action, as these samples of soil draw up water from the pan. One of the most important functions of the soil is here exemplified. Some- times simple experiments like these show in tang- ible, concrete form, the results that may be expected from a farm practice that must be extended over a number of years in order to achieve these same results in the field. CHAPTER V THE BENEFITS OF TILLAGE TILLAGE — stirring the soil — is the simplest and commonest operation on the farm. Pos- sibly this is why it is understood the least. There are a hundred farmers who can explain per- fectly the theory of a balanced ration to a dozen who know all the benefits of the ordinary soil-stirring that occupies their time more than any other farm practice. This is largely due to the fact that there are two perfectly obvious benefits of tillage — the ground must first be stirred to make a mellow seed bed, and it must be stirred to kill the weeds that dispute with the crops for possession of the land. The necessity for stirring the soil to ac- complish these ends is so apparent that many have looked no further for the benefits of tillage than those that appear on the surface. The Present Emphasis on Good Tillage. — During the past twenty-five years there has been a marked change in the attitude of farmers toward tillage. Probably no other farm operation has advanced farther in the quarter century, not only in a better understanding of its purpose, but also in the effi- ciency with which it is performed. During the last quarter of the ninteenth century emphasis was placed most emphatically on tillage — "good tillage," "thorough tillage," "better tillage," and similar captions were the subjects for more articles in farm papers and more talks at farmers' institutes than any other operation of farming. The results 97 98 SOILS of this campaign, or "tillage era," as It has been called, are seen everywhere in better crops and more fertile fields. Just now we seem to be passing through a "humus era" in our agricultural development. The benefits of green manuring and cover crops are being heralded far and wide — perhaps over-emphasised a bit — as the benefits of tillage may have been overstated; for humus, as well as tillage, is only one of many factors that enter into the profitable production of crops. It is well, however, that each of the important points in good farming is before us so prominently for a time; it brings them to the attention of men who would not consider them so carefully were they not stated so emphatically and discussed so exclusively. TILLAGE TO PREPARE THE SEED BED The primary object of stirring the soil is to pre- pare it to receive the crop and to eliminate com- petition with other plants. In the wild, seeds are sown on untilled land and very few find a congenial seed bed and grow into lusty specimens of their kind. They may find the soil upon which they fall hard, cold and unresponsive, or already pre- empted by other plants of the same or other kinds. Even if the seeds germinate they at once engage in a life struggle with their neighbours for food, water, sunshine, a struggle that is relentless and inexorable. A very few plants, favoured by some accident in position, get a start over the others and slowly choke them to death, or keep them in wan and feeble subjection. Nature is satisfied, appar- ently, with small returns for her prodigal seed sow- ing; if one seed in a thousand brings forth fruit unto the harvest she is satisfied. THE BENEFITS OF TILLAGE 99 Man requires a larger increase. It is in his power to secure it in two ways; he can make the condition of the soil favourable for the germination of the seeds and the growth of the plants, and he can prevent competition by isolating his plants. All of these conditions are secured by tillage. The plow buries wild plants and loosens and deepens the soil; the harrow makes it mellow to receive the seed; the cultivator kills the weeds that would dispute with the crop for possession of the land. Simple as these statements are, they are funda- mental truths. An Improvement on Nature. — The farmer whose land yields the most increase is the one who im- proves upon Nature the most, in sowing seeds and in growing plants. He sows seed, not in Nature's haphazard way, wherever the wind blows, on good soil or poor, but only upon soil that is congenial for that plant and that has been specially pre- pared to receive it. He grows plants alone, not m a hand to hand struggle with other plants that he does not want. In fact, a man's success in farming is measured largely by his ability to re- move from his plants the uncertainties and the competition that these plants would have to face were they growing in the wild. This result is accomplished largely by tillage. Good tillage is especially needed in making the seed bed. The farmer who does the most harrow- ing is usually rewarded at harvest time far beyond the value of the time spent. All seeds need a mellow soil, a warm soil and a well ventilated soi1 in order to germinate quickly and grow fast. Plow- ing and harrowing make the soil finer and secure these conditions; and the degree of mellowness, warmth, and aeration it has is governed very largely 100 SOILS by the thoroughness with which the land is fitted. It is one of the common remarks at farmers' insti- tutes that too little attention is paid to the "tillage of preparation," as it is sometimes called; that farmers content themselves with plowing and then harrowing the soil once or twice before seeding, when perhaps three or four harrowings and one or two turns with the clod crusher would have paid. Seeds will not germinate readily if they are placed between three or four large lumps of soil. No matter how moist the lumps are, the seeds dry out fast because they do not touch the soil on all sides. If the lumps are broken into fine soil and the seeds are planted in this, they have an even and constant supply of water. It is as impracticable and un- profitable to sow seeds upon lumps as to spread fertiliser upon lumps. The number of times that it will pay to harrow when fitting a seed bed depends entirely upon its texture; a sandy loam soil may be as mellow and friable after one turn around the field as a clay loam is after three turns. Moreover it is impossible to make some soils mellow, even with a dozen harrowings. The trouble lies deeper — it may be lack of humus or poor drainage, which must be corrected in other ways. But up to a certain point tillage does fine, loosen, drain, aerate, and warm the soil and fit it for growing a profitable crop. Some soils respond to this tillage of prep- aration better than others; a good farmer soon finds out, by experimenting and observing, how thoroughly it pays to fit his land. He may be surprised to find that one or two extra turns with the harrow will pay him much more when harvest time comes than the cost of the labour. THE BENEFITS OF TILLAGE 101 TILLAGE TO KILL WEEDS The second object of tilling — that of killing weeds — is forced upon the attention of the farmer with back-breaking and sweat-rolling regularity. A weed is a plant that is not wanted — whether it is a Canada thistle in the pasture, a daisy in the meadow, quack-grass in the corn or "pusley" in the garden. The plant may be innocent enough in itself, and may sometimes even be grown as a crop, as when sand vetch sown this year for hay comes up next year in the corn planted on the same land. A weed is a plant out of place, accord- ing to man's scheme, so he becomes its bitter enemy. The Tirade Against Weeds. — From the amount of wordy abuse that weeds have to stand from man one would think that they are free moral agents and capable of choosing be- tween the already overcrowded wildwood, where they would have to fight for a living, and the in- viting farm lands where the soil has been made soft and comfortable. If one were to ask a thousand farmers in this country, ''What is the greatest trouble you have in farming? "the com- plaint that would rise most readily to the lips of nine hundred of them would be *'I could get along all right if it was not for those pesky weeds." Weed recipes, purporting to be short cuts to the extermination of this torment, are offered by the score. Many bulletins and several books on weeds keep constantly before him the danger of relaxing watchfulness against the great pest. It would al- most seem, from all that is said about and against weeds, that if only those plants that we put into the soil could grow, and no others, the chief impediment 102 SOILS to the farmer's prosperity would be removed and he could take a half holiday six times a week. Friendly Words for Weeds. — In recent years there has grown up an entirely different attitude toward weeds on the part of some people. We are told that weeds are a great blessing, not a curse. The reason given is that if there were no weeds to kill, many farmers would not cultivate their soil; hence the other benefits of tillage — saving moisture and set- ting free plant food — would not be secured as often as they are now, when a multitude of weeds makes it necessary to till frequently. We have also been told that if a man cultivates his land as often as he ought, in order to secure these other benefits of tillage, weeds will not bother him much. Here, then, are two extreme views concerning the warfare between man and weeds. One man says that all that it is necessary to do is to cultivate often enough to keep down weeds and the other benefits will be secured in so doing. The other man says that if the soil is tilled as it ought to be in order to save water all the weeds will be killed in so doing. Both are radicals. The fact is that sometimes the soil should be stirred when there are no weeds in sight; and sometimes weeds are so bad that the soil must be stirred two or three times as often as would be necessary were we considering only soil moisture and plant food. During a hot, muggy July, with heavy thunder storms about every other day, the hoed crops would not suffer for lack of water were it not for weeds. Purslane, ragweed, crab-grass and a host of other worthies luxuriate over the ground, choking and stifling the crop and pumping immense quantities of water from the soil. The chief way in which weeds injure crops is by w o H p-i >» S ■« C JL 35. POTATOES IN DIRE NEED OF TILLAGE Soil water is being lost rapidly, and the plants need it .^ IJiiii 36. POTATOES LUXURIATING UNDER A MULCH OF LOOSE. DRY SOIL This preserves the moisture to them. This crop will "pan out"; the other will not THE BENEFITS OF TILLAGE 103 robbing them of water. They do use some plant food, but the loss is not as great. These weeds must be killed, even if one has to use the cultivator twice as often as would be necessary otherwise. On the other hand there may come a dry August during which few weeds start, but it is very essential that the cultivator be run over the ground once or twice a week so as to keep a layer of loose dry soil be- tween the precious soil moisture and the air which is hungry to suck it up. I have a little garden back of my house. During a rainy spring if I worked it enough to keep down all weeds it would be about three times a week, which is about three times oftener than it would be necessary to cultivate were soil moisture and plant food the chief con- cern. The question as to whether weeds or the saving of water, should be the guide to the fre- quency of tillage depends upon the locality and tne season ; it is as often one as the other. Weeds a Spur to the Sluggard. — Weeds, are how- ever, a mentor that we but half appreciate. It is easy to advise "Till as often as is necessary to keep soil water from escaping," but the escape of soil water is a very intangible thing, likewise the setting free of plant food, a benefit of tillage that will be mentioned shortly. We cannot see either of them, and most of us are apt to be careless about the things we cannot see. But weeds are very much in evidence. If the average man sees a dozen lusty pigweeds waving triumphantly above his early potatoes he will be much more likely to cultivate and hoe his garden than if he happens to notice that there is a thin, moisture-losing crust on the surface of the soil. Every good farmer has a big bump of pride which begins to thump impatiently 104 SOILS when his crops get weedy, especially if they are close to the road. So he begins to stir the soil with a cultivator and to dig into it with a hoe; then the chief mission of weeds in farming has been ac- complished. From the beginning of husbandry they have pricked men on to till the soil. Now we know of other reasons for keeping the soil stirred around our plants, reasons that are important enough to mate the best farmers till when there are no weeds. But weeds will always remain the spur of the sluggard — and a fairly reliable tillage guide to the rest of us. TILLAGE TO SAVE WATER Aside from preparing the soil to receive the crop and killing the weeds that would compete with the crop, tillage accomplishes another result that may be even more valuable to the farmer. It saves soil water, as has been described in the preceeding chapter, by establishing a mulch, which makes it impossible for much water to evaporate. The amount of water that is saved by keeping the sur- face of the soil thoroughly stirred may be as much as one-third of the total amount that the soil re- ceives. Snyder found that the soil of a corn field which had been cultivated frequently contained 17 per cent, of water in the layer of soil from 9 to 17 inches deep, while the same layer of soil in another part of the same field, but which had not been tilled, contained only 12 per cent, of water. The efficiency of a soil mulch in preventing the escape of soil water needs no further proof than observation in orchard, field and garden. During a summer drought the corn leaves shrivel first THE BENEFITS OF TILLAGE 105 where the farmer has cultivated least. Just be- neath the loose dry soil of his cultivated field he finds moist soil, with plant roots revelling in it. On an uncultivated field he may have to dig down a foot or more before he finds moist soil. Even a casual examination of the farms in any community will convince a man that the operation which con- tributes most largely to success or failure in farming is tillage, chiefly in its relation to the saving of soil water. Tillage to Increase the Water-holding Capacity of a Soil. — Besides saving water by surface tillage tne farmer can increase tne capacity of his soil to hold water by deep tillage, as by fall plowing and by subsoiling. These operations loosen the soil to a depth of 5 to 14 inches and thereby enable it to retain more of the water that falls upon it as rain or snow, a large part of which runs off as surface drainage when the soil is hard, carrying with it, perhaps, much fine soil. The shallow plowing so common in parts of the South is responsible for much of the loss of soil by washing in this region. Heavy clay soils and other soils that are quite compact, so that they absorb water very slowly, are benefited by subsoiling and fall plowing. Soils containing a large amount of sand are not bene- fited by this treatment — they are already too loose. The methods of plowing and subsoiling are con- sidered at length in the following chapter. DRY FARMING An important phase of tillage, in its relation to the saving of soil water, is the farm practice now commonly called "dry farming." In reality all farming that does not make use of irrigation is dry 106 SOILS farming, but the term is commonly understood to mean the growing of crops in the arid or semi-arid regions without irrigation. In recent years much interest has been manifested in dry farming, and its methods have been applied with increasing success over a constantly widening territory. The sections where it is practised are chiefly eastern North Dakota, eastern South Dakota, western Kansas, western Oklahoma, central Texas, eastern Washington, eastern Oregon, and scattered areas in Idaho, California, Utah, Montana, Colorado, New Mexico, Wyoming and Arizona. These regions include approximately 300,000,000 acres. Nevada is said to be the only arid state in which dry farming cannot be practised successfully. For the most part dry farming is practised on the border land of aridity, and on land in arid regions that it is impossible or impracticable to irrigate. There are many millions of acres of land in the arid and semi-arid regions that are above the "ditch line"; that is, they lie so high that the ex- pense of bringing water to them would be greater than the returns. Of such a nature, for example, are the high bench lands in the Cache Valley, Utah. Moreover, the amount of water in the arid and semi-arid regions that is available for irrigation is sufficient to water but a small portion of the entire area. Dry farming is the only kind of farming possible on millions of acres of land in the West. Dry farming is an attempt to grow the common crops with the minimum amount of moisture. Most of the sections in which it has been successful have a rainfall of from 10 to 15 inches, from 2 to 5 inches of which, and often more, is lost by drain- age and seepage. Some dry farming sections have less than 10 inches of rainfall, yet crops are grown HHF*j ^StjimmgammBas^j^^. 1 j - 37. WATER HELD BY A COARSE AND BY A FINE SOIL The finer a soil is the more water it will hold. An abundance of soil water is as essential to the production of large crops as an abundance of plant food. Tillage makes a soil finer 38. A LUMPY SOIL The soil in these lumps is useless to crops for the time being, as the root hairs feed only on the outside of small particles. Break up these lumps by wise tillage and by adding humus and so increase the " pasturage" of the crops 39. A PERFECT SOIL MULCH It is five inches to moist soil. The surface layer of dry soil acts as a blanket 40. WHERE TROUBLESOME WEEDS ARE WONT TO CONGREGATE AND TO MULTIPLY Keep the fence rows clean or, better yet, do away with them altogether. Many fences and walls are unnecessary THE BENEFITS OF TILLAGE 107 that compare very favourably with those of Eastern farms that receive from 30 to 40 inches. Dry farming is never resorted to, however, except when irrigation is impossible or inexpedient. It is an illustration of wnat can be done by tillage to con- serve soil water that every farmer in the humid East may consider with profit. Dry Farming Methods. — The success of dry farming is based upon a most thorough application of the principles of tillage. Two things are essen- tial : the subsoil must be put in condition to receive and hold all the water that falls upon it, and the surface soil must be made dry and mellow to pre- vent the escape of that water by evaporation. A third essential, in some cases, is to secure seeds that are adapted to these trying conditions. In preparing the subsoil, an effort is usually made to leave it compact. Sometimes this is done with a special tool called a subsoil packer. This is a bevel wheel roller that follows the plow, rolling down and packing the subsoil. Each of its ten wheels has V-shaped rims which press deeply into the soil, compacting it below. The object is to make the subsoil so firm that the air spaces will be very small, hence air will not circulate freely through the soil and dry it out. The soil packer usually accompanies a steam plow outfit. which is fenerally used in dry farming. A weighted disk arrow, with disks set straight, is also used. The harrow is then put on — the same day if possible — and three or four inches of the surface soil is made into the most efficient kind of soil mulch, which is renewed frequently. Keep the harrowing close up to the plowing. The mulch established in dry farming would be a revelation to those Eastern farmers who barely scratch the surface 108 SOILS of their fields, scarcely keeping down weeds, . and who complain about drought. The combination of tools sometimes used in dry farming is remarkable. Frequently one 32-horse- power traction engine will drag twelve 14-inch plows, two corrugated iron rollers, two clod crushers, besides harrows and seed drills, the whole making a long procession, with unbroken land in front and smooth and seeded land behind. Such an outfit prepares and seeds about 35 acres a day. When the rainfall is very scanty it is necessary for success in dry farming to summer-fallow the land every other year. The object of the summer fallow is to store water for the next crop. Excellent tillage, together with packing the subsoil in some cases, is the simple and easy secret of dry farming. It is the application, in an almost perfect way, of a principle that has been known, but usually very imperfectly applied, for several hundred years. Crops Under Dry Farming. — The crop grown most largely under dry farming is Durum or macaroni wheat. This was introduced into Amer- ica from Russia by the United States Department of Agriculture about ten years ago and has proved a most valuable acquisition. In Russia it has been grown successfully for many years on the steppes, where the rainfall is less than 10 inches. The readiness with which this remarkable plant lends itself to dry farming, and the wonderful increase in its culture, is shown by the fact that the first large crop of macaroni wheat in the United States was harvested in 1901, while the crop of 1905 was close to 30,000,000 bushels. Average crops are 15 to 25 bushels of wheat per acre in the arid region regions, and 30 to 50 bushels in the semi-arid regions. It thrives only in a very dry climate. THE BENEFITS OF TILLAGE 109 Besides Durum wheat, Turkestan alfalfa, Kaffir corn, sorghum, emmer, dwarf milo maize, and a number of forage grasses are grown under dry- farming. Rye and barley are also grown some- what. It is important to sow less seed than in humid farming, 30 to 35 lbs. per acre is usually enough. This seed should be grown in semi-arid, not in humid, sections. The present interest in dry farming in many parts of the West amounts to little less than a speculative fever. Dry farming companies are being organised to plant farms of 3,000 acres or larger. The values on "desert" land are appre- ciating rapidly, in some cases running from $2.50 to $50 an acre in two or three years. Undoubtedly dry farming is doing much and will do vastly more to reclaim land formerly considered worthless be- cause of lack of water for irrigation. Next to irrigation it is the most important agricultural practice of our times in the arid West. Yet it is altogether likely that land will be used for dry farming which ought never to be cleared of sage brush. The present enthusiasm over dry farming bears some of the ear-marks of a boom. There are bound to be some disappointed and some ruined practitioners of dry farming, just as there were thousands of disappointed and ruined "rain- belters" in western Kansas, Nebraska, and the Dakotas twenty years ago. Undoubtedly the area that can be brought under profitable dry farm- ing may be greatly extended, as better methods for husbanding scanty rainfall become more gener- ally known and practised. But there is an unusual amount of risk connected with it, and no man should undertake this kind of farming until he has investigated it thoroughly. Whenever 110 SOILS possible irrigation should be used to supplement dry farming. TILLAGE TO PROMOTE FERTILITY The longer a soil lies idle, so far as the farmer is concerned, but is covered with Nature's crops year by year, the richer it becomes. The chief reason for this is pointed out in Chapter XII. Nature's crops die, decay and are returned to the soil, adding to it what they have taken out and improving its texture; the farmer's crops are mostly removed. On the other hand, it is also true that tillage makes the soil more fertile. It will do so as long as the supply of humus that is in the soil when it is cleared for cropping is maintained, and provided as much plant food is added to the soil each year as is re- moved in crops. But since neither of these con- ditions are complied with, it usually happens that the longer the soil is tilled the poorer it gets. The falling off in its ability to produce crops would be very much greater, however, were it not for the food-producing power of tillage. How Tillage Increases Fertility — The explana- tion of the power of tillage to increase fertility is very simple. In Chapter I it was stated that the chief agency that has broken up the rocks and made them into soil is weathering — the action of water, air, heat and cold. This action is still going on; soils are being weathered, as well as rocks and stones; their grains are becoming finer, their plant food more available. Tillage makes a soil more fertile chiefly because it loosens it, thus allowing a free entrance to these agencies that make it finer, and hence expose more surface for the roots to feed upon. Every time that a soil THE BENEFITS OF TILLAGE 111 is plowed, harrowed or cultivated it is loosened, and air, water, heat and cold enter it more freely and attack it more vigorously. Nearly all farm soils, even some that produce poor crops, contain enormous quantities of plant food (Chapter XI), most of which, however, is in such a form that the plants cannot use it, being "unavailable" as the chemist says. Tillage makes much of this latent plant food available from year to year, by pro- moting better weathering. Tillage mixes the soil grains and changes their relative positions so that certain particles are brought together that have been separated before, and there is greater likelihood of chemical changes. It may carry to the surface grains of soil that have been lying several inches deep for many years, thus exposing them to weathering. It fills the soil with air which hastens the decay of vegetation, thus making humus and a large amount of carbonic acid. This carbonic acid becomes a part of the soil water and greatly increases its power to dis- solve plant food from the mineral portion of the soil. The better aeration of the soil due to tillage is favourable for the growth of the valuable nitro- gen-fixing bacteria described on page 40 . The activities of other beneficial germs in the soil are promoted by the warmth, drainage and aeration that follow tillage. If it were not for these benef- icent effects of tillage soils would become "worn- out" much sooner than they do now from con- tinued cropping with little return. Tillage the "Poor Man's Manure" — Tillage has been called "the poor man's manure," with some fitness. Stirring the soil does enrich it to the ex- tent that it enables the farmer to use more of the native plant food in the soil. But it is not a manure 112 SOILS in the sense of plant food applied. The value of thorough tillage to increase fertility was first dem- onstrated about 1730 by a wise old English farmer, Jethro Tull. We read in his "Horse Hoe- ing Husbandry" that he planted wheat in rows far enough apart to allow tillage between them, and raised more profitable crops without adding ma- nure than his neighbours, who manured highly but tilled little. In his enthusiasm Tull made the mistake of believing that tillage could take the place of fertilising, which we now know to be wrong. Good tillage — deep plowing, thorough harrowing, frequent cultivating — will largely reduce the fertiliser bill or delay the day when fertilisers and manures will be needed, because it enables the farmer to get the most from the soluble plant food already in the soil. But there always comes a time when tillage must be supplemented with manuring or fertilising. Tillage is not fertilising; but, if done thoroughly, it may save much fertilising. THE ALCHEMY THAT FOLLOWS THE PLOW Thus it is seen that simply stirring the soil, the commonest work on the farm and the work which often receives the least thought, sets at work many agencies that exert a profound influence on the productivity of the land. Every tiller of the soil should know something of the wonderful alchemy that follows the plowshare and cultivator tooth. As he plows, harrows, cultivates, rolls, drags, he should think, not that this is so much dirt that he must handle, so many weeds that he must kill, but that he is getting the soil laboratory ready for the delicate reactions and subtle changes that are a part of the wonderful process by which soil is made THE BENEFITS OF TILLAGE 113 into plants. There is much more to tillage than burying trash, killing weeds and mellowing lumps. The farmer who sees only these things when he stirs the soil is not getting as much pleasure from his business as he might. As he trudges up and down the long field behind the sweating team, turning the moist earth into crumbling furrow slices, or guiding the cultivator between rows of thrifty plants, the work will seem less irksome if he thinks of these wonderful activities that he has set in motion, and plans how he may keep the soil laboratory in the best running order. CHAPTER VI THE OBJECTS AND METHODS OF PLOWING PLOWING is of greater antiquity than any other tillage operation because it was found necessary to break ground so that seeds could be planted long before stirring the soil for other purposes was thought of. Four thousand years ago, and probably earlier, the plow was the chief and usually the only implement of tillage. The style of plow that was used at different periods in the history of the world is a very reliable index to the agricultural development of the time; just as to-day we gauge the ability of a farmer chiefly by the skill and thoroughess with which he handles the soil, r .*.,.», •- *.•,, The Early Plows. — The primitive plow was a small tree having a small branch starting out from it in the form of the letter V. The trunk of this was the beam, and the branch, which was much shorter than the other and was sharpened, was the point. The beam and point were often braced by being tied together with a withe; a handle was made by lashing another branch to the beam. When this crude tool was dragged along the sur- face it scratched the ground to a depth of three or four inches — deep enough to allow seeds to be planted, which was considered the only reason for plowing in those days. This very unsatisfactory tool was replaced by wooden plows of various pat- terns, most of which simply stirred the soil, but did not invert it. Not till about the eleventh 114 METHODS OF PLOWING 115 century were plows with iron points used to any extent. These plows were made by local black- smiths in different localities and were thus ex- tremely variable in style and in value, according to the skill of the blacksmith. Greater uniformity and a decided increase in the value of plows re- sulted from the discovery of how to make plow- shares of cast iron, in 1785, and of case hardened or chilled shares, in 1803. Early American Plows. — As late as the begin- ning of the nineteenth century the plow commonly used in this country was made mostly of wood, the mouldboard and point being partially protected by worn-out horseshoes and other scraps of iron that were nailed upon them. It was often about twelve feet long and required eight to ten oxen to draw it, and one man to ride upon the beam. A good cast iron plow had been made by Charles Newbald, an American farmer, and patented in 1797, but it never became popular solely because of the prejudice against the innovation. Farmers said that cast- iron plows "poisoned the land" and "caused weeds to grow." By 1810, however, most of the prejudice. against iron plows had passed away and they came into common use. These early cast plows, however, were mostly made of one piece, and when the point was dulled the whole plow was useless. The next step was to provide inter- changeable points so that the plow could be easily repaired. It was not until near the middle of the last cen-) tury that plow makers clearly comprehended the chief function of a plow — to pulverise the soil. Hitherto their efforts had been directed mainly toward making a plow that would invert the soil and so bury trash. The early plowshares had 116 SOILS been broad, high and bent over at the top very little, so that they inverted the soil very neatly but did not crumble it much. It was soon seen that the only way to accomplish this end was to make the furrow slice twist as it turned over. Then was produced the modern broad, flat plowshare with overhanging mouldboard, which accomplishes this result admirably. Subsequent to this discovery, during the last half of the nineteenth century improvements on the plow followed rapidly. The length of the beam and handles was increased and the latter set lower, thus making the plow much easier to control. The jointer, that most useful adjunct of the modern plow, was introduced and improved. One of the greatest troubles with the early plows was that they did not "scour" well; that is dirt collected on the mouldboard, making it rough and greatly reducing its efficiency and increasing the draft. The introduction of the Oliver chilled plow, in 1870, was a notable event in plow making. About 1 870 gang plows were introduced. The first gang plows were two or three plows fastened to one beam. These were very cumbersome and were soon superseded by the sulky gang plow, which is largely used to-day, especially in the West. Various methods of hardening the mouldboards of plows were tried, until carbonising or chilling came into general use for both steel and cast iron plows. Plow making has reached its highest development in America, from which plows are shipped to all parts of the world. There are about 9,000,000 plows in use on American farms, representing an investment of $80,000,000 for this tool alone. The Modern Plow. — The modern plow is the O 8 u u W 2 E s H .g ° | 42. FLAT-FURROW PLOWING— THE SLICE COMPLETELY INVERTED Handsome, but does not crumble soil enough. Good for burying herbage a. CLAY SOIL PLOWED WHEN TOO WET Note the glazed appearance of the furrow-slice. This will make the soil cloddy METHODS OF PLOWING 117 product of more than forty centuries of slow im- provement. During this time it has developed from a crooked stick, which barely scratched the surface and served no other purpose than that of permitting the seed to be sown, to a tool that pul- verises the soil, increases its water-holding capacity, adds to its fertility and has a more important in- fluence on the productiveness of the land than any other single treatment that it receives. Many attempts nave been made to introduce substitutes for the plow in preparing the soil for crops, but none have been uniformly successful, although various ingenious spading tools are of considerable utility in special cases. The improvement of the plow and of plowing will continue. Where it is practicable for the farmer to use greater power, deeper working plows will be used, which will pulverise the soil to a much greater depth, thus increasing its water-holding capacity and its productivity. The fact that the plow — the most important tool of agriculture — was improved more during the nineteenth century than in all the centuries that precede, well illustrates the changed point of view, in this new era, when the best thought and the highest inventive genius of the world are being brought to bear upon the problems of the farmer. Two centuries ago this would not have been possible. THE OBJECTS OF PLOWING Aside from crumbling the soil, the chief objects of plowing are to destroy wild plants so that culti- vated plants may be grown in their place; and to bury the trash, as corn stubble and potato vines, so that the soil may be made ready for a new crop. 118 SOILS A plow that does not accomplish both of these re- sults is faulty. All refuse should be covered so deeply that it is not brought to the surface by the harrow. This can usually be done without com- pletely inverting the furrow slice. A broad and deep furrow buries trash better than one that is narrow and shallow. If tall herbage is to be plowed under, as in plowing under a green manur- ing crop or a heavy growth of weeds, a chain with one end attached to the beam of the plow and the other to the end of the double-tree will make it easier to bury the plants, especially if a jointer is used also. Sometimes it is necessary to rake the coarsest part of the manure into the furrow in order to bury it completely. Herbage and refuse that is plowed under deeply decays more rapidly than if it is turned under with a shallow furrow, because the surface soil is dryer. When there is a large amount of herbage or trash to bury the team should be stronger and the furrow deeper than if the soil is unencumbered. If the furrow slice is com- Eletely inverted herbage and trash is buried best, ut the soil is not pulverised much. It is possible to bury herbage and trash with a crumbling furrow. Pulverising the Soil. — Unless a plow pulver- ises the soil so that the harrow can finish the pro- cess easily, it is not doing all that should be ex- pected of it. Plows differ greatly in the way which they leave the furrow. The furrow-slice is some- times completely inverted and lies flat on the bot- tom of the preceding furrow; this is called "flat- furrow plowing." Other furrows stand nearly edgewise without being crumbled much; this is called " overlapping-f urrow plowing." Still others are broken to pieces entirely; this is called "rol- ling-furrow plowing." METHODS OF PLOWING 119 The way in which the surface is left by a plow depends chiefly upon the style of the mouldboard that is used; the bolder or more overhanging it is the more completely is the furrow-slice broken. An overhanging mouldboard prevents the furrow- slice from turning flat and leaves it rough. A rolling furrow-slice buries herbage and trash about as well as a flat one if a jointer is used; and it crumbles the soil much better. A plow that turns this kind of furrow is the best for most conditions. Flat-furrow plowing is the handsomest but the poorest plowing, in most cases. The soil is not crumbled and, what is even more important, the least amount of surface is exposed to the air. It is also more difficult for the harrow teeth to take hold of the tips of these slices and break them without distributing the sod or herbage beneath. But flat-furrow plowing covers trash and herbage better than the other types of plowing, so that it may often be used to advantage for f)lowing stubble land, especially if it is fairly Lap-furrow plowing, in which the furrow-slice is only partly inverted, being left on edge and par- tially overlapping the preceding furrow-slice, leaves the soil fairly well pulverised and with a ridge surface so that it is easily mellowed and fined by the harrow, but it does not bury trash or herb- age well. It is especially valuable for fall plowing, particularly of clayey soils, as it leaves many air spaces beneath the furrow-slice and the soil is fully exposed to weathering. It is well worth while to have two or three types of plows on hand and use each acording to the results it accomplishes and the purpose in view. This costs more, but greater efficiency results. 120 SOILS A very slight difference in the lines of the mould- board may make wide results in plowing. Much depends upon the nature of the soil. Sandy soils may be plowed with a flat furrow-slice with much less detriment than clayey soils, which need much loosening and pulverising. If a tenacious soil is plowed so that the furrow-slice is completely in- verted it is much heavier and colder, for the season at least, than if the furrow-slices were overlapped. Plowing to Prepare the Seed-bed. — It is expen- sive work fitting soil to receive the seed. Plowing usually represents less than one-half the cost of preparing land for the crop ; harrowing, dragging, planking, etc. if well done, cost more. One of the objects in plowing, then, should be to leave the soil in such a condition that as little subsequent tillage as possible will be needed to fit the land for the crop. This means that the plowman should not be satisfied with the handsome flat-furrow plowing that took prizes at the agricultural fairs 50 years ago, but which requires much expensive harrowing to make it mellow. He should turn a furrow-slice that is just as loose and crumbly as possible and still bury the trash, so that the labour of harrowing may be reduced. The kind of plow that should be used, and the condition in which the land should be left, depends upon the kind of soil and the crop to be grown upon it; but whenever a plow is purchased its ability to pulverise the soil should be the chief measure of its value. Plowing to Promote Fertility. — It does this by all the ways mentioned in the previous chapter. It exposes the soil to weathering more completely so that more of its insoluble plant food is made available. It lets in the air which corrodes the minerals, forms carbonic acid with the humus and METHODS OF PLOWING 121 enters into many chemical and physical combina- tions that have an important influence on soil fer- tility. Deep plowing brings to the surface sub- soil that has not lost so much of its plant food as the surface soil, not having been weathered so com- pletely. After one or two seasons this rich, raw soil becomes weathered sufficiently and is then utilised by crops. Furthermore, the mere fining of the soil by plowing increases its fertility by pre- senting a large surface for the roots to feed upon. The work of the nitrogen-fixing germs and of other useful agencies that make for fertility is wonder- fully hastened by the warmth and aeration induced by plowing. It is chiefly the depth to which the plow stirs soil that gives it preeminence among tillage tools. Plowing to Deepen the Soil Reservoir. — Plowing may be made the means of increasing the water- holding capacity of a soil. Soils of a close texture, as the clays and clay loams, may be made to hold more water by deep plowing, because rain will sink into the loosened soil better. But sandy soils should not be plowed deeply; they are too leachy at best. Light soils through which water passes too readily may be made somewhat more retentive by plowing them at the same depth every year. The tramping of the horses and the weight of the plow tend to com- pact the soil at the bottom of the furrow, making a kind of artificial hard-pan, or "plow bed, "which checks the downward passage of water somewhat. The depth at which this hard-pan should be formed is six to eight inches, depending upon the rooting habits of the crop grown. On the other hand, in plowing heavy soils the aim should be to prevent the formation of the hard-pan by varying the depth from year to year. The benefit of deep plowing 122 SOILS to prevent the washing of clay soils is pointed out in a following paragraph. Plowing to Drain the Soil. — Plowing may also be made the means of draining a soil. It is best to have a soil of such texture that all water falling on it will be absorbed or pass through it. But this is rarely possible, particularly when the soil is heavy. Such soils, especially if nearly level, may often be plowed into "lands" to advantage. The dead furrows may be in the same place for several consecutive seasons, thus throwing the soil into slightly elevated beds. Lands from 15 to 30 feet wide are often used, but lands 60 to 75 feet wide drain the soil more efficiently, because not enough water may flow into narrow dead-furrows to make sufficient current to carry it off. Even when the field is fairly well drained, naturally or artificially, it is best to leave dead fur- rows from 30 to 50 feet apart, though not in the same place for succeeding years. Plowing to Establish a Mulch. — In addition to its value for increasing the capacity of a soil to hold water, plowing is one of the best means of prevent- ing the evaporation of water already in the soil. King, who has made many noteworthy experiments on tnis subject, concludes "In the conservation of soil moisture by tillage there is no way of develop- ing a mulch more effective than that which is pro- duced by a tool working in the manner of a plow, to completely remove a layer of soil and lay it down again, bottom side up, in a loose condition." HOW DEEP TO PLOW There is sometimes much discussion about how deep the soil should be plowed. It is as impossible METHODS OF PLOWING 123 to answer this question definitely and conclusively for all farmers as it is to prescribe that corn should be planted the first week in June everywhere. The best depth for plowing depends upon conditions; these each farmer must study for himself. No general statement can be made ; "plow deep" is sound advice in many cases, and very bad advice in others. The depth to plow should be governed mainly by the nature of the soil. As a general rule, the heavier the soil the deeper it should be plowed, for heavy soils need the loosening, draining and aerat- ing effect of deep plowing. Such soils are com- monly plowed from seven to ten inches deep. On the contrary, the lighter the soils the more shallow should they be plowed, since deep plowing makes the soil looser, and it is already too loose and leachy. If, however, humus is being plowed under, as manure or a cover crop, the plowing can be deeper. Sandy soils are commonly plowed four or five inches deep. If, however, it is desired to form an artificial hard-pan on such soils they may be plowed deeper. On raw soils it is well to plow about half an inch deeper each year until a depth of nine or ten inches is reached. The depth to plow should be influenced by the feeding habit of the crop to be grown. Are its feeding roots mostly in the first foot of soil or in the first five feet ? Plowing for fruit trees and root crops should be deeper, as a rule, than for other farm crops. Plow somewhat deeper in midsummer and fall, when the soil is apt to be dry, than in spring when the soil is cold and wet. In the humid sections farm manures or green manures plowed under at that time decay quicker near the surface than 124 SOILS eight or nine inches deep. If the soil is damp and it is desired to dry and warm it for an early plant- ing, say of corn, it should be plowed more shallow than ordinarily. This is not advocating shal- low plowing for heavy lands in general, but stat- ing what may be done in certain cold, wet and late seasons. Eight inches may be considered deep plowing for many soils ; rarely is it practicable to plow more than eleven inches deep. Most field crops feed much more deeply than is commonly realised. Corn, parsnips and sweet potato roots occupy the ground to a depth of four or five feet and may go several feet deeper, depending upon the nature of the subsoil. It is safe to say that, on an aver- age, the roots of field crops forage five to six feet deep. But most of the feeding roots are in the plowed ground, because this is the richest, warmest and the best ventilated part of the soil. Therefore, the deeper the soil is plowed, within certain limits, the greater will be the productivity, because more of this congenial pasturage is provided for the roots. Subsoiling. — The subsoil sets a limit to the depth at which certain soils can be plowed. It may be yellow or of a different nature than the surface mould, and contain a large amount of raw plant food. If much of this raw soil is mixed with the surface soil the productivity of the land is apt to be seriously reduced for a number of years, or until weathering has acted upon the subsoil brought to the surface. About 1850 there was a widespread discussion in this country on the advantage of deep plowing. It led to the introduction of an implement with two plows upon one beam; a small one which turned a furrow three or four inches deep followed by a larger one which ran six 45. AN IDEAL PLOW FOR ORDINARY WORK This is the plow used in Fig. 44. Note the lines of the mouldboard, the angle of the handles, and the jointer, beam wheel, and clevis 46. A CHEAP AND RATHER INEFFECTIVE WOODEN-BEAM PLOW Compare mouldboard with preceding and note absence of overhang. Too shallow- working for any work but furrowing out for planting METHODS OF PLOWING 125 or eight inches deeper, turning its furrow-slice upon that of the smaller plow. These plows proved impracticable, chiefly because they left the raw subsoil on top of the ground and buried the rich surface soil at the bottom of the furrow. The introduction of the subsoil plow, a little later, remedied this fault. This follows the plow and stirs the soil in the bottom of the furrow to a depth of five to ten inches, but does not bring it to the surface. There are two types of subsoil plows. One is shaped something like a harrow tooth ; the other consists of a wedge-like shoe on the lower end of the bar. There is much difference of opinion concerning the value of the subsoil plow in general farming. It is not used nearly as much as it was fifteen years ago. The general conclusion seems to be that it is of service only on the heavier soils, which need better aeration and need to be deepened. But the soil that is loosened by the subsoil plow quickly falls back and becomes compact again, so subsoiling affords only tem- porary relief. Moreover, subsoiling may be a positive injury to some soils by destroying the earthworm burrows that effectively aerate and drain the subsoil. The lessened appreciation of the subsoil plow in recent years is due largely to the more general practice of under-drainage. Under-drainage loosens, deepens and aerates the soil permanently and to a much greater depth than subsoiling. Subsoiling should follow, not precede, under-drainage. It augments every good effect of drainage. At present the use of the subsoil plow is confined mostly to fairly well-drained lands which have a hard and dry subsoil; and for breaking up a hard-pan that is close to the surface. Subsoiling is usually in- 126 SOILS jurious to a wet, clayey soil, making it puddle. It is practised chiefly for crops that nave long roots, notably for parsnips and carrots. The cost of subsoiling is from $1.50 to $3.00 per acre, or fully as much as the cost of plowing. It is customary to subsoil about every third or fourth year. Deeper Plowing Desirable. — The probability is that the future improvements in plows will be largely along the line of increasing the width and depth of the furrow without adding much to the draft. The farmers of a century hence will stir the soil deeper than we do, and so have more of it directly under their control. But many farmers of to-day do not plow nearly so deeply as they might and ought. This is especially true in the South, where the one-negro-one-mule-one-plow combination is thought to be the best solution of the problem. One mule can hardly furnish power to turn even four or five inches of soil. A large proportion of the Southern soils are clay, especially in Tennessee, Georgia, Alabama and Mississippi. These clayey soils, being very fine grained, absorb water very slowly. Hence, if they are not loosened and deepened by deep plowing the rains quickly overflow them and the surface drainage washes away the fine, rich soil and the fertility of the land with it. There are other causes of this washing (see Chapter XI), but shallow plowing is now and has long been one of the principal causes. Farmers in other parts of the country are losing nearly as much by persisting in the old-time shal- low plowing of four or five inches, when they might easily double the feeding pasturage of their crops. Many of the farmers of the western prairies, in Nebraska, Dakota and contiguous states, plow very shallow. Sometimes the land is plowed only three METHODS OF PLOWING 127 to four inches deep — sometimes it is not plowed at all for a year or two, the surface being simply scratched sufficiently to cover the seeds. When the tough prairie sod was first broken in the pioneer days, about seventy-five years ago, it was necessary to plow very shallow. The great " prairie breaker" of those days had a beam nine to ten feet long, was pulled by eight to twelve yoke of oxen, and turned a furrow 18 inches to two feet wide and not more than 2 or 3 inches deep. This served its purpose admirably, but as soon as the native grasses were subdued it was seen that deeper work- ing plows were needed. Shallow-working "sod plows*' are still used for subduing sod. Prairie soils are so open in texture and rich to such a depth that deep plowing does not give the beneficial results that it does in many other parts of the country. But it is quite certain that in the long run it pays to plow these soils deeper than the mere surface scratching that is now given to many of them. DRAFT IN PLOWING The power that it takes to plow, and the amount of draft required, have an important influence on the depth of plowing and the amount of pulverisa- tion accomplished. Experiments by Anderson showed that it takes 55 per cent, of tne total draft in plowing to cut the furrow slice, and 12 per cent. to turn it; the 33 per cent, remaining is used in the friction of the sole and the landslide. An old share point makes plowing as hard work for three horses as a new point does for two. The use of a bold mouldboard increases the draft very slightly, not over 2 or 3 per cent, more than when a straighter mouldboard is used. This is a small price to pay 128 SOILS for the much greater efficiency of the bold mould- board. A plow not adjusted properly may require 50 per cent, more energy to move it. The investigation of Sanborn, in 1888, showed that the use of a coulter or jointer increases the draft and the use of a beam wheel decreases the draft. He also found that the deeper a plow works, the less draft it requires in proportion to the size of the furrow-slice. That is, it does not take twice as much power to turn a furrow 8 inches deep as to turn one 4 inches deep, but less than this — about 10 per cent, for each additional inch in depth, according to results at the Utica Plow Trial in 1867. Likewise the wider the furrow the less power is required in proportion to the soil turned. With a bold mouldboard a furrow may be turned two or three times as wide as it is deep; if the mouldboard is less overhanging it is necessary to turn narrow furrows in order to leave the soil in good shape. Heavy Teams Do Better Work. — It is a mistake to plow with a light team, and nothing but the most shallow and least efficient plowing can be done with a single horse or mule. A light draft not only makes the plowing more shallow than if a heavy team were attached to the same plow, but the plow works in a jerky manner, and it is harder for both team and man. Roberts says: "If the little plow turning a furrow only nine or ten inches in width and six inches deep could be exchanged for a plow capable of handling a furrow sixteen inches wide and ten inches deep; and the two 900 pound horses replaced by three of 1,200 each, the necessity for subsoiling would be obviated and the cost of plowing diminished rather than 47. SHIFTLESS PLOWING IN NORTH FLORIDA The land is plowed only where the rows of the crop are to go; after the crop is growing the farmer "breaks out the middles" 48. A TURNING UNDER THICK HERBAGE WITH THE AID OF A CHAIN One end is fastened to the beam, the other to the doubletree 49. THE APPEARANCE OF LAND AFTER FALL PLOWING Soils that "puddle" should not be plowed in the fall 50. THE APPEARANCE OF THE SAME LAND THE FOLLOWING SPRING The soil has been weathered and the texture improved. Fall plowing also promotes earliness METHODS OF PLOWING 129 increased, wherever the fields are large and fairly level. The larger team could get through three acres while the smaller is getting through two; thus, by adding one-half more to the daily cost of the team, without any increased expense for plow- man, half as many acres again will be turned, and much better." Horses that walk fast are better than a slow team, not only because they cover more ground, but also because they do better work; the faster the plow moves, provided there are no obstructions, the better is the soil pulverised. Large level fields are plowed better and quicker with a two or a three shore gang plow and four to six horses than if the power is divided into three teams pulling three single plows; and the saving of plowmen is worth con- sidering in these times when farm help is scarce. A still greater concentration of power is commonly practised in the West, where it is not uncommon to see fifteen or twenty horses pulling a single gang plow. When two or more teams are used on one plow the doubletrees of the forward teams are chained to the ring of the neck-yoke of the beam team. The Power for Plowing. — Next to the style of plow, the kind and quality of the motive power is the chief factor that controls the depth and thor- oughness of plowing. In America the ox, horse and mule are used almost exclusively, being the cheapest. Traction engines are quite frequently used in the West, especially in the arid and semi- arid regions. In many cases steam power has not been as satisfactory as horse power, because it costs more — horse flesh is cheap in this country. In Europe, where horses are dearer and machinery cheaper, steam power is often more practicable. 130 SOILS Either a traction engine or a stationary engine is used. The former is run back and forth across the field dragging behind it a gang plow with six to twelve plows. A 25-horse-powerengine is commonly used. A steam plow outfit complete costs from $2,000 to $4,000. It is run by two men and plow- ing usually costs about 50 cents an acre as against 75 cents io $1 by team. The stationary engine runs the gang plow by means of wire cables. The traction engine has been found more practicable in this country than the stationary engine, but the latter is used more commonly in Europe. There, too, electricity is used as a power for plowing. Some German fields are plowed with power se- cured from an electric trolley which is stretched above the field, giving, it is claimed, a cheaper and more satisfactory power than steam. Steam, electricity or any other machinery power will not become a very important feature in Amer- ican plowing for many years to come, except in the West. It is solely a question of economics — what kind of power is cheapest. Horses and mules are the cheapest power at present on the majority of American farms. We would naturally expect that machine power will first become practicable in this country where farming is done on a very large scale, and where the land is suffi- ciently level to make machine plowing feasible. The great farms of the western plains furnish these conditions and here steam plows are becoming common. However, in view of the recent astonish- ing developments in farm machinery, it would not be surprising to see within a quarter of a century some kind of a small power plow adapted for the farmer who tills less tnan a hundred acres. One can even imagine the small farmer of fifty years METHODS OF PLOWING 131 hence riding over his field in a sort of automobile plow and handling it with brake and lever. There have been more remarkable improvements than this within a generation. But certain New England fields, at any rate, will never be plowed with an automobile plow unless the rocks in it weather with remarkable rapidity during the next few decades. It is more than likely that a willing team of Clyde or Percheron horses and a skilful man guiding the handles of a good walking plow, will be, for many years, the cheapest and most effective method of getting the soil ready for a crop on 90 per cent, of American farms. THE ESSENTIALS OF A GOOD PLOW There are many styles and makes of plows, each different from the others in some respect. The kind of plow that should be bought depends upon the use for it and upon the way it is built. Do not buy a plow by its name or the reputation of the firm, any more than you would buy fertiliser by brand or a cow by pedigree. The essential parts of a good plow are briefly discussed below: The Beam. This may be of iron, steel or wood. A wooden beam is cheaper and lighter than a metal beam; for these reasons a majority of the plows now found on farms have wooden beams. Walnut and ash make the strongest plow beams. Steel beams, which are much lighter than iron beams, are rapidly replacing wooden beams, being much stronger. The Mouldboard is the most important part of a plow; its shape should be studied carefully by a plow buyer, so as to note how it will lift, turn and pulverise the soil. The general shape of the 132 SOILS mouldboard should be spiral. This most important principle in the construction of the mouldboard was first stated clearly in 1839 by two plow makers, Samuel Witherow and David P.ierce. "The main object is to pulverise the soil, and the only way in which it can be effected is by bending a furrow-slice on a curved surface forward so that it shall be twisted, somewhat in the manner of a screw/* The more nearly spiral a mouldboard is, the more completely will the soil be inverted, but it is not pulverised to any extent. The extent to which the mouldboard pulverises depends mostly on the steepness of its upward curve and the abruptness of its outward curve; that is, the upper or rear end is curved more sharply than the lower or forward end. This "bold mould board," as it is called, draws slightly harder and clogs a little more than those having a more moderate curve, but its much greater effectiveness in pulverising the soil more than compensates for these objections. The abrupt mouldboard is adapted for nearly all plowing, except for the fall plowing of clayey soils and for breaking new land, when a plow having a long and gradually sloping mouldboard is more effective. The Coulter, or cutter, may be in the form of a knife or a rolling disk. The disk coulter is usually more useful than the knife coulter, which clogs easily. It is especiallv serviceable for plowing under litter, as cornstalks and straw, which it rolls down and cuts. The jointer, however, is now used more for this purpose. The Jointer, or skim coulter, is a most service- able attachment, especially when stubble, grass or manure are to be turned under. When herbage is plowed under without a jointer there is likely to METHODS OF PLOWING 133 be a line of it left between the furrows. It skims a shallow furrow and deposits the herbage in the bottom of the furrow where it is covered by the furrow-slice of the mouldboard. It also pulverises the soil, if set deep enough to keep the furrow-slice from turning too flat. Both coulter and jointer increase the draft and should be kept sharp. The Beam Wheel, or truck, which is attached to the end of the beam, is useful simply for steadying the plow. It should not be used to regulate the depth of the furrow, for if it is set low in order to make the plow turn a shallow furrow, it acts as a brake. If it is used merely to make the plow run more steady by reducing the effect of the motion of the horses, whiffletrees and eveners, it reduces the draft to a considerable extent. The Share, or plow-point, cuts the bottom of the furrow-slice from the land. It should be kept sharp, especially if grass or other roots are to be cut. The draft of a plow with a dull share is about 7 per cent, greater than the draft of a plow with a sharp share. Shares may be renewed or sharpened. The Clevis, or bridle, is the metal attachment at the end of the beam used to regulate the depth and width of the furrows. The hitch on the clevis is raised to increase and lowered to decrease the depth; the clevis is swung to the right to increase width and swung to the left to reduce it. The clevis on swivel plows is changed by a lever from the handle. With some plows the change is ef- fected by moving the beam at the handles. Some plows have only notches in the clevis for holding the draft ring. There is a double clevis in use. In brief, the characteristics of a good plow are these : It should be as light as is consistent with de- sired strength. It should run steadily and have 134 SOILS as light a draft as possible. It should pulverise the soil as well as turn it. WHEN TO PLOW Most plowing is done either in early spring, just before the planting of the crop, or late in the fall. The chief factor that decides this question is that of convenience. The best time to plow, however, depends upon the climate, the soil and the crop, as well as upon the convenience of the farmer. It is not necessarily the same for adjacent farms. Fall Plowing. — Land is plowed in the fall chiefly in two cases ; to improve its texture and to prepare it for fall seeding. Clayey soils, if not liable to puddle, are benefited most because it exposes them to weathering. Sandy soils may be greatly in- jured by fall plowing, because they are already too leachy. Where there is danger of washing from plowing clayey soils in the fall Roberts recom- mends that single furrows be drawn across the field about four or five feet apart; as, for example, between rows of corn. These improve the soil by weathering, make it earlier and it does not run together or puddle. These furrows are easily levelled in spring with a scantling chained cross- wise under the front end of the harrow, and driven lengthwise of the furrow. This makes more work, but it pays on cold, wet clays. It should never be practised on any soils that wash badly during the winter. Fall plowing is practised more in growing wheat and other cereals, and in market gardening, than for other crops. It is an almost universal practice in many sections of the West. It should be done early, when the ground is fairly dry. An incidental METHODS OF PLOWING 135 advantage of fall plowing, in some cases, is that it destroys wire- worms. Land for fall seeding should be plowed, if possible, two or three weeks before sowing. Lap-furrow plowing is preferable. Land plowed in the fall may be benefited by being plowed again in the spring before being seeded ; but usually a good disking is sufficient. The Spring Plowing. — Spring plowing should be done early, before the days when a hot sun and drying wind suck from the unplowed soil much of the water that the crop could use to great advan- tage. A soil may lose as much as twenty tons of water per acre weekly by being left unplowed late into the spring. This is equal to 1.75 inches of rainfall. Early plowing also dries and warms the surface soil so that it may be planted early. Further- more, the earlier soil is plowed, the more spring rain it catches. If the land is covered with a catch crop there are additional reasons for plowing it early; the herbage will decay better, and if the catch crop is one that lives over the winter, as rye, it will be prevented from reducing the supply of water in the soil by its spring growth. The popular rule "Plow as early in spring as the ground works up mellow" epitomises the experience of many generations of farmers. The exact time to plow in spring depends mostly on the wetness of the soil. If the soil is light and porous it may be plowed, oftentimes, two or three weeks earlier than heavy soil on the same farm. Not till the soil crumbles readily when turned up in the furrow-slice is it in the best condition for plowing. If it is turned over in clods there will be trouble. The texture of a clayey soil may be nearly ruined by plowing it once or twice when it is wet; the soil is thrown into great clods which 136 SOILS it may take several years to mellow. There is always a tendency to plow heavy soils too early, when they are wet, since early plowing means so much to the success of the grains which thrive best upon these soils. On the other hand, it is equally unprofitable to plow when the soil is very dry, as such a soil is likely to be puddled by rains when the lumps have been pulverised by the harrow. In both fall and spring plowing it is al- ways better to plow a week or more before seeding so as to allow the loose soil to settle, thus increasing its ability to supply film water to the seed. WHEN PLOWING IS DISPENSED WITH In a few sections of the country, especially in the Southeastern States, some farmers have a way of plowing only one or more furrows where each row is to be. The crop is then planted and the ground between the rows is plowed later. This "breaking out the middles" is a back-handed way of plowing, for the soil cannot be plowed and fitted nearly as conveniently and thoroughly after the crop is started as when the land is unoccupied. The only excuse for this practice is a rush of work at planting time, and it is doubtful if even this ought to be valid. There are occasions when it is best not to plow at all. If a mellow seed bed can be prepared readi- ly without plowing, and the surface soil is plenty rich enough, the land may be simply harrowed deeply in the spring and sown to the grains, which prefer a compact soil beneath the surface. Farmers in the prairie states sometimes follow this plan. Sometimes land from which beans or other crops have been removed is harrowed in preparation for METHODS OF PLOWING 137 fall seeding of grain. These cases, however, are very rare, as compared with the almost universal experience that thorough plowing is the best prep- aration of a seed bed. USEFULNESS OF THE DIFFERENT KINDS OF PLOWS There are a number of distinct types of plows > each of which is adapted for certain conditions. Furthermore, there are many makes or brands of each class of plows and these differ widely in construction and in value. The merits of the five most important classes of plows — landslide, swivel, sulky, disk and gang — will be discussed briefly. When it comes to choosing between the different makes of the same type of plow, the buyer must scrutinise the construction of each, especially the mouldboard, as advised in preceding paragraphs. The Landside Plow is the oldest and most com- mon type of plow. Probably five-sixths of all the plows used in the country belong to this class. It turns a furrow only in one direction , usually to the right; and more perfectly than swivel plows, which turn the furrow in either direction. It leaves a dead-furrow, which is no disadvantage on most land, as it assists in drainage. The Swivel Plow is constructed so that a furrow may be turned to the right or to the left, thus mak- ing it possible to plow a field so that all the furrows are turned one way and no dead-furrows are left. It is especially adapted for plowing hillsides, be- cause it leaves no dead-furrow to collect water. For this reason it is sometimes called the hillside plow. For general purposes, however, it is not usually considered quite as efficient as a landside plow. 138 SOILS The Sulky Plow is a plow mounted on wheels, with provision for the driver to ride and to con- trol it with a lever. The plow itself may be a swivel, which is turned at the end of each furrow; or there may be two landside plows, one turning the furrow-slice to the right and the other to the left, these being used alternately so that the plow- ing is back and forth, not around the field, and no dead-furrows are left. The landside construction is usually considered somewhat superior to the swivel construction in sulky plows. Under ordinary conditions the draft of a sulky plow is no greater than the draft of a landside plow doing the same amount and quality of work. A large part of the weight of the plow falls upon the axles, so that the friction on the sole of the plow is greatly relieved. A sulky plow weighing three ot four times as much as a landside plow does no: pull any harder, even with a man mounted upon it. If the soil is soft, so that the sulky wheels sink into it or clog, the draft is increased. Two heavy horses can pull it, but three are better. A good sulky plow, properly adjusted, should turn as even and deep a furrow as a landside plow, and soire- what wider. If the soil is hard or rooty, it keeps in the ground better than a landside plow. Tiis type of plow is of service only on comparatively level land; it is not practicable on hilly and ro:ky land. The mechanism of a sulky plow is not difficult to operate nor does it get out of O'der easily. Wherever it can be used to advantage the sulky plow saves the time and strength of the pow- man; it is being used more every year by Ameiican farmers. The Gang Plow differs from the sulky plow chiefly in the fact that it turns more than one firrow METHODS OF PLOWING 139 at a time. From two to twelve plows are mounted upon a frame, all turning furrows the same way, one following another. The sulky gang plow pro- vides a seat for a man; others have handles, like a landside plow, and are guided by the plowman. The latter commonly have two to four plows, run on low wheels. Some of the largest gang plows are reversible, like a sulky plow; they have two gangs, one right hand and one left hand. Gang plows are practicable only where there is a large area of fairly level land to be plowed. In this country they are used chiefly for plowing in the West. The chief saving that they effect is in decreasing the number of plowmen and in getting a larger area plowed when the weather and soil are suitable. Power is furnished by horses, mules, or steam, principally by horses but frequently by steam in this country. A steam gang plow, combined with a seeder and harrow has reduced the time required for manual labour in plowing, seeding and harrowing, in the production of a bushel of wheat, from 38.8 minutes in 1830 to 2.2 minutes at the present time; and the cost of human and animal labour for the same operations, from four cents to one cent per bushel. It takes from six to eight horses to handle a four-furrow gang plow. When adjusted right a gang plow should do as good work as a sulky or landside plow. It is probable that they will be used to an increasing extent in this country, especially in the West; but the sulky plow is better adapted for average conditions in the East. Disk Plow. — This implement is beginning to be used quite extensively in arid and semi-arid farming. It consists of a tempered steel disk, either single or in gangs of two or more, which is 25 to 30 inches 140 SOILS in diameter and set at an angle to the surface of the soil, so as to invert and pulverise it. The disk is kept from clogging by an adjustable scraper. It is mounted on wheels and provided with levers, as in a sulky plow. The disk plow is commonly used with steam power. It is especially valuable for hard, sticky soils, and has been found most practicable in "dry farming" in the West. It does not appear that it will supplant the mouldboard plow in the East, but it can be used to advantage in humid regions for breaking up the "plow bed" or "plow sole" formed by plowing heavy land with a mouldboard plow at the same depth for several years. ADJUSTING THE PLOW IN THE FIELD A good plow, handled or adjusted improperly, is no better than a poor tool. The same implement can do first-class plowing and very poor plowing, according to the skill of the man who holds it. When a plow is taken to the field the first thing to do is to adjust it properly — the adjustment varies with the team, the type of soil and the object sought. It pays to spend some little time in getting a plow adjusted rignt. Professor W. P. Brooks gives the novice at plowing some excellent suggestions on this sub- ject; they are here condensed, and slightly modi- fied: Hitch the team as close to the plow as pos- sible and hitch to the lowest hole in the clevis. Start the plow and note whether the furrow is sufficiently deep; if not, hitch higher one hole at a time until the plow cuts at the right depth. If the furrow-slice is turned over flat, and a lap or rolling furrow is desired, it may be because the METHODS OF PLOWING 141 furrow is too wide in proportion to its depth; to correct this, the clevis must be moved to the left. If the furrow stands too nearly on edge it is narrow in proportion to its depth; move the clevis to the right. A plow that is properly adjusted should run in the soil for some distance without being held, cutting a furrow of even depth and width, provided the soil is free from stones and other obstructions. If it will not do this either the plow is a poor one, or, what is more likely, it is not cor- rectly set up or adjusted. When it runs all right, lower the beam wheel until it just touches the sur- face. Thus adjusted the plow will do its best work as easily as it can be made to run. CHAPTER VII HARROWING AND CULTIVATING EVEN the best plowing is but the beginning of good tillage. Unless followed by thor- ough harrowing and, for crops planted in in rows or drills, by thorough cultivation, the har- vest is likely to suffer. The necessary tillage sub- sequent to plowing is of two kinds. The first is fitting the land to receive the seed, by harrowing, rolling, planking, brushing, etc. This tillage be- fore the crop is planted, together with plowing itself, is sometimes called "the tillage of preparation." After the crop is planted the only kind of tillage needed is cultivating, called "the tillage of con- servation," because its chief function is to save, or conserve, the soil water. This distinction is made to emphasise one very important fact; that if the tillage of preparation is judicious and thorough, the tillage of conservation will be easy and effec- tive. The best cultivating cannot atone for hasty and imperfect harrowing. Many of the tools used for harrowing are equally valuable, in a modified form, for cultivating, since the main object of both is the same — to stir and fine the surface soil. OBJECTS OF HARROWING The plow leaves the soil in a rough condition, too rough and hard, in most cases, for planting. Some light sandy soils are so completely pulverised and levelled by good plowing that 142 HARROWING, CULTIVATING 143 they are sometimes seeded without being har- rowed, but this practice is rarely profitable. The plowed ground must be loosened and pul- verised so that the seeds will touch moist grains of soil on all sides, instead of lying between clods and lumps. The chief object of harrowing, then, is to make a fine and mellow seed-bed. In so doing it increases fertility, prevents the evaporation of soil water, makes the soil warmer and accomplishes all the other benefits of tillage. That the harrow teeth fertilise and water the soil as well as fine it, is a figure of speech that is based upon realities in the field. Harrowing may also be a means of covering the seed and of killing weeds. Better Harrowing Needed. — The necessity for harrowing more thoroughly than is commonly done needs to be repeated and reemphasised. Some farmers are content with one or two har- rowings, or merely enough to break up the largest lumps and enable the seeds to germinate. But that is not enough. We harrow to increase the feeding area of the roots all through the season by giving them finely divided soil in which to spread. We harrow to put the soil in the best possible con- dition to catch and hold the rains. We harrow to warm the soil, to aerate it and to promote the activity of the germ life that is so essential to its fertility. This means that the ground should be gone over more than is necessary to merely break up the lumps so that the seeds will germinate. It means harrowing and cross-harrowing, three times, four times, six times if necessary ; or until all of the upper four or five inches of soil upturned by the plow has been made as nearly like an onion bed in mellowness as the texture of the soil will permit. 144 SOILS It does not pay to skimp harrowing in the rush of the busiest season of the farmers' busy year. A farmer once told me that every time he went over a certain piece of land with his cutaway harrow, in preparing it for corn, he received more than seventy- five cents an hour for the work when the ears were bushelled. Of course there is a limit, for every soil, to the number of times that it will pay to harrow it. Eight harrowings might give a larger crop than three harrowings, but would the increase be enough to justify the expenditure ? It is worth while for every farmer to find the point where better tillage ceases to be profitable on his soil. When he ascertains this he will be surprised to find how far this limit is beyond the common practice of the neighbourhood . KINDS OF HARROWS AND USEFULNESS OF EACH Harrowing tools are of innumerable patterns. Most any ingenious farmer can make a harrow that will do good work. There used to be a great many home-made harrows and cultivators, but now the patent implements are so reasonable in price and superior in efficiency that it scarcely pays to get one made by the local blacksmith. All harrows and cultivators are of four general types. The first class, represented by the spike- tooth harrow, press the soil down while pulver- ising it. The second class, represented by the spring-tooth harrow, lift the soil while pulverising it. The third class, represented by the Acme harrow, slice the soil and lift and turn it some- what. The fourth class, represented by the cut- away, roll over and cut the soil. There are 52. A HOME-MADE SPIKE-TOOTH HARROW, IN TWO SECTIONS This type of harrow is unexcelled for putting on the finishing touches in fitting land. It is not efficient on a stony or soddy soil 53. A SULKY HARROW The middle teeth can be removed so that the implement will straddle a row of plants, then becomes a cultivator HARROWING, CULTIVATING 145 numerous variations of and gradations between these four types. Some soils are benefited most by a type of har- row which may be almost valueless for other soils near-by; hence we have farmers who would not use any other harrow than a cutaway and spike- tooth, because these especially suit the soil on their farms. They even dispute with neighbours who have a different kind of soil and who think nothing is equal to a spading harrow and an Acme. More- over, they may be growing a different kind of a crop, which may mean that a different preparation of the soil is needed. The fact is there is no best harrow any more than there is a best plow or best breed of cows. The best harrow is the one that prepares a particular soil for a particular crop most satis- factorily; and soils and crops differ about as much as the farmers that handle them. The farmer should experiment with several types of harrows and find the best for his purpose. The Spike-tooth Harrow is a most efficient tool under certain well-defined conditions. There are more home-made spike- tooth harrows on Ameri- can farms than any otner tillage tool. Some of the older home-made spike-tooth harrows are square, but more commonly they are A-shaped, with teeth set vertically on the side pieces only and a horse- shoe nailed to the nose for a chain ring. These harrows did imperfect work as compared with the spike- tooth harrows of the present time. Recent improvements in this time-honoured tool have greatly increased its usefulness. These are the addition of many more teeth; providing that they may be adjusted to run either vertical or slanted backward at various degrees; and making the har- row in several sections, which facilitates cleaning 146 SOILS the teeth of entangled weeds. The implement is now made with a steel or iron frame, usually rectangular, and should be provided with a shoe. The more the teeth slant backward the more shallow do they work and the greater is the smooth- ing effect of the tool. The teeth should be set straight only when it is desired that they work deeply and tear up the soil. The size of the spike-tooth harrow varies from a single six-foot section to the forty-foot wide smoothing harrow of many sections that is used on prairie grain fields. The latter are drawn by four to six horses and cover thirty to forty acres a day. The width of all harrows has increased in recent years and is still increasing in obedience to the same demand that has given us gang plows. The wider a harrow is the steadier it runs. Usefulness of the Spike-tooth Harrow — The spike-tooth harrow is seldom used now to tear up rough-plowed ground, as it was some years ago before improved harrows were available. The old time spike- tooth harrow had a few long, heavy teeth which tore up sod quite effectively, especially when weighted with rocks, or pro- vided with a platform for the driver. At the present time most spike- tooth harrows are of the type called "smoothing harrows," having numerous small and short teeth. When the teeth are so short that the bar in which they are set scrapes the ground when it is in use, the implement is often called a "drag." This type of harrow is chiefly valuable for one purpose — to put the finishing touches on a piece of land that needs to be made very mellow and very level for seeding. It is usually preceded by a stronger and deeper- working tool, as a disk or spring-tooth harrow. 54. A SPRING-TOOTH HARROW The depth at which it works is regulated by the levers. It is often made larger than this. The same tool is used as an orchard cultivator 55. THE WORK OF A SPRIXG-TOOTH HARROW It is particularly serviceable for loosening a compact soil, as the teeth pull up, and is a valuable tool on stony, cloddy, and soddy land. It is often desirable, however, to level off the high ridges left by a spring-tooth harrow "SWEEPS" ATTACHED TO A PLOW-STOCK, FOR "LAYING BY" CORN They cut off large weeds, but injure roots and leave the soil ridged 57. THE EFFECT OF USING THE ABOVE TOOL FOR CULTIVATING A COTTON FIELD Note the high ridges from which much water evaporates, and the deep furrows which favour the washing away of fine soil HARROWING, CULTIVATING 147 A second occasion when a spike-tooth harrow may be used to advantage is in tilling a crop before it has come up, or even afterwards. Land in corn or potatoes, for example, may be run over a few days after planting with a shallow-working spike- tooth harrow with the teeth slanted backward; this will kill the young weeds and check the escape of moisture. This kind of tillage can be repeated to advantage every few days until the plants are two or three inches high, or until they are bruised by passing between the teeth. The spike-tooth harrow presses down into the soil and compacts it more than most other har- rows. It has something of the effect of a roller. For this reason it is somewhat more useful on light, sandy soils which need compacting, than upon heavy soils, although its compacting effect is not sufficiently injurious to warrant its being discard- ed for finishing and smoothing the heavier soils. Spring-tooth Harrow. — The curved spring teeth of this popular tool enable it to clear obstructions easily; for this reason it is especially valuable on stony, rooty or stumpy land. The teeth can be set by a lever to run at various depths; this also affects the quality of the work done. The spring- tooth harrow leaves the soil in ridges of consider- able height, which is a disadvantage in many cases, as it causes the soil to lose more water from the greater surface exposed to evaporation. This objection may be overcome by following it with a smoothing harrow. A section of smoothing har- row is frequently attached behind the spring- tooth harrow, or a joist or plank, say 2 inches by 6 inches, or a heavy iron pipe may drag behind it. Any one of these devices is quite successful in levelling the ridges left by the broad teeth. 148 SOILS The spring-tooth harrow is a good implement for rough work, and especially for stony ground. It is very popular for orchard tillage, partly be- cause the teeth spring over the roots with little damage to them. It is not so serviceable when sod, green manure, or a large quantity of strawy manure has been plowed under, as the teeth are likely to dig out part of this material and leave it on the surface. On rough land the spring-tooth harrow is jerky and hard upon the horses' shoulders. The draft of a spring-tooth harrow set moderately deep is about equal to the draft in plowing, but it is easier for a team to plow all day than to pull a spring- tooth harrow all day, because the plow runs more evenly. The jerkiness of the common type of this harrow — in which all the weight rests upon the teeth — is largely overcome in a more recent form, which is mounted on wheels. All the weight of this implement rests upon the wheels, thus allow- ing the teeth to pull up and loosen the soil, and re- lieving somewhat the unevenness in draft. Even the common type of spring-tooth harrow, however, leaves the soil lighter than most other harrows because of the upward pull of the teeth. It is this advantage, as well as durability and the ease with which obstructions are cleared, that makes the spring-tooth harrow so popular. It can be bought by sections in various sizes; the wider it is, within reasonable limits, the cheaper will the harrowing be done. Acme Harrow. — This is the most noted repre- sentative of a type of implements known as the coulter harrows, so called because they have teeth that have been twisted, somewhat resembling a plow coulter. The teeth first cut the soil, HARROWING, CULTIVATING 149 then raise, turn and pulverise it, doing the work of a plow on a small scale. It has been stated that the plow makes the best mulch to prevent the escape of soil water. The great efficiency of the Acme and similar harrows rests upon their appli- cation of the cutting, raising and pulverising action of a plow. In the judgment of many people the Acme harrow will give satisfaction over a wider range of conditions than any other type. It will work from one to four inches deep, as is desired. Following the plow it breaks up the furrows as well as any other tool unless the land is rocky or the sod tough, in which case a disk or spring- tooth harrow is better. It leaves the soil nearly as level and mellow as a smoothing harrow. Rolling Harrows. — Harrows of this class have one or more revolving shafts to which are attached a number of disks, which are either entire, as in the common disk harrow, or notched, as in the spading and cutaway harrows. These harrows work deeper than harrows of any other class. They are especially valuable for working heavy soil, tough sod and intractable land of any sort. Two things decrease their value for estab- lishing a soil mulch — they leave the soil in rather high ridges, which evaporate much moisture; and, if not adjusted properly, the disks do not stir all the surface, but leave a triangle or cone of unstirred soil. The ridges may be levelled by dragging a section of a smoothing harrow or a heavy joist be- hind, but the draft on harrows of this type is heavy enough without this additional burden ; it is some- what greater than a plow, in most soils. Usually the disk, cutaway and spading harrows should be used only to do the rough work of fitting 150 SOILS the land; to tear it and bring it up to the point where an Acme or smoothing narrow can be used to advantage. They are sometimes used as a sub- stitute for the plow, when deep tillage is not necessary or is not practicable; as to tear up the sod in an old orchard that it is proposed to culti- vate, or to fit land for fall wheat after a crop of beans has been harvested. Some Western farmers fit the land in spring for the cereals, using one of these harrows which can stir the ground 5 inches deep. The great trouble with any one of these rolling harrows, in the hands of a careless workman, is that the disks will be so set that they plow out wide, deep groves, leaving untouched ridges between them, which are lightly covered with loose soil. In order to completely stir the soil and establish an efficient mulch the disks should be set so that they will enter the soil at a wide angle. Rolling harrows are made in two sections or gangs and the gangs throw dirt in opposite directions, usually from the centre outward. This makes it necessary to overlap in order to keep the ground level, but a better way is to level it with a smoothing harrow. The comparative merits of the three leading rolling harrows — the disk, cutaway and spading — is the subject of much needless dispute. Some farmers are partisans for one and some for another, according to the way it strikes their fancy or the way it works on their soils. In general they handle the soil in about the same way. Probably the disk harrow is used more than the other two at the E resent time, partly because it is less likely to reak. The Meeker harrow, which is used by many market gardeners and truck farmers, is HARROWING, CULTIVATING 151 essentially the same as the disk harrow, except that it has many very small disks permanently fixed in a rectangular frame, instead of a few large ones. It leaves the soil about as smooth as an iron rake and is used solely for preparing a very level seed- bed. WHEN SOIL IS READY TO HARROW In harrowing, as well as in plowing, there is a good deal in catching the soil at the right time. If the land is inclined to be wet and the upturned furrows have a glazed appearance it is well to let them dry before harrowing. Several hours, or even several days, may be needed to bring them to that stage of dryness when the soil will crumble nicely. No other consideration should influence one to harrow before this. It is better to lose some of the water in this soil by evaporation than to run any risk of injuring its texture. On the other hand, if the soil turns over mellow and ready to be harrowed at once the time to catch it is right then, before it becomes dry on top. A delay of a single day in harrowing a plowed field may mean that half an inch or more of the precious water in it has been lost. After the furrows have dried out con- siderably they may become hard and cloddy and will be pulverised with greater difficulty. The soil should be moist, not wet or dry, in order to do the most effective harrowing. Some of the lighter soils dry out very quickly in the furrow, even in an hour or two. If it can be done without too much inconven- ience it is best to harrow these soils within a few hours after they are plowed — certainly the same day. When but one team is plowing on a 152 SOILS light soil it will pay to take it off the plow and hitch it to the harrow early enough to make a mellow seed bed of the furrow-slices before nightfall. This is much better than to defer harrowing until the plowing is finished. The subsoil is compacted in narrowing; this starts capillary action and water is drawn from the soil below, and would escape were it not for the mulch of fine soil left on the surface by the harrow. The compacting effect on the subsoil by harrowing is a benefit on most soils. LEADING TYPES OF CULTIVATORS As the term is commonly used, a cultivator is any toothed implement that is used to stir the soil after it has been fitted, chiefly for the purpose of killing weeds and preventing the loss of soil water. Many harrows are used as cultivators under certain conditions; as when a spring-tooth harrow is used to preserve the soil mulch in an orchard, or when a spike-tooth harrow is used to run over the potato field when the sprouts are still small enough to slip between the teeth without injury. When narrowed down to its most distinctive usage a cultivator is a toothed implement drawn by one horse and used for inter-tillage, or for preserving the mulch between rows of plants. Most of these kinds of cultivators, however, are only small harrows with handles attached, and they stir the soil in about the same way as the harrows that have been described. All kinds of cultivators are some- times called "horse hoes," but this name seems to be especially fitted for the broad-tooth coulter cultivators. The following classes of cultivators include most of those in common use, but there is an almost HARROWING, CULTIVATING 153 endless variation in the details of construction in each class. Shovel-tooth or Coulter Cultivators. — Probably more of the cultivators used in this country belong to this class than to any other. The teeth of dif- ferent cultivators vary greatly in shape and size; nearly all enter the ground at an angle and are rounded on the front side. Many coulter culti- vators work up the soil like a plow, lifting, turning and pulverising it to some extent. The soil is loosened to a depth of two to five inches, depending upon the style of cultivator and upon the adjust- ment of the lever with which many coulter culti- vators are provided. The surface of the soil is left either quite level or in rather high ridges, de- pending upon the width of the teeth. The wider they are the rougher they leave the soil. Cultivators with about five broad teeth work the ground deeply and are especially valuable for loosen- ing heavy or compact soil ; but for the purpose of killing weeds or preserving a mulch, a cultivator with more and narrower teeth is much better. There are too many broad-toothed, deep-working cultivators used and too few narrow-toothed shallow- working tools. Each kind is most useful for a certain definite purpose ; the one for loosening a hard soil, as after planting or after a beating rain; the other for preserving the shallow mulch that is the most useful and economical kind of tillage during the summer. Various attachments accom- pany coulter cultivators, such as wings for hilling or ridging, and rolling disks to cut off strawberry runners. Spike-tooth Cultivators. — Implements of this class have become very popular in recent years, and deservedly so. The spike-tooth cultivator is 154 SOILS simply a spike-tooth harrow, shaped like an A, with handles attached. It may be worked shallow and leave the surface very level; for this reason it is considered one of the best tools for preserving the soil mulch after it has been made by deeper Working tools. The teeth may be straight on one end and bent forward on the other and it should be easy to reverse the ends. The bent end works deeper. Most makes are also provided with a lever to regulate the depth at which the teeth work. The spike-tooth cultivator is not a good implement for killing weeds except when they are less than half an inch high. It is preeminently a tool for making a mulch. If weeds get a start the broader teeth of the coulter cultivator will up- root them much better. The advantage of using a spike-tooth harrow as a cultivator for stirring the entire surface of the soil, where corn, potatoes, peas, beets and many other crops have been planted, has already been alluded to. Many people are afraid to use this harrow for this purpose, thinking it will pull up the crop as well as the weeds. But little if any injury to the crop results from this harrowing, chiefly because the seeds of the crop have been planted deeply and the soil firmed around them; while the weed seeds are mostly on or near the surface; hence young weeds have a much slighter hold upon the soil than the crop. The harrow may be used for cultivating these crops until they are four to six inches high; it is the most economical culti- vating that can be given. Spring-tooth Cultivators, usually with five teeth, are occasionally used. Like spring-tooth harrows, they work deeply, loosening the soil for four or five incnes if necessary. For this reason they are quite HARROWING, CULTIVATING 155 serviceable on the heavier soils. But the superior value of shallow cultivation has been demonstrated so conclusively that it is doubtful if the spring- tooth cultivator has any advantages over the more common coulter cultivator and spike-tooth culti- vator, except for the specific purpose of loosening a hard soil. It is not as efficient a weed killer as the coulter type of tool. Sulky Cultivators. — Probably 90 per cent, of the cultivators used in the United States are walking coulter or spike-tooth tools, or some gradation be- tween the two. Sulky or riding cultivators are used principally in the "corn belt" of the Missis- sippi Valley and are seen occasionally in the East. In most of them the teeth are in two gangs with a space between for the row of corn or other plants. Two horses are used, one walking on one side of the row and the other on the opposite side, the cultivator wheels straddling the row and the teeth working on both sides of it. Sulky cultivators nearly all have coulter teeth, but a few have spike teeth, spring teeth or even disks. The coulter teeth are preferable in most cases. Disks are apt to work too deep close to the rows. Disk culti- vators are excellent, however, for chopping up and destroying large weeds, if the crop gets very foul. Several different sets of shovels are usually pro- vided, including extra shovels which may be attached so as to run where the row space is left, thus making a sulky harrow which stirs soil for its full width and is used to prepare the soil for planting. The chief advantages of a sulky cultivator are that it covers more ground than a walking implement and saves the strength of the farmer. But it does not do as good work, as a rule, since it 156 SOILS is impossible to guide it so carefully. It always damages the young plants more than a walking cultivator, even when the very serviceable plant guard attachment is used on each side of the row to prevent dirt from being thrown against the young plants. Moreover, a sulky cultivator is consider- ably harder to draw than a walking cultivator. Weeders. — The essential principle of all the several kinds of weeders is one or more rows of long, flexible teeth which stir the ground a good deal like the teeth of a horse rake; not being curved at the lower end, they do not stir it deeply. The teeth are either round or flat. The more common weeders stir a section of soil from six to nine feet wide; there are also adjustable weeders in two sections which stir from two and one-half to seven and one-half feet of soil. Weeders are useful for three purposes — to kill very young weeds; to preserve a shallow mulch after the soil has been loosened by a deeper working tool; and to cover broadcasted seed. They are used chiefly for stirring the entire surface of the ground that has been planted to row crops, as corn, potatoes, parsnips and market-garden crops in general, doing the same work as the smoothing narrow, but not stirring the soil so deeply. The teeth tear up and kill tiny weeds just appearing on the surface, but since the crop plants are anchored firmly in the soil by deeper roots they readily pass between the flexible teeth without injury. A weeder is not effective unless it is used very frequently, or often enough to prevent any weeds from getting sufficiently large to resist the teeth. It cannot be used successfully on stony soil. In some sections, and especially in market gardens, weeders are used very extensively; some truckers HARROWING, CULTIVATING 157 do most of their tillage with them up to the time when the plants get too large to pass between the long teeth without bruising. Since the weeder stirs the soil no more than an inch and a half to two inches deep, it should be supplemented with the cultivator whenever the soil gets hard. This is especially true on the heavier soils, which are apt to get caked beneath the very shallow mulch made by the weeder. The weeder is a special purpose tool, as compared with the coulter culti- vator, which is a general purpose tool. It is most useful in growing crops under intensive culture and on soils of the best texture. CULTIVATING TO KILL WEEDS How often to cultivate depends upon the nature of the soil, the kind of crop, the dryness of the season, the prevalence of weeds, etc. It is a local and personal problem. This much is certain; one should cultivate often enough to keep down weeds, at least during the early part of the season. This advice would appear to be superfluous were it not that so many farmers do not keep down weeds. Weeds injure the plants and reduce the yield in several ways. They crowd and shade the plants, thus keeping part of the life-giving sunshine away from them, making them spindling, like forest pines which are drawn up to a great height in their desperate struggle with each other to get light. They steal food from the plants. Every young corn plant that is being choked above ground by the tops of weeds is also being jostled below by 158 SOILS their roots. These are in every inch of soil that the corn roots have penetrated, disputing with them for its richness. There are many figures on the amount of plant foods removed from the soil by various crops, but how about the amount of plant food taken out of the soil by a big crop of weeds in a potato field ? It is true that the weeds are plowed under eventually, so that the plant food they use is not lost to the soil; but it is lost to that particular crop, anyhow, and the crop would have been bigger if the plants could have had the use of all the surface richness that the shallow-feeding weeds have gobbled up. I like to see a farmer stop his cultivator, even on his way to dinner, to pull up a particularly lusty and arrogant weed. He knows it is robbing him. The insidious drain that weeds make upon the most available fertility of our fields is not appreciated half as much as it ought to be. Weeds Steal Water. — Weeds rob the plants of water as well as of food. They use as much and sometimes more water than cultivated plants in proportion to their size and weight. It is in this way that they inflict the greatest injury to crops. The plant food they use is restored to the land, and perhaps the crop of another year may use it, but the water they use is lost; most of it passes off into the air through their leaves. There are figures on how much soil water is used in growing a crop of corn or potatoes; how much water is used in growing a big crop of weeds between the corn or potatoes ? Perhaps not so much, but certainly nearly as much. Where soil moisture is as important as it is in most parts of the country the 58. THE MOST COMMON* TYPE OF DEEP-WORKIXG COULTER-TOOTH CULTIVATOR It is excellent for breaking a crust and loosening a hard soil, but a shallow-working tool with narrower teeth is better for making a mulch 59. YOUNG CORN IN NEED OF A CULTIVATION This crust, formed by a beating rain, is evaporating water. It should be pulverised into a mulch 60. A CULTIVATOR THAT IS REALLY A PLOW Usually it is unwise to "plow out" corn in this way, unless the soil gets very hard. Plow deeply in spring, fit the land thoroughly, and cultivate shallow thereafter 01. CULTIVATING AT A DISADVANTAGE The rows of corn that cross this steep North Carolina hill must be cultivated skilfully to prevent washing. Note that rows are nearly level HARROWING, CULTIVATING 159 farmer can ill afford to spare water, even to grow weeds that will enrich his soil when plowed under. He had better grow plants to plow under in late fall, after the crop has ceased to need much water. This advice is unnecessary for the majority of farmers, who hate a weed and understand how much it works against their interests. But some farmers appear to have gotten so accustomed to having weeds in their fields that they have come to view them with greater leniency, even with toler- ation. Weeds, like the poor, are always with us; we are liable to grow indifferent to both. Cultivation is the greatest weed-killing device yet known, at least for crops that permit of inter- tillage. Some people are always looking for some new or patent way of getting rid of weeds with little labour, but no good substitute for cultivation has yet been found. In making the earth yield her increase nothing can take the place of stirring the soil. Most weeds are annuals; these are shallow rooted and are easily uptorn by the cultivator teeth. Some, however, are perennials and deeper rooted. These may require special treatment, such as rotation of crops. THE BEST TIME TO KILL WEEDS In cultivating to kill weeds it makes a difference what stage they are in. The vulnerable stages of most weeds are immediately after they have sprouted, and when they are in flower. Some perennial weeds, especially pasture weeds, may be killed best when in flower; but the sprouting stage is the time to attack most weeds on cultivated 160 SOILS land. Weed seeds are mostly in the first inch or two of soil; a very shallow cultivation will expose the sprouting seeds and young weeds to the merci- less sun. Many of the finer-seeded kinds are buried so deeply by a deep-working cultivator that they never come up again, especially if a coulter cultivator is used. It is easy to kill weeds in this way, but it is difficult to kill them after they are so large that cultivator teeth do not uproot them, and cultivating must be supplemented by hoeing and hand-pulling. There is no better illustration of the old adage **a stitch in time saves nine" than in the killing of weeds. It pays to be forehanded in cultivating more than any other work on the farm. The time to start the cultivator is when the ground is covered with tiny weeds, just appearing above the surface, whether it has been six days or sixteen days since the last tillage. A delay of three or four aays, or until the young weeds get their roots established two or three inches deep, means that many of them will not be uprooted by the cultivator. That is the beginning of a foul field. The profit in growing ordinary farm crops depends largely upon the farmer's ability to do as much of the work as pos- sible with horse labour, which is cheap, and as little as possible with manual labour, which is dear. Many farmers have demonstrated that it is easier and cheaper to kill weeds with the culti- vator than to let many of them grow large and then be obliged to hoe and pull them. More culti- vations are necessary, but less hoeings. When Weeds Get a Start. — Weeds are most apt to get a start during the interval between the time that the crop is planted and when it is up. The season may be cold and backward, and ten days HARROWING, CULTIVATING 161 or two weeks may intervene. At the end of this time ground which was mellow and weedless when planted is covered with a dense mat of small weeds. Most of these can be worked out with a cultivator, but some of them are already rooted so firmly that the cultivator teeth do not uproot them. From this beginning may be traced the growth of many a weedy field. In recent years farmers and gardeners have come to appreciate more fully the advantages of harrowing the soil once or twice before the crop is up. Weeders are also used; in small home gardens an iron rake answers very well. In this way the crop starts off clean instead of foul. Where freedom from weeds is as important as it is in growing onions the rows are sometimes marked by sowing a few radish seeds with the onions; these sprout long before the onions and show where the scuffle hoe can go be- fore the onions are up. When the crop is "laid by," or after the last cultivation, is another dangerous time for the prop- agation of weeds. The cultivation of many crops is stopped in early or mid-summer, either because the tops are so large that it would injure them to crowd between the rows with a cultivator, as for potatoes; or because it benefits the plant to grow more slowly during the latter part of the season, as for fruits. This period of relaxation on the part of the farmer becomes the busy season of some weeds. They crowd in beneath the crop and get so firmly established that many of them are on hand to bother the farmer after the next spring plowing. If perennial weeds are allowed to make leaves at any time during the summer or fall they are likely to appear again next spring. There are two ways of handling this difficulty: one is to keep the weeds 162 SOILS cut out with a hoe during the latter part of the season; the other is to sow some catch crop at the time of the last cultivation, to catch and use the leaching plant food and water, to keep the soil from washing and to crowd out weeds. Both are worth being considered by the man who wishes to keep his farm clean. Weed Collectors. — There are other ways of helping to keep down weeds besides cultivation. One of the most important is to change the crop, which is discussed fully under rotation of crops in Chapter XI. Another is to keep fence rows, corners, pastures and all waste places about the farm clean. The fence row around the field is often full of the very weeds that the farmer is fighting by cultivation. Never allow bad weeds to go to seed in these places; mow them frequently. A much better plan, however, is to dispense with the fence, and other weed-catching obstructions, as much as possible. Fences and walls are unsightly and they are a nuisance unless they serve the necessary purpose of keeping out stock. There are many more fences in this country than there is any need of, especially in the older Eastern States. Riding over certain parts of New England, one would think that the farmers of a generation or two ago put in most of their spare time building stone walls, so checker-boarded is the country with them. Of course the stones had to be picked off the land, but surely there was a cheaper way of disposing of them than by laying them up into walls five feet high and three feet thick, around every two or three acres of the farm; to say nothing of the amount of land thus covered and made useless. It is good to see the present reaction from fence and wall building HARROWING, CULTIVATING 163 No more of them are being built now than are needed to confine stock, and portable fences are being used more and more. This adds much to the sightliness and convenience of the farm and much, also, to its freedom from weeds. The Prevalence of Weeds in Sown Crops. — Weeds are most apt to overrun a place when crops are grown that permit of no cultivation. Witness for example, the devastation of the Canada thistle, Russian thistle, devil's paint brush, etc., in the grain fields of the Mississippi Valley. Pro- fessor I. P. Roberts says, "It is believed that the time is not far distant when wheat, oats, barley, and indeed all grains that are now broadcasted or drilled, will receive inter-cultural tillage similar to that now given to maize (corn), and this will not be by hand, as in some portions of Europe, but by horse-hoe tillage." This time is a long way off in America, where tillable land is abundant and cheap, but undoubtedly the drift is in that direction — fewer plants per acre, more tillage, larger yields. When the cereals, now more grievously affected with weeds than hoed crops, are brought under this system of culture, they will be relieved from weeds by the magic that lies in cultivator teeth. Over three centuries ago quaint Thomas Tusser expressed one of the most important facts in the agriculture of his times, and of ours, in the couplet: "Good tilth brings seeds, 111 tilture, weeds." CULTIVATION TO SAVE WATER In the humid sections of our country, if the season is fairly wet one does not need to worry much about cultivating to save water early in the season. 164 SOILS If he cultivates as often as the weeds poke them- selves above ground, which they do with astonish- ing alacrity and in countless numbers after each tillage, he will have established the best kind of a water-saving mulch. This is especially true in a wet May, and most especially true in a muggy, thundery July, when "pusley" starts up from the ground and grows a foot long in a single night, so it seems to our disheartened eyes. But there are times when cultivation is necessary and profitable, when we have few if any weeds to spur us to the exertion. This is apt to be the case during a sum- mer drought when the soil is dried out several inches deep and the weed seeds in the surface soil cannot get moisture enough even to germinate. There are few if any sections of the country where it is not necessary at some time, during an average season, to cultivate for the explicit and sole purpose of preventing the loss of soil water. One season, however, may be so wet that the cultivation that prevents weediness is all that is necessary; the next season may be so dry that the cry of the crop is continuous and loud for more water, rather than for less weeds. Signs of the Need of Cultivation to Save Water. — It is not difficult to tell when it will pay to cultivate, even when there are not enough weeds to justify it on that score. One has only to examine the sur- face soil. If it is hard, baked, cracked, or even if it has only a thin crust, there is work to be done. Soil water passes off rapidly into the air only so long as the surface soil is compact. If this is loosened the water cannot creep readily from grain to grain, and so is held below the layer of loose soil. The first aim of the cultivator, then, especially HARROWING, CULTIVATING 165 when his plants are trying to weather a dry season should always be to keep a few inches of loose soil on top of the ground. When it gets compacted again, as it always does after a while, loosen it again, weeds or no weeds. Eventually the loosened soil falls back into place and becomes com- pacted again by its own weight; but one slight rain will make more of a crust over it than two weeks of settling. That is why it is more difficult to pre- serve a soil mulch in humid regions than in the semi-arid sections of the West. Where there is no rain whatever during three or four months of the growing season there is not much diffi- culty in making and keeping a most efficient dust mulch. In the East, where the cultivation of one day may lose half its value because of a slight shower the following night, it is a more tedious job. However, the Western man needs a better mulch — he has much less water to use and has to guard it jealously. How Often to Cultivate. — There can be no rule as to the frequency of cultivation for saving water except this: cultivate often enough to keep the surface soil at least fairly mellow and free from crust. To do this may take eight cultivations one year and twelve the next year, on the same field. An adjoining field, with soil having a greater ca- pacity to hold water, may give equal results from naif as much tillage. The reliable guides are the way the crops grow and the condition of the soil. When the corn leaves begin to curl in the heat of the day, when the lower leaves of the peas begin to shrivel and droop, when the potatoes look dispirited and the sugar beets droopy, the time has come for some energetic work. If the ground is hard, loosen it deeply with 166 SOILS a shovel-tooth cultivator and smooth it off with a spike-tooth cultivator afterward. Repeat this with the latter tool often enough to keep a mulch over the roots of the plants that will preserve the coolness and water that have been lost to them before. The results of a few extra cultivations in a dry season, as seen in the corn bin or cotton basket, are sufficient to convert any man to the wisdom of mulch-tillage, even when weed-tillage is not needed. HOW DEEP TO CULTIVATE Within ten or fifteen years there has been a very decided movement in favour of shallow cultivation. Experiments have shown quite conclusively that there is as much value, so far as preventing the escape of water is concerned, in two or three inches of loose, surface soil as in four or five inches. This pre-supposes, of course, that the tillage of prepara- tion— plowing and harrowing — has been thorough and timely so that the soil is loosened deeply and pulverised completely. The result has been that many of the old-fashioned, deep-working, hard- pulling and root-cutting cultivators have been relegated to the junk heap, and the shallow-working coulter and spike-tooth cultivators occupy their place in the tool shed. We do not hear so much about "plowing out" crops as formerly — they are cultivated. There are still many unwieldy, plow- like cultivators in use, especially in the cotton belt, but they are fast disappearing. If the soil has been thoroughly loosened and pulverised before the crop is planted there is no need of stirring it more than three inches deep, at the most, after that. Aside from the energy HARROWING, CULTIVATING 167 lost in increased draft, deep cultivation is wasteful of soil water, because it brings to the surface a large amount of moist soil which soon becomes dry. The moisture in this soil might better have been left below where it could have been used by f)lants. Moreover, a deep- working cultivator eaves the soil in ridges, thus exposing more sur- face for evaporation; for some water is lost from the soil even when it is covered with the very best mulch. Furthermore, the valleys made by deep cultivation are the beginning of erosion. Deep cultivation may cut many of the feeding roots of the crop. The roots of plants naturally seek the richest part of the soil. The soil near the surface usually contains the most plant food, because so much soluble plant food has been left there by the evaporation of soil water, and be- cause the surface soil contains more humus, more germ life, more air and more of everything that makes for fertility. In all ordinary soils the largest proportion of feeding roots is found immediately below the range of cultivator teeth, provided that part of the soil is in good texture. In a warm climate plants root deeper than in a cool climate. Deep cultivation during the growing season cuts off innumerable rootlets and root hairs that are foraging in the richest places they can find. To "plow out" a corn field four or five inches deep, in July, is to practise root pruning of a severe character. Some farm crops do not seem to be injured appreciably by this kind of root pruning, but none are benefited by it, and some are injured. Deep tillage may be given the crop early in the season, if necessary, but shallow tillage after it begins to shoot. When- ever the soil becomes hard, as after a beating rain, 168 SOILS a deep cultivation may be needed. Crops that root deeply, as fruit trees, can be tilled more deeply than crops that are shallow-rooted. The aim should be to keep the soil water from getting above that part of the soil in which the roots feed most. The safest and best general practice, according to present information, is to fit the land deeply and thoroughly before planting, and to cultivate not over three inches deep thereafter, and sometimes less. A loose, dry mulch three inches deep is as valuable a water-saver and weed-preventer as one five inches deep. However, when a soil becomes compact beneath the surface, as clayey soils are very apt to from the tramping above, it is certainly wise to stir it deeply. THE ADVANTAGE OF LEVEL CULTURE In earlier years nearly all crops were hilled or ridged when cultivated. Now there is a strong preference for level culture whenever practicable. This preference is based on two facts; that level culture is obviously easier and cheaper; and that less water is lost since it exposes the minimum amount of soil surface to the air for evaporation. How much more surface is exposed when the soil is left like this A than when it is left like this — ? Probably the chief reason why the farmers and gardeners of a generation ago hilled their corn, pota- toes, and beans, ridged their cotton and planted their onions, carrots, and parsnips in raised beds, more than at present, is because farm soils were not then as well drained as they are now, there being comparatively little under-drainage at that time. There are but two occasions for ridging land: HARROWING, CULTIVATING 169 when the soil is poorly drained, and when the crop needs banking to secure a special result, as celery to blanch the stalks, or potatoes to protect the tubers that crowd out of the ground from being sun-scalded. If potatoes are planted deeply enough, however, all the tubers will form below the surface and hilling is unnecessary. In the Southern States it is often thought neces- sary to use two long narrow blades or "sweeps" which cut large weeds just below the surface and ridge the soil somewhat. In the same section a cultivator with one broad blade, quite similar to a plow, is used to throw enough soil over the large weeds at the base of the corn or cotton plants to smother them. This leaves the plants on rather high ridges. It is extremely doubtful if the practice is wise except, perhaps, on the heavier and wetter soils. If corn, tomatoes, beans, cucumbers, melons, okra, peppers, cotton, and other heat-loving plants are grown upon land that is inclined to be some- what cold and wet it may pay to hill or ridge them ; but there is abundant evidence that on soils that are even fairly well drained this practice is a disad- vantage. Very wet soils, especially creek bottom land and meadow muck, are often cultivated in ridges, beds, or hills with excellent results. In all cases the ridges should be no higher than is nec- essary to accomplish the purpose for which they are made. Not only should hilling and ridging be dispensed with on soils that are rather deficient in moisture, but also the surface should be left as level as possible, by using a shallow-working, narrow- tooth cultivator. In a wet season it may pay to use a deep-working, ridge-forming cultivator, on a soil that is normally so dry that level culture is best for 170 SOILS it. Likewise it may be wise to use a ridge-making cultivator in early spring on some soils, to warm and dry them, and replace this with a shallow- working cultivator after the crop is well started and the temperature of the soil is higher. PREVENTING LOSS OF WATER FROM SOD How to prevent the loss of soil water in sod land is a more difficult problem, but something can be done. A dressing of manure not only en- riches the soil but also acts as a mulch to it, preventing much water from escaping from the bare places between the plants. The gist of the whole philosophy of treating sod land, so as to get full benefit from the water in it, is to have no bare or unshaded places. If the grass plants stand so thickly that all the surface is shaded, most of the water lost from the soil passes off into the air through the plants, much to our profit. But if the meadow is getting worn out, and needs reseeding, a large part of the soil water is lost by evaporation from the bare places between the tufts of grass. Weeds, daisies, dock, thistles and the like may take pos- session of these bare places that appear in the sod ground when the grass roots begin to get weak; then the loss of water is greater. In handling sod land so as to get the most value from the water in it, endeavour to force most of this water through the grass plants, by keeping the turf dense and clean through occasional plowing and reseeding, and by top-dressing. It is quite possible to have a sod too thick, the result being that many weak grass stalks of poor quality are produced, but turf that is too thick is not nearly as common as turf that is too thin. CHAPTER VIII ROLLING, PLANKING, HOEING FARMERS have long noticed that grain sprouts quickest wherever the horses' hoofs have trod. Gardeners have observed the benefits of walking above newly planted vegetable seeds. They have noticed, also, that the soil on the bottom of the hoof track or foot print is more moist than adjacent soil. The conclusion has been that compacting the surface soil makes it more moist; this view is held by many farmers. Rolling, which had its origin in these observations, is practised by many with the idea that it increases the amount of moisture in the soil. ROLLING TO ASSIST GERMINATION The chief object of rolling on many soils is to increase the amount of water supplied to the ger- minating seeds, but rolling does not actually in- crease the total amount of water in the soil; it diminishes it. Rolling compacts the surface soil, bringing the particles closer together so that film water passes upward more readily and is lost by evaporation. But while passing upward much of it comes into contact with the seeds and is absorbed by them; thus the seeds are supplied with more moisture and germinate quicker and better, even though it is at the expense of a loss of water to the soil. Since so much of the success of a crop 171 172 SOILS depends upon quick germination, we can afford, on some soils and in some seasons, to sacrifice a good deal of water for the sake of gaining this important result. The soil at the bottom of the hoof-mark or foot- print is more moist than the surrounding soil be- cause it is more compact and losing more water by evaporation, having no mulch above it. The soil in a field that has been rolled is more moist on top than if it had not been rolled, but the soil below the compacted portion, from five to twenty inches deep, is much dryer than it would have been had the surface been left loose. In other words, the upper five or more inches of soil have been made more moist, by rolling, at the expense of the soil beneath. Within twenty-four hours after rolling this difference can be noticed. Part of the loss of mois- ture from rolled soil is due to the fact that the surface is left very level and smooth, so that it offers less obstruction to the wind. The velocity at which the wind passes over rolled ground may be nearly twice as great as on rough, unrolled ground. This means that much more moisture is sucked from the soil by the wind. When Rolling to Assist Germination is Practicable. — The farmer must decide whether the gain from rolling, in better germination, is greater than the loss, in the reduction of the total amount of water available for the growth of the crop. That depends upon the rainfall and upon the moisture-holding capacity of the soil. Rolling for the purpose of assisting germination is of greatest value on the lighter, looser and coarse- grained soils, especially the sands and sandy loams. These are so open that the air may circu- late through the surface soil quite freely, drying it ROLLING, PLANKING, AND HOEING 173 and stealing water that the seeds need. They are so loose and coarse-grained that the seeds are not sufficiently in contact with the soil to absorb enough water from it. Rolling very light soils is not only an aid to germination, but may also in- crease their capacity to hold water, providing they are covered with a mulch afterward. It is rarely necessary or practicable to roll clay soils for the purpose of supplying more moisture to assist ger- mination, but they are often rolled to accomplish other results. Making a Mulch after Rolling. — Most of the rolling now done is on land that has been seeded to grain or grass, and it is done immediately after the seed has been harrowed in. In a majority of cases the surface is left compact, as it comes from the roller, and remains so through the season. This is a waste of water. A way to secure all the benefit of rolling and avoid all the disadvantages is to make a shallow mulch on the surface after rolling. Rolling compacts from five to twenty-four inches of soil ; if the upper inch or two are loosened into a mulch, the water drawn up from below as a result is prevented from escaping and most of the seeds get the benefit of it as well. This means that whenever the loss of water by rolling is a detri- ment, as on light dry soils, the roller should be followed by a very shallow-working harrow, as a spike-tooth harrow with the teeth slanting back- ward, or a weeder. In some parts of the country a brush drag is used for this purpose. This is usually made of six or eight small white birch trees, twelve to eighteen feet long. The butt ends of these are fastened into a 2x4 inch end piece, at such a distance apart that the trees lie side by side and cover 174 SOILS an area of ground about eight to ten feet wide. When dragged over a newly seeded and rolled field the tough twiggy branches stir the surface soil thoroughly to the depth of one to two inches, making a very effective shallow mulch after a heavy rolling. It is better to defer making the mulch for twenty-four hours after rolling, by which time the moisture will have come to the surface. Other Illustrations of the Principle of Rolling. — The practice of making a mulch after rolling sowed land is not common. Most farmers who roll their seeding leave it so. When rainfall is liberal and the soil is fairly heavy and retentive, so that the saving of water is not a first consideration, this is probably the best plan. But if the summer rain- fall is insufficient and the soil quite open, it will usually pay to harrow or brush afterward. On the other hand, the practice of making a mulch after rolling, or otherwise compacting land that is to be put into hoed crops, is necessarily very common. In fitting sandy soils it is well to roll them before the last narrowing. In garden operations there are numerous and forceful illustrations of the value of establishing a mulch above compacted soil. When I was little more than half as high as a hoe handle, and helped my father plant corn, I used to wonder why he patted down the earth above the kernels and then scattered a hoeful of soil loosely on top of this. The gardener who makes a round . melon hill, patted smooth on top and covered with loose soil, and who walks on his row of beets and then covers his tracks; the fruit grower who stamps the earth around the roots of the fruit tree he is planting but leaves it loose on top; the florist who presses his ROLLING, PLANKING, AND HOEING 175 cineraria or petunia seeds into the soil with a board — all are illustrating, on a small scale, the phil- osophy of rolling. OTHER BENEFITS OF ROLLING The chief purpose of rolling, in ordinary farm practice, is to increase the supply of moisture for the seeds, but it may serve other useful purposes, or it may be used for these alone and not for mois- ture. Rolling to crush lumps is a profitable and common practice on soils which become cloddy. Great care must be taken, however, not to roll these soils when they are wet, as they are then cemented into a hard crust by heavy rolling. There is a time between wetness and dryness when the clods crush easily; this is the time for rolling. The seeds are brought into close contact with the soil by rolling, while they might lie dry and unre- sponsive among the clods. Rolling heavy soils in spring after seeding is beneficial if the season is dry, but injurious if the season is wet. The benefits from crushing clods lie not only in the improvement of the soil conditions as affecting germination, but also in the liberation of the plant food that has been locked up in the lumps. Rol- ling heavy soils, when the chief object is to crush clods, is always attended with more or less un- certainty as regards its influence on the moisture of the soil; so it is usually preferable in such cases to break the lumps with a planker or clod-crusher instead of running the risks of rolling. An in- cidental benefit of rolling, on some soils, is that it presses all small stones on the surface into the ground, so that they will not interfere with harvesting. 176 SOILS Rolling May Warm the Soil. — Rolling has a marked effect upon the temperature of the soil. It makes it warmer if the weather is clear and warm, but colder if the weather is cloudy and cold. King recorded an average difference of nearly three degrees between the rolled and the unrolled soil of the same field at a depth of three inches, the rolled soil being warmer. The soil becomes colder during cold weather and warmer during warm weather than if it were rolled, since on the unrolled field there is more surface exposed to the air. The more firmly a soil is packed on the sur- face the better does it conduct heat; so that during the night and during cold rainy weather the rolled land is colder at the surface than the unrolled land. Incidental Benefits of Rolling. — Incidental bene- fits of rolling in some cases are that it puts the soil into such a condition that other tools can handle it more effectively; it leaves the surface in better shape for marking; it smooths the soil so that small seeds may be distributed over it more evenly. Fall-sown grass, clover and grain are often rolled in very early spring to lessen the likelihood of injury from heaving by freezing and thawing and to make the surface smoother for mowing. 1 hese, however, are insignificant as compared with rolling for moisture and for crushing lumps. From the foregoing statements it is evident that rolling may be beneficial or detrimental, according to the soil and the season; it is a practice that must be used with discretion. In general, it may be said that rolling accomplishes two very useful purposes; it increases the water-holding capacity of light soils and aids the germination of seeds in them; and it crushes the lumps of cloddy soils. The tendency is to restrict the use of the ROLLING, PLANKING, AND HOEING 177 roller to the first purpose on light soils, where firm- ing the soil is the chief result sought; and to use the planker for the latter purpose on heavy soils, where fining the soil is the end desired. More rolling is done on spring sown grain after the seed is harrowed in than for any other purpose. If the season is dry this gives excellent results; if it is wet and the soil is somewhat clayey the texture of the soil may be injured and a crust formed. If a cloddy clay soil is rolled after having been plowed when it is too wet the clods are likely to be pushed into the ground instead of being pulverised. In rolling, as in plowing, everything depends upon "catching the soil at the right time." THE KINDS OF ROLLERS When the main reason for rolling is to compact the soil, the roller should be as heavy as is ex- pedient. The larger it is in diameter the heavier it should be. It is well to have a roller of large diameter for it pulls easier in proportion to its weight. For ordinary purposes a roller should weigh at least 1,500 lbs. Wooden rollers, which are usually made in one, two or three sections, are cheap and quite effective, although many of them are light. Their rolling surface soon becomes rough, thus increasing the draft. Iron or steel rollers, which are usually in more than two sections, last longer, do better work and pull easier. The more sections a roller has the less it furrows the ground in turning around. Some iron rollers are made with teeth or with corrugated surfaces or blades; these are claimed to be more effective in breaking lumps, but they often clog badly, thus in- creasing the draft and decreasing the effectiveness. 178 SOILS PLANKING Closely allied to the roller in its effect upon the soil is the tool variously known as a planker, clod- crusher, smoother and sometimes as a drag, boat float or plank harrow. The terms "drag," ' float," and "boat," however, are more properly applied to the tool known as a "stone boat" in the East, which is about c2x5 feet, smooth on the bottom, not corrugated, and which is used, not for mellowing the soil but for hauling stones from the field, plows and harrows to the field and similar work. The planker is usually home-made and therefore is not uniform in construction. A few cultivators have planker or clod-crushing attachments. Nearly all home-made plankers are made of two hardwood planks about 2x8 inches and 6 to 8 feet long. Notches about two inches deep and eight inches apart are made in each of these bed pieces and into these are nailed or bolted c2-inch planks about six feet long, each plank overlapping the one next to it, like clapboards. Or several planks may be merely overlapped and bolted together. Some prefer to have a space of several inches be- tween the planks. This is pulled broadside and exerts a powerful pulverising and smoothing in- fluence on the surface, especially if weighted with a driver or stone ballast. The planker has very little compacting effect, as compared with the roller, because its much lighter weignt is distributed over many square feet of sur- face; while all the weight of the roller rests upon the narrow line where its curved surface touches the soil. The planker is distinctly a clod-crushing and levelling implement. In this respect it resem- bles the harrows and is very properly called a 63. A CLODDY SOIL THAT WOULD BE BENEFITED BY ROLLING If the lumps are crushed, the soil fits tighter around the seeds, and there is more feeding surface for the roots 64. A FOUR-SECTION IRON' ROLLER WEIGHTED The more sections a roller has the less it cuts into the ground in turning ROLLING, PLANKING, AND HOEING 179 plank harrow. The planker is now used where the roller was formerly — to crush the lumps on heavy loams and clay soils that do not need com- pacting. On tenacious soils it is a common f)ractice to use the disk harrow after plowing, fol- owed by the planker, the Acme or spike-tooth harrow and then the planker again, alternating harrowing and planking the soil until it is brought into the right condition. The last turn should be with the planker, as it leaves the surface mellow and smooth, so that fine seeds may be sown or the land marked out for planting. The planker breaks up many of the small lumps that slip through harrow teeth and presses others into the ground where they can be torn out and broken to pieces by the subsequent harrowing. The planker is one of the most useful tools that any farmer can have, especially if the soil is somewhat heavy. It is never used to compact the soil around the seeds, as a roller, but is always used like a harrow — as a pulveriser and leveller after plowing. It is superior for this purpose to the roller; it should be used in place of the roller in all cases but two; upon light soils which need compacting and upon seeding. HOEING In primitive agriculture the plow and the hoe were about the only tillage tools used. Of late years the hoe has been used less and less as an implement of tillage. It has been forced aside by the increasing necessity for doing as much of the work on the farm as possible with horse power. The harrow, the cultivator and the weeder now do much of the work that was formerly done with the 180 SOILS hoe and do it much better. It is noticeable that where hand labour is cheap, as in parts of the South, a much larger proportion of the farm tillage is done with the hoe than where labour is dear, as it is in most parts of the North and West. A negro and a hoe is one of the typical scenes of the South. It is likely that the hoe will become of still less importance in farming, as we learn better ways of circumventing the weeds before they are big and as we are forced to perfect other means of growing crops with as little hand labour as possible. Aside from its use as an aid to planting, which is constantly lessened by the increasing use of plant- ing machines, the hoe will always be useful for two purposes ; to kill large weeds that have escaped the cultivator and to stir the soil close to the plants where the cultivator teeth cannot work without danger of injuring the plants. The hoe is a very poor tool for making a mulch; it stirs the ground deeply in some places, lightly in others and usually parts of the surface are left wholly undisturbed, or are raised slightly by the passing of the blade be- neath them. It does not lift, crumble and invert the soil, as do cultivator teeth, unless the soil is very mellow and dry. As an implement for conserving moisture, therefore, the hoe should be used only where a cultivator cannot be used; that is, close to the plants. Hoeing to Kill Weeds. — For killing large weeds the hoe has no equal, but this is an expensive way of killing them. Most of them can be killed when very small by frequent shallow cultivation. There are various styles of cultivator teeth and attach- ments to cultivators that are designed to skim be- low the surface and cut off large weeds. These ROLLING, PLANKING, AND HOEING 181 wings, sweeps and other special weed-killing de- vices should be a part of every farm equipment; if used in time they should reduce the area that needs hoeing to the parts adjacent to the rows. Here is where the hoe must be used, especially if it is found desirable to ridge the rows. With some crops the weeds that start between the plants can be killed when very small by using the spike- tooth harrow or weeder over the entire surface. But after the plants are too large for this it is a strug- gle to keep down the weeds in the rows. They get a start close to the plants and gradually en- croach upon the cultivated area. It is then time to "cut out" the rows; and it is likely the work- man will have to pull some of them by hand, so closely are their roots and stems entwined with the crop. Good and Poor Hoeing. — The easiest and most rapid way to hoe is to barely skim the ground with the blade at a very slight angle to the sur- face, scarcely disturbing the soil, but cutting off the weeds. The hardest and slowest way to hoe is to strike the blade into the ground at a sharp angle, lifting and turning two or three inches of soil. The former is preferable on the lighter and looser soils, the latter on the heavier soils and especially when the ground about the plants has become compacted by rains or tramping. Some men use the hoe as they would a pick; it does little good in this way so far as conserving moisture is concerned. As a general rule, hoeing, like culti- vating, should be deeper in spring than in summer, and for the same reasons. It is as much an art to hoe well as to cultivate well, and sometimes just as much depends upon it. Not one man in ten gets as much out of a noe as 182 SOILS there is in it. It is not enough to hoe merely to kill weeds, it should also save soil water and secure all the other benefits of tillage. This means that the soil should be stirred around the plants to a nearly uniform depth, not merely stabbed deeply in places and a thin layer of loose soil scattered over the unstirred soil between. It also means that the surface should be left nearly level, not in hog- troughs. Many farmers who are careful enough with their cultivating are slovenly with their hoeing. Market gardeners, however, have learned that it pays to put as thorough a man at work with the hoe as with the cultivator, Styles of Blades. — The blade of the hoe used in general farming does not vary much in size and shape. The essential thing is to keep it sharp and bright, which it will not be if hung up in the apple tree all winter. The business hoe makes frequent visits to the grindstone. As a general rule the blade on a new hoe is too broad to work handily; when it gets worn down an inch or two, it cuts the soil easier and better. Hoe blades having rounded teeth on the cutting edge are preferred by some. Some gardeners have many hoes of different sizes and shapes, some of them with blades only an inch wide for picking out weeds between vegetables; or with the handle inserted between two blades of different widths. Others are shaped like a narrow triangle; or heart-shape, with the lower end notched; or with the blade reduced to the merest hook, so that a stray weed can be tweaked from the ground with a twist of the wrist. The handles of some of these aristocratic hoes are knobbed on the end and variously curved. This is too gingerly work for most of us. The old-style hoe blade, about three and one-half inches by six inches, ROLLING, PLANKING, AND HOEING 183 answers every purpose when used with timeliness and thoroughness. MISCELLANEOUS HAND TOOLS There is an almost endless variety of hand tillage tools designed to be used when the rows are too close together to admit of horse tillage or for work- ing close to the plants. These are of far greater relative importance in gardening, especially in market gardening, than in general farming, be- cause gardening is usually conducted under more intensive culture than general farming. Wheel hoes, hand cultivators, scuffle hoes, hand weeders and the like are indispensable in commercial or home gardens, but rarely needful on farms where staple crops are grown, because these must be grown with as little hand-labour as possible in order to make them pay. Moreover, the hand tools can be used to best advantage only on soil that is exceedingly mellow and free from stones — a con- dition that many farms cannot meet. In short, they are tools for intensive culture; hence they are of greater value to the gardener, who is forced to locate very near his market on valuable land, and who must adopt intensive culture in order to make the business pay, than for the farmer who grows staple crops, and who can locate further from the market on cheaper land where such intensive methods are not needed. It is noticeable that even in gardening operations the tendency is more and more to dispense with hand tools. Crops that were formerly planted in rows twelve or fifteen inches apart, so that tillage had to be done by hand, are now frequently planted in rows twenty-eight or thirty inches apart so that 184 SOILS the cultivator may run between them. Some horses have a mathematical eye and will keep their feet between rows two feet apart without leading; and the spike-tooth cultivator can be narrowed to work between these rows, thus saving much wheel hoeing and hand hoeing. It is harder and much slower work to push a wheel or scuffle hoe than to follow a cultivator. There are conditions, however, when close planting may be desirable, as in the home garden or in market gardens close to towns, or for certain crops that thrive best when the plants partially shade each other, as onions and root crops. Hand Cultivators. — Nearly all hand-tillage tools beside hoes may be classified as hand cultivators, scuffle hoes or scarifiers, and hand weeders. Hand cultivators, erroneously called wheel-hoes, are of a great variety of patterns, but all attempt to do the work of a cultivator on a small scale. The larger the wheel and the wider the tire the easier it over- rides obstacles. Those with two wheels are steadier, and also useful for straddling the row and cultivating on both sides. Several styles of inter- changeable teeth are usually sent with each tool, including spike teeth, coulter teeth, hillers or ridging sweeps and a large furrowing shovel. A hand cultivator does excellent work in mellow soil; it is one of the most serviceable of gardening tools. Many prefer it to the scuffle hoe for tilling onions, carrots, radishes, lettuce and other closely planted crops. Scuffle Hoes. — These are of service chiefly between rows planted less than fifteen inches apart, as onions, carrots and the like. They are made in various styles, but all have a single blade which is pushed with a jerky motion along ROLLING, PLANKING, AND HOEING 185 the ground, cutting from one-half inch to one inch below the surface. The blade varies from half an inch to four inches in diameter and is rectangular, crescent or looped. The style most commonly used is attached to a long straight handle. A better style for some purposes is attached behind a wheel, thus becoming in reality a wheel hoe. The handle style is better after the tops of the plants begin to lean toward the middle of the row.! The scuffle hoe, like the common hoe, is a poor tool for making a mulch, but a most excellent tool for killing weeds. It barely skims the ground, cutting off weeds just below the surface and run- ning very close to the row; but the soil is not in- verted or loosened much. Very often it is simply sliced. An excellent plan for tilling close planted crops is to alternate the hand cultivator and the scuffle hoe. They complement one another; the former makes a mulch, but some of the larger weeds may slip through its teeth; the latter cuts off the weeds, but is a poor mulch-making tool. In addition to these larger hand tools there are many kinds of hand weeders for even finer work. Some are patterned after the original hand weeder, — the outspread fingers. Others are scuffle hoes with a small blade and short handle. Where it is necessary to do much hand weeding close to the plants, and it sometimes is in market gardening, these little tillage tools will save the fingers and facilitate the work. SELECTING FARM TOOLS Before leaving the subject of tillage tools, a word about the selection and care of farm tools in general may not be amiss. The first cost of farm tools is 186 SOILS high and they lose from 5 to 25 per cent, of their valuation every year, even with the best of care. They are a very expensive part of the farm equip- ment, more expensive in proportion to their utility than almost any other item in farm management. It is business policy to get along with just as few tools as possible. Many American farmers have too many. Some men seem to have a sort of mania for collecting everything new or unique in the way of tools. They lie around beneath the apple trees, back of the woodshed and beneath the eaves of the overcrowded tool shed, rapidly falling into disuse, then into rustiness and finally into rottenness. It is an expensive pastime. Every tool that is not used represents just so much capital, not tied up, but wasted. I know a farmer who has over twenty-five kinds of plows and harrows, yet he uses but six or seven in the work of his farm and finds these sufficient. He has at least $600 tied up in tools that he rarely uses and could get along without just as well. This is not business. The first cost of the few tools that are absolutely necessary is large enough and their depreciation rapid enough, without adding the weight of tools that are not needed. It is all right to try new tools if it can be afforded, but most people had better stick to the few tools that they have found necessary for satisfactory results. A Variety of Tools Needed. — These remarks about the common and needless waste on American farms because of a superfluity of tools are not meant to deny that a considerable variety of tools are needed on most farms. A good farmer, like a good mechanic, has a tool for every purpose, the best one to accomplish a certain specific result in handling the soil or crop, not one that is fairly ROLLING, PLANKING, AND HOEING 187 good for several purposes. He is not satisfied to use a spike-tooth harrow after the plow when a heavy disk harrow is needed to chop up the sod. He does not like to get along with a walking plow, however excellent work it may do, if a sulky plow will do the work as well, and easier and cheaper. To get each part of the farm work done in the best possible manner and at the least cost is the point that should decide the question of what kind of tools and how many. Five might do the work after a fashion; but if ten would do it enough better, quicker, easier and cheaper to more than pay for the cost of the other five it is economy and profit to have them. One-plow-one-harrow-one-culti- vator farmers are the kind that say "farming don't pay." Just how many tools it will pay to buy is, there- fore, a problem for each farmer to decide. He should not stint himself on those that are really necessary; a few bushels more corn per acre, the result of fitting the land better with a good tool, will pay for it in a single season. He should be careful not to indulge himself in tool getting, with- out sufficient justification for the outlay, however pleasurable that is to the man who loves to handle soil. First of all he will need to consider the kind of soil to be handled. Certain tools do better work on heavy soils than on light soils ; if the farm has several types of soils, as is most likely in north- ern United States, it may pay to keep tools for each. The crops to be grown will also determine to a large extent the types and number of tools needed. Finally the size of the farm or the area of the crop will determine whether it will pay to buy a certain useful tool to do a certain amount of work. This must be the deciding point. Often it would be 188 SOILS extremely useful to have a certain tool, but the amount of work that it would be called upon to do is so small that it would not pay for itself. Tools represent so much capital and have such a vital relation to the productivity and economical management of the farm that the problem of what kinds to get and how many deserves more attention from farmers than is usually given it. CHAPTER IX DRAINAGE OF FARM SOILS NO OTHER farm practice has added to the value of agricultural lands in the eastern part of the United States more than under- drainage. Excess of water in the soil is as fatal to most farm crops as deficiency. A soil must be able to rid itself of surplus water before it can be cropped and it often happens that this is the only defect of many soils that are otherwise very valuable for farming. Fortunately it is usually quite practicable to remedy this defect by drainage. A Problem of the Eastern States. — Drainage is, for the most part, a problem of the states east of the Mississippi. Probably it would pay to under- drain from 20 to 30 per cent, of the farm land in this region. On the prairie lands of the central West under-drainage is practised more than in any other part of the country, and it has added immeasurably to the wealth of that section. West of the Mis- souri and Mississippi in general, and in the regions of scanty rainfall in particular, the drainage of lands is often necessary, especially on alkali soils, and is frequently used ; but it is insignificant when compared with the need of drainage in the humid regions of the East. What irrigation is to the West, drainage is to the East, although both are needed more or less each side of the great rivers. Until quite recently drainage has received the most attention in this country; now irrigation has come to the 189 190 SOILS fore and claims, and receives, its due. A large share of the unprecedented progress in American agriculture during the past twenty-five years is due to the more general use of these two coordinate farm practices, each of which has the same general purpose in view — to give the crop an adequate and equable supply of moisture. The surplus water in a soil, which it is purposed to remove by drainage, all comes from rainfall; but rarely is it only that which falls upon the soil itself. The water may flow upon it as surface drainage from higher land, or it may come from below, being rain that has fallen upon higher land, sunk into the soil, followed a ledge of rock or layer of impervious soil, and finally found its way to the surface of the lower land as a spring, oozing from a hillside or bubbling up from the subsoil. Quite often level land which is not surrounded by higher land, and which contains only the water that falls upon it, is benefited by drainage because the soil is shallow. In such cases the most beneficial result of drainage may be, not to remove excess water, but to increase the amount of moisture that the soil can hold — a seeming paradox that is explained farther on. WHEN DRAINAGE IS NEEDED Two kinds of soils need draining; those that have too much water, and those that are too shal- low. The signs of poor drainage are obvious. Swamps, marshes, meadows and all other low land on which water stands for any considerable time may be drained, provided there is fall enough to secure an outlet. These low lands may be those which collect surface drainage, or seepage from 65. A THREE-SECTION IRON ROLLER Iron rollers are more efficient and more lasting than wooden rollers and do not clog as much'. They should weigh not less than 1,000 lbs. 66. A HOME-MADE, THREE-SECTION WOODEN ROLLER Note the device for keeping it clean. Wooden rollers quickly wear out eft * * o C3 £ 3 •V I 4- M THE DRAINAGE OF FARM SOILS 191 nearby higher land: or they may be lands that are regularly flooded by fresh water or by tides. Farm land which dries out slowly in spring, mak- ing the working and growing season shorter, or on which water stands for a long time after heavy rains, needs to be drained. If water oozes into the plow furrow the soil is too wet for good farming. The kind of plants that take possession of a field, before it is broken up or after it has been laid down in sod, or after it has been neglected for a year or more, are usually a reliable index to its need of drainage. If bog and water-loving plants become established here and there, especially sedges, rushes and mosses, the soil is too wet. Certain spots in the field, usually the lowest places, will indicate their need of drainage in this way, although most of the field is all right. All of these surface indications, however, should be supplemented or verified by an examination of the water table. Dig a hole in the field from four to six feet deep. If water stands in this hole within three feet of the surface or less, during most of the growing season, it is quite certain that the roots of cultivated plants do not find enough room, air and warmth in that soil to produce the largest crops. The growth of the crops themselves supplies evi- dence. On poorly drained soils the plants start slowly, look sickly and stunted, and never make the profitable growth of neighbouring plants on well-drained soil. Both yield and quality are re- duced. Within the boundaries of one field there are often both well-drained and poorly drained places. The contrast in the growth of plants under these two conditions is usually sufficiently marked to impress the farmer with the need and profit of draining the land. 192 SOILS Under-draining to Deepen Shallow Soils. — There is another class of soils — those that are shallow — that are improved by being drained, but these are not too wet except for short periods. First, there are the soils that have a hardpan close to the surface, perhaps within one to three feet. This hardpan may be a stratum of rock, but more often it is a layer of stiff and impervious clay. The rock hard- pan cannot be improved, but the clay hardpan can. Water cannot readily penetrate it. It is like the bottom of a shallow pan; when a heavy rain comes, the pan soon fills and overflows, making surface water. This can escape by surface drainage or by evaporation. But such a soil quickly dries out and suffers in a drought, because it has so little depth. What is needed is to deepen the soil — to lower the bottom of the pan — so that it will hold more water. There are two important ways of deepening a shallow soil. If the hardpan is close to the surface, stirring the surface with a subsoil plow helps, since it loosens the soil deeper than the plow, thus en- abling it to hold more water. But the loosened soil becomes compacted again in a few years; at best the results of subsoiling are only temporary. Under-drainage is permanent subsoiling; it takes away the water that has cemented the subsoil, and permits the air to enter it, thus promoting all the fining, loosening and mellowing influences of weathering. The value of under-drainage for deep- ening a soil is witnessed on thousands of Eastern farms. Draining to Improve Texture. — Still another type of soils — those poor in texture — is often greatly benefited by being drained. These are mostly the clayey soils that get hard, lumpy, and THE DRAINAGE OF FARM SOILS 193 unmanageable when dry, and sticky when wet. They are not what would be called wet soils, neither are they shallow, but they are not mellow and they run to extremes, either very dry or very wet. It is impossible to work them early in spring. Heavy rains put them in such a condition that they cannot be cultivated for several days after the crops begin to need tilling. The surface bakes and cracks. Such soils are improved by plowing under a green-manuring crop, by under-drainage, or by both. In many cases the addition of humus is sufficient to bring the soil into good heart; in extreme cases under-drainage must be called to the aid of humus. Land drainage is not chiefly concerned, as many suppose, with carrying off surplus water from very wet soils. Drainage adds far more to the value of farm soils, and to the profits in cropping them, by improving soils that are shallow, or in bad tex- ture, or but slightly wet, than by removing excess water from very wet soils. Many thousands of acres of swamps, meadows and marshes have been brought under profitable husbandry by drainage; but the combined area of these is very small com- pared with the hundreds of thousands of acres of farm lands that are not excessively wet, but that have been greatly improved by the same means. Drainage, and especially under-drainage, is of greatest service upon land already under cul- tivation, but which is not yielding maximum crops because of inequalities in the water supply. Far- mers should make a critical examination of each field in this respect, regardless of the length of time that it has been cultivated. Deficiencies may exist that never have been suspected. 194 SOILS LAND WITH GOOD NATURAL DRAINAGE The foregoing remarks should not obscure the fact that in some cases it may be more practi- cable to buy land that has good natural drainage than to drain wet land. All farm soils need drain- ing; but fortunately most soils are well-drained naturally. There is a great area of American farm soils that have almost perfect natural drainage, and a still greater area of soils that are drained quite satisfactorily. These are mostly sandy or loamy soils, or soils rich in humus; and especially soils that have an open subsoil which is sandy, or gravelly or of about the same nature as the surface soil. Water passes through some of these soils so readily that they can be worked a few hours after a heavy rain. The bulb fields near Puget Sound, Washington, have a soil so open that men can work in it within an hour after a rainfall of over one inch; yet it is very retentive and moist at all times. The causes of this very equable condition are the large amount of humus that the surface soil contains, and the subsoil of fine, sandy loam. One of the first points to look after when buying farm land, then, is its drainage, for Nature can drain land much cheaper than man. Dig several holes, five or six feet deep, to see what kind of subsoil lies beneath the surface that looks so promising. The value of a soil for cropping de- pends almost as much upon the former as upon the latter. The "lay of the land" is also impor- tant. Sloping land is not necessarily well-drained land. A slope may provide good drainage, and it may not. It carries off much excess water as surface drainage, to be sure, but we wish the soil THE DRAINAGE OF FARM SOILS 195 drained for at least four feet below the surface. Some of the most poorly drained farm soils are on slopes. They are usually clayey and may have springs oozing from them. In other words, a slope is an aid to good drainage, but the nature of the soil and its elevation with refer- ence to surrounding land are far more important factors. WHEN IT WILL PAY TO DRAIN LAND Not all land that would be greatly benefited by being drained will it pay to drain. It is a question of economics as well as of securing maximum pro- ductiveness. It might be more practicable, for example, to put a certain field of hard and rather wet soil into grass, which usually grows fairly well under these conditions, or at least better than most other farm crops, than to go to the expense of draining it for corn, cotton or rye. The more exacting the crop, as regards an equable supply of moisture, the more likely is it that it will pay to drain the land. Likewise the higher the value of land, and the more intense the culture, the greater are the arguments for drainage. Again, it might pay to drain land used for special crops which have a high value per acre, as market-garden crops, when it would not pay to drain this land if it were planted to staple crops, which have a lower value per acre. Furthermore, it might not pay to drain a certain field if the far- mer has plenty of other land which is better drained, and land is cheap. Much also depends upon the kind of soil, and the difference between its present value and its value after being drained. The same system of drainage may add $10 per acre to the 196 SOILS value of a poor soil, and $100 per acre to the value of rich soil. These, and other points in farm economics, should decide the practicability of draining land, after the need for draining it has been clearly proved. There is much farm land now producing indifferent crops, and the owners do not even sus- pect that its mediocrity is due to poor drainage. The first cost of draining land is large and the returns from the outlay are not immediate; they are distributed over many years. It may be several years before the drains have paid for them- selves. This fact is responsible for much of the hesitancy among farmers about undertaking an improvement that they readily admit is needed. They hate to "bury their money," or to put into the soil and out of sight an improvement the operation of which they cannot watch. The same argument, however, might be raised against the use of a fertiliser; the operation of neither can be watched, but the effects of both are readily seen. There is a deepening interest in farm drainage as land increases in value and as it becomes correspondingly necessary to make plants comfort- able, so that they may be grown at the lowest possible cost of production. EFFECT OF DRAINING ON THE SOIL The direct benefits of draining land have al- ready been pointed out in the chapters on the nature of the soil and on soil water. The most important result is that it makes the soil warmer. A wet soil is cold, chiefly because the water in it is con- stantly evaporating, and evaporation is a cooling process. To illustrate this: If the bulb of one THE DRAINAGE OF FARM SOILS 197 thermometer is covered with wet muslin, and the bulb of another similar thermometer is left un- covered, the wet thermometer may register as much as 15 degrees cooler when both are swung in dry air. This is due to the cooling effect of the evaporation of the water. Moreover, water is a poor conductor of heat; wet soils warm in the sun slowly, because the water they contain holds down the temperature. There is usually a difference of 5 to 10 degrees between drained and undrained soil in the same field. In fact, the temperature of a soil in summer is very largely determined by the amount of water it contains; the wetter it is the colder it is. Warmth is one of the chief essentials for the germination and growth of farm crops ; it is the coldness of a poorly drained soil, more than the mere excess of water it con- tains, that is responsible for most of the unsatis- factory growth of crops upon it. Draining a soil allows the air to enter it more freely. If all the spaces between the soil grains are filled with water air cannot enter. Air is one of the most important agencies that help to make a soil productive. It changes the rock particles of the soil into plant food and is essential to the decay of plants in the soil, making humus. Seeds must have air or they will not germinate. The soil bacteria that make fertility cannot thrive without air; the more thoroughly and the more deeply a soil can be aerated the richer it should be, and the better should plants grow upon it. The depth to which air penetrates the soil increases when the water-table is lowered by drainage, hence a larger feeding area is presented to the roots. Draining a Soil Makes it More Moist. — Al- though, it may seem a paradox, draining a soil may 198 SOILS make it more moist at the times when moisture is needed most. This is a feature of drainage that many people find hard to understand, yet the explanation is very simple. Drainage lowers the water-table, thus increasing the volume of soil above it in which the roots of plants can feed, for they can use only film water. The larger the area of soil above the water-table, the more film water there is for the plants to use. They root deeper and so are farther away from the dry surface soil. Furthermore, a soil is more mellow after being drained than before, so it can absorb and hold more water as film moisture, and its ability to draw up water from the water-table is increased. Under- drainage simply carries off free or standing water, thus leaving more room for the film water that plants use. Hence it is that a drained soil is dryer in a wet time and more moist in a dry time than before it was drained. In humid regions under-drainage may be equiva- lent to irrigation as a means of supplying water to the crop. The farmer who drains his land owns more soil than he did before ; for until the water- table was lowered he had the use only of the soil above it, the only part in which the roots of his plants can feed. If he lowers the water-table two feet he adds a layer of soil two feet thick to his property. He has two feet more of soil in which the roots of his plants may find nourishment. This is the cheapest way of increasing the size of the farm. After a soil has been drained the roots of plants penetrate it deeper, earthworms burrow deeper in it, air follows these channels and the ventilation of the soil is still further improved. A system of tile drainage is itself very effective in aerating the 68. COjvN "DROWNED OUT" The aggregate loss of crops by poor drainage is enormous, loss can be prevented Much of this 69. MEADOW ON WHICH WATER HAS BEEN STANDING The land now has no value for cropping. It could be drained at a slight expense . . . *aKd| jK^f^ll ^^C*f*- • "*^B| Ml L ■ ;M*3 i^;;;» •ilL-\aiiM ■ v ,j M>%\ - J^H mm ■5v*!BH^B3*fl*R-f ■ ■ ■ * ' Wk :-: ^ffMraWSr:' v . '•■ <; \3raHHE 70. A SOIL WELL DRAINED NATURALLY BY A GRAVELLY SUBSOIL Examine the subsoil when purchasing land 71. SURFACE DRAINAGE BY "PLOWING INTO LANDS" The dead furrows in this meadow are io pares apart. They lead the water into a shallow ditch on the side of the field THE DRAINAGE OF FARM SOILS 199 soil. Most of the time the tiles carry air, as well as water. When the surface air is much warmer than the soil air, as on a warm day in early spring, a system of tile drains may supply a slight bottom heat, or at least be the means of equalising tem- perature. Thus a good system of under-drainage aerates the soil both from above and from below. Practical Results from Draining Land. — The practical result of the better aeration and increased warmth secured by draining land is that the soil becomes richer and more productive. Not only does more plant food in the soil itself become available, but also the manures or fertilisers that may be applied are more effective, since they too must first be treated with Nature's chemicals before the plants can use them. The beneficial bacteria of the soil, which thrive only in warmth and mois- ture— not wetness — are encouraged to multiply. The season is lengthened at both ends; the soil can be worked earlier and later, so crops have the use of it longer. If a poorly drained field is sloping there may be a considerable loss of fertility by surface washing. After this field is drained, rains sink into the soil more readily, as it is looser and dryer, and so a large part of the surface washing is checked. The cost of growing a crop is reduced, especially in preparing the seed bed, for a mellow, well-drained soil is easier to handle and can be brought into the right shape quicker than cloddy, poorly drained soil. Seeds germinate better, because the soil is warm and dry instead of cold and wet. The quality as well as the yield of the crop is often improved. This is particularly true of grass or hay; that which grows in well- drained meadows or pastures is of much higher 200 SOILS value for feeding than that which grows in wet land, not only because the better grasses thrive in the well-drained soil, but also because they actually contain more nutriment. These and other benefits of draining wet, shallow or hard soils may be crystallised into one sentence ; drain- ing increases the producing capacity of such soils and enables the man who tills them to put his crops upon the market at a lower cost of production. WHAT KIND OF DRAINS TO USE Soils are drained in two ways, by surface drains or by under-drains. Which method should be followed is mainly a matter of expediency and of thoroughness. Surface drainage is secured chiefly by means of open ditches. The objections to open ditches as compared with under-drains are numer- ous and forceful. They cost more than tile drains, both to make and to maintain. More soil must be moved for surface drains than for under-drains in order to make the ditch of the needed capacity and to give the banks sufficient slope so that they will not wash. Ditches need frequent repairing and cleaning out, the sides cave in, they become choked with plants, many of which may be noxious weeds, and the soil washes in. Ditches take up much valuable space and hinder the use of teams. In order to thoroughly drain a wet field the ditches would need to be so close and so large that they would occupy one-fifth to one-sixth of the area. This is too much to lose if under-drains will do just as well. Furthermore, the loss of water from open ditches by evaporation is very great. It amounts to from 40 to 50 inches THE DRAINAGE OF FARM SOILS 201 of water a year, in the Eastern States, and much more than that in the arid regions. These objections are sufficiently forceful to make drainage by open ditches entirely impracti- cable when tile drains can be used. There are many sections of the country, notably in the South, where it is dangerous to provide any kind of sur- face drainage, because the soil washes so badly. All kinds of surface drains everywhere carry away more fertility than would be lost through under-drains. In most cases it is better that excess water should pass through a soil instead of over it. WHEN DITCHES ARE PRACTICABLE There are, however, conditions under which surface drainage is not only useful, but is about the only kind of drainage that is at all practicable. In peaty or muck bogs, fresh and salt water marshes, cranberry bogs and the like, the open ditch is the only feasible method of drainage, at least for the larger drains. In these cases the main object is to carry off the flood or surface water; the water- table is not lowered to the depth that is necessary for most farm crops. Whenever it is wished to lower the water-table of such lands to four feet and to plant them with the common farm crops, it is usually necessary to supplement ditching with tile drainage. Tile drains cannot be laid in marshes in which the peat is not well rotted until they have been partially drained by open ditches. When a peat soil is drained it shrinks; if tile drains had been laid the tile would soon be found too near the sur- face. In such cases it is preferable to first put in 202 SOILS open ditches to dry out the marsh until the shrink- age has occurred. Get a crop started upon the marsh as soon as possible, as it hastens decay. Later these ditches may be deepened and tile drains laid in the bottoms of them. According to King, another occasion when open ditches are feasible is in draining very level land underlaid by a very fine clay. These places are usually found where a lake once existed. Water moves through the fine clay so slowly that tile drains would not be effective unless laid so close that the expense would be prohibitive. Such soils should be plowed into lands from twenty to thirty feet wide with the dead-furrows emptying into shallow ditches. Ditches are also useful to provide an outlet for under-drains, and to catch surface drainage on slopes, or at the foot of slopes. In other words, ditching is useful mainly for taking care of surface water, and for removing the excess of water in the first foot or two of soil. Deep and thorough drainage, such as most farm crops demand, can usually be best secured by under-drainage. HOW TO DIG A DRAINAGE DITCH The depth, width and grade of a ditch depends chiefly upon the amount of water to be removed, the lay of the land and the nature of the soil. In marsh lands the ditch may usually be cut to a depth of four or six feet, and with almost vertical sides. Peat or muck soil is not liable to wash or cave in, being more or less fibrous, especially if the water-table is not lowered sufficiently to dry out the soil so deep that it will shrink and crumble the banks. Ditches in an upland soil, however, 72. DRAINING WET LAND WITH AN OPEN DITCH Ditching is much inferior to tile draining, where the latter is expedient, being more expensive in the long run and not as lasting. But only ditches are practicable on some marsh land. The sides of this ditch are too steep AN OPEN DITCH WITH GRASSED SIDES ON AN EASY SLOPE, SO THEY DO NOT WASH All ditches take up much room. They become foul with weeds and must be cleaned out 74. LAYING A TILE DRAIN The difch is four feet deep. The line of tiles is given a fall of one to four inches in ioo feet. The joints are fitted together carefully 75. A TILE THAT HAS BEEN CLOGGED BY TREE ROOTS The whole drain may be obstructed in this way. Lay sewer pipe when the drain passes near trees, and cement the joints THE DRAINAGE OF FARM SOILS 203 must have sloping banks. If the soil is a tenacious clay a slope of 15° to 20° may be sufficient to hold the banks. More often a slope of 45° is barely enough to prevent caving in, which means much extra work. The greater the fall of the ditch, the flatter should be the banks. In many cases, especially for wet meadows, the best kind of ditch is merely a broad hollow, about one or two feet deep and six or eight feet wide. These places may be grassed over, if in a meadow ; if the land is used for tilled crops and the ditch serves as a water carrier only in winter and early spring, it may be planted. All kinds of farm machines can pass over such a ditch; it is the most serviceable kind whenever it will drain the land sufficiently. On nearly all comparatively flat land, and especially on western prairie land, there are many shallow natural water-courses, variously called "runs," "draws" and "sloughs." The heavy spring rains turn these into drainage channels. If necessary shallow ditches, ten or twelve feet wide and two feet deep, may be scooped out in these draws with plow and scraper and the bottom and sides seeded to grass. The Grade. — The grade of an open ditch must be low. A fall of five or six inches in a hundred feet is usually about all that an ordinary soil will stand without washing, especially if the banks have not enough slope. If it is necessary to make curves in a ditch, they should be very gradual, particularly if the fall is greater than it ought to be, for when the ditch runs full the water will tend to eat into the outer bank, as it does in streams. When an average ditch is running full after a freshet a fall of two inches in a hundred feet makes a current of about four miles an hour. This 204 SOILS current quickiy undermines steep banks unless the soil is very fibrous or clayey. It is usually best to grass over open ditches ; some sort of herb- age will soon cover the banks anyhow, but grass roots are more valuable as soil binders. The distance apart of open ditches is governed entirely by the nature of the land. In marsh land the small laterals, which may be about three feet deep and three feet wide on the bottom, are fre- quently placed from 40 to 100 feet apart, and empty into larger main ditches, which are five or six feet deep and equally wide on the bottom. In some cases it is better to dig larger ditches from 150 to 200 feet apart. PLOWING INTO LANDS This simple and very common device for surface drainage has already been mentioned in Chapter V. It is useful solely for removing the excess of free water, especially that which stands upon the sur- face. Plowing a field into lands makes very shallow open ditches. It is quite common to leave dead-furrows about fifteen or twenty feet apart, thus throwing the soil into slightly raised beds or lands. The dead-furrows should usually lead to open ditches on the side of the field. This dries out the soil and warms it earlier in spring. If the soil is liable to remain wet late into the spring, and especially if it is a heavy clay, the dead- furrows may be in the same place for several years, thus deepening the hollows and elevating the lands. On average soils, however, the dead-furrows should be made in different places each year. According to Roberts, lands five or six paces wide do not THE DRAINAGE OF FARM SOILS 205 drain off the surface water of nearly level fields as effectively as lands twenty to twenty-five paces wide, "because not enough water is carried into any one of the dead-furrows to produce a current sufficient to overcome the obstruction offered by clods and friction." Surface drainage by dead- furrows is most practicable on very fine clay soils, through which water passes so slowly that it would be almost useless to lay tile drains beneath them. Sometimes the dead-furrows may be joined by cross furrows, so as to convey the water away along a natural depression. THE ACTION OF UNDER-DRAINS In most cases under-drains are more efficient and more practicable than surface drains. Under- drains may be of stone, boards, brush, or other materials, but tile drains made of baked clay are now used almost universally. Drain tiles have come into common use within fifty years. There are now many thousands of tile factories at work in the United States. Any clay that will make good bricks is suitable for making tiles. Few parts of the country where tiles are most needed, especially east of the Mississippi, are without facilities for making drain tiles. The philosophy of under-drainage is simple. An open passage is made through the soil below the water-table; that is, below the point at which water fills all the spaces between the soil particles. It is like boring a hole into a water tank two feet below the point where the water stands in the tank, and inserting therein a pipe. The water is lowered to the level of the bottom of the pipe. Lines of 3-inch tiles are run through the subterranean 206 SOILS lake ; tney lower its surface to the level of the bot- tom of the tile at the points where each line of tile runs. But the level of the water-table rises higher between the lines of tile, as water cannot move as freely through the soil as it does in the open. Thus the surface of the water-table of a tile-drained field is something like a series of crescents, the lines of tiles being at the lowest points. The height to which the water-table rises be- tween the lines of the tiles depends upon the distance apart of the drains and the character of the soil. The farther apart they are, the higher the water rises between them. The more sandy or porous the soil, the more nearly does the water-table come to the level of the drains over all the field. Thus, if under-drains are placed four feet deep in a sandy soil, and a similar distance in a clayey soil, the water-table of. the former might be lowered to an average level for the field of three and one-half feet and the latter to two and one-half feet. It must be clearly understood that under-drains carry off only free water, never film water. Fur- thermore, they remove no water from a soil unless the water-table is above them. Water does not run into them, it is squeezed in. For instance, if a line of tile drains is placed four feet deep in a soil in which the water-table is four feet six inches be- low the surface in summer, none of this water will get into the tiles until the water-table has been raised to four feet, or over, as it might be early in spring after heavy rains. Water enters tile drains through the joints and also through the walls of the tiles. It is not necessary, as many suppose, to leave a crevice be- tween the tiles for the entrance of water. No THE DRAINAGE OF FARM SOILS 207 matter how tight a joint is made, water will pass in freely. In laying tile, therefore, the object should be to make as tight a joint as possible, so that dirt will not enter and clog the tiles. PLANNING THE DRAINAGE SYSTEM The attempt to drain a piece of land, no matter how small, should be preceded by careful planning. The direction of the drains, the distance between them and the grade should be plotted on paper. The aim should be to lay out the system so as to secure sufficient fall and give adequate drainage with the least digging and the least amount of tile. To this end it is necessary to make few outlets and junctions and not to lay two lines of tiles so close together that they both drain an area that could be drained by one line. On small areas having a noticeable fall, the drains may be located by eye and the planning may be done without the aid of a surveyor; but much land that requires draining is quite flat and it is extremely difficult to give the drains the right grade without the assistance of an instrument. It does not pay to go to the expense of buying tile and dig- ging ditches only to make a botch of the job by trying to save the cost of the services of a competent drainage engineer. Nine times out of ten the work of laying out the drainage system on a large area should be entrusted to a surveyor. The owner of the field should, however, con- tribute his knowledge of local conditions. He should know, for instance, the source of the water it is expected the drain will remove — whether it comes from overflow, springs or otherwise — so that the drains may be laid to cut off the supply 208 SOILS with the least amount of digging. He should know the wet spots in the field and if the outlet of the drainage system is to be on the bank of a stream, he should know the high- water mark of the stream. Only the man who tills the field and observes the condition of the soil at all times of the year can locate a drainage system upon it most eco- nomically. It may be cheaper and better to have a large job done entirely by a drainage engineer. He has a force of men who are familiar with all the ins and outs of the business, and can dig a ditch, lay tile and finish the work much quicker than men who are unused to the business. It is especially important that the man who lays the tile should be skilled, or if not skilled at least very careful. Cheap help for this work is poor economy. In planning a system of under-drainage the various points should be considered in the following order: First, select the best outlet. Second, lo- cate the position of the main or mains. Third, ascertain the difference of level between the out- let and the highest point in the main, and de- termine the grade. Fourth, locate each of the laterals. Fifth, find the difference in level between the highest point in each lateral and the point where it joins the main, and de- termine the fall. Under all circumstances work from the outlet or outlets back to the furthermost laterals. Make an exact plan of the system on paper, drawn to a scale. A man usually thinks he can remember just where the drains are located, but in a surprisingly short time all traces of them on the surface are obliterated and recourse must be had to a map. Failure to make a map may cause THE DRAINAGE OF FARM SOILS 209 much inconvenience and useless digging when the drains need attention later. THE OUTLET The first point to look after is the outlet; the water must be carried off after it is collected by the tiles. More than one drainage system has given poor service solely because a suitable outlet was not provided. The channel into which the drainage system discharges may be a natural water course, as a river, creek, brook, or rill, or it may be an open ditch constructed for the purpose. If a natural water course, it is very essential that the outlet of the drain be at least several feet above the highest point at which the water in the stream has been known to stand. This precaution is necessary to prevent the stream water from backing up and filling the lower end of the drainage system, wnich not only prevents the drainage water from escaping, but also allows the stagnant water to deposit sediment on the bottom of the tiles and choke them. All the water in a tile drainage system should be in motion all the time. The outlet is the most vulnerable part of a drainage system; it is the only part that comes to the surface. Hence it will pay to deepen and straighten the course of the stream at that point, if necessary, in order to make it doubly sure that the drainage water will meet no obstruction in passing from the outlet. For the same reason it is usually best to have as few outlets as possible; to collect the water from many or several lines or systems of drains into one main with a single outlet. Sometimes, however, it is cheaper to have several outlets, one for each system, instead of 210 SOILS uniting all into one main. The cases are rare when it is best to let each line of tile have an in- dependent outlet. The outlet should be kept clear of weeds and soil, guarded from the tramping of animals and protected from injury by frost. In the Northern States it is not safe to run the ordinary soft tile to the surface. The last ten feet, at least, should be of more durable material, as a box drain made of 2-inch plank; or, better yet, the last ten feet may be of glazed sewer tile. Cast iron sewer tiles are sometimes used. It is well to face the bank at the outlet with brick or stone. There should be a wire screen over the outlet to prevent the entrance of small animals. Examine the outlet at least twice a year to see that it is free. THE GRADE OF TILE DRAINS The amount of fall or grade that under-drains should have depends upon the contour of the land, the length of the drains and the character of the soil. The first thing to do is to locate the outlet above all possible danger from obstruction by back- water. The height above the outlet of the highest point of land that is to be drained must next be determined. For example, there may be a dif- ference of seven feet between the outlet and the upper end of the main, and the distance is 1,200 feet. This means that the main may have a fall of five inches per hundred feet, which is about right. The main drain must follow the lowest land from the outlet to the head of the drainage system, and be given as much fall as possible, within a reason- able limit, so that the lateral drains will have sufficient fall. The fields that are most likely to THE DRAINAGE OF FARM SOILS 211 need draining are apt to be rather flat and there may be considerable difficulty in deciding off-hand where the lowest land is, and along what line be- tween the outlet and the upper part of the field the greatest fall may be secured. In doubtful cases a level should settle the question. Having established the outlet and located the main drain on the lowest land, next locate the lat- erals, or collecting drains. The fall of the entire system must now be considered. In general it should be from 5 to 8 inches in 100 feet. If this grade can be secured there should be no difficulty in laying a system that will work perfectly. But very often 2 or 3 inches in 100 feet, or even less, is as much fall as can be had. Excellent drainage systems are now in operation that have a fall of 2 inches in 100 feet, and there are occasional ex- amples of farm drainage systems that work with a fall of even §-inch in 100 feet. But these can be constructed only with the aid of a skilled engineer. In farm drainage a fall of at least three inches should be sought ; if one must content himself with less grade he should employ a surveyor and give greater attention to the laying of the tiles. On the other hand, too much fall in a drainage system is equally undesirable. A fall of 12 inches in 100 feet is considered about the limit of safety. A greater grade would carry the water so fast that there would be danger of loosening the tiles. This is especially true on lighter soils, which frequently have tile drains washed from them after a very heavy rain. If any of the tiles are loosened suffi- ciently to admit soil the whole system may be ruined eventually. If possible it is best to have all the drains laid at a uniform grade, from the upper end of the system 212 SOILS to the outlet. If it is necessary to change the grade it should preferably be from a less fall to a greater, say from 3 inches to 4 inches in 100 feet; if the grade is reduced there is greater likelihood that the sediment in the water will settle in the lower part of the system. To avoid this, if a reduction in grade is necessary, put a "silt basin" at the point where the change is made. This is made by sinking an 8-inch, 10-inch, or 12-inch tile below the level of the ditch, and notching it on one side for the drainage water to flow in, with a lower notch on the opposite side for the first tile of the new grade. The soil dropped in here should be cleaned out occasionally. Carry the silt basin to the surface with glazed sewer tile ; or, if the line of tiles is large, dig a larger basin and brick up the sides'. Silt basins should be covered all the time with iron, stone, or plank to avoid accidents and freezing. Silt basins are really small wells; they enable the farmer to see if his drains are working properly, as well as collect silt. They may be placed at the junction of the sub- mains and the mains, even if there is no change in grade, so as to give an opportunity to examine the working of the drains. DEVICES FOR ESTABLISHING GRADE The most important part of under-drainage is the grade. If the grade is insufficient the water stagnates and the tiles become filled with soil. If any part of the system, even a few feet of it, is below grade the whole system suffers. Hence the necessity of securing the services of a skilled drainage engineer if a large area is to be drained. The use of a surveyor's level is not indispensable to good draining, but is extremely helpful. If a THE DRAINAGE OF FARM SOILS 213 small area is to be drained, and the land is not very flat satisfactory work may be done by a care- ful man without a level. A Home-made Level. — There are many simple devices for establishing a grade. King recom- mends a "water level," which is easily made at home. It is made of a piece of f-inch gas pipe, four feet long, with a T exactly in the center and an elbow at each end. A piece of pipe about six feet long is inserted in the T and sharpened at the lower end, making the standard which is thrust into the ground. A short piece of glass tube, J -inch in diameter, is cemented into each L and the top of each tube is fitted with a cork. Each tube should project exactly the same distance above the L. Fill the gas pipe with water, coloured with ink or bluing, until it just shows in both of the glass tubes when the pipe is exactly horizontal. When using this improvised level, stick the standard firmly into the ground, remove the corks and adjust it until the water shows that the horizontal pipe is perfectly level. Then step off four or five feet and sight across the top of the two tubes. If used carefully, this instrument does quite accurate work for short distances. There are many ways of using this and other kinds of levels. The simplest way, for drainage work that is not complicated, is to first set the level some 50 or more feet from the outlet. Sight back to the outlet, set the measuring rod on the ground and note the height at which the level sight strikes the rod. It may be 4 feet 6 inches, for example. With the instrument in the same position find the height at which the sight strikes a rod, set about 50 feet m the opposite direction, along the line which 214 SOILS it is supposed the drain will run; say at 5 feet. The difference between the back-sight and the fore-sight is thus six inches, showing that the land has a fall of 6 inches in 100 feet, or in the dis- tance between the two points at which the rod stood. The instrument may now be moved forward and similar measurements taken for the remainder of the main and for the laterals. The fall that the entire system can have is thus determined. The next thing to do is to stake out the drains. Beginning at the outlet drive into the ground a stout peg 8 or 10 inches long until it is flush with the surface. Drive similar pegs 50 feet apart along the line where the ditch will come and about 12 inches to one side of the centre of the ditch. About a foot from these "grade pegs" drive "finders," stakes which project a foot above the ground and guide one to the grade pegs. The work of determining the grade and depth of the ditch may now be begun, using the level as indicated above and taking the height of the top of each grade peg by placing the rod upon it. Thus, if it has been determined that the drain may have a fall of 4 inches in 100 feet, at which grade it will be 3 feet 6 inches deep at the outlet, if the next grade peg is four inches higher than that at the outlet it shows that the bottom of the ditch at that point should be 3 feet and 8 inches below the level of the grade peg. Measurements are taken all along the line in the same way and the depth which the ditch should be at each fifty-foot point is re- corded in a book, and on each of the finder stakes. When laying the tile a cord is stretched along the tops of tne grade stakes and the depth for laying THE DRAINAGE OF FARM SOILS 215 is determined with the aid of a measuring rod, which has an arm at a right angle and long enough to reach to the line. A Sighting Method. — Brooks recommends a simpler and scarcely less accurate device for secur- ing the right grade. Drive two stakes at the outlet, one on each side of the position of the ditch, so that when firm their tops are a little over six feet above the level of the drain at the outlet. Thus if the outlet must be 3 feet 8 inches deep the tops of the stakes will be a little over 2 feet 4 inches above the level of the ground. Nail a light, narrow board from stake to stake so that the top of it will be level and exactly six feet above the bottom of the drain. Go to the upper end of the drain and place a similar grade board just 6 feet above the bottom of the ditch there; if the drain is 300 feet long, and a grade of 3 inches in 100 feet can be secured, this grade board will be nailed 9 inches above the sur- face. At intervals of 50 feet on the line of the drain set similar pairs of stakes. The height at which to nail the grade boards on these is deter- mined by sighting from the lower to the upper grade boards, or vice versa. Dig the ditch nearly to the desired depth. Now stretch a stout cord very tightly from the top of the grade board at the outlet to the top of the grade board at the upper end of the drain, and midway between the stakes, where the centre of the drain should be. Brace the upper and lower grade boards to prevent the line from sagging. When the ditch is completed the bottom at all points should be exactly six feet below the cord. The success of this device depends upon the accuracy with which the sighting is done and the 216 SOILS grade boards nailed, upon a taut cord, and care- ful measuring to the cord. The latter operation is done with a rod and great care should be taken to hold it exactly vertical. A spirit level will aid in this. See that the cord does not stretch during changes in the weather. When carefully executed this simple method of grading gives very satis- factory results. There are many other home-made devices for establishing grades, as the walking level, and those in which a spirit level is used. When the field has a noticeable slope a careful workman can make a fairly accurate grade by simply watching the flow of water in the ditch. But it is not best to depend upon the eye alone, except, perhaps, for very small fields which have a pronounced slope. THE NUMBER AND DIRECTION OF DRAINS This is determined by the contour of the land and the character of the soil. If a more or less con- tinuous depression runs through the field, some- where near the middle, the drains would probably have but one outlet, with one main following the depression, and with laterals running obliquely from it to the surrounding higher land, unless something could be gained by a short cut. If there were two depressions there might be two mains, which would unite to make one outlet. If the whole field slopes slightly in one direction, say toward an open ditch, the water in which never rises above the point at which the outlet of the drains would be, mains might be dispensed with altogether and the field drained by parallel lines of small tile running from the upper end of the field to the ditch, each having an independent outlet. THE DRAINAGE OF FARM SOILS 217 The mains should make sweeping curves, not abrupt ones. The laterals also may join the mains at any angle, depending entirely upon the grade. If the main is in a marked depression it may be necessary to run the laterals nearly parallel with it for some distance, so as not to make their fall too great, making a long acute angle; but if the main is in a very slight depression the laterals may be almost or quite at right angles to it. In any case they should be given a slight curve before they join the main, so that the water may be carried into the main with the current, not across it. When draining land that has a marked slope the lines of the tile may be run up and down the slope, across it, or obliquely. If there are springs on the slope these will be cut off most effectively by cross-slope drainage, otherwise it makes little difference which method is chosen except for the difference in fall. Most drainage, engineers prefer to run the drain obliquely down the slope when- ever it is expedient. There are thus many systems of laying out tile drains, each of which has merits under certain conditions. The contour of the land, the character of the soil and the position of the outlet usually decide this question. In fact, it is often necessary to put in a combination of several systems on one field, because of the variation in contour. In planning any system of tile drains the aim should be to use 3-inch tiles in preference to larger sizes, wherever they can do the work, for the larger size of tiles add greatly to the expense of the system. Every field is a new problem; no one can tell how the drains ought to run without studying the field. 218 SOILS DISTANCE BETWEEN UNDER-DRAINS This depends chiefly upon the nature of the subsoil and the depth of the drains. The ease with which water can pass through the subsoil to the drains would naturally have much influence in determining the distance apart of the laterals. Water will pass to the drains through a sandy sub- soil from ten to one hundred times more rapidly than through a stiff clay subsoil. The coarser the subsoil and the freer it is from hard-pan the more readily does water move to the drains and the farther apart they may be placed. In other words, the more open the subsoil is the farther apart should the drains be, for the excess water in such soils quickly drains off. The movement of water in compact subsoils is very slow. The depth of drains should be considered in deciding their distance apart; the deeper they are the lower do they make the water-table. Under- drains do not lower the water-table of the entire field to their own level. At the point where the drains are placed it is lowered to that level, but midway between two lines of drains it may be several inches or even several feet higher, depend- ing upon the openness of the soil and the ease with which water passes through it laterally. The water-table of an undrained field is a series of curves or crescents, the lower ends of each curve being on a level with the bottom of the drains. So the deeper drains are placed the farther apart they may be without danger of the water-table coming too near the surface, midway between the lines of drains. The common distances apart for laying tile drains are 20 to 30 feet on deep, very compact clays; THE DRAINAGE OF FARM SOILS 219 40 to 70 feet on average loams with a rather open subsoil, and 100 and even 200 feet on very open soils. A safe distance for average loam soils in the Eastern and Central States is 40 to 50 feet, if the depth is not less than 3^ feet; and 25 to 40 feet on heavy clay soils. Many fields may be ex- cellently drained with some lines of tile 40 feet and some 100 feet apart, according to the nature of the soil in different parts. DEPTH OF UNDER-DRAINS The deeper the drains are placed, within reason- able limits, the better they work. But beyond a certain depth the expense of moving soil increases faster than the advantage gained in the way of better drainage. In certain soils it may cost about twice as much to dig a ditch four feet deep as it does one three feet deep. For ordinary farm crops the depth to which the ground water should be lowered need not be over four feet, and frequently less. If the land is too wet only in the early Dart of the season, and it is desired merely to ower the water-table sufficiently to dry out the and quickly in early spring, drains placed two and one-half or three feet deep will usually answer the purpose. It may happen that the only available outlet is so high that it is necessary to place the drains at less depth than what is considered best, so as to secure sufficient fall for the entire system. Again, if the field has a sandy or gravelly subsoil some four or five feet below the surface, it would be unwise to place the drains so deep that the water-table would be lowered into the sand or gravel, because this coarse soil has poor capillary power and the soil 220 SOILS * above it would be but poorly supplied with film water after the water-table is lowered into it. In the Northern States it is absolutely necessary to lay tiles below the frost line anyway, for they are easily heaved and cracked by frost. This means a depth of two to three feet, and even four feet in the northern prairie states. In the Red River Valley of Minnesota and the Dakotas the ground freezes six feet deep, and there is much doubt as to whether tile drains are practicable there. It is not prac- ticable to try to place drains so deep that the roots of ordinary crops will not enter them, for these roots commonly run from five to ten feet deep. The best depth for drains on average soils is three and one-half to four feet. There are few cases where lateral drains should be five feet, or over, but mains are frequently laid at that depth. It is rarely expedient to lay deep drains in stiff soils ; shallow drains are much better, for water moves slowly through heavy soils. Land that is to be permanently in grass may have the drains laid more shallow, not only because the grass will prevent the ground from freezing so deep, but also because grass thrives when the water-table is nearer the surface than is best for most tilled crops. Under-drains in such lands are often laid two and one-half to three feet deep with excellent results, especially if the soil is not very heavy. Thirty inches is about the minimum depth, under any circumstances, at which it is practicable to lay drains. When laying drains in peaty land make allowance for the settling and shrinking of the soil from the decay of the vegetable matter. THE DRAINAGE OF FARM SOILS 221 KINDS OF TILES At least eight styles of tile have been used since the beginning of tile drainage, but at the present time practically all farm under-drainage is done with round tiles. Sole and double-sole tiles, which are flat on one, two, or four sides, are heavier and can be joined together only in two ways ; whereas a round tile can be joined to its neighbour at anypoint. Six or eight-sided tiles with a round bore are quite popular in the West and have all the merits of round tiles, except that collars cannot be used with them, which is unnecessary in most cases. How- ever, they have no advantage over ordinary round tile and it is doubtful if they can be laid as rapidly. There are a number of special forms of tiles for certain uses. "Elbows" or L's are made in all sizes, either with a slight curve or a curve of 45 degrees. They are used principally for the mains. At the point where a lateral empties into the main, or a sub-main into the main, "junction pieces," or branch tiles, are necessary. These may be Y's or T's, the Y's usually being preferred. The use of a Y is almost indispensable at junctions, in order to prevent an accumulation of soil and displacement of the tiles at that point. "Collars" are tile rings two or three inches long, which are slipped over the outside of the tiles to cover the joint. They pre- vent soil from washing in and hold the tiles in place ; but they cost so much and the incovenience of applying them is so great that they are impracticable except where there is great danger of tiles being displaced, as where the fall is sharp and the soil rather light. "Enlarging tiles," which taper, are useful at the point where the drain changes from one size to a larger size, as from a 3-inch 222 SOILS to a 4-inch, making the joint much more perfect than if the 3-inch tile were butted against the larger one. When buying tiles it is important to stipulate that all be perfect. Some lots of tiles contain many that are not fit to be used in a drainage system; one poor tile may undo the work of many good ones. Good drainage tiles do not crumble and when struck on iron have a ringing, metallic sound, not a dull, wooden sound, showing that they have been well burnt. Tiles that are badly warped or chipped at the ends are worse than useless. They should be smooth inside and cut square on the ends. Glazed tiles are more durable than unglazed, but there is little difference in efficiency. SIZE OF TILES A system of tile drainage should have sufficient capacity to carry off the excess water of the heaviest rains that fall, inside of twenty-four to forty-eight hours. The time when under-drains are most taxed is in early spring when the soil is already saturated. The greater the fall of the system the smaller the tiles may be, because water is carried off more rapidly. Formerly 1- and l|-inch tiles were quite commonly used for lateral drains; now 2-inch tiles are the smallest used, for it costs but little more to make them than the smaller sizes. They are easier to lay to grade and safer. Two- inch tiles are still used in the Eastern States, but not so much as formerly, being largely replaced by the 3-inch size. The sizes of mains and sub-mains are capable of fairly accurate calculations, as their capacity varies with the square of their diameters. THE DRAINAGE OF FARM SOILS 223 Wheeler makes the following estimate of the relative capacity of different sizes of tiles : A 2^-in. tile will carry l£ times as much water as a 2-ln. tile " 3 " " " " %\ " " 4 ' ( a t ' " 5 " 5 ' C (C 4 ' " 5£ " 6 ' it i " 12£ Ln8 ' C( c " 25 a a << a Chamberlain gives these rules for estimating the size of mains: When the fall is not more than 3 inches in 100 feet the diameter of the tiles should be squared and the result divided by 4. Thus a 3-inch main will drain 2| acres; a 4-inch main, 4 acres ; a 5-inch main, 6| acres ; and so on. When the fall is greater than 3 inches, square the diameter and divide by 3. In this case a 3-inch main will drain 3 acres; a 4-inch main, 5 J acres; a 5-inch main, 8^ acres; a 6-inch main, 12 acres, etc. These rules have been found to be quite reliable on ordinary soils. On heavy soils the different sizes will drain more than the area given, as water moves through them more slowly. Elliott says, "For drains not more than 500 feet long a 2-inch tile will drain 2 acres. Lines more than 500 feet long should not be laid of 2-inch tiles. A 3-inch tile will drain 5 acres and should not be of greater length than 1,000 feet. A 4-inch tile will drain 12 acres; a 5-inch tile, 20; a 6-inch, 40; and a 7-inch tile, 60 acres." The capacity of tiles is thus seen to vary widely in the judgment of experts. The size of the main increases as it proceeds toward the outlet and receives the drainage of the larger area. 224 SOILS DIGGING THE DITCH The largest expense of establishing a system of under-drainage is in moving the soil. Many steam and horse-power machines have been invented for doing this work, but most of it is still done by hand. Most of the machines require more power than can ordinarily be furnished conveniently; but some, that are designed merely to loosen the surface, are very serviceable. If a large area is to be drained it will be economy to hire men who have had expe- rience in the business, when they can be had. In order that no more soil may be moved than is absolutely necessary, it is customary to stretch a stout line 4 or 5 inches back from where one side of the ditch should be and cut true to the line. The width of the ditch on the surface need not exceed 20 inches, even for large mains, and 12 or 15 inches is ample for lateral drains. Beginners always dig ditches wider than is necessary. The ditches should taper downward evenly, being but 4 or 5 inches wide on the bottom, if 3-inch tiles are to be laid. In case the drains are laid more than 4 feet deep it may be necessary to make them a few inches wider. The surface soil may be partly moved with a plow if it is not very heavy or very stony. After the line is stretched a very deep furrow is turned with an ordinary plow, which may then be followed by a trenching plow, or another furrow may be turned with a landside plow. Part of the soil is thus moved out, and part is so loosened that it is handled easier. The trench is then finished with a spade. Many, however, prefer to open the entire ditch with a spade. An ordinary spade answers the purpose for a small job, but a ditching THE DRAINAGE OF FARM SOILS 225 spade, which has a narrow, curved blade about 18 inches long, is preferable. The soil should oe placed on the edge of the ditch, not thrown away from it. Both surface and subsoil are placed upon the same side of the ditch, and usu- ally it is not necessary to keep them separate. In some cases it may be cheaper to have the ditch dug by contract, except grading the bottom to receive the tiles, which should be done by an experienced and careful hand. If quicksand is encountered the sides of the ditch will need to be supported with boards, braced by sticks between them. Besides the spade, a tile hoe is a convenient but not indispensable tool. It is used for cleaning out and grading the bottom of the ditch. It comes in various sizes, according to the size of the tiles laid, and makes a half-round groove into which the tiles fit snugly. Ditching should be begun at the outlet and the main should be laid back to the first lateral. This junction is then made and two or three tiles of the lateral are laid before the main is laid further. LAYING TILES It is well to begin laying the tiles as soon as a strip of ditch is graded, for if a storm arises enough water may run into the bottom of the ditch to spoil the grade. Usually it is best to begin laying the tiles at the lower end of the system. They are first placed in a line along the edge of the ditch. The man who lays the tiles may stand in the ditch or he may stand on the edge of it and handle the tiles with tile hooks, with which they may be turned and twisted until the joints are satisfactory. Professional tile layers often do very rapid and satisfactory work without getting 226 SOILS into the ditch; inexperienced men had better lay the tiles by hand. The joints should be as close as possible; here is the place for extreme care. There is no danger that water will not enter the tiles freely enough, even with the closest joints, but there is always danger that soil will wash into the tiles. All tiles have a slight curve; turn them in the bottom of the ditch until they fit against each other snugly. If junction or branch tiles are not used at the junction of the laterals with the main, the former may be let into the latter through a hole cut into the main with a small pick or short, pointed hammer; but the two should be joined very neatly and the joint packed with clay. A better way is to pick a hole in the top of the main, another near the end of the last tile of the lateral, and place the two open- ings together after plugging the end of the lateral with a stone and clay. Some drainage experts think it pays to put cloth, paper, sod, and other coarse materials over the joints before filling in the soil: others find this is not necessary. FILLING THE DITCH In filling the ditch be especially careful not to displace the tiles and to get the soil packed tightly about them, so that there may be no chance for a water channel outside the tiles. Usually it is best to cover the tiles four to eight inches deep as fast as they are laid, using the soil last thrown out, if it is clay. This is done by a man in the ditch following the man who lays the tiles, while a third man on the bank shovels in soil, being careful not to throw in large stones. This is tramped around THE DRAINAGE OF FARM SOILS 227 and over the tiles, care being taken not to move them out of line. The remainder of the ditch is filled very rapidly in any way that is handiest. An ordinary scoop scraper may be used if the team is hitched to it by a long chain and works on the opposite side of the ditch. Sometimes the ditch may be filled most economically entirely by hand. A wooden scraper shaped like a snow plow drawn backward is some- times serviceable for filling a ditch when the soil is mellow. A road scraper is very serviceable for finishing the filling after the ditch is nearly closed. It is well to tramp the soil several times in the process of filling. Leave the soil around the ditch rounded, for it will settle. It is not absolutely necessary to fill in the subsoil first and the surface soil last, but this should be done as far as is convenient. OBSTRUCTIONS IN TILE DRAINS If the grade is too flat to carry off the water before the sediment in it settles, or if any tiles are displaced, the drains may soon become partially filled with soil. This is especially likely to occur when the subsoil is clay. The time of greatest danger is the first two years; after that the soil becomes compacted about the joints. It is some- times necessary to dig up poorly laid tile drains every three or four years and clean out the mud in them. When the fall is sharp and uniform, and the joints well made, there ought not to be any trouble from this source. The filling of tiles by the roots of trees is another possible cause of trouble. These often enter the joints and fill the interior of the tiles with a dense 228 SOILS wad of small roots, completely closing the bore. Willows, elms, white maples and other water-loving trees are the worst offenders. If possible, avoid laying drains within thirty to sixty feet of trees, according to the size of the trees. If a line of tiles must run close to a tree use sewer pipe near it and cement the joints. This is the great difficulty in tile-draining orchard land. The roots of other farm crops rarely clog a tile drain. The obstruction of drains by animals, as frogs, muskrats and rats, is prevented by covering the outlet with wire netting or iron grating. When a drain is clogged the land near the ob- struction gradually becomes wet, and but little water flows from the outlet. A partial obstruction may sometimes be removed by flushing, which is done by closing the outlet of the drain until the drain and the surrounding soil are filled with water, then opening it. The comparative level at which water stands in small deep holes dug parallel to the suspected drain will usually locate the exact point of an ob- struction. COST OF LAYING TILE DRAINS This is from $12.00 to $60.00 per acre according to the number of ditches opened, the nature of the soil and the cost of tiles and labor. The more the larger sizes of tiles are used the greater is the expense. The expense of digging the ditch and lay- ing the tiles should average about $3.00 to $4.00 per 100 feet for laterals, and more proportionately for the mains. The cost of tiles varies greatly; the list prices of the manufacturers are usually THE PLOW MAY BE USED TO FACILITATE THE REMOVAL OF SURFACE SOIL FOR DRAINS Usually, however, the work is done entirely with a ditching spade 77. OUTLET OF A TILE DRAIN CLOGGED BY SOIL SO THAT THE DRAIN DOES NOT WORK It should be kept free of all obstructions, and is preferably bricked up. A wire screen keeps out small animals that might obstruct the drain THE DRAINAGE OF FARM SOILS 229 subject to large discounts. On an average they will cost: 2-inch tile $1.00 per 100 feet H <« <( 1.30 ii <• s «< it 1.50 i* « 4 ensable, but the furrows they make should be evelled off with a shallow- working implement, as a spike-tooth cultivator. The practice of ridging corn, potatoes, cotton, and other crops is responsible for much gullying. Unless ridging is made necessary by poor drainage, it is rarely a profitable practice. Deep plowing and deep planting may accomplish the same re- sult, with less danger. Level culture should be practised wherever erosion is likely to be serious. The somewhat detailed attention given to ero- sion in this chapter is not out of proportion to its importance in the farm economy of this country. Erosion is stealing from many farms the fertility that should have been bequeathed to posterity. There should be an increasing concern among farmers about this phase of soil fertility. FALLOWING AND SOIL FERTILITY Fallowing — leaving land uncropped for one or more seasons — was a common farm practice up to the beginning of the last century. The Mosaic law commanded that land should be fallowed one year in seven. At present it is rarely practised in America, except in the arid regions, although still quite popular in many parts of Europe. The chief reason for this is the rapid improvement of tillage tools. The crude tillage tools of earlier years pulverised the soil so imperfectly, that the in- crease in available plant food* by weathering was very slow; hence crops quickly exhausted the soil. It was soon noticed that if land was cultivated while it was being rested it would be more productive thereafter. The chief advantage MAINTAINING SOIL FERTILITY 297 of the old-time fallowing was that it promoted weathering and so increased the amount of soluble plant food in the few inches of surface soil that were stirred by the clumsy tools of that time. Modern tillage tools prepare the soil so thoroughly and deeply that a larger area is laid under tribute, and weathering, and other agencies that increase fertility, have a better opportunity to work. There are still occasions, however, when fallowing is beneficial and sometimes very essential. Fallowing to Store Water. — The value of fallow- ing in American farming is chiefly in storing water in the soil and cleaning the land of weeds, rather than in increasing the amount of soluble plant food in the soil. In the semi-arid and arid sections of the West where "dry farming'* is practised, fallowing is often indispensable. The land is cropped one year and fallowed the next, or it is fallowed one year in three. Fallowed land is plowed and harrowed so that the soil will receive and hold all the rainfall. Where the rainfall is less than ten to fifteen inches such a proceeding may be absolutely necessary. King found that the fallowed part of a certain field contained 203 tons more water per acre in the spring succeeding the fallow than the part that was not fallowed. Even at the end of the season, after large crops of grain had been taken from the land, it contained 179 tons of water more than the unfallowed land. This shows that summer fallowing has a marked and lasting influence on the moisture content of soils. It is likely that fallowing to store water will always be practised in America far more than fallowing for any other specific purpose. Fallowing to Set Free Plant Food. — Fallowing increases the amount of available plant food in the 298 SOILS soil, especially nitrogen. The soil of the fallow field is stirred frequently and is warm and moist, conditions that are favourable to making inert plant food soluble. This plant food is stored for the crop of another year unless the soil is leachy, in which case much of the quickly soluble nitrogen may be lost. This is the chief disadvantage of fallowing on certain soils. It is doubtful if it is ever wise to fallow land chiefly for the purpose of increasing its supply of available plant food. Usually the same result can be secured, without losing the use of the land, by a rotation of crops and better tillage. Fallowing may be used to advantage in some cases for cleaning land of weeds, especially the weeds that gain a foothold in grain farming. Bare summer fallowing is an excellent means of getting rid of both perennial and annual weeds, especially the Canadian thistle. But if summer-fallowed land is not kept harrowed, fallowing may increase weediness. The Methods of Fallowing. — Land that is to be fallowed should be plowed early and at once fitted thoroughly. Most of the weeds will immediately start to grow ; these may then be killed by plowing again or by harrowing. In some sections fallow land is plowed three times during the season. Such a mixing and interchanging of particles cannot help but make a soil more fertile, as well as increase its moisture content and improve its tex- ture. In some cases one plowing and one to three harrowings, at intervals during the summer, may be about as effective as three plowings. The im- portant point is to keep noxious weeds from start- ing; some fallows are allowed to become foul with weeds. If the fallow is to be followed by rye or MAINTAINING SOIL FERTILITY 299 wheat, the last plowing is usually given before the middle of August, so that the soil may have time to settle and become compact before seeding. Oftentimes a short fallow may be practicable. This consists simply in tilling the soil during the few weeks that may elapse between the harvesting of one crop, as barley, clover, or oats, and the sow- ing of the next crop, as wheat. Occasionally land is left idle for several weeks, or longer, when it ought to be at work, either growing a green-manure to plow under, or being subjected to the weathering that is set in motion by tillage. Summary of Value of Fallowing. — In American farm practice, fallowing is used to advantage chiefly for increasing the water content of soils, and for cleansing them of weeds, rather than for increasing their supply of available plant food and improving their texture. It is often practicable in the dry sections but rarely in the humid sections. It is not adapted to leachy soils. In this country fallowing is practised chiefly in the arid and semi-arid regions, under dry farming, and mostly in the culture of wheat and oats. ROTATION OF CROPS Rotation of crops is the order or system in which crops are grown upon the same land, and refers to the sequence of crops when a number of different kinds are grown, in distinction from the one crop system. Very early in the history of agriculture it was noticed that many crops grew much better if they followed some other crops than if grown con- tinuously on the same land. Centuries ago En- glish farmers divided their land into three parts, 300 SOILS one part being in spring-sown grain, another in fall-sown grain, the other third being summer- fallowed. In more recent years farmers have noticed that it not only benefits some crops to follow different crops, but also that it often makes a de- cided difference what crops are associated in the rotation. The practice of growing different crops in suc- cession, instead of one crop continuously, did not originate with man. Crop rotation is almost universal in Nature. The oak forest is cut off and soon the land is shadowed with pines. The pines grow lusty, fall before the woodman's ax, and oaks or white birches take their place. The low-bush blueberry and the arbutus flourish in the hardwood clearings. Everywhere we niay see that Nature rarely follows one of her crops with another of the same kind of plant. The wise economy of her rotations we may study with profit. WHY A ROTATION IS BENEFICIAL A rotation is usually beneficial in several ways; sometimes one benefit is most pronounced, some- times another. The explanation that one naturally thinks of first is that it affects the relative supply of the different plant foods in the soil. Every farmer knows that some crops are "harder upon the soil" than others. The chemist, also, says that some plants use more plant food than others. Different crops take from the soil, not different kinds of plant food, as some suppose, but different amounts of the same plant foods. Thus wheat needs more phosphoric acid and less potash than fruits. Oats require more potash than corn. Crop- ping a soil continuously with corn, for example, is MAINTAINING SOIL FERTILITY 301 likely to exhaust it sooner of the available plant food that corn needs than if clover, wheat and potatoes are grown in a rotation with corn. The producing power of a soil is measured by the amount of the essential plant food it contains which is least abundant; if it contains 20,000 lbs. of potash and only 2,000 lbs. of phosphoric acid, it can produce no larger crops than the supply of available phosphoric acid is sufficient to nourish. A rotation of crops, if it is well planned, does not subject the soil to a continuous drain of plant foods in the same pro- portions; it changes the proportions and so makes the plant food in the soil go farther. The Different Rooting Habits of Crops. — Another reason why a rotation of crops is easier on a soil than single-crop farming results from the different rooting habits of plants. Timothy or blue grass, for example, are shallow-rooting; they draw most of their nourishment from the upper six inches of soil. Clover and alfalfa are deep- rooting ; their long tap roots penetrate many feet deep in all ordinary soils, gathering a large amount of food below the depth to whicn the roots of timothy and blue grass penetrate. The roots of corn forage deeper than the roots of oats. Mangels, sugar- beets and parsnips root deeper than round turnips and table beets, and so on with other farm crops. The relation of this fact to soil fertility is the advantage to the soil of having crops grown upon it that root at different depths. A soil may be almost exhausted of available plant food for shallow-rooting crops yet contain much for deep-rooting crops. The fertility of the soil is thus conservea by ro- tating crops that not only differ in their demands upon the soil but also in the relative area of soil that they place under tribute. 302 SOILS A third advantage of rotating crops, in its rela- tion to soil fertility, is the opportunity provided for improving the texture of the soil. When crops are harvested the roots and stubble are plowed under, and since crops vary in the amount of herbage returned, and the depth and extent of the root system, there is greater likelihood that all parts will be benefited by the humus resulting from the decay of roots if several crops are grown. Further- more, a rotation permits the use of cover crops, catch crops, and other means of improving texture, as discussed in Chapter XII. Rotation oj Crops and Weediness. — Certain weeds go with a certain crop ; they seem to find a niche in its cultivation that just fits their needs. Thus we have quack grass in the asparagus bed, purslane in the onions and Canada thistles in the wheat. Furthermore, some crops can be kept free from weeds much easier than others. Note how much faster weeds multiply when sown crops are grown, as rye, oats or wheat, than when crops that are inter-tilled are grown, as corn and potatoes. In this country, weeds cause the greatest loss in the grain fields of the West, where continuous cropping, with or without summer fallow, is practised. Wherever the single-crop system is dominant, weeds become a serious nuisance. A specific instance where a rotation of crops may be used for cleaning land of weeds will call attention to the usefulness of the practice. Wild carrot and plantain are very troublesome weeds in some localities, especially in the Northeastern States. These plants do not produce seeds until mid-summer. If a two-year rotation of wheat or rye and clover is practised these weeds may be almost completely exterminated, for as soon as MAINTAINING SOIL FERTILITY 303 the clover is cut they immediately throw up their flower stalks. These may be mowed a few weeks after the clover is removed, but a better way is to plow the clover stubble soon after the first cutting, in preparation for winter wheat or rye. The value of a rotation of crops for killing weeds depends largely upon the fact that different crops receive different kinds of tillage. Different tools are used. Weeds that escape destruction under the system of tillage given one crop are caught by the tillage of another. Sown crops, especially grains, should be rotated with tilled crops. Grains cover the ground sparsely and there is no inter-tillage, so weeds like the "paint-brush," Canada thistle, dock, and Russian thistle, find an excellent oppor- tunity to gain a foothold. Some crops that grow very rapidly and quickly shade the ground, as potatoes, are not as apt to be weedy as slow-growing and sparse-foliage crops. This should be re- membered when planning a rotation. Insect and Disease Injury Lessened by Rotation. — • Each crop has its own peculiar troubles. Some of these are fungous diseases. These are spread mostly by seed-like bodies called spores; each disease has a different kind of spore, which can cause the disease only upon a certain crop. Thus the spore of potato scab can make scab on po- tatoes, but no other disease, either on potatoes or any other plant. The longer a certain kind of crop is grown upon the same piece of land the more the land becomes infected with parts of diseased plants and with spores, and the greater is the like- lihood that the crop will be injured by the disease. This is particularly true of such common diseases as potato scab, and the club root of cabbages and turnips, which increase very rapidly on crops grown 304 SOILS for several years on the same soil. It is less true of corn smut, onion smut, and ergot, which increase slowly. A change of crops deprives these fungous diseases of the only kind of plants upon which they can feed, so they disappear. Moreover, crops are less vigorous when grown continuously upon the same land, and are therefore more susceptible to disease. A number of important insect pests of farm crops may be controlled to a greater or less extent by crop rotation. In general, each crop has its own pests, although insects often feed on more than one kind of plant. Meadows kept for a long time in grass are likely to become infested with the larvae of the May beetle, and with wire worms. A rotation will prevent this. Keep the Soil Busy. — If but one crop is grown, the soil is usually left bare during part of the year. This is poor farming, except when the land is pur- posely fallowed. No ground should be allowed to remain idle when it might be growing crops, either to sell or to turn under. The busier a soil is kept, provided the right kind of crops are grown, and provision is made for green-manuring, the more productive it should be. This is more true of Eastern than of Western farming. As land becomes dearer, it becomes increasingly important to keep it busy all the season by means of a well-considered rotation. Aside from maintaining or increasing the fer- tility of the soil, a rotation may economise labour. It distributes the labour throughout the year, since crops differ in the time when they are sown and the time it takes to bring them to maturity. This more continuous employment may be exceedingly ad- vantageous, enabling the farmer to secure cheaper MAINTAINING SOIL FERTILITY 305 and better help, and to give his stock a greater variety of foods. There is, furthermore, a con- siderable advantage in having the money for crops coming in at different seasons of the year. It is better for the average man to have $3,000 in in- stalments during the year than $4,000 in a lump. The extent to which crop rotation is practised is a reliable index to the development of the agri- culture of a region. As farming becomes more intensive, specialised and refined, rotations in- crease. In some of the Western States a systematic rotation of crops is now almost unknown. CHOOSING CROPS FOR A ROTATION One could plan an ideal rotation, so far as main- taining the fertility of the soil is concerned, which it would be utter folly to put into operation because of economic conditions — the demands of the market, the amount of help available, and similar factors. Few rotations meet all the requirements, both of the soil and of farm economy. It is usually a question of adopting the rotation that gives the most gain and the least loss; so the planning of a rotation is largely a local and personal matter. There are, however, some general prin- ciples that ought to be considered. 1. A rotation should contain as many years as is practicable of the crop that pays the greatest profit per acre. The "money crop" should dic- tate the rotation. The less profitable crops should be subservient to the money crop, and should make the soil congenial to it. If cotton is the money crop, and the soil is well adapted for growing it, build the rotation around cotton and let the other crops bolster it up. If hay is the money crop, and the 306 SOILS soil makes a strong meadow, keep the land in hay up to the point where the soil would be injured and the yield reduced by retaining it longer in sod. If corn is the money crop, grow corn to the limit of the soil's patience and rotate it with other crops that are most serviceable in maintaining the fer- tility of a first-class corn field. Maximum profit is the main point to observe in planning a rotation, bearing in mind that no crop is profitable if it is secured by robbing and impoverishing the soil. 2. A rotation should preferably contain at least one crop that improves the soil. This "green crop" may be grown specifically for a green- manure, as a catch crop of rye after corn; or a crop which is harvested, but which nevertheless improves the soil by its growth, as clover or cow- peas. The improvement may be in texture, by plowing under humus; or it may be in actual enrichment, by growing a leguminous crop, as is considered in the next chapter. If it is at all ex- pedient, a leguminous crop should be included in the rotation. 3. If possible, the rotation should include crops that feed at different depths, and that are dissimilar in habits of growth. Deep-rooting crops should al- ternate with shallow-rooting ones. 4. If the money crop is sown, the rotation should include a "cleanser," a crop that is cultivated, so that the land may be kept free from weeds. In Europe, roots, as turnips, potatoes and swedes, are commonly used as a cleanser; in this country corn and potatoes are most largely grown for this ourpose. Reducing these suggestions to a simple form, a rotation ought to contain a money crop, a manurial MAINTAINING SOIL FERTILITY 307 crop and a cleansing crop, and give as wide varia- tion in habit of growth and food requirements as is practicable. This general rule is necessarily sub- ject to many exceptions. Sometimes the whole scheme may be upset by economic exigencies, as the relative value of the different crops, the imme- diate need of the farmer of money, fluctuation in the price of live-stock feeds, etc. TYPICAL SYSTEMS OF ROTATION The number of years that a rotation may last varies from two to eight or even more. "Four course" rotations, lasting four years and including four crops, are most common. As a rule, the poorer the land, the shorter the rotation. Fixed rotations are not as common in the United States as in Great Britain. Many good farmers habitually change crops upon their land with quite satisfactory results, without following any definite system. The only sort of rotation followed by many farmers is to alternate a grain crop with a green crop, and a cultivated crop with an uncultivated crop. As this embodies two of the most important principles in crop rotation, one will not go far wrong in follow- ing these simple rules, even though specific crops are not assigned in the rotation. Any number of exigencies may arise that may make it desirable to modify or depart from a system of crop rotation ; but it is well to have some definite system in mind and follow it as closely as possible. A few examples of common systems of rotation in the United States will show how the principles outlined above are applied. 1. Potatoes, winter wheat, clover. This rotation is frequently used when the money 308 SOILS crop is potatoes. Nothing is more favourable for potatoes than to turn under a clover sod before planting. The clover is sown with the wheat or is seeded in the growing wheat in early spring. It is the manurial crop of the rotation and potatoes is the cleansing crop. This can be made a two-year rotation by plowing under the clover in early spring, in time to plant potatoes, not allowing it to mature a crop. Rye may be substituted for wheat and sweet potatoes or tomatoes for potatoes, without lessening the value of the rotation. This rotation may be secured with but one plowing. Plow the sod in either fall or spring, plant the potatoes early and use a harrow to prepare the seed bed for wheat after the potatoes are harvested. This can be made a four-course rotation by seeding with clover and mixed grasses; then it becomes an excellent rotation for the dairyman. 2. Corn, oats, wheat, grass and clover. This is a favourite in the "Corn Belt." It is economical of labour, but is open to serious ob- jection in two respects — when wheat follows oats it is not possible to prepare the seed bed for wheat properly; and two uncultivated crops of about the same feeding habits are together. It is customary to manure the corn; if commercial fertilisers are used, they are applied to the wheat. 3. Corn, wheat, oats. Where corn is the leading crop this is, in some respects, a better rotation. The chief criticism of it is that one must wait until the corn is ready to harvest before seeding to wheat, which may be so late that the wheat does not make enough growth to stand the winter. Wherever it is practicable to grow potatoes an even better corn rotation is: MAINTAINING SOIL FERTILITY 309 4. Corn, potatoes, wheat, clover. The clover sod is manured heavily before being planted to corn. This is an almost ideal rotation, since the crops of cereals alternate with a root or clover crop. Under certain conditions the crop of wheat may be dispensed with, making: 5. Corn, potatoes, clover. In this and similar rotations the second crop of clover should not be cut, but should be plowed under to enrich the soil and feed the corn. The essential point in rotations for stock farming is to provide the maximum amount of roughage and succulence. One of the most useful rotations for this purpose is: 6. Turnips, barley, mixed grasses and clover, wheat. This is the noted "Norfolk system" used ex- tensively in England. If it is not desired to intro- duce grain so frequently, this can be made a six- course rotation by cutting the grass and clover meadow three years, thus keeping one-half the farm in hay. This rotation may be modified in many ways to meet varying conditions, as by substi- tuting oats for barley, rye for wheat, mangels or sugar beets for turnips. In this rotation the cereals are separated by roots, which is the cleansing crop, and clover, which is the manurial crop. It is one of the most perfect rotations in existence. A popular dairy-farm rotation is: 7. Potatoes, one year; corn, two years; grass and clover, three years. The corn may be put into the silo the second year. The grass and clover mixture is sown when the corn is cultivated last. If desirable, one year of corn or one of meadow may be omitted. The main object in a dairy rotation is to secure a 310 SOILS continuous supply of food. The necessity for ac- complishing this may make it necessary to adopt rotations that are not ideal, so far as maintaining the fertility of the farm soil is concerned. The abundance of manure may offset this disadvantage. When either the small grains or hay are the specialties a common rotation is : 8. Wheat or rye; clover, or clover and mixed grasses, three to six years. In the "Cotton Belt" one of the most successful rotations is: 9. Cotton, rye or clover, corn. Catch crops of cowpeas are used between these crops. In addition to main-crop rotation, catch crops and cover crops are used in diverse ways. The foregoing are but a few of many rotations in common use on American farms. In the Ap- pendix is a list of the rotations commonly practised or recommended in each of the states. These lists have been prepared by authorities on the subject and are a record of the best current practice in crop rotation. SINGLE-CROP FARMING It must not be inferred that it will never pay to grow a crop continuously on the same land. Often this is the only feasible course — as in some Western grain farming; and again it may be best for certain crops, as onions and tobacco. A summer fallow may be introduced instead of another crop. There are numerous instances of wheat and corn being grown continuously, with little diminution of soil fertility. In the noted experiments of Laws and Gilbert, in England, wheat has been grown con- tinuously on the same land for over sixty years, MAINTAINING SOIL FERTILITY 311 yet the yields for recent years are much above the average. These are scattered exceptions. The evidence is overwhelming that, in general, the single-crop system, if continued very long, means ruin. Mention should be made of "succession crop- ping," as practised by market gardeners especially. By setting out plants from hotbeds, by inter- planting and by very high culture, they are able to take three or four different crops from the same land in a single season. The value of the crops removed in one year by skilled market gardeners often reaches astonishing figures. One Massa- chusetts gardener is reported to have secured a net profit of $2,000 an acre, in 1906. The chief aim of the market gardener is to keep the land busy all the time. He depends little upon the natural fertility of the soil, but mostly upon the very large amounts of manures and fertilisers that he uses, so his rotation is chosen for its economic advantages, rather than for the main- tenance of fertility. SELLING FERTILITY The maintenance of fertility is a larger and broader problem than how to utilise home re- sources to advantage, and how to buy fertilisers economically. The farmer should ask himself, "How much fertility am I selling from my farm each year ?" The soil is a great bin of plant food from which we draw a small supply each year. It is not like a bin of wheat — to be drawn on each year until exhausted, because it is constantly re- ceiving new food from the decay of plants, weather- ing of stones and other sources. But cropping 312 SOILS does impoverish farm soils of available plant food, reducing their value for cropping, temporarily at least. This plant food is being shipped off in butter, eggs, hay, corn, apples, wheat, cotton, potatoes, and in every other crop that goes to market. The fertility that goes off in crops never returns to that land. But some crops, or part of them, stay on the farm. These are the crops that are fed to stock and the manure returned to the land. A Bank Account with the Soil. — In reality, when we sell crops we are selling the fertility of the soil, not only the nitrogen, potash and phosphoric acid the crops have used, but also a certain amount of good texture or " condition" which is lost by the growth of the crop. A farmer should know the relation between the price received for his crop and the amount of plant food contained in it. The amount of fertility lost to the farm by the sale of different crops varies greatly. The loss in grass and cereal crops is much greater than in vegetable and fruit crops. If a ton of wheat, which contains 38 lbs. of nitrogen, 19 lbs. of phosphoric acid and 13 lbs. of potash, sells for 60 cents a bushel, the nitrogen in it sells for 41 cents a lb., and the phosphoric acid and potash for 14 cents a lb. If a ton of milk, which contains 12 lbs, of nitrogen, 4§ lbs. of potash and 3| lbs. of phosphoric acid, is sold for $30, the nitrogen in it brings $2 per lb., and the phosphoric acid and potash about 70 cents per lb. If, however, cream or butter is sold and the skim milk fed to hogs, calves or chickens, most of the plant food is recovered in the manure of these animals. MAINTAINING SOIL FERTILITY 313 Hay is one of the most exhausting crops. If it is sold, practically the entire crop leaves the farm, carrying from it large quantities of plant food, which is sold at a very low price per pound. When a crop that contains a large amount of plant food, as hay, sells for a low price, it is usually best to sell it not as hay, but as a manufactured product — as milk or butter, for example. The farmer ought to think of the several thousand pounds each of nitrogen, potash and phosphoric acid that his soil probably contains, as so much capital stock. He draws a cheque upon his soil bank every time he removes a crop from it. He should see to it that every pound of plant food that leaves the farm as raw material — like grain , hay, potatoes, or as manufactured products — as milk, butter, beef, pork, eggs, wool, brings him a profitable income. On investigation the farmer may find that he is selling plant food at a ruinous price. Then there are two alternatives: to grow other crops which contain less fertility and sell higher per pound of plant food contained; or to sell the crops as manufactured rather than as raw material. This enforces the necessity of introducing stock of some kind to manufacture the crop into products like butter, eggs, or pork, which, when sold, do not diminish the farm fertility bank account to any appreciable extent. Then begins di- versified farming, of which stock husbandry is the backbone. The Minnesota Agricultural Experiment Station has published the results of experiments on the loss of fertility under different systems of farming. The gain of nitrogen from growing clover is not considered in the following figures: 314 SOILS APPROXIMATE LOSS OF PLANT FOOD IN ONE YEAR FROM 160 ACRES OF LAND UNDER DIFFERENT SYSTEMS OF FARMING System of Farming All grain Mixed grain and general Mixed potato and general Stock Dairy Phosphoric Acid Pounds 2,460 1,003 991 35 76 Potash Pounds 4,020 1,047 2,435 59 85 Nitrogen Pounds 5,600 2,594 2,363 898 809 Commenting on these results the report says, "With stock farming, when all the crops are fed to the stock on the farm and a small amount of milled products is purchased, there is practically no loss of potash and phosphoric acid except in handling the manure. When the manure is well cared for the loss of these plant foods is less than is stated. When all the skim milk is fed on the farm and a part of the grain exchanged for more concentrated mill products, there is no loss but a constant gain of fertility." These figures are, of course, only approximate and subject to much variation; but they show where the heaviest drafts fall on the soil under different systems of farming. The type of farming followed, whether stock, fruit, grain, hay or otherwise, is usually determined by economic conditions that are of far greater im- portance than the question of maintaining soil fertility. A farmer grows the crop or rears the stock that he thinks will be most profitable in his situation as regards soil, climate, market and sim- ilar factors. He is more concerned about growing crops that pay this year and next, than about hand- ing down to his son a farm on which the soil has not MAINTAINING SOIL FERTILITY 315 been seriously impaired in fertility. But the larger consideration of maintaining soil fertility for other generations surely deserves serious thought from the farmer of to-day. In any case it is likely that he will have the subject brought to his attention by self interest. The effects of pursuing a system of farming that continually takes from the land and returns nothing or little to it may be seen within a generation, or even within a decade. Each year thousands of American farmers are radically modifying their systems of husbandry for the pur- pose of maintaining the fertility of their farms. Sometimes this must be done, apparently, at the expense of self interest, at least for a few years. Some of the crops that have paid best either must not be grown at all or grown less frequently. But a series of years may tell another story. DIVERSIFIED FARMING The number and kinds of crops grown are largely determined by the distance to the market. Eastern farmers, who are close to large markets, grow a greater variety of crops than Western farmers. Cot- ton in the South, corn in the Central States and small grains in the West are the most conspicuous examples of single-crop farming in the United States. There are many small single-crop areas, as Aroostook County, Maine, which is devoted largely to the culture of potatoes. Single-crop farming does not necessarily mean that but one crop is grown; it may mean that one main crop is grown with a few secondary crops. Small grain farming, even though wheat, oats, and barley are grown, would be considered, in its effect on soil fertility, as single-crop farming. 316 SOILS The chief disadvantages of a too rigid adherence to single-crop farming are the unequal distribution through the year of labour and of returns, and the certain exhaustion of the soil sooner or later, by almost continuous cropping with one plant or close- ly related plants. Single-crop farming, if persisted in, means ruin. Diversified farming is one of the strongest props of soil fertility. Undoubtedly the farming in some sections of the country, especially the far West, must be single-crop, or practically so, in order to be profitable, for the farmer must grow what he can sell at a profit. But other crops should be introduced whenever possible. It is very hard to persuade the farmer who has been growing corn, or wheat, or cotton, and little else, that it will be for his interest to diversify his farming. These have been his money-making crops. Yet the time alwavs comes when he is forced, by the lessening fertility of his soil, to introduce "green crops," to feed more stock, and to rest his over- worked land. KEEPING LIVE-STOCK TO MAINTAIN FERTILITY Theoretically, the most economical way of maintaining the fertility of the soil is by growing crops to feed live-stock and returning their excre- tions to the soil; practically, this is the most en- during method. If all the conditions for caring for and applying manures were perfect, from 70 to 90 per cent, of the plant food in what the animals eat would be returned to the soil in the manure and urine. Practically a much smaller per cent, than this is recovered, for there is always loss in storing and handling manure. But even granting that the percentage of plant food that can be recovered in MAINTAINING SOIL FERTILITY 317 manure is considerably less than is commonly stated, the keeping of live-stock remains one of the most economical methods of maintaining soil fertil- ity under certain conditions. These are largely eco- nomic ; as to whether the animals or their products will find a ready market at profitable prices. The stock-feeding solution of the problem of maintaining soil fertility is meeting with more and more favour in every part of the country. The farmers of the West, who have seen their crops gradually dwindle under single- crop farming, are awakening to the necessity for a more diversified husbandry, and especially stock husbandry. The farmers of the South are begining to realise that it will pay to split the time-honoured rotation of corn and cotton with a green crop, which may be fed to stock and the manure used to bind together the clay soils which wash so badly. One-third of the land now in cotton could be made to produce as much cotton as at present, if the other two-thirds were used for forage crops for stock. The South has the great advantage of an almost continuous grazing season. In every branch of crop produc- tion there is a renewed appreciation of the oldest and most reliable three-course rotations — the land produces crops, the crops pass through farm animals, the manure is returned to the land. Even the great practical value of green-manuring, which has been demonstrated so conclusively the past few years, has not diminished the demand for animal manures; and green-manuring is usually resorted to only when a sufficient quantity of animal manure cannot be had. This growing appreciation of animal manures and of stock husbandry as a means of maintaining fertility is not misplaced. There are few parts of 318 SOILS the country where live-stock husbandry, in at least one or more of its many branches, is not prac- ticable. There is in progress an evolution toward diversified farming, which is based very largely upon the advantages of combining more or less stock husbandry with all other types of farming. Undoubtedly there are conditions when the keeping of stock is impracticable, or when the same results may be secured more advantageously by the use of green-manures, by buying animal manure from others, or by using commercial fertilisers. But these cases are few as compared with the great majority of American farms upon which stock husbandry, in some form, ought to be one of the chief means of maintaining fertility. Remember the Flemish proverb: "No grass, no cattle; no cattle, no manure; no manure, no crops." THE EXCRETORY THEORY OF SOIL FERTILITY There has been advocated during the last two or three years a new theory of soil fertility, especially as it relates to the rotation of crops. In the fore- going pages are presented the most commonly accepted beliefs and practices concerning soil fer- tility; what it is and how it may be increased and maintained to best advantage. Now comes a radically different interpretation of the nature of the Eroblem from a few scientists, whose conclusions ave been reached after extended study and are therefore entitled to a very careful hearing. Do Plants Excrete? — The most important point in the new theory of soil fertility is the positive statement that the roots of plants do excrete sub- stances that correspond in function to the excretions MAINTAINING SOIL FERTILITY 319 of animals. This is used to explain the value of a rotation of crops. We have been accustomed to believe that the reason why a rotation of crops results in increased yields is because the different feeding habits of the crops bring a larger area of soil under tribute, and equalise the demand upon it; because it improves the texture of the soil; be- cause it alleviates weediness, disease and other difficulties. The new explanation is that the bene- fit of rotating crops is not due so much to those factors — although their importance is not denied — as to the fact that a rotation puts a new kind of plant into a soil that has become clogged with the excretions of the old crop and which has therefore become so "unsanitary" that the old plants can- not grow well. The new plant is not injured by the excretions of its predecessor and so makes a vigorous growth. The second radical change of view that the new theory introduces is in regard to the action of manures and fertilisers. We have been believing that the value of supplying manures and fertilisers to the soil is that they actually enrich it with the plant food they contain and that this plant food that we apply is actually needed by the crop and is used by it. The new conception is that manures and fertilisers are valuable chiefly because they aid in renovating the soil, or in cleansing it of the plant excretions, or "toxic" matter, although they do supply plant food. In other words, fertilisers are chiefly beneficial not because they enrich soil but because they purify it. They act not upon the plants but upon the soil; they purify the soil from the excreta of the crop that has been grown and so affect the growth of the crop that is to be grown. No soil physicist would champion a theory that 320 SOILS so completely controverts our generally accepted beliefs unless there were abundant and weighty evidence to prove that it is at least plausible. It will be impossible to give here more than a bare summary of the abundant evidence submitted in support of the new theory. Briefly stated the main lines of argument are: 1. Practically all soils, including those that now produce poor crops or are said to be worn out and supposed to be exhausted of available plant food, are really rich in available plant food. 2. The cause of their unproductiveness, then, is the condition of the soil, not its chemical content. The problem of soil fertility is not concerned so much with the amount of plant food in the soil as with the condition of the soil. 3. Plants excrete from their roots poisonous substances which are to the plants what manure is to animals — the wastes. If the same kind of plant is grown continuously on the same land, the soil becomes so clogged with this plant manure that this kind of plant will no longer thrive in it, but other kinds of plants will. 4. A water-culture of an unproductive soil — an exact duplication of the soil water in that soil upon which plants feed — will not grow plants well until the impurities in it have been removed with carbon black; after this is done plants grow very vigorously in it. The chemical com- position of the water-culture is the same as that of the soil water of the unproductive soil in the field. 5. Humus is Nature's carbon black. If an abundance of humus is present in the soil it absorbs these plant excrements and the soil is kept in a sanitary condition. 6. Commercial fertilisers are valuable not merely "■si c E.S 3.3 cd H "Boa < £&§ •c n "6-S S o a *- 1- P, C3_S C *J2 oj a*~ c PC s a „ rf . - c > & 3 C 1* ' 90. HAY THAT WILL SOON BE BALED AND SHIPPED TO THE CITY The plant food in the hay is then lost to the farm. But if the hay were fed to cattle, most of the plant food in it is recovered in the manure. In selling crops we sell the fertility of the land 4gj fej*r, . . ■S3E£r£> ■ , It- ' < 91. CLOVER FOLLOWING WHEAT— ONE OF THE COMMONEST ROTATIONS IN THIS COUNTRY A rotation of crops is necessary to the highest success in most types of farming. If possible include a legume, as clover, in every rotation MAINTAINING SOIL FERTILITY 321 for the plant food they contain, but also for their cleansing action upon the soil. Manures benefit the soil chiefly because the humus in them cleanses the soil. 7. The practical application is to rotate crops, and to use farm manures and green manures, which supply the humus that cleanses the soil of plant excretions. In the wild the soil cleanses itself by the constant addition of decaying plants. The clash between the current belief and the new belief is mainly this : The prevailing belief explains the unproductiveness of soils that the chemist finds to be very rich in plant food by saying that the soil is in poor texture and hence has not the conditions of warmth, aeration and moisture that are essential to plant growth. The new conception explains the same situation by saying that the worn-out soil has become unsanitary because of an accumulation of excretions from the roots of plants, not enough humus being present to absorb them. These two interpretations of the cause of infer- tility are radically different, but there is no dispute about the remedies. In either case they are good tillage, a rotation of crops and the addition of humus to the soil in the form of farm manures and green manures. In either case these remain the most valuable means of maintaining the fertility of farm soils. So the farmer will continue to rotate crops, and to use barn and green manures, unmind- ful of the controversy that is being waged in the scientific world concerning the exact way in which they benefit the soil. CHAPTER XII GREEN MANURING AND WORN-OUT SOILS ONE of the most significant phrases that has recently come into our agricultural vocab- ulary is "Keep the soil in good texture." The older farmers of to-day heard nothing about this in their early years, although many of them were skilful in securing the results now expressed by these words. Like many another idea in agriculture, good texture has been talked about and exploited to a degree that is not, perhaps, com- mensurate with its real importance in the successful tilling of the soil. Good texture, like the liming of soils, is but one of many important factors that enter into that most complex problem of modern agriculture — how to maintain the fertility of the soil. However, it is a subject that is not generally understood by those who till the soil, and one that cannot be overlooked or disregarded without loss. There are thousands of acres of land that produce indifferent or unprofitable crops for no other reason than that the soil is poor in texture. WHAT IS MEANT BY " GOOD TEXTURE* ' Land is in good heart or good texture when it is in the right physical condition for growing crops. This means that it possesses the qualities expressed by such common farm words as mellow, loose, friable, porous, easy to work; and is not hard, 322 MANURING AND WORN-OUT SOILS 323 cloddy, lumpy, leachy. It is not concerned with the mere richness of the soil in plant food, but it is concerned with the way in which that plant food is served to the growing crops. It does not mean the amount of water that a soil contains, but it does mean the facility with which that water is presented to the crop. In other words, good tex- ture means that the machinery of the soil is well oiled and in running order; not that there is plenty of raw material — plant food — in it, out of which a profitable crop can be manufactured. In the language of the farm, the texture of the soil is the way it " works up." Everybody who has handled soil knows exactly what is meant by that. HOW NATURE SECURES GOOD TEXTURE There are several ways of putting in good texture a soil that has become cloddy, stiff, and in "bad heart." The most practicable way, usually, is Nature's way — to keep it filled with humus. "Humus" is another word that is fast becoming established in the vocabulary and in the practice of the successful farmer of to-day. "Humus," "green manure," and "good texture" express a trinity of agricultural ideas that are improving our farming more than anything else except, pos- sibly, plant breeding. Although the term humus is now in common use, there is much haziness about the conception that underlies it. The best illustration of the use of humus is found in Nature's farming. Here is a piece of virgin soil. For centuries it has nur- tured herbs, grasses, vines, shrubs, trees. In numberless cycles plants have been born upon it, have grown to maturity, reproduced their kind, 324 SOILS died, decayed, and have returned to the soil. From their substance have sprung other plants. Each year the soil becomes richer from the return of its children and is able to nourish lustier off- spring. It may thus come to have upon it great trees, standing so high and so thick that we won- der how such a thin, rocky soil can support them. Then a farmer clears the land, uproots the stumps, subdues the herbage, and plants corn. For a few years, perhaps for many years, the crops are large; but after a while they begin to dwindle. The farmer then seeks to maintain his yields by ap- plications of fertilisers. These help some, but do not seem to restore the land to its early pro- ductive power. The farmer begins to wonder where the trouble lies. How can his pygmy crops of grain exhaust the soil more than the great forest crop of Nature's farming ? He takes a sample of his soil to be analysed. The chemist tells him that the soil contains enough of all the necessary plant foods to grow seventy-five bushels of corn per acre for several hundred years. Yet the yield has fallen from sixty to forty bushels per acre, and applications of fertilisers /though they increase the yield considerably, do not secure the results of fifty years ago. Why is this ? A Farmer's Logic. — The farmer, and I assure the reader that he is not hypothetical, then began to notice more carefully the growth of crops on different parts of his farm. One season he noticed a bigger growth of corn in a certain spot. He remembered that the thresher was set up on this spot two years before and a considerable amount of fine straw and chaff had remained on the ground and had been plowed under. He recalled that last spring the plow had pulled easier and the soil 92. LOSS OF FERTILITY BY EROSION The finest and richest soil from this field of winter wheat is being washed into the creek. Such land ought to be in sod or, at least, the drills should run crosswise of the slope A GEORGIA FIELD THAT ONCE PRODUCED A BALE OF COTTON PER ACRE, NOW RUINED BEYOND REDEMPTION BY GULLYING Shallow plowing, the lack of humus, and carelessness about "breaks" brought this about RICHNESS RUNNING OFF IN THE BOTTOM OF THE DEEP FURROW MADE BY RIDGING THIS COTTON Some day this land will be called "worn out" 95. A "BREAK" OF CORN STALKS USED TO CHECK GULLYING Note that this one collected much soil until a new gully formed over it. Hay, cotton stems, brush, weeds, etc., are also used. Many Southern hill farms need attention in this matter all the year MANURING AND WORN-OUT SOILS 325 had worked up mellower on this spot. This gave him an idea. The chemist had also told him that he could buy of a fertiliser dealer all the plant food that there is in a ton of good cow manure for two dollars, yet this farmer knew from experience that he could get better results on his land from one ton of manure than from five dollars' worth of any commercial fertiliser he had ever bought. Per- haps the manure had other values besides its plant food value. He went to the cow pasture and kicked over a heap of dry cow dung that had lain there many months. Evidently the rains must have washed out practically all its plant food. The substance that remains is mostly indigestible vegetable mat- ter that the cow has eaten; it is fibrous, holds water like a sponge, and is easily incorporated with the soil. He knows that it is good for plants, though it contains little or no plant food. Following this clue, the farmer went to his wood- land. Beneath the living plants about him are the dead and decaying trees, underbrush, herbage, leaves. He can barely trace upon the ground the outline of a one-time forest monarch that is slowly passing into mould, and already nourishes a thrifty colony of mosses and ferns. Beneath the carpet- ing leaves is the rich, black, forest mould. It is made of the leaves, branches and trunks of a genera- tion ago. It holds water like a sponge. Upon it Nature is growing a crop that must be many times more exhaustive of plant food than any crop of maize. The farmer came to this conclusion: "It is this decaying vegetation that my soil needs. My farm has been cropped with corn, oats and pota- toes for fifty years. No vegetation has been 326 SOILS returned to it except the stubble and roots of the grain, the roots of the potatoes and a few weeds. For fifty years my father and I have been exhausting the soil of its vegetable matter. No wonder the soil gets cloddier and harder to work every year; it needs more of this material to sepa- rate the particles and make it looser and more fibrous. I know why it suffers more from drought than it used to — it has not enough of the spongy material in it to hold the moisture. I am going to try growing some crop to plow under and decay in the soil. I believe it is the lack of this material more than the lack of plant food that reduces my yields." The farmer who made these remarks to me, about eight years ago, has since then more than veri- fied the accuracy of his conclusion. Each year he now devotes a portion of his farm to clover, vetch, field peas, rye, rape, or some other crop that fits into the rotation, and plows under the herbage. His soil is growing richer and his fertiliser bill has been cut in two. Soil that formerly was lumpy, "run together," and baked is becoming mellow and in good heart; its texture has been improved by the addition of humus. This farmer is only one of thousands who now make use of "green manure," as such a crop is called, for the improvement of their lands. I once heard a speaker at a Farmers' Institute say: "The key to maintaining the fertility of the soil is to have plants decaying in it all the time, as is the case in uncleared land." This statement of the problem is forceful and Eractical. He did not mean, of course, that umus alone can maintain fertility. No amount of green-manuring can enrich a soil in the MANURING AND WORN-OUT SOILS 327 mineral plant foods — potash and phosphoric acid — and there are many soils that are ex- hausted of these. Fertilisers and manures must be used to make good this loss. But he did mean that a majority of the soils that now pro- duce unsatisfactory crops, and are said to be "worn out," need the humus that comes from decaying plants more than mere additions of plant food. This practice is becoming a noteworthy feature of American farming. HOW HUMUS BENEFITS THE SOIL Humus benefits the soil in several ways. Its greatest benefit is in improving texture. Mix a little leaf mould, gathered from the woods, with a pailful of light, sandy soil ; it gives the soil more "body," and makes it less leachy. Add leaf mould to a pailful of stiff clay soil that clods, bakes and cracks in the field; the clay be- comes more porous and works up better. Wet it and it does not puddle. These same results farm- ers secure, on a commercial scale, in their fields. The relation of good texture to the fertility of cloddy land lies in the uselessness of the clods. The root hairs of plants feed on the outside of the smallest particles of soil. If, therefore, a large proportion of the soil is lumpy and in bad heart the feeding area or "pasturage" is reduced that much. This is why we hear about plant food being "locked up" in lumps — it is where the plants cannot get to it. This is why it is said, and truly, "Fining the soil may be equivalent to fertilising it." One way of fining the soil, and hence of increasing its productive power, is to im- prove the texture by adding humus. 328 SOILS Storing the Rain. — Another benefit that humus confers upon a soil is that of increasing its power to hold moisture. A sand may contain enough plant food for a crop, but the crop will not grow because the sand cannot sup- ply the plant with water — it is too leachy. Plants not only need water to drink, but water is also needed to carry food that is dissolved in it to the plants. Soils deficient in humus dry out quickly in a time of drought. There may be an abundance of plant food in the soil, but it is useless for the time being if there is not enough moisture to dissolve it and carry it to the plant. Where do you find fish- worms in a "dry spell?" I dig in the moist soil beneath the chips of the old woodpile. Chips have decayed there in the soil for years. It is full of humus, and moisture, and worms. Is not the soil blacker, richer, and more moist where the cur- rant bushes have been mulched every year with manure or straw ? So in the larger operations of the farm, the addition of humus to a soil from which it has been ''burnt out" by years of clean tillage has a marked effect in increasing the power of that soil to hold moisture. Humus Enriches the Soil. — When a plant decays in the soil it returns to the soil practically all that was taken from it. But there are additional bene- fits. In the decay of the plant certain acids are formed that help to dissolve some of the unavail- able, or unpalatable, plant food in the soil. All humus is a store of nitrogen; green-manuring is the cheapest means of maintaining the supply of this plant food. If the plants grown for green- manuring are "legumes ' they are especially valuable for adding nitrogen. MANURING AND WORN-OUT SOILS 329 TWO KINDS OF GREEN MANURE Almost any herbaceous plant has some value when plowed under as a green manure. The weeds that get a foothold in the garden and corn- field in late summer serve one useful purpose in this way. But the trouble with weeds for green manure is that we cannot depend upon them. They come in where they have a mind to, not as we desire. Usually they are rank in the hollows, where the soil is rich and needs no humus, but shun the knolls, where the soil is hard and needs humus badly. Sometimes weeds may be turned to good account for green-manuring, but usually a special crop must be grown. There is a distinction between crops for this pur- pose. They may be " leguminous ' ' plants or ' ' non- leguminous." A leguminous plant is one that, among other characteristics, bears its seeds in a certain kind of a pod, called by botanists a "legume." Peas,beans, clovers, vetches, alfalfa, soy beans, cowpeas, are examples of leguminous plants commonly used for green-manuring. If it is known that the soil is more or less lacking in the plant food, nitrogen, a leguminous crop should be grown for plowing under in preference to a non- leguminous crop, like rape, buckwheat or rye. Through the little warts or nodules on their roots leguminous plants may feed upon the nitrogen that is in the soil air, instead of drawing upon the supply that is in the soil. When these plants are plowed under, therefore, the soil is enriched with the nitrogen that they have gathered. The plants themselves are richer in nitrogen, and have a higher feeding value, when the nodules are on their roots. This wonderful process of "nitrogen-fixing" has 330 SOILS far-reaching practical application. The bacteria in these nodules, which can be seen in various sizes on the roots of most legumes, are so small that it would take 10,000 of them placed side by side to measure an inch. Yet these tiny germs save the farmers of this country millions of dollars that would otherwise have to be spent for fertilisers containing nitrogen. If the soil does not need nitrogen, but does need humus, a non-leguminous crop like rye or rape may be grown. The leguminous plants, however, are the great soil "renovators." The clovers in the North and the cowpea in the South have built up thousands of acres of soil and vastly increased their producing power. Most of these plants, especially clovers and alfalfa, benefit the soil in still an- other way; they deepen it through their deep- rooting habit. Clover roots bore down into the soil several feet, bringing up and using plant food that is beyond the reach of the roots of most field crops. This is handed over to the surface soil when the plants are plowed under. But some soils will not grow clover. The kind of crop that should be grown for green-manuring, and how to grow it, depend upon the special conditions of each farm. WHEN A GREEN-MANURING CROP MAY BE GROWN If the soil is badly "run down/' and the land can be used for a green-manuring crop without sacrificing too much, the crop may occupy the ground the entire season or even for several sea- sons, as when red clover is sown in the spring, cut the following year and the second crop of that sea- son plowed under. As a rule, however, it is more MANURING AND WORN-OUT SOILS 331 practicable to grow green manures between other crops, or as a part of a definite system of rotation. The rotations listed in the Appendix point out many ways in which a green-manuring crop may be grown without losing time. The effort should be to have a "green crop" in the rotation every few years, or at least a sod to plow under occasion- ally; for there is humus and richness in a sod as well as in a crop grown especially for plowing under. Catch Crops and Cover Crops. — There are two ways of introducing a green-manuring crop for part of a season. One is the use of a "catch crop/' which is grown during the season between the time when one money-making crop is harvested and another planted. Catch crops are used most by market gardeners. Another way is to use a "cover crop," which is sown late in the season after the main crop is out of the way, so that it makes some growth in the autumn, and perhaps in early spring also. A cover crop not only adds humus to the soil but it also protects the soil from heaving in spring. It catches and holds the soluble plant food that would other- wise be lost in seepage; this is returned to the soil when the crop is plowed under in spring. It also catches the snows and drys out the soil earlier in spring. One of the commonest cover crops is rye sown in corn or cotton at the last cultivation. Cover crops are now extensively used in fruit growing. In addition to their other benefits, cover crops in the orchard make the trees mature their wood and fruit buds earlier in the fall and so lessen danger of winter injury. There are hundreds of ways in which a green-manuring crop may be intro- duced, depending largely upon the system of 332 SOILS farming and the value of the land. It does not pay to allow land to lie bare and idle, unless necessary to store water in arid farming. Keep it busy. Fill in the chinks between the money crops with catch crops or cover crops that will maintain fertility; and, if engaged in staple-crop farming, endeavour to include a green-manuring crop in the general rotation. FERTILISING VALUE OF ROOTS AND STUBBLE It is not always necessary to plow under the entire crop in order to gain substantial benefit from green-manuring ; in fact, it is seldom practicable to do so. The roots and stubble of a mature crop of cowpeas or clover contain about one-third of the soil-improving value of the crop. It is usually more practicable, particularly with leguminous crops, to harvest the hay, especially if it is fed on the farm and the manure used to enrich the farm. Thirty- five per cent, of the soil-improving value of red clover is in the roots and stubble left after the crop is cut. If the crop is fed or pastured, and the manure returned to the land, the soil gets from 80 to 90 per cent, of the full manurial value of the crop, while the farmer also gets its full value for feeding — a case of eating your cake and having it too. Stock husbandry is the key to many pleasant sur- prises like this. GREEN MANURES NOT COMPLETE FERTILISERS Green-manuring alone cannot be expected to maintain the fertility of the soil on most farms, although it will contribute very largely to that end. When crops are grown and turned under there is no 97. A HILLSIDE THAT GULLIED BADLY UNTIL COVERED WITH BERMUDA GRASS AND LESPEDEZA These hold the soil perfectly. There are many cultivated slopes that ought to be seeded 98. THE DENSE TURF OF BERMUDA GRASS This is the great soil-binder of the South. It takes complete possession of a pasture in two or three years, and is valuable for feeding. It spreads like "quack grass" MANURING AND WORN-OUT SOILS 333 actual gain of plant food, except nitrogen if legu- minous crops are grown. No green manures return to the soil any more potash and phosphoric acid than they took from the soil. No matter how long and how skilfully green-manuring is con- ducted, it will not enrich the soil with one pound of the mineral plant foods, although it may make the mineral foods already in the soil more available, which may amount to the same thing, so far as crop production is concerned. A sharp distinction should be made here : green-manuring may actually enrich the soil in nitrogen, but it cannot enrich the soil in potash and phosphoric acid ; it may, however, so improve the texture of the soil that plants can use more of the potash and phosphoric acid already there. When we remember that most farm soils, even the poorest, contain tons of plant food, we can believe that in practical effect, though not in reality, green-manuring may enrich the soil in all the plant foods. The mere amount of plant food in the soil is nothing to us: it is the ability of the soil to transform this material into plants that inter- ests us. Green-manuring helps the soil to do this as no other farm practice does, except the use of barn manures. We cannot expect green-manuring to relieve us of the necessity for buying and using the mineral plant foods ; but we do expect that, in certain systems of farming, it will make unnecessary the purchase of nitrogen, and that it will greatly reduce the amount of the mineral plant foods that need be applied. INOCULATING THE SOIL Under some conditions a leguminous crop that is plowed under may make the soil richer by a 334 SOILS hundred or more pounds of nitrogen; under other conditions it may add little if any nitrogen to the soil except that which it has drawn from the soil. In order that a legume may gather nitrogen from the air there must be " nitrogen-fixing bacteria" in nodules on its roots. If the legume is grown in a soil that has never been used for that crop, or not for several years, there may be none of these bac- teria in the soil. If there are none the crop will not thrive, or very few nodules will be found on the roots, and when there are no nodules nitrogen is not gained. If a leguminous plant is dug up and no nodules can be found on the roots, one may be reasonably sure that the plant is not gathering from the air the plant food that costs fifteen cents a pound in commercial fertilisers, but that it is living on the nitrates in the soil. Inoculating With Old Soil. — If no bacteria are present, they must be supplied. A few of them often cling to the seeds of the crop, sometimes enough to inoculate the soil quite thoroughly after one or two crops of the legume have been grown in it. Usually, however, it is best to in- oculate with soil taken from a field on which that particular crop has been grown successfully. This soil contains millions of the germs; wnen it is broadcasted or drilled in, the bacteria are spread and will find the roots of the leguminous crop when it is planted. From 400 to 800 lbs. of soil is sufficient. It is best to take the soil several inches below the surface and in a part of the field on which the plants had many nodules the year previous. The practice of sprinkling old soil over a new field has given luxuriant crops of legumes after failures to get a satisfactory stand. Inoculating With Artificial Cultures. — Another MANURING AND WORN-OUT SOILS 335 way to introduce the needful bacteria is to buy one of the several artificial cultures. Of these, " nitro-culture " is probably most widely known. These preparations contain a large quantity of the bacteria somewhat as a yeast-cake contains the bacteria that make bread rise. The "soil yeast- cake" is dissolved in warm water and this water sprinkled on a quantity of soil, which is then dis- tributed on the new land. Very uncertain results have attended the use of nitro-culture and similar preparations; in some cases the soil has been in- oculated with bacteria very successfully; in other cases no beneficial results have followed. It is evident that the method of preparing these cul- tures has not yet been perfected. Undoubtedly the use of artificial cultures of this and other beneficial bacteria will some time become common and suc- cessful, but at present the safest way is to get old soil if it can be had. Some of those who are exploiting these preparations have not made it clear, as they should, that in- oculating the soil with this material assists none but leguminous crops to secure nitrogen; and, furthermore, that it may help to enrich the soil in no plant food except nitrogen. The "yeast-cake" idea appeals strongly to the popular imagination and the most absurd claims are sometimes made for the artificial cultures. Soil inoculation is but one of many means of maintaining fertility, and usually it is a very incidental means. Each Crop has Different Bacteria. — Not one kind of bacteria performs this service, but many — a differ- ent kind on each leguminous crop. According to present knowledge, the bacteria that aid clover to feed on nitrogen from the air, do not aid alfalfa, cowpeas or any other crop. This means that one 336 SOILS must get old soil, or an artificial culture, for each kind of leguminous crop grown. It is probable that the several kinds of bacteria will be found to be more or less interchangeable, but the safest way is to get the kind that go with the crop to be grown. It is often found that the first year a leguminous crop is grown the stand is poor and the growth unsatisfactory; or that there are few nodules on the roots, snowing that little nitrogen is being secured. But the second year the crop will be better and the roots have more nodules, because the bacteria have increased. In growing legumi- nous crops, therefore, it is often best to re-seed on the same land until the soil becomes well filled with bacteria. Often if a poor stand of clover or alfalfa is plowed and the land at once re-seeded a much better stand is secured. Poor Soils Benefited Most. — If the soil is already quite well supplied with available nitrogen legu- minous plants growing in it get very littlenitrogen from the air; they will draw upon the nitrogen in the soil. Leguminous plants live on nitrogen of the air only when they have to ; when there is very little nitrogen in the soil. Cowpea plants on poor soil usually have many more nodules on their roots than cowpea plants on a rich soil; showing that the former are living mainly on the nitrogen of the air, while the latter are living mainly on the nitro- gen in the soil. Even on a soil already rich in nitrogen, leguminous*crops do return more nitrogen to the soil than they draw from it; but the poorer the soil the more nitrogen there is added to it. The same crop of cowpeas may add 100 lbs. of nitrogen to the soil or 25, according to the extent to which the plants have been obliged to get nitrogen from the air. This calls attention again to the peculiar 99. SOIL IN POOR TEXTURE It needs more humus to make it mellow 100. ON LEFT, A CLOD OF CLAY SOIL; ON RIGHT, DECAYING STEMS AND LEAVES, WHICH BECOME HUMUS Mix the humus with the clay and note improvement. The same thing can be done in the field, on a larger scale, by plowing under a green manure 1U1. NODULES, OR TUBERCLES, ON THE ROOTS OF SOY BEAN In these live the bacteria that may take nitrogen from the soil air, and turn it over to the plant. Only "leguminous" plants — as clover, pea, cowpea — can do this 102. COWPEAS ON "WORN-OUT" COTTON FIELD Note the tiny gullies; the fine soil has been mostly washed away. The cowpeas, when plowed under, will give body to this thin soil and enrich it MANURING AND WORN-OUT SOILS 337 value of leguminous crops for improving poor soils. These bacteria do not multiply on sour or wet soils, which is one reason why light soils are usually more benefited by green-manuring than heavy soils. PLOWING UNDER A GREEN MANURE It is a common mistake to allow a cover crop to grow late into the spring, and until it gets woody, before plowing it under. Too much rank herb- age may dry out the soil that season. The earlier it is plowed under the more moist the soil is, as a rule, and the quicker the plants decay. If f)ossible, it is best to plow under a green manure at east two weeks before planting the succeeding crop, so that it may partially decay. If the crop is not hardy, as oats or buckwheat, it is usually best to allow the herbage to lie on the surface during the winter, and plow it under in spring rather than to plow in the fall. Little if any of the manurial value of the crop is lost by leaving it on the ground during the winter, and it protects the surface from washing. Such crops as the cowpea and soy bean are exceptions to this because their leaves fall off and are blown away. When plowing under a large amount of herbage, a drag chain is serviceable. In general, it is much better to plow under small crops of herbage two or three times than to plow under a large quantity at one time. Like every other farm practice, green-manuring has limitations. Some crops do poorly if planted on land where a green crop has just been plowed under. Alfalfa, wheat, rye, oats, barley, and buckwheat are among these. This is partly be- cause the decay of a large amount of herbage in the 338 SOILS soil results in fermentation, and the soil becomes more or less acid; and partly because the herbage loosens and dries out the soil before it has become thoroughly decayed. Potatoes and corn do not seem to mind this. In any case it is best, if prac- ticable, not to plant a crop for at least two or three weeks after a large amount of herbage has been plowed under, but to keep the land fallow. Lim- ing the soil at the time of green-manuring is often beneficial. If only stubble is plowed under, or a scanty crop of herbage, these precautions are not necessary. LEGUMINOUS CROPS FOR GREEN-MANURING Red Clover is the king of green-manuring crops, especially in the Northern States. This is partly on account of its very deep root system, which bores through, loosens and drains the subsoil and brings deep-lying plant food to the surface. It does not catch well on soils in bad heart ; such soils must first be improved by plowing under rye and other coarser crops. The seeding is ten to twenty pounds per acre. In the North, seeding is in early spring or in August; in the South, September or October sowing is preferred. Usually the crop is cut or pastured one or two years, and the after- math is plowed under. Unquestionably red clover is the most valuable plant in Northern farming, where the maintenance of soil fertility as well as the largest immediate profits, is considered. If it can be worked into a rotation to advantage this should be done. Be sure the land is not deficient in lime. The preeminent value of red clover for improving soils is strikingly illustrated in some experiments by Henry W. Geller. Many pots of ordinary soil MANURING AND WORN-OUT SOILS 339 had added to them these materials: (1) Fresh manure, at the rate of 20 tons per acre; (2) Clover stems from an old field, dried and ground to meal; (3) Ground wheat straw; (4) Ground peat. The effect of these different forms of humus on the crop grown in the soil to which they were added, was very marked. Mr. Geller concluded, "Of all the different kinds of organic matter applied, clover liberated the most plant food"; and again, "The greatest yield was obtained from the soil to which clover was applied, it being three times as large as the yield of untreated soil; while the crop from the manured soil was twice that of the untreated soil." The Cowpea is to the South what clover is to the North. It grows anywhere south of the Ohio river, and in some places farther north, especially along the Atlantic Coast. It is planted only in spring or summer, as frost kills it. Cowpeas may be sown after wheat, oats, or rye and the crop cut for hay in time for fall crops to be sown. The roots feed almost as deeply as those of clover and the plants thrive on a very poor soil, provided it is not too wet. It is seeded at the rate of one and a half to three and a half bushels per acre, either broadcast or drilled in, and is cultivated two or three times. The vines soon cover the ground. They are commonly cut for hay; rarely is it best to plow under the entire crop. The cowpea is most valuable as a catch crop; it fits in nicely after the harvesting of one staple crop and before the planting of another. One of the best ways of building up worn-out cotton land in the South is to sow rye in the fall, plow it under in spring, harrow and let the land lie fallow for a month, then sow cowpeas. Cut this crop for hay and sow rye again. Three or four years of this 340 SOILS treatment will make a marked improvement in the soil. Both of these crops thrive on very poor land. The cowpea has worked miracles on thou- sands of acres of Southern land; it is a great blessing to Southern agriculture. Crimson clover deserves third place in the list of soil-improvers. It is grown chiefly along the Atlantic sea-board from Massachusetts to Georgia, and is used almost entirely as a cover crop. It is sown from the last of July to the first of October at the rate of fifteen to twenty pounds of seed per acre, either between rows of standing crops, as , corn or cotton, or after the crop has been harvested. The peculiar value of crimson clover lies in its ability to grow late into the winter, and to begin growth again early the next spring, thus accumulat- ing much herbage before the spring plowing. It gathers nitrogen most industriously during this period. It makes good winter pasture. In the South, crimson clover complements the cowpea, since it grows at a season when the cowpea aoes not. In the North it is equally at home and is valued highly. Alfalfa is the greatest soil-improver of arid farming in the West. At the Wyoming Experi- ment Station land on which alfalfa had been grown produced $16 worth more of potatoes and oats per acre than similar land that had not been in alfalfa, and this increase was secured at no cost. In late years the culture of alfalfa has extended over many parts of the East. Wherever it can be grown to advantage, as a part of the farm rotation, alfalfa is one of the very best means of maintaining fertility, although it is grown primarily as a forage or hay crop. It prefers an open subsoil, being the most deep-rooting of any farm crop; this makes it of 103. A FIELD OF COWPEAS GROWN TO IMPROVE THE SOIL The cowpea is to the South what clover is to the North — the great soil renovator 104. A SINGLE COWPEA VINE, TWELVE FEET LONG, ON A NORTH GEORGIA FARM The tops will be cut for hay, but the roots and stubble, when plowed under, greatly improve the soil, as they contain a third of the soil-improving value of the plant 105. VELVET BEANS GROWN FOR A GREEN MANURE IN FLORIDA The vines are often 30 to 40 feet long. This legume largely replaces the cowpea in Florida 106. THE RIGHT PLACE FOR A COVER CROP— TO PROTECT THE BARE GROUND OF CORN FIELD OVER WINTER Nature's cover crop of weeds is not evenly distributed. Rye sown at the last cultivation in summer is a popular cover crop for corn MANURING AND WORN-OUT SOILS 341 unusual value in improving the soil. Seeding is at the rate of twenty to thirty pounds per acre, and after spring frosts in the North; fall seeding is preferred in the South. The sod is cut for three to eight years; hence alfalfa can be used only in a long rotation. Other Leguminous Green Manures. — The four plants mentioned above are the great soil-improvers of America. Other crops are often or occasionally grown. Canadian field peas are frequently grown m the North, especially on rough soils, and either alone or sown with grains to support the vines. The seeding is one and a half to two bushels per acre. Market gardeners often grow garden peas, pick the pods and then plow under the vines, thus getting double value from the crop. Vetches of various kinds, particularly the smooth vetch and the hairy vetch, are often used, especially in the Pacific Northwest. Vetches are used extensively for orchard cover crops in the East. The seeding is about one bushel per acre. Hairy vetch may become a bad weed unless looked after sharply. The soy bean, also called "soja bean" and " Jap- anese pea," is very serviceable in many sections. It is hardier than the cowpea and can be grown farther north. When grown for soil improvment the whole crop should be plowed under, as the roots and stubble do not contain such a large pro- portion of the plant foods as clover and cowpea stubble. White sweet clover and lupines are sometimes grown for green-manuring. NON-LEGUMININOUS CROPS FOR GREEN-MANURING Rye is the most useful of plants that improve the soil when plowed under, but do not enrich it in 342 SOILS nitrogen, not being legumes. It is commonly used as a cover crop, sown in corn, after potatoes, etc., from August first to November first, the seeding being one and a half to three bushels. It is especially valuable for building up light soils or soils in such bad texture that legumes do not thrive. Rye grows late and begins growth very early in spring, thus using and returning to the soil much nitrogen that would be leached away from bare soils at this time. It makes good winter and spring pasture. Wheat is sometimes used for the same purpose. Oats and buckwheat are used when a crop is needed which will be killed by winter. Buck- wheat is especially valuable for very light and poor soils. Rape is a valuable forage and green-manuring crop, especially as a cover crop. Like rye, it grows until the ground freezes, and begins growth again very early the following spring. Winter rape, however, is not hardy in the Northern States ; spring rape, especially Dwarf Essex, is valued there. White mustard is frequently used to improve light sandy soils and is especially useful as a catch crop. It grows very rankly in late fall and is not killed until the ground freezes. The seeding is about one-third bushel per acre. It does not become a weed. THE RENOVATION OF WORN-OUT SOILS How to restore productiveness to soils that have lost their power to produce profitable crops, and are said to be "worn-out," is one of the great farm problems of to-day. There are hundreds of thousands of acres of worn-out soils in the Atlantic MANURING AND WORN-OUT SOILS 343 States. The older soils of the East, which have been cultivated, more or less, for two or three cen- turies, were the first to decline. Gradually the area of worn-out soils is extending westward. Even some of the Mississippi Valley soils that fifty years ago were thought to be of inexhaustible fertility, are now said to be about worn-out. The history of the East is being repeated in the West. The virgin soils there are now said to have an inexhaustible wealth of fertility; yet sooner or later the crops on even these wonderful soils will decline. Then those agricultural freebooters whose whole idea of tilling the soil seems to be that of merely skimming off the cream of Nature's in- crease, will pass on to virgin soils, leaving behind land that it will take years of careful farming to bring back to its normal productive- ness. The agricultural history of our country, so far as soil management is concerned, is far from being a credit to the genius of our people. It has been marked by the most ruthless soil robbery on the largest scale that the world has ever known. Virgin lands have been cleared, their fatness wrung from them with little or no returns, until the crops have dwindled to but a fraction of the bountiful harvests of pioneer days. Then the son, who has fallen heir to the inevitable result of the spend- thrift farming of his father, moves West. The most disheartening feature of all is that nine times out of ten he follows there the same course which has brought poverty to so many farm homes in the East. Western farming is as improvident now as Eastern farming has been, and still is to a con- siderable extent. We cannot escape from the criticism of J. J. Hill: "American farmers have 344 bOlL/S barely skimmed the soil; there is little intensive farming in this country." The problem of worn-out soils is vital now and is becoming more insistent as our agriculture ages. Fortunately the East has at last awakened to the exigencies of the situation, and is reclaiming her worn-out soils with satisfactory results. It is to be hoped that before the rich farm soils in the Mississippi Valley and westward have been brought to the low productiveness that many Eastern soils have now reached — and they are surely trending that way — Western farmers will adopt the methods of husbandry that are necessary to maintain fertility. How to Begin the Work of Soil Improvement. — ■ The methods that are of service in renovating worn- out soils include all the points in soil management that have been noted in the preceding chapters. Undoubtedly there are a few worn-out soils that are exhausted chemically: they are actually deficient in plant food. But most of them are worn-out physically. They are unproductive, because they have been mismanaged. This mismanage- ment may have consisted partly in bad handling, such as plowing too shallow, or when the soil was wet, or in not checking erosion. It is more likely, however, to be due to mismanagement as regards rotation of crops; and probably it is due most of all to mismanagement as regards maintaining the supply of humus in the soil. Most worn-out soils are in special need of humus. Green-manuring is of greater importance in the renovation of worn- out soils than any other factor. In most cases the quickest and easiest way, to begin with, is to grow leguminous crops for green- manures. But green-manuring will be made more MANURING AND WORN-OUT SOILS 345 effective, and certainly more remunerative, if it can be associated with some form of stock hus- bandry, so that the crops may be fed or pastured on the place and the manure returned to the soil. Stock-feeding, not clover, cowpeas nor any other plant, is the key to the most economical main- tenance of soil fertility in general farming. There are few sections of the country where it is not practicable to raise some kind of stock. When animal manures are not available, how- ever, green-manuring alone will improve worn-out soils, but less economically. Commercial fer- tilisers have little value for restoring a worn-out soil if, as is usually the case, the texture of the soil, not its chemical contents, is at fault. They are of far greater usefulness after the soil has been put into good heart by green-manuring or the addition of animal manures. The final step in the improvement of a worn- out soil is to put it into a rotation of crops which is not exhaustive and which makes provision for a continuance of the various farm practices that maintain fertility. Thousands of acres of land in the East, thought to be worn-out, have been restored to bountiful productiveness by these methods. CHAPTER XIII FARM MANURES FROM the beginning of agriculture, appli- cations of manures have been the chief means of maintaining the fertility of farm soils. Manuring has been assisted, to some extent, by green-manuring and crop rotation. In modern agriculture increasing prominence is being given to these latter practises. But it is not likely that manuring will ever be displaced as the most widely practiced and most economical method of main- taining the fertility of the land. The vital relation between stock husbandry and crop husbandry has been emphasised in the pre- ceding chapter. The practical advantages of associating these two coordinate branches of agriculture are more generally admitted to-day than at any previous time. Farmers are beginning to abandon the wasteful methods of pioneer days, to curtail the present extravagant use of artificial fertilisers, and to rely more and more upon Nature's provisions for maintaining fertility and the excre- ments of animals — the return of plants to the soil. The first provision is discussed in the preceding chapter; the second in this chapter. HOW MANURE BENEFITS THE SOIL The real value of manures and their effect upon the soil were not known until quite recently; and it is altogether probable that even now we have but just begun to understand the manifold ways in 346 FARM MANURES 347 which manure improves the soil. There was a time when the value of manure was thought to be only or chiefly the value of the plant food it con- tained. It was even said that since a ton of stable manure contains but $2 to $4 worth of nitrogen, pot- ash and phosphoric acid, that the same amount of plant food could be obtained and applied more cheaply in the form of a commercial fertiliser. This is true; but the conclusion must not be drawn that manure might well be supplanted by commercial fertilisers. From the chemist's point of view a ton of manure may be worth but $2, because that is the value of all the plant food in it. From the farmer's point of view manure may be worth several times that amount. The farmer knows that he cannot buy $2 worth of artificial fertiliser that will give the results on most soils that one ton of manure will. This fact, which is realised by farmers everywhere, has led to a very careful investigation of the ways in which manure benefits the soil, aside from adding the small amount of plant food it contains. These supplementary benefits, which the chemist knows nothing of and does not consider in his estimates of the value of different kinds of manures, are often of far greater practical value in crop production than the plant food that the manure contains. Manure Improves Texture of the Soil. — The chief value of manure, on many soils is not the plant food it adds but its beneficial effect upon the tex- ture of the soil. In the preceding chapter it was shown that most farm soils, even those that are unproductive and worn-out, contain large amounts of plant food; and that the cause of the unpro- ductiveness is more apt to be that the soil is in poor condition, or bad heart, than that it is exhausted of plant food. 348 SOILS One of the great functions of manure is to improve the condition of the soil, so that the plant can more readily use the plant food in it. Examine old, dry, cow dung in the pasture. The plant food in it has been mostly washed out; a spongy, fibrous material is left which, when crumbled, presents such equable conditions of moisture and temperature, that florists like to sow cineraria and other extremely fine and delicate seeds upon it. This material, which is about one- quarter of the original substance of manure — the balance being water — is composed mostly of food that the animal did not digest. When incorpo- rated with the soil it greatly improves the texture, loosening a heavy, compact soil and binding to- gether a light, leachy one; making the soil more friable, warmer, more retentive of moisture and more congenial to plants in every way. In three years' experiments, King found that manured fallow ground contained eighteen tons more water per acre in the first foot of soil than similar land unmanured, while the total gain of water in the first three feet of soil was thirty-four tons. Being already fine and partially decayed, the vegetable matter in manure is at once thor- oughly incorporated with the soil, becoming humus; while a green-manuring crop plowed under is con- verted into humus slowly. No one who has seen the almost magical improvement in a hard, clay soil by a single liberal dressing of manure can doubt that its value is largely, sometimes mostly, in its effect upon soil texture. The Bacteria in Manure. — Aside from the humus it adds, manure benefits the soil in other ways, most of which are still imperfectly understood. It is known that manure contains countless numbers of lor. A IMMON, AND AN EXTREMELY WASTEFUL METHOD OF STORING FARM MANURES Rains and the drippings from the eaves may wash out two thirds of the plant food in this manure before it is spread upon the land 108. THE DARK-COLOURED PUDDLE IN THE BARNYARD CONTAINS THE ESSENCE AND THE RICHNESS OF THE MANURE No man can maintain the fertility of his farm economically if he permits such a waste 109. THE MANURE PILES FROM THIS BARN DRAIN INTO THE POND, WHICH IS COVERED WITH "DUCK MEAT" IN TESTIMONY OF ITS RICHNESS Good for ducks, but the land of this farmer needs that fertility badly 110. MANURE WAG< >.\. WHICH RECEIVES THE MANURE FROM THE STALLS AND FROM WHICH IT IS SPREAD ON THE LAND FACH DAY The sooner manure is got upon the land the better FARM MANURES 349 bacteria that are beneficial to the soil. When the vegetable matter in manure decays in the soil certain acids and ferments are produced which have a decided influence upon the supply of available plant food. In short, the addition of manure to farm soils sets in motion a series of activities which profoundly affect the productivity of the land. All this is in addition to the plant food value of manure. It is altogether probable that we do not know half of the direct and indirect benefits of manure upon farm soils. But we do know enough about it to place its agricultural value far above its plant food value. Commercial fertilisers influence the soil almost solely in regard to its supply of plant food ; farm manures influence all the soil conditions which are essential to the production of profitable crops. There is no comparison whatever between the two. THE COMPARATIVE PLANT FOOD VALUE OF DIFFERENT MANURES The amount of plant food in different kinds of manure depends upon the animals from which it came and the care it has received. Analyses of the excretions of various animals are given in the Appendix. It will be noted that horse manure is ricner in nitrogen than either cow or hog manure. An average sample contains about 6 per cent, of nitrogen, 3 per cent, of phosphoric acid and 5 per cent, of potash. It is, however, liable to "fire fang," or ferment, unless kept compact and moist; this lowers its value somewhat. Horse manure varies in composition more than any other, because of the greater variety of ways in which it is handled, particularly as regards the use of bedding. Cow and hog manure contain more water than 350 SOILS other kinds and are relatively poorer in plant food, especially in nitrogen. An average sample of either contains about 4 per cent, of nitro- gen, 2 per cent, of phosphoric acid, and 5 per cent, of potash. Sheep manure is commonly richer than the manure of any other farm animal, except poultry. It is comparatively dry and since it is usually al- lowed to accumulate in pens, where it is tramped hard by the animals, it is less apt to suffer a loss of plant food than other kinds. Ordinarily it con- tains about 8 per cent, of nitrogen, 2 per cent, of phosphoric acid, and 7 per cent, of potash. Poultry manure is the richest of farm manures, largely because it contains the semi-solid urine, and there is little waste. It is especially rich in nitrogen and phosphoric acid. An average sample contains 12 per cent, of nitrogen, 9 per cent, of phosphoric acid and 6 per cent of potash. Average values for different manures are : Sheep manure, $4.20 per ton; mixed farmyard manure, $2.25 per ton; hen manure, $6.50 per ton; hog manure, $3.20 per ton; livery-stable manure, $2.45 per ton; cow manure, $2.43 per ton. These figures are based solely on their plant food content and do not consider the value of the manure for improving the soil in other ways. THE QUALITY OF MANURE The age and the condition of the animal influence the quality of manure. Manure from young ani- mals is not as rich as that from full grown animals, because the former digest a larger proportion of their food than the latter. Cows in milk return only about 65 to 75 per cent, of the manurial value FARM MANURES 351 of their food in their excrements, while cows that are being fattened return 80 to 90 per cent. The kind of food that the animal eats has a marked effect upon the richness of its manure. The more grain there is fed to them, especially such foods as wheat bran, gluten meal and cotton-seed meal, the richer the manure, since these grains are rich in protein. Animals fed solely on hay of poor quality produce manure that is much inferior to that of grain-fed animals. In short, the richer the ration, the richer the manure. The kind and quantity of bedding used affects the value of manure, also the individuality of the animal. Some animals use a larger proportion of their food for making milk, or beef, or mutton, than others; what is not used is recovered in the manure. HOW MANURE IS WASTED There are still many sections where barn manure is not used upon the land, and, in fact, is considered a nuisance. In parts of Oregon farmers give away manure for the hauling, and are glad to be rid of it. In counties of California and Oklahoma manure is dumped into the river. Some Missouri, Kansas, and North Dakota farmers use it to fill up holes, or dump it in heaps beside the fields and roads. Some South Dakota farmers burn it to get rid of it. In Idaho it is frequently seen piled as high as a barn. The waste of manure in parts of the West is a painful sight to the Eastern farmer who knows that the land will soon be in need of it. On the very farms where manure is thrown away in this manner the soil is often greatly benefited by it, even now. These improvident methods, how- ever, are becoming less and less common. 352 SOILS The plant food in manure is subject to serious loss. Although there may be but little plant food in manure, as compared with artificial fertilisers, yet most of it is very soluble and is easily lost, if the manure is not handled carefully. The plant food in manure is wasted in two ways; by leaching and by fermentation. The Leaching of Manure. — No other farm practice has been discussed more than that of al- lowing plant food to leach from manures. One can scarcely attend a farmers' institute without hearing about it, or read a farm journal without seeing a reference to it. All this agitation has probably saved many million dollars, worth of plant food that otherwise would have been wasted. Yet is it doubtful if one per cent, of American farm- ers realise what they lose by neglecting to care for manures properly. One estimate places the annual loss of plant food on American farms, by leaching from manure that could easily have been prevented, as $200,000,000 or over four times what is paid each year for commercial fertilisers. If the leaks on a few farms are noted, and the number of farms in a neighbourhood that suffer similar losses are counted, one will conclude that this estimate is not too high. The saving of manures is indeed a threadbare subject; but there is such urgent need that farmers adopt better methods of handling manures that one is justified in harping upon it One of the most common farm scenes in eastern United States is a row of manure piles beneath the eaves of the barn. Each pile extends up to the hole or window out of which it was thrown from behind the cows or horses. Water from the roof drips upon it; rains and snows beat upon it; winds FARM MANURES 353 dry it. After a heavy rain the puddles in the yard are black with richness that has leached from these piles of manure. This is the fertility of the farm running to waste. Manure handled in this way may lose over half of its plant food. Roberts found that a ton of manure exposed in this way for six months lost 42 per cent, of its plant food. Another ton exposed from April 25 to Sept. 22 lost 60 per cent, of its nitrogen, 47 per cent, of its phosphoric acid and 76 per cent, of its potash, a loss in value from $2.80 per ton to $1.06. When the pile of exposed manure is finally hauled away it has lost a large part of its soil-improving value. A dark- coloured stain on the side of the barn is pretty good evidence of shiftless farming in this respect. The loss of plant food from manure by leaching depends largely upon the climate; the wetter it is the greater the loss. In the arid and semi-arid regions it is not large; but in every case it is large enough to set every farmer to thinking how he may best prevent it. Loss from Fermentation. Another way in which manure often loses value is by heating, or fermenta- tion. When manure is piled up, especially horse manure, it begins to heat and decay. This fer- mentation is caused by the growth of bacteria. These need heat and air; the warmer the manure is, and the more loosely it is piled, so that it is full of air, the more quickly it heats. The nitrogen in fermenting manure is rapidly changed into am- monia, which escapes into the air. Every one has noticed the pronounced "smell" of manure piled up loosely and heating. It is plant food escaping. The heating of manure also injures it in another way. Part of the vegetable matter in it, which becomes humus when applied to the soil, is burned. 354 SOILS The higher the manure heats, the greater is the loss. Dry, white, "fire-fanned" manure has had a large part of its humus-making material destroyed. Loss from the Escape oj Urine. — A third way in which manure loses value is by failing to catch the liquid portion. This contains more nitrogen and more potash than the dung; yet, in many cases, liquid manure is allowed to run to waste, while the dung is saved. Moreover the plant food in the liquid portion is immediately available to plants. It should be saved as carefully as the solid portions of the excrements. HOW TO CARE FOR MANURES Leaching usually causes more loss of plant food from manure than either fermentation or the waste of liquid manure; attention should first be given to preventing this loss. There are two ways of doing this : by hauling the fresh manure from the stable and spreading it upon the land at once; and by piling it under cover. Hauling manure direct from stable to field in- volves little or no loss of fertility, as compared with storing it, and is the most satisfactory method whenever it is expedient. Usually, however, it is not expedient to do this at certain seasons of the year; it would interfere very seriously with other farm work, while the hauling of stored manure may be done to advantage in late fall and very early spring when other work is not pressing. Usually at least a portion of the manure must be stored, especially that made during the busy months of seed time and harvest. In this case there is but one sane thing to do; that is, to pile the manure under cover. This is the only safe way FARM MANURES 355 to prevent leaching; a single, heavy, summer shower may leach away enough plant food from an exposed pile to pay a large part of the slight expense of covering the pile. Covered barnyards are sometimes practicable. The animals tramp the manure and so keep it from fermenting. The cattle are exercised and watered there, in winter especially. It is neces- sary, however, to use a considerable quantity of bedding and to keep the yard dry. A yard 30 x 50 feet is large enough for fifteen to twenty cows, but they should be dehorned. Manure Pits. — Another method, preferred by many, is to build shallow, covered cement pits, adjacent to the stable. Into these the manure is dumped; the liquid manure from the gutters in the stable may drain into them. In large dairy stables manure is collected on trucks or cars which are run on tracks to these pits. The pits should be large enough to hold the manure made in several weeks,? or as long as it is convenient to wait before hauling it to the field. This is one of the most practicable ways of storing manure. If a cement pit cannot be had, and the manure must be stored outside the barn, it is a simple matter to build a shed over it. But part of the liquid in the manure will drain off, and the farmer can ill afford to lose it. Therein is the great ad- vantage of covered cement pits. Many barns are built so that the manure can be shoved down a scuttle into a cellar. In some cases the cellar is cement-lined and excellent con- ditions for storing manure are thus secured. Often the cellar bottom is not cemented allowing the loss of part of the liquid manure. Cellars beneath the stable do very well, so far as the saving of manure 356 SOILS is concerned; but there are decided sanitary objections to this method. The stable above is almost sure to be bad-smelling. Thorough ventila- tion and the use of gypsum will do much to alleviate this condition; but manure should be stored away from, not beneath, the animals, especially in a dairy. The manure of animals confined in pens, as sheep and young stock, is usually stored without serious loss, if it is allowed to accumulate and an abundance of bedding is used. The manure is tramped down very firmly by the animals, all the liquid portion is absorbed, and there is little loss by fermentation or leaching. How to Prevent Loss by Heating. — The fermenta- tion that makes manure deteriorate in value takes place only when it is piled loosely, so that air passes through it readily. Compacting the manure, as with the tramping of animals, prevents this loss. Manure must also be only moist, not wet, in order to ferment; so that if it is kept wet with the liquid excrement, there is little likelihood that it will heat. Sometimes it is practicable to wet the manure occasionally. If fermenting manure has a small amount of fresh manure mixed with it the heating will be checked. Methods of Saving Liquid Manure. — The simplest way to save liquid excrement is to provide plenty of bedding to absorb it. Many materials are used for bedding and these affect the value of the manure. It is commonly thought that strawy manure is not as valuable as clear manure ; yet the straw in manure may have absorbed much of the liquid excrement, so that strawy manure may be really more valuable than that which contains little straw. The objects of bedding are not only to keep the animals comfortable and clean but also to catch FARM MANURES 357 the urine and to increase the bulk of the manure so that it can be distributed more evenly. Straw is most generally used and is quite satisfactory. Marsh hay, cornstalks, leaves, sawdust and shav- ings are used more or less. The two latter should be used in moderate quantities; in large amounts they lower the value of the manure. Pine needles are believed to injure the manure. Fine, dry sand or soil is, sometimes used to advantage, and oc- casionally peat or muck. These earthy materials have greater value for bedding than strawy mate- rials because they absorb ammonia gas as well as liquids, and so save nitrogen and keep the air of the stable sweet. The plan of collecting the liquid manure and distributing it upon the fields by means of a tank with a sprinkling attachment has not been found generally practicable. Ordinarily it is more satis- factory to absorb the liquid manure with bedding. The use of bedding will not entirely prevent the loss of plant food from the stable. There is al- ways a considerable amount of ammonia escaping, as the sharp odour about stables bears evidence. This can be prevented by using chemical ab- sorbents which enter into combination with the ammonia, making a salt of ammonia that is not volatile. Land plaster (gypsum) is most com- monly used for this purpose. Kainit and super- phosphate are used to some extent, enriching the manure not only with the nitrogen they catch but also with the plant food they contain. These materials should be scattered in the stables at the rate of one to two pounds per animal daily, and also over the manure piles. Dry sand, earth, peat or muck answer quite well for this purpose. 358 SOILS AMOUNT OF MANURE MADE ON THE FARM The amount of manure that will be made during a year by a given number of animals is capable of fairly accurate calculation. A common estimate is: Horse, 12,000 lbs. of solids, and 3,000 lbs. of liquids. Cow, 20.000 " " " " 8,000 " " Sheep, 760 " * 380 " " Swine, 1,800 " " " " 1,200 " " Another method, resulting from many careful experiments, is to multiply the amount of "dry matter" in the food for one year by 2.1 for the horse, by 3.8 for the cow, by 1.8 for the sheep. Add to these figures the weight of bedding used. Thus if a cow eats thirty pounds of dry matter a day she will produce about 30 x 3.8, or one hundred and fourteen pounds of manure a day; besides the bedding. The age of the animals, their condition and their food influence the amount of manure made. According to Heiden's rule for calculating man- ure, the following quantities of cow manure may be expected from feeding one ton of the feeds named: GREEN FEEDS Pounds Corn fodder 1,590 Rye fodder 1,797 Red top 2,465 Oat fodder 2,903 Orchard grass 2,074 Timothy 2,942 Hungarian grass 2,220 Red clover 2,243 Crimson clover 1,482 Alfalfa 2,166 Cowpeas 1,260 Soja beans 2,188 Corn Silage 1,605 FARM MANURES 359 DRY FEEDS Pound* Corn fodder 4,439 Orchard grass hay 6,920 Red top hay 6,996 Timothy hay 6,282 Hungarian grass hay 7,089 Red clover hay 6,505 Crimson clover hay 7,020 Alsike clover hay 6,935 Alfalfa hay 7,035 Cowpea hay 6,858 Soja bean hay 6,428 Millet hay 6,931 The amount of plant food in manure may also be estimated with considerable accuracy, if one knows the kinds and the amounts of foods that the animal consumes. Numerous digestion ex- periments have shown the amounts of the fer- tilising materials in various feeds and fodders that are ordinarily recovered in the manure. Knowing the amount of each feed and fodder that each animal eats, the amount of potash, phosphoric acid and nitrogen in each food, and the percentage of this that is commonly recovered in the manure, one can tell how rich the manure should be. Most farms do not produce enough manure to dress the fields satisfactorily. Sometimes manure may be bought to advantage, especially livery- stable manure, city street sweepings, or stockyard manure. Ordinarily it will not pay to give over a dollar a ton for average barnyard or stable ma- nure, and not this much if the haul is long. If the farm is near a town, stable manure may often be obtained for the hauling, especially if the farmer agrees to haul it away whenever necessary. 360 SOILS WHEN TO APPLY MANURES No advice can be given that is generally ap- plicable, but a few suggestions will snow the great diversity of practice. In general the sooner ma- nure is spread upon the soil after it is made, the more will the soil be benefited. But other con- siderations affect this point. The state of decay and the kind of crop must be considered. Rotted manure — that which has partially decayed — may be applied to better advantage in the spring than fresh or "green" manure. Rotted manure is commonly preferred for the lighter soils and fresh manure for the heavier soils. Market-garden crops, especially, prefer rotted manure, chiefly because its plant food is somewhat more quickly available than that in fresh manure, and these crops need this to make a quick start and a very rapid growth. Gardeners often make manure into a compost with leaves and vegetable and animal refuse of all sorts. The material is put into a long, low, flat-topped pile which is turned over and mixed several times. Ordinarily it is allowed to rot for two years. One of the most common practices on American farms is to broadcast fresh manure on grass land that is to be plowed after the next crop of hay. Another is to manure heavily for corn, which does not object to large amounts of coarse fresh manure, and to follow corn with a crop that prefers to have the manure quite well rotted, as it will be after having lain in the soil a year. Spreading Manure in Winter. — On a majority of farms most of the manure that is available is produced during the winter months when the animals are housed. Farm work is usually light FARM MANURES 361 at that time of the year and it would be a great advantage to spread the manure frequently during the winter rather than to wait until early spring, when roads, lanes and fields are miry and when other farm work demands attention. But some farmers fail to spread manure in winter because they think much of the plant food in it will be washed away. Usually the danger of loss is far less than is feared. Manure spread upon the land in winter loses little of its value unless the land is quite steep so that there is considerable surface washing. If the land is fairly level there need be no appreciable loss. Manures spread at this season do not fer- ment, because the temperature is too low. Man- ure spread in winter should be applied to land on which plants are growing, as on sod or on cover crops. It is especially desirable to manure in winter land that is to be planted to Indian corn. Sometimes heavy snows make winter spreading impracticable. HOW MUCH MANURE TO USE In applying manure the amount of the different plant foods in it should be kept in mind; also whether it is being used chiefly to improve the tex- ture of the soil or to supply plant food. The nature of the soil and the crop are other deciding points. Manures are often applied too freely. Rarely is it profitable to apply over 40 two-horse loads per acre, and 25 to 35 loads is about the maximum amount under most conditions. Ordinarily farm- ers use from 4 to 10 cords of cow manure per acre; market gardeners, however, who grow plants under special conditions so that their methods cannot 362 SOILS be compared with the methods of general farming, often use 30 to 50 cords per acre. A cord of fresh cow manure weighs about three tons. Light Dressings Desirable. — If a certain field is in special need of the mellowing and enriching effect of manure, a heavy dressing may be given; but usually it is more profitable to spread 30 cords of manure over 10 acres, if 30 cords is all that can be had, than to put ail of it on 5 acres. A moder- ate increase in yield on 10 acres is better than a heavy increase on 5 acres. The farther a field is from the barn, the less likely it will pay to haul a heavy dressing of manure to it; for manure is bulky and expensive to handle. It may be more practicable to put humus into such fields by green-manuring, and perhaps commer- cial fertilisers can be used there to advan- tage. Although manure is a complete fertiliser, it is not well balanced since it usually contains much more nitrogen than either of the other two plant foods. An abundance of nitrogen promotes a very vigorous growth of leaves and stems, but it is not so valuable for developing seeds and fruits. Too heavy applications of manure may make the wheat lodge or the fruit soft. For this reason if only a limited amount of manure is available, it is best to use it most freely on the crops that are valued chiefly for a very vigorous growth of stem or leaf, as the grasses, clover, most garden vegetables, and forage crops. Commercial fertilisers should be used on manured soil to supply the plant food that manure is deficient in and so balance it; as by using superphosphate on land manured for cotton. 111. MANURE PILED IN THE FIELD, TO BE SPREAD LATER This is often more convenient than spreading direct from the wagon, but it must not be left in piles long 112. SPREADING MANURE FROM THE WAGON ON CORN STUBBLE A manure spreader does the work more evenly but not more cheaply 113. BUYING PLANT FOOD IN SACKS This is practicable only to supplement home resources. Be sure you know what kind of actual plant food is in the bag, and how much. Buy by analysis, not by brand ALL or OUR CRINDINC AND MIXING IS DONE BY MACHINERY. 200 POUNDS .LOW GRADE BLOOD AND BONE J PUT UP BY THE > |& 0. PAINTER FERTILIZER COMPANY JACKSONVILLE, FLOmDA fmlnttr, UCI 114. A FERTILISER TAG TAKEN FROM A SACK, SHOWING THE GUARANTEED ANALYSIS OF THE FERTILISER Some of the analyses printed on fertiliser taps, while perhaps true, are apt to be misleading. The farmer should be able to figure out from the tag how much he could afford to pay for the fertiliser FARM MANURES 363 HOW TO APPLY MANURE The most practicable method in many cases, especially in winter, is to spread it direct from the wagon, cart, or sled. Fresh manure distributed from wagons in winter is not apt to be spread very evenly and should be scattered in spring with a brush drag. The manure may be dumped in piles, which are spread later. The merit of this plan is that it economises team work, so the rela- tive cost of team and hand labour must be consid- ered. If the manure is dumped in piles, it should be spread very soon; otherwise the ground on which it is piled becomes over-rich. Some farmers leave manure in the field in piles for several months ; their crops are decidedly "spotted" for two or three seasons thereafter. Manure spreaders are of little advantage to the average farmer, chiefly because they carry such a small load in proportion to the draft, and their expense. They do, however, distribute manure more evenly than it is usually done by hand. CHAPTER XIV COMMERCIAL FERTILISERS ONE OF the most striking features of American agriculture is the extraordinary rapidity with which the commercial fertil- iser industry has developed. Bone, wood ashes and a few other natural products have been in use for centuries, but the first use of artifi- cial fertilisers — the "phosphates" of the modern farmer — was about 1845. Not till after 1860, how- ever, were they used to any great extent. The annual fertiliser bill of American farmers to-day is close to fifty millions of dollars. This is paid mostly by the farmers of about twenty of the Eastern States, for commercial fertilisers are used very little in most of the Western States. In round numbers, we have paid about a quarter of a billion of dollars for artificial fertilisers in the last five years. In no other country are commercial fertilisers used to the extent they are here. Yet only a small per cent, of our farm soils have shown the need of fertilising. When the millions of acres of rich, Western farm lands have passed through the same history of gradual decline as those in the East — as they certainly will — what will our fertiliser bill be, a hundred years hence ? Where is this enormous and rapidly increasing expense account leading us ? Are the results secured by the present lavish use of artificial fertilisers sufficient to justify us in continuing the practice or is there a cheaper way of solving the problem of declining fertility ? 364 COMMERCIAL FERTILISERS 365 Changed Economic Conditions. — The rapid growth of the fertiliser trade is not necessarily an indication that American farmers have preferred artificial fertilisers to farm manures. Since 1865 we have passed through great economic and social changes which have favoured the use of artificial fertilisers. The most important of these, as related to agriculture, is the rapid growth of cities. This has developed the great market- garden, fruit and trucking interests which are the chief users of commercial fertilisers. Market-garden and truck farmers, many of whom are, of necessity, located near cities on high-priced land, often find it im- practicable to keep stock or give up the use of their expensive land for green-manuring, even for a short season. They must keep a money-crop growing upon it every day of the season. With them, the soil is merely the medium for transforming the plant food which they spread upon it into merchant- able crops. The modern market garden near a large city more nearly resembles a manufacturing establishment than a farm. Under such con- ditions, the use of artificial fertilisers, as well as purchased manures, is probably the most prac- ticable course to pursue. There are also many instances where artificial fertilisers are seemingly almost indispensable — as, for example, in the cul- ture of pineapples on the almost barren sands of eastern Florida. The staple-crop farmer, however, has not these peculiar economic conditions to contend with. The time-honoured methods of maintaining soil fertility by green-manuring, by a rotation of crops and by the use of animal manures — he can use if he chooses. Unquestionably commercial fertilisers will be used more and more extensively in market 366 SOILS gardening and in the culture of special crops and on certain soils; but the indications are that their use in general farm practice as a chief source of fertility is on the wane, while the use of the more natural resources, green-manuring and farm ma- nures, is on the increase. Often artificial fertilisers have been used to remedy temporarily the effects of poor texture, due to mismanagement. Com- mercial fertilisers, if used at all in general farming, should be applied sparingly and as a supplement to natural resources, not as the main source of fertility. WHAT COMMERCIAL FERTILISERS ARE MADE OF The term is usually applied simply to materials which contain the essential plant foods — nitrogen, potash and phosphoric acid. These are found in many materials: some are mineral products, as nitrate of soda, muriate of potash, phosphate rock; some are animal products, as dried blood and tankage, which are wastes from the slaughter houses, and boneblack, which is a refuse in refining sugar. These raw materials are combined in various ways, and in different proportions, per- haps treated with acids. One brand of commercial fertiliser may be made of two or three of these raw materials ; another may contain many kinds. Complete and Incomplete Fertilisers. — Com- mercial fertilisers are either "complete" or "in- complete." A complete fertiliser contains all three of the essential plant foods ; an incomplete fertiliser contains but one or two. Most fertilisers sold in this country are complete. The reason for this, from the manufacturer's point of view, is obvious. He knows little or nothing of the kind of soil upon COMMERCIAL FERTILISERS '367 which the fertiliser will be applied, or of its needs as regards plant food. In order to be sure that it will be of some benefit on all soils, then, it is neces- sary for it to contain all three plant foods. But, as will be emphasised later on, very few soils really need additions of all three; some need only one. In such cases the use of a complete fertiliser is wasteful. Many Brands. — Most fertiliser manufacturers sell many brands, or different combinations of raw materials. Some firms sell as many as forty-five brands, each one, presumably, different from all the others, and designed to meet the needs of cer- tain soils or certain crops. Thus we have Smith's Mortgage-lifter Fertiliser, Jones' Sure-crop Fer- tiliser, Brown's Special Potato Fertiliser, White's Corn Fertiliser, and so on. In one year 1,112 brands of fertilisers were sold in the State of New York alone. In most states the number is from 150 to 300. State Supervision of the Fertiliser Trade. — How shall the farmer know which of these many brands to choose? Some of them are just what his soil and crops need; some would be almost worthless to him. The national and state governments have now come to the assistance of the farmer in this important matter. State laws specify that no fer- tiliser manufacturer or dealer shall sell any brand of fertiliser in any state, either direct from the factory or through an agent, until the brand has first been registered with some appointed authority, usually the Director of the State Experiment Station. The manufacturer is further required to put a tag on each bag of fertiliser, giving an anal- ysis of its contents specifying the amount of each of the essential plant foods it contains. Every year 368 SOILS the Experiment Station of each state in which fer- tilisers are used extensively, collects samples of the fertilisers offered for sale in that state, and analyses each one to see if it contains as much plant food as the manufacturer claims that it does. If it is found to contain less than the guarantee on the tag specifies, the manufacturer is subject to prosecution. The effect of this state supervision of the fer- tiliser trade has been very satisfactory. The feneral standard of the business has been raised, lach year the Experiment station of each state publishes a bulletin listing all the brands of fertilisers that have been registered for that year, also the guaranteed analysis of each as shown by the manufacturer's tag, and the actual value, as shown by analyses at the Experiment station. Farmers who use fertilisers should get these bulletins. Studying Fertiliser Tags. — Some of the guaran- tees printed on fertiliser tags are misleading. The real analysis is sometimes obscured by adding to it statements of valueless materials that the fertil- iser contains, and by repeating the real analysis in another form, thus making the buyer who is not skilled in such matters think he is getting more for his money than he really does. Roberts states that the following guarantee was on a fertiliser sold in New York: Per cent. Total bone phosphate 30 to 35 Yielding phosphoric acid 14 to 16 Soluble bone phosphate 22 to 26 Yielding water-soluble phosphoric acid 10 to 12 Total available bone phosphate 26 to 30 Available phosphoric acid 12 to 14 Insoluble bone phosphate 2 to 4 Yielding insoluble phosphoric acid . . . 1 to ^ COMMERCIAL FERTILISERS 369 What a lot of dust-raising! Doubtless it is all true; and the manufacturer nas complied with the law that requires him to state on the tag the amount of plant food contained in the fertiliser. But the buyer wants to know just one thing — how much available potash, phosphoric acid, and nitrogen the fertiliser contains. This tag should have read r Per cent. Soluble phosphoric acid 10 Reverted phosphoric acid 2 That is all there is in it of value to the farmer. The most reliable manufacturers print on their tags a bare statement of the amount of actual plant food the fertiliser contains. Repetitions in Guarantees. — Another fertiliser tag reads: Per cent. 1. Ammonia 3 to 5 2. Available phosphoric acid 11 to 13 3. Total phosphoric acid 15 to 19 4. Total bone phosphate 27 to 30 5. Actual potash 12 to 14 6. Muriate of Potash 18 to 22 There are several repetitions in this complete fertiliser. Contrary to the common idea among farmers, ammonia is not nitrogen; it is only four- fifths nitrogen, the other- fifth being hydrogen, which has no value as a fertiliser. It will be necessary to multiply the 3 per cent, of ammonia by .82, the actual percentage of nitrogen in am- monia. This shows that there is 2.46 per cent, of the plant food nitrogen in this fertiliser, instead of 3 per cent. There is 11 per cent, of available 370 SOILS phosphoric acid in this fertiliser, as shown in No. 2, out of the total amount of phosphoric acid it con- tains, 15 per cent., indicated in No. 3. We are not concerned about the bone phosphate in No. 4, because this is merely a repetition of the figures given for phosphoric acid; 46 per cent, of bone phosphate is actual phosphoric acid, and this has already been stated in Nos. 2 and 3. There is 12 per cent, of actual potash, which is that found in the muriate of potash and repeated in No. 6. The guarantee of this fertiliser might better be : Per Cent. Nitrogen 3 Available phosphoric acid 11 (furnished in bone phosphate) Insoluble phosphoric acid 4 Potash 12 (furnished in muriate of potash) Always take the lowest per cent, given. Rarely does a fertiliser contain more than the minimum amount of plant food stated in the guarantee. THE FORMS OF PHOSPHORIC ACID The way in which the amount of phosphoric acid is stated is one of the most common sources of confusion. The nitrogen and potash in com- mercial fertilisers are mostly soluble and available to plants. But the phosphoric acid in fertilisers is more complex. It is usually not alone but com- bined with different amounts of lime, making "phosphates of lime" or "phosphates." On fer- tiliser tags one will find these terms: "available phosphoric acid," "soluble phosphoric acid," "in- soluble phosphoric acid," "reverted phosphoric acid." "Available" and "soluble" phosphoric acid are the same, for only plant food that is soluble in COMMERCIAL FERTILISERS 371 soil water can be available, or useful to plants. This valuable kind of phosphoric acid has but one part of lime with it and two parts of water: Lime ^^ Water— ^Phosphoric acid. Water"""^ This is the kind of phosphoric acid that is found in superphosphates. It quickly dissolves in water and plants can use it at once. In some guarantees it is called "water-soluble phosphoric acid." "Insoluble phosphoric acid," on the other hand, has three parts of lime to one of phosphoric acid, and has no water, thus: Lime>^^ Lime-— -Phosphoric acid. Lime-^ This is the kind of phosphoric acid found in fresh bones and in the various "rock phosphates" taken from the mines. Since it cannot be dissolved in water, insoluble phosphoric acid has no value whatever as a plant food unless it can be changed into soluble phosphoric acid. As bones rot in the ground the insoluble phosphoric acid in them slowly becomes soluble, losing part of its lime. A quicker way to change this into plant food is to treat it with acids, which is the way superphos- phates are made. In studying fertiliser guarantees, remember that the "insoluble phosphoric acid" is not plant food and cannot become so until it has been made soluble. When applied to the soil, insoluble phosphoric acid may gradually become soluble. Hence it is customary, when figuring on the value of a fertiliser, to count the insoluble phosphoric acid as worth about one-half as much as the soluble. Some chemists, however, do not con- sider it worth even that much. 372 SOILS The "reverted phosphoric acid" on fertiliser tags is intermediate between the soluble and the insoluble, thus: Lime ^^ Lime — —^Phosphoric acid Water^^ Reverted means turned back; this is phosphoric acid which was once soluble but is gradually be- coming insoluble, since more lime has been added to it. If soluble phosphoric acid in the soil is not quickly used by plants it tends to revert. In this condition it is not quite as readily used by plants. However, the reverted phosphoric acid given in fertiliser analyses may be considered about as valu- able as the soluble. Sometimes a tag will read "phosphoric acid soluble in ammonium citrate." This is reverted phosphoric acid, ammonium citrate being the weak acid used by chemists to dissolve it. Points that the fertiliser buyer should remember when studying guarantees are: 1. Look for the percentage of nitrogen. If the analysis gives the percentage of ammonia, remem- ber that it is but four-fifths nitrogen. If the analysis says "equivalent to nitrate of soda," remember that but 15 per cent, of nitrate of soda is the plant food nitrogen. 2. Look for the percentage of potash. If the tag says, "equivalent to sulphate of potash," or "equivalent to muriate of potash," remember that but half of sulphate or muriate of potash is the plant-food potash. 3. Look for water-soluble phosphoric acid or available phosphoric acid. Insoluble phosphoric acid has half value; reverted phosphoric acid is slightly less valuable than soluble. COMMERCIAL FERTILISERS 373 4. Look out for re-statements in the fertiliser tags, thus: 1. Bearing total bone phosphate . 2. Yielding phosphoric acid 3. Soluble bone phosphate .... 4. Yielding water-soluble phosphoric acid 5. Total available bone phosphate . Per cent. 30 to 35 14 to 16 22 to 26 10 to 12 26 to 30 Statement No. 4 is the only one worth considering; the others are mainly re-statements in another form. "Equivalent to" or "Yielding" usually means that the plant food in the fertiliser has al- ready been stated in the guarantee in another form. To convert one material into another, when there is repetition, use the following table: To convert the guarantee of Multiply by Ammonia . . . into Nitrogen 82 Nitrate of soda . " Nitrogen 16 Bone phosphate . " Phosphoric acid . . . .45 Muriate of potash " Potash 63 Sulphate of potash " Potash 54 5. Pay no attention to anything in the guarantee that is not plant food. The amounts of "mois- ture," "silicic acid," "carbonic acid," "mag- nesia," "alumic oxid," "ferric oxid," and other materials that the fertiliser contains are of no interest or value to the buyer. CALCULATING THE VALUE OF A FERTILISER FROM THE ANALYSIS The value of a commercial fertiliser is based solely upon the amount of plant foot that it con- tains. Animal and green manures are often quite valuable for their effect upon the condition or "heart" of the soil; but commercial fertilisers have little or no value in this respect. When 374 SOILS buying a fertiliser the farmer should consider just two things; the amount of plant food in it and what it costs per pound in this form. It is a simple matter to estimate the value of a com- mercial fertiliser from its guarantee, provided the guarantee is not too confusing. Suppose a fer- tiliser is offered with the following guarantee: Per cent. 1. Ammonia 2 to 4 2. Available phosphoric acid 10 to 12 3. Total phosphoric acid 14 to 17 4. Equivalent to bone phosphate . . . . 30 to 37 5. Potash 9 to 11 6. Equivalent to sulphate of potash . . 16 to 20 The first thing to do is to draw a line through statements 4 and 6, because 4 is a repetition of 2 and 3, while 6 is a restatement of 5. The ammonia must now be reduced to nitrogen by multi- plying 2 per cent, by .82, giving 1.64, the percent- age of actual nitrogen in the fertiliser. Since there is 14 per cent, of phosphoric acid in the fer- tiliser and but 10 per cent, of this is available, the inference is that the other 4 per cent, is insoluble. A simplified statement of the contents of this fertiliser is : Per cent. Nitrogen 1.64 Available phosphoric acid 10 Insoluble phosphoric acid 4 Potash 9 The number of pounds of each plant food in a ton of this fertiliser is then determined: 1.64% of 2,000 lbs.= 32.8 lbs. of nitrogen in a ton. 10% of 2.000 lbs.=200 lbs. of available phosphoric acid in a ton. 4% of 2,000 lbs.= 80 lbs. of insoluble acid in a ton. 9% of 2,000 lbs.=180 lbs. of potash in a ton. COMMERCIAL FERTILISERS 375 The trade values of the different plant foods in commercial fertilisers vary slightly from year to year but generally a pound of nitrogen is worth seventeen cents; a pound of potash four cents; a pound of available or water-soluble phosphoric acid, four and a half cents; this is what the several plant foods can be bought for in raw fer- tilising materials. The valuation of this partic- ular fertiliser is: Per ton Nitrogen, 32.8 lbs. @ 17 cents per lb. . . . $ 5.57 Available phosphoric acid, 200 lbs. @ 4^ cents per lb 9.00 Insoluble phosphoric acid, 80 lbs. @ 2 J cents per lb. 1.80 Potash, 180 lbs. @ 4 cents per lb 7.20 Total value per ton $23.57 Such a fertiliser may cost $36 per ton, or more. The difference between this sum and $23.57, the actual value of the plant food in it, covers the cost of mixing, bagging, handling and the profit. On an average it costs about $8 per ton to mix, bag, and handle a ton of fertiliser before it finally reaches the buyer, and allow a fair profit for all concerned. If $8 is added to the actual plant food value of a fertiliser, as determined from the guaranteed analysis, the buyer knows what would be a fair price to pay for the fertiliser. LOW-GRADE FERTILISERS EXPENSIVE To meet the demand for a cheap fertiliser — a lot of fertiliser for the money — many manufac- turers sell "low-grade fertilisers" for $15 to $26 per ton. But it costs as much to mix, bag, and handle a ton of fertiliser containing $15 worth of plant food as it does a ton of fertiliser containing $30 worth of plant food. Furthermore, the cost 376 SOILS of applying it to the land is greater, since more has to be applied to give a certain result. Usually plant food can be bought more cheaply in a con- centrated, or "high-grade fertiliser" than in a low grade. Even though a low-grade fertiliser may contain some high-grade materials, as sulphate of potash and nitrate of soda, the plant food in it usually costs more because this is weighed down with so much useless bulk. The farmer cannot afford to pay for bulk. Every pound of material in a ton of fertiliser which is not plant food adds to the price which the farmer must pay for the plant food. Usually the more concentrated the fertiliser, and hence the higher the price per ton, the cheaper it is. But one cannot make a mistake in buying a low-grade fertiliser if he figures on the guarantee. ADVANTAGES OF HOME-MIXING OF FERTILISERS It is a convenience to buy fertilisers mixed and ready to apply, provided the buyer examines the guarantee and finds that he can buy plant food in this fertiliser about as cheaply as though he bought the raw materials and mixed them himself; and provided, too, that this brand of fertiliser contains the several kinds of plant food in the right pro- portions for the soil and the crop to be grown. But this is not usually the case. Few farm soils need applications of all three plant foods; many need but one. Many brands of commercial fer- tilisers contain all three and the farmer may be buying plant food that his soil does not need, and so wasting his money. The raw materials out of which commercial fer- tilisers are made, may be bought and mixed on the COMMERCIAL FERTILISERS 377 farm. There are several advantages in doing this as compared with buying commercial brands. The most important one is that of being able to use but one or two of the plant foods, as is found necessary, and to gauge the proportions of each to suit the needs of the soil and the crop. There is also a saving in the cost of plant food, because the raw materials are mostly concentrated, and there is less expense in handling them. Added to this is the difficulty of always determining with absolute certainty the exact amount of plant food in a brand of commercial fertiliser owing to the ambiguous wording of many guarantees. On the other hand, it is sometimes difficult to buy these raw materials; they are not so generally distributed over the country, as brands of mixed fertilisers. Again, the mixed fertilisers are apt to be ground more finely than the unmixed. If a man uses but little fertiliser, it is likely that he will find it more expedient to buy a commercial brand; but if he uses a considerable amount it may be cheaper for him to buy plant food in the raw materials, not mixed. Most fertilizer dealers sell the raw materials as well as mixed fertilisers. The following raw materials are most com- monly used: SOURCES OF NITROGEN Nitrogen is the most costly of the three plant foods. For this reason special attention should be given to the means of producing it on the farm, as discussed in the two preceding chapters. The chief commercial sources fall into two classes: the "nitrates," which are salts; and "organic nitrogen," which is the nitrogen in plant and 378 SOILS animal materials, as cottonseed meal, dried blood, etc. Plants can feed on a nitrate but not on organic nitrogen. It is necessary for the plant or animal product to thoroughly decay, during which process the organic nitrogen in it is changed into a nitrate, before plants are able to use this kind of food. This shows the value of knowing the source of the different plant foods in a fertiliser. Nitrate of Soda (Chili Saltpetre), is the chief commercial form of nitrogen as a nitrate. Large deposits of this salt are found in the arid sections of South America. It contains from 15.5 to 16 per cent, of nitrogen. Nitrate of soda is dissolved in soil water almost immediately and becomes at once available as plant food. For this reason it should not be applied to land until the crop is planted, or just before. It is especially valuable for giving crops a quick start, and for promoting a luxuriant leaf and stem growth. Dried Blood is collected from slaughter houses. Red blood contains 12 to 14 per cent, of nitrogen, and black blood 6 to 12 per cent. This material decays very quickly in the soil, so that its plant food is quickly available for crops. It is one of the best sources of nitrogen. Cottonseed Meal usually contains 7 per cent, of nitrogen, together with 1§ to 2 per cent, each of potash and phosphoric acid. The nitrogen in it is as quickly available to plants as that in dried blood. This material can often be used to best advantage, however, by feeding it to stock and recovering most of the nitrogen in manure. Sulphate of Ammonia is a by-product in the manufacture of boneblack, illuminating gas and coke. It usually contains about 20 per cent, of nitrogen, being the most concentrated source of COMMERCIAL FERTILISERS 379 this plant food. The nitrogen in it is nearly as quickly available to plants as that in nitrate of soda. It should not be mixed with muriate of potash, as the muriate causes a loss of ammonia. Less important sources of nitrogen are the fol- lowing animal products: hoof meal, dry ground fish, tankage, Peruvian and other guanos, horn and hoof meal, wool and hair waste, dried meat or meal; and two vegetable products, linseed meal and castor pomace. These materials are usually obtained with greater difficulty and are less valuable for the farmer unless he is so situated that he can buy them advantageously. The amount of plant food in each of these is given in the Appendix. SOURCES OF PHOSPHORIC ACID The principal sources of phosphoric acid are phosphate rocks and bones. In most cases the phosphoric acid is in combination with lime, mak- ing a phosphate of lime. Only a fertiliser that contains phosphoric acid is a " phosphate, " but this term is often applied by farmers to all fertilisers. For many years bones were the main source of phosphoric acid and they are still largely used. Raw Bone is that which has not been treated in any way, except by grinding. It should contain about 4 per cent, of nitrogen and 22 per cent, of phosphoric acid ; but only 5 to 7 per cent, of the phosphoric acid is soluble, the remainder being insoluble. For this reason the phosphoric acid in raw bone is but slowly avail- able to plants, its usefulness extending over several years. 380 SOILS Boiled and Steamed Bone. — Most of the bone used as fertiliser has been boiled or steamed to free it from fat. The fat is objectionable in a fertiliser and is valuable for soap; the meat contains nitro- gen and is used in making glue. Boiling or steaming reduces the amount of nitrogen in the bone, so that it contains about 28 to 30 per cent, phosphoric acid and only about 1| per cent, of nitrogen. About 6 to 9 per cent, of the phosphoric acid is soluble. Boiled or steamed bone, however, can be pulverised much finer than raw bone and this greatly increases its value for immediate use. It is much used in mixed fertilisers and is especially valuable for meadows. Both raw and boiled or steamed bone are sold under various trade names, as "meal," "dust," and "fine ground bone." These terms refer to fine- ness, not to composition, and there is no uniformity; the "bone meal ' of one manufacturer may be as fine as the "bone dust" of another. The finer it is, the better, since it decays more quickly. Dissolved Boneblack. — Raw bones are burnt until they become "animal charcoal" and are readily crushed into a fine powder. This "bone black" is used in refining sugar. It is then turned over to the fertiliser dealer, who finds that it con- tains 32 to 36 per cent, of phosphoric acid, mostly insoluble, and a small amount of nitrogen. Bone- black is sometimes used directly as a fertiliser, but more commonly is treated with oil of vitriol to make the phosphoric acid in it more soluble. The re- sulting product is "dissolved boneblack" which contains 15 to 17 per cent, of soluble phosphoric acid and is one of the most important of the phos- phates. Some superphosphates are dissolved boneblack. COMMERCIAL FERTILISERS 381 Rock Phosphates. — Other sources of large amounts of phosphoric acid are mineral deposits in South Carolina, Georgia, Florida, Tennessee and Canada. These rock phosphates are mostly the fossil remains and the dung of animals, chiefly fish-eating birds. This rock differs widely in composition. South Carolina rock phosphate, dis- covered in 1868, is most generally used. It con- tains 26 to 28 per cent, of phosphoric acid, most of which is insoluble. This South Carolina rock is ground very fine and sold as "floats." Floats are often used for certain crops, especially on moist soils rich in humus. This raw, cheap, slowly- available mineral phosphate may often be used instead of the high-priced, quickly-available superphosphates, especially on perennial crops like fruit trees and grasses. It is becoming quite a common practice to use floats for the main supply of phosphoric acid and to supplement it with small amounts of a superphosphate. Florida rock phosphate, discovered in 1888, is more variable in composition than that found in South Carolina. It contains from 18 to 40 per cent, of phosphoric acid. The phosphoric acid in it seems to be much more slowly available than that in South Carolina rock. Tennessee rock phosphate, discovered in 1894, contains 30 to 32 per cent, of insoluble phosphoric acid and is used chiefly in making superphosphates. Phosphate Slag, also sold as "Thomas slag," "Thomas phosphate meal" and "basic slag" is a by-product in the manufacture of Bessemer steel, phosphorus being an impurity in iron ore. The slag is ground to a fine powder and contains 15 to 20 per cent, of phosphoric acid, much of which is soluble in soil water and so is quickly 382 SOILS available for plants. This material is considered one of the best phosphates for general use, espe- cially on moist soils rich in humus and poor in lime. It is produced in this country in considerable quantities. Superphosphates. — Any phosphate, either bone or mineral, which has been treated with acid to render its phosphoric acid more soluble is called a superphosphate. One popular superphosphate — dissolved boneblack — has been mentioned. Dis- solved bone, made by treating raw ground bone with sulphuric acid, is another. It contains 13 to 15 per cent, of available phosphoric acid and 2 to 3 per cent, of nitrogen. The most common super- phosphate is that made by treating ground rock phosphate with sulphuric acid. The great fault of the raw rock and raw bone phosphates is their slowness; plants derive little benefit from them the same season that they are applied. To over- come this, the manufacturer mixes some strong acid with them, usually sulphuric acid. This makes most of the phosphoric acid in them soluble. Contrary to the belief of some, a well-made superphosphate contains no free acid that will make the ground "sour." The acid used in making it is all combined with lime, making gypsum, which is itself a valuable dressing for some soils. However much difference there may be in the agricultural value of raw bone phosphates and raw mineral phos- phates, a superphosphate made from one is as good as a superphosphate made from the other, per pound of phosphoric acid; the kind of raw material does not count after it has been treated with acid. COMMERCIAL FERTILISERS 383 Besides dissolved bone and dissolved boneblack, which are the common bone superphosphates, "plain superphosphate," "acid phosphate," and "dissolved rock" are standard sources of this plant food. These are all superphosphates made from rock phosphate. That made from South Carolina rock is most common; it contains 12 to 14 per cent, of soluble phosphoric acid. The "double superphosphate," containing about 45 per cent, of available phosphoric acid, is not used much in this country. It is more difficult to decide what material to buy as a source of phosphoric acid than either of the other plant foods. The first question that arises is whether a raw bone or a raw mineral phosphate should be bought, or a superphosphate. The relative cost of the plant food in the different materials, its availability, and the special needs of the soil and crop must determine this. A pound of phosphoric acid can be bought in raw rock phosphate for two and a half cents; in raw ground bone for four cents and in a super- phosphate for five to six cents. Crops that mature quickly, including most vegetables, need quickly available fertilisers; while plants which grow for several seasons, as fruit trees and grasses, are able to get along with a certain amount of slowly available fertiliser. The cru- ciferous plants, as cabbage and turnip, ap- pear to do very well on the raw phosphates. Use as much of the slow-acting, but cheap, raw phosphates as practicable. Oftentimes a combination of superphosphate, for quick results, and raw phosphate, for general en- richment, is the best solution of the prob- lem. 384 SOILS SOURCES OF POTASH There are few commercial sources of potash; the most important are wood ashes and the Ger- man potash salts. Wood Ashes. — Until the discovery of the potash salts, this was the chief potash fertiliser. Wood ashes are often leached with hot water to extract the potash for soap-making and other purposes. The ashes remaining contain only one-third as much potash as before — usually but 1 or 2 per cent. — besides 1§ per cent, of phosphoric acid and 30 per cent, of lime. Unleached wood ashes, if well cared for, should contain 6 to 9 per cent, of potash, 2 per cent, of phosphoric acid, and about 32 per cent, of lime. Hardwood ashes are richer than softwood ashes. Wood ashes are so variable in composition, ac- cording to their source, impurities and care, that one should buy them only on a guaranteed analy- sis. A good sample is worth about twenty cents a bushel for the plant food in it, which is almost all immediately available. In addition, wood ashes have an important indirect value, due to the lime they contain. The price paid for them, how- ever, should be based on their plant-food content only. In this case the potash in them costs a trifle more than that in the German salts; but the indirect benefit of wood ashes is often so marked that their great popularity as fertiliser is justified. When they can be bought at about the same price per pound of plant food, or a little more, as other potash fertilisers, prefer the ashes. Besides wood ashes, cotton-hull ashes are a valuable but limited source of potash; lime-kiln ashes usually contain less than 1| per cent, of potash COMMERCIAL FERTILISERS 385 and 1 per cent, of phosphoric acid; coal ashes contain no plant food whatever but may benefit the soil by improving the texture. German Potash Salts. — Deposits of crude potash salts in Germany were discovered in 1859. Min- ing was begun in 1862 and the product of the mines is now about 750,000 tons a year. The supply seems inexhaustible. Three kinds of Ger- man potash salts are commonly used in this country : kainit, muriate of potash, and sulphate of potash. Kainit is one of the crude salts, just as it comes from the mines. It contains about 12 per cent, of actual potash and 33 per cent, of common salt, together with other salts. This extremely large percentage of salty material makes kainit un- desirable for the heavier soils and for some crops; but it is beneficial to light soils, and to certain crops, as asparagus, that appreciate salt. Since it contains so low a per cent, of potash, a pound of potash in kainit costs more than a pound in the refined salts. For this reason it is rarely used except when its indirect benefit, because of its saltiness, is needed. Sylvinit, another crude salt, is very little used in this country. Muriate of Potash is used in the United States more than any other potash fertiliser. It is very highly concentrated, containing about 50 per cent, of actual potash. Potash in muriate at $40 per ton costs four cents a pound, which makes this the cheapest source of potash. There are two occasions when muriate of potash should not be used. Certain crops, notably to- bacco, sugar beets, onions, and potatoes, are quite noticeably injured by the chlorine which this salt contains in large amounts. Again, if the soil is deficient in lime, heavy applications of muriate 386 SOILS of potash will be likely to aggravate the trouble. If it is necessary to apply potash every year, alter- nate the muriate with the sulphate, or with wood ashes, and give the land an occasional dressing of lime. Never mix muriate of potash with sulphate of ammonia; the latter will lose part of its nitrogen. The muriate is especially valuable for the lighter soils, because it attracts moisture. Sulphate of Potash is bought in two forms, "high grade" and "low grade." The former con- tains 51 to 53 per cent, actual potash, which in this form costs four and one-half cents a pound at the current price of $45 a ton. High-grade sul- phate of potash can be used safely for all crops. Unlike the muriate it does not increase the loss of lime from the soil ; although the potash in it costs a trifle more than that in the muriate, the sulphate is generally preferable for this reason. It is especially preferable for tobacco, sugar beets, onions and potatoes. Low grade sulphate of potash con- tains about 26 per cent, of potash combined with magnesia, which has a beneficial effect on some soils. But the potash in it costs more than in other forms, so that it is not used much in this country. Many other materials are occasionally used as fertilisers, such as tobacco stems and stalks, wool and hair waste, seaweed, crude fish scrap, etc. The amounts of food in the most common of these are given in the Appendix. MIXING THE RAW MATERIALS If but one plant food is to be applied, the material is put upon the land as it comes from the dealers; if two or three are to be applied, the COMMERCIAL FERTILISERS 387 materials must be mixed. The mere mixing re- quires little skill, but it is very important to get the right proportions of the different plant foods in the mixture. We will suppose that excellent results have followed the use of 1,000 pounds per acre of a certain brand of fertiliser containing 4 per cent, of nitrogen, 8 per cent, of potash and 6 per cent, of phosphoric acid ; but it is found that the* plant food in this fertiliser costs more than it can be bought for in raw materials. This means that for each acre, a mixture containing 40 pounds of nitrogen, 60 pounds of potash, and 80 pounds of phosphoric acid is needed. By referring to the figures of the amounts of plant food in each fer- tilising material, we find that the 40 pounds of nitrogen may be obtained in 250 pounds of nitrate of soda, or 200 pounds of sulphate of ammonia, etc. The 60 pounds of potash may be obtained in 120 pounds of sulphate of potash, or in 114 pounds of muriate of potash, etc. The 80 pounds of phosphoric acid may be obtained in 533 pounds of dissolved South Carolina rock, or in 250 pounds of Florida phosphate, etc. If sulphate of ammonia is found to be the cheapest source of nitrogen, sulphate of potash, of potash, and dissolved South Carolina rock, of phosphoric acid, the mixture would be: 200 lbs. sulphate of ammonia 120 lbs. sulphate of potash 533 lbs. dissolved South Carolina rock 853 lbs. for an acre; larger quantities in proportion. It often happens that some fertilising materials which can be bought to advantage contain more than one kind of plant food. Thus a good sample 388 SOILS of unleached ashes should contain 8 per cent, of potash and 2 per cent, of phosphoric acid ; in such a case each plant food should be figured out independently. If a fertiliser containing 10 per cent, of potash and 5 per cent, of phosphoric acid is needed, and ashes can be bought very reasonably, it will only be necessary to add to the ashes a sufficient quantity of muriate of potash, and of superphosphate, for example, to make a fertiliser having the desired analysis. The actual mixing of fertilisers is easily done. The right quantities of the several materials are dumped upon a tight, smooth floor and are shovelled over until thoroughly mixed. The mixture may then be put through a sieve. It is best to keep the several ingredients separate until a short time before the fertiliser is needed. Any fertiliser con- taining ammonia should not be mixed with lime, as lime attacks ammonia and nitrogen escapes. If highly concentrated fertilisers are mixed, as muriate of potash and bone ash, it is often de- sirable to add a quantity of some other material, not plant food, as dust, dry soil or land plaster. This gives the mixture greater bulk so that it can be distributed much more evenly, especially if light applications are to be made. The saving in buying raw materials and mixing them at home is often 25 to 40 per cent, over the cost of the same amounts of plant food if bought in the average manufactured article. WHAT KINDS OF FERTILISER TO USE There are two great problems in using com- mercial fertilisers. The first is, "What kind and what amounts of plant food does my soil need?'* COMMERCIAL FERTILISERS 389 The second, "In what form can I buy each plant food cheapest?" What and how much fertiliser to apply as a fertiliser depends upon the deficiency of the soil, the needs of the crop, the system of farming, and kindred matters. Soil Analyses as a Guide to Fertilising. — If the crops are unsatisfactory, and this cannot be wholly explained by a poor texture of the soil, a deficiency of available plant food may be sus- pected. But what kind of plant food, and how much fertiliser will it pay^ to apply ? The first thing that many farmers do is to send a sample of the soil to a chemist to be analysed; for, they argue, if crops grow on plant food in the soil, surely an analysis of the soil should show just what it needs. But the chemical analysis of a soil rarely gives reliable information about the best way to fertilise it. The analysis of a certain soil may show that there are 5,000 pounds of phosphoric acid in the upper nine inches, but it does not and cannot show how much of this vast amount is soluble, or in such a form that plants can use it; this makes a great deal of difference, from the farmer's point of view. An analysis often points out glaring deficiencies and gives hints that may be valuable in fertilising a soil; but it is by no means a reliable guide, and it usually bears no relation to the method of fertilising which will be found most profitable on that soil. It is generally understood, however, that cer- tain types of soils have special needs. Clay and other heavy soils are usually rich in potash, but poor in phosphoric acid; sandy soils, and all others deficient in humus, lack nitrogen; peat and muck 390 SOILS soils need potash and phosphoric acid more than nitrogen, especially potash. Questioning the Soil. — A good farmer will not long be satisfied to fertilise solely on hearsay evi- dence. He will observe the effects of different fer- tilisers on his own crops and, gradually learning the peculiar needs of his soil, will fertilise accordingly. It is not necessary to lay out an elaborate series of plot experiments with fertilisers in order to determine with considerable accuracy what fertiliser pays best on a certain soil. In many cases it is enough merely to test different fertilisers as a part of the regular farm practice; in other cases it will pay to lay out fertiliser plots. In either case, the testing should be done methodi- cally and the results should not be interpreted too hastily. A common way of testing fertilisers is to use different kinds indiscriminately, until one is found that answers the purpose. This hit-or-miss method is usually unsatisfactory. Another way is to apply each of the three plant foods separately and in combinations. This is an exact and reliable method. In these experiments it is cus- tomary to use nitrate of soda, sulphate of potash, and superphosphate as the sources of plant food, since these materials each contain but one kind of plant food. These fertilisers may be applied to different rows of plants, or to plots of the same size. Plots one rod wide and eight rods long, containing Tar of an acre, are a convenient size. The plots should be long and narrow, so as to cover inequalities of soil. If the land is sloping, run them up and down the slope. Make every condition in the several plots as nearly alike as possible, COMMERCIAL FERTILISERS 391 except as to the kind of fertiliser applied. It is best to leave between plots a strip of land at least four feet wide, which is unfertilised; this prevents the fertiliser applied to one crop from affecting the crop in an adjoining plot. The full experiment would look like this: Plot 1 Nitrate of Soda, 8 lbs. Plot 2 Acid Phosphate, 16 lbs. Plot 3 Plot 4 Sulphate of Potash, 8 lbs. If it is desired to test the value of different com- binations of plant foods, add : Plot 5 Nitrate of Soda, 8 lbs. Sulphate of Potash, 8 lbs. Plot 6 Nitrate of Soda, 8 lbs. Sulphate of Potash, 8 lbs. Acid Phosphate, 16 lbs. Plot 7 Nitrate of Soda, 8 lbs. Acid Phosphate, 16 lbs. Plot 8 Stable Manure Plot 9 Sulphate of Potash, 8lbs. Acid Phosphate, 16 lbs. Plot 10 392 SOILS The fertiliser should be applied broadcast and harrowed in lengthwise, not crosswise, of the plots. The amount used should be somewhat larger than in the field at large; if the plot is yu of an acre satisfactory amounts are 8 pounds of nitrate of soda, 8 pounds of sulphate of potash and 16 pounds of superphosphate. The fertiliser may be mixed with dry soil or sand in order to dis- tribute it more evenly. Throughout the season give all plots the same care. In comparing the crops grown under the dif- ferent methods of fertilising it is well to take only the inside rows of each plot, if no unfertilised strips have been left between plots, because the outside rows may have been affected by the fertilising of the adjacent plots. The yields of the several plots may be measured for comparison. Such a test as this, even though not carried out in every detail, gives valuable results to the man who is obliged to use commercial fertilisers. It is well to repeat the experiment two or three years and upon the same land if possible. The Needs of Different Crops. — The chemical analysis of a crop is of very little practical value to the man who wishes to know what fertiliser to apply to that crop. The proposition looks plaus- ible, however. The chemist tells the cotton farmer that the crop of cotton plants which produce 190 pounds of lint per acre draws an average of 40 pounds of nitrogen, 16 pounds of phosphoric acid and 25 pounds of potash from the soil. The farmer will then apply these amounts of the plant food each year, but adding a little more, because probably part of it does not reach the crop. But the chemical analysis of a crop is no more reliable as a guide to fertilising that crop than the COMMERCIAL FERTILISERS 393 chemical analysis of a soil. Both are useful hints, and may point out striking needs or deficiencies, but other factors are much more important. An experiment at the New York State Experiment Station, for example, showed that a fertiliser con- taining nearly the proportions of plant food used by the potato plant was much less useful than one containing very different proportions, based on the experience of observing growers. An abun- dance of phosphoric acid in the soil contributes more to the profitable growth of the cotton crop than either of the other plant foods; yet an analy- sis of the cotton plant shows that it contains less phosphoric acid than either nitrogen or potash. The needs of the soil and the needs of the crop cannot be studied separately and independently with any degree of satisfaction ; they are coordinate and complementary. Crops do differ, however, in their demands upon the soil. A knowledge of the special needs should be helpful to the man who does not have the results of a home fertiliser test to guide him. A few general suggestions follow: The small grains — wheat, rye, oats, and barley, are especially benefited by an abundance of nitro- gen and of phosphoric acid. The latter is espe- cially needed in the development of grains. Indian corn, a very exhaustive crop, is more apt to need applications of the mineral plant foods especially phosphoric acid, than of nitrogen. Forage crops, including the grasses and grains grown for forage, but not clovers, are most apt to need nitrogen. The clovers, including all legumes, need potash and phosphoric acid, but not nitrogen; they also draw heavily on lime. 394 SOILS Root and tuber crops are more variable in their demands. Potash should be the most important ingredient of a fertiliser for sweet and Irish pota- toes— the sulphate is preferred to the muriate; phosphoric acid for turnips and nitrogen for beets and carrots. Root crops need quick-acting fertiliser. Fruits. — The period of growth of tree fruits is extended over a longer time than other farm crops, and so slow-acting fertilisers may be used upon them to advantage. The small fruits, however, as strawberries and raspberries, must have quick- acting fertilisers. Potash is of special importance in a fruit fertiliser. Market-garden crops in which the chief object is to secure the crispness and tenderness that comes from a rapid growth, as celery, radishes, cabbage, lettuce, etc., must have an abundance of quick- acting fertiliser, particularly of nitrogen. Cotton especially enjoys an abundance of phos- phoric acid. These general suggestions on the fertilising of different crops merely indicate what many people have found profitable. They are subject to many exceptions, depending upon the kind of soil on which the crop is grown. So it all comes back to the elemental problem of questioning the soil. This will ever be an experiment for each farmer; no one else can perform it for him. THE RELATIVE IMPORTANCE OF THE THREE PLANT FOODS Phosphoric acid is regarded by many as the most important of the three plant foods; not be- cause it is more essential to the profitable growth of crops, but because it is more likely to be lacking COMMERCIAL FERTILISERS 395 in ordinary soils than either potash or nitrogen; and, furthermore, because the commercial supply of phosphoric acid is apparently more limited than that of the other two plant foods. In most cases the supply of nitrogen may be maintained without difficulty with barn manure and green-manuring. Potash is found more in the straw than in the grain ; the grain, which is rich in phosphoric acid, is commonly shipped away from the farm while the straw remains. From the point of view of the future supply, then, phosphoric acid is the most important of the three plant foods. From the point of view of the plant, however, one food is as important as another. Plant foods are often spoken of as though each one performed certain definite functions ; as ' * Potash makes fruit, ' ' "Nitrogen makes stem and leaf growth," and "Phosphoric acid fills out the grain." Undoubt- edly each of the three plant foods does exert a special influence in one of these several directions, but all are essential to the well-being of the plant. "Fertilising for fruit" or "fertilising for grain" or "fertilising for growth" is apt to be one-sided and unsatisfactory fertilising. The plant as a whole is the unit; fertilise to make a symmetrical, well- developed plant; not for an abnormal develop- ment of any part. WHEN TO APPLY COMMERCIAL FERTILISERS This depends first of all upon the solubility of the fertiliser. One would not apply nitrate of soda, which dissolves almost immediately in soil water, in the fall ; much of the nitrogen in it would be leached from the soil by spring. But one might apply raw bone meal in the fall, because this 396 SOILS becomes available quite slowly. The more soluble a fertiliser is, the more necessary it is to apply it at or about the time it will be needed most by the crop. As a class, the nitrogen fertilisers are more quickly soluble and more apt to be lost by leaching than the other plant foods; they should usually be applied in the spring or during the summer, as needed. The potash and phosphoric acid in fertilisers are not subject to serious waste; they remain in the soil until taken out by plants, com- bining with lime, silica and other minerals in the soil. This is called the "fixing" of these plant foods. It usually takes place within a week after the fertiliser is applied. With the exception, in some cases, of raw bone and raw mineral phos- phates, it is best to apply fertilisers in the spring. The special needs of crops also influence the time for applying fertilisers. Many crops need a special stimulus at certain times and under cer- tain conditions. Thus, if wheat on light land has passed through a severe winter it may need an application of nitrogen in the spring, in addition to the regular fertiliser provided for it the fall pre- vious. Or again, beets that are being forced for bunching will profit by several light dressings [of nitrogen at intervals of two weeks, instead of put- ting all the fertiliser into the ground at planting time. HOW TO APPLY FERTILISERS The method of applying fertiliser is mostly a matter of expediency. In a majority of cases it is best to broadcast it over the entire surface after plowing and before the last harrowing. Most of COMMERCIAL FERTILISERS 397 the common fertilisers suffer no Iocs if left on the surface, but it is generally considered best to work all fertilisers into the soil, because this mixing brings the plant food within reach of the roots more quickly. There are some fertiliser distrib- utors on the market that do the work cheaper than it can be done by hand; fertilisers may also be drilled in. Whether part or all of the fertiliser should be put into the hill or drill depends upon the soil and the crop. Nothing is lost by broadcasting it, for the roots of the crop will lay every foot of soil under tribute ; but an early start may be gained by putting part of the fertiliser in the hill or drill, if it is quickly available. This is especially profitable on light and poor soils, particularly if but little fertiliser is used; and for market garden crops, as earliness counts for more with them than with general farm crops. In any case only a part of the fertiliser should be put in the hill or drill; most of it should be broadcasted. With grains, however, all the fertiliser may be drilled in. Fertilisers used on hoed crops that are growing should be cultivated in between the rows. A nitrogen fertiliser ap- plied after the crop has started should not be put on when the leaves are wet; if much of the fer- tiliser sticks to the leaves, injury may follow. The amount of fertiliser to apply depends upon the kind of soil, the value of the land, the kind of crop, the market value of the crop, the amount of manure available, whether green-manuring has been practised, the system of farming, and many other factors. No general statement can be made that is of any value. Perhaps a general average for stable crops on the poorer soils of the Eastern States is 20 pounds of nitrogen, 80 pounds of 398 SOILS potash, and 100 pounds of available phosphoric acid. Be especially chary in the application of nitrogen. One hundred pounds per acre of nitrate of soda is usually sufficient if used alone. If used with the mineral plant foods, this application may be doubled or trebled. WHEN IT WILL PAY TO USE FERTILISERS This depends not only upon the condition and needs of the soil, but also upon the money value of the crop and the value of the land. The higher the value of the land or the crop the more will it pay to fertilise liberally, in order to secure maximum yields which will pay interest on the large amount of capital invested. The largest use of commercial fertilisers is made in market gardens and in special crop farming, as the growing of onions, tobacco, and fruit. It might pay to use a ton of commercial fertiliser on an acre of garden vege- tables on Long Island when it might not pay to use 500 pounds on an acre of wheat in Ohio, although both soils were equally in need of fertilising. It is a question of economics as well as of crop culture. It depends also upon the thoroughness of the farming; a good farmer, especially one who tills the soil thoroughly and keeps it in good texture by the use of green manures and animal manures, makes the use of commercial fertilisers pay, but a poor farmer does not. The physical condition of the soil — which the farmer can largely control and modify — has more to do with the profit in using them than any other factor. Many farmers are not securing the profit from fertilisers that they might if their soil was in better texture. COMMERCIAL FERTILISERS 399 Fertilisers are so easy to get and easy to apply, that there is a tendency to use them hastily, without regard to their content and the needs of the soil ; and to use them in much larger quantities than is really necessary. The rational course to pursue is to use them only to supplement farm re- sources of fertility; and to use them only up to the point where they return the largest ratio of profit for the expenditure. Certain materials that furnish little if any actual plant food, but exert a very beneficial effect upon the soil, are called ' ' indirect fertilisers " or " amend- ments." The most common of these are lime and land plaster and, to a very slight extent, salt. THE BENEFITS OF LIMING Lime is an important factor in maintaining the fertility of certain farm soils. It is a plant food. If a soil contained no lime, plants would not thrive upon it. Although most soils contain sufficient lime for the needs of the crop, some soils become exhausted of it and it is then needed not as an indirect, but as a direct, fertiliser. Lime may benefit certain soils by improving their texture. When applied to a light, leachy soil, it makes it more retentive. When applied to a clay, it has the opposite effect; the very fine soil grains are cemented together and consequently the soil is made more porous. The practical effect is that liming a sandy soil makes it less leachy, while liming a stiff clay makes it more crumbly; the condition of both is greatly improved. A third effect of applying lime to a soil that is deficient in it, is that it makes the plant food in the soil, especially the potash, more soluble. 400 SOILS Much of the potash in our soils is insoluble, being "locked up" in compounds with silica. Lime attacks the silica and sets free the potash. It also prevents the loss of soluble phosphoric acid in the soil The practical effect of this is that liming may be equivalent to fertilising, for a time. But since lime supplies no potash, phosphoric acid, or nitro- gen, the soil is eventually made less productive. This is the basis for the old adage, "Liming makes the father rich and the son poor." The most important function of lime in modern agriculture is to sweeten sour soils. A soil that contains free acid is "sour," or acid. Such soils, though they may be rich in plant food, usually produce inferior crops ; but if this acid is neutralised by adding lime, they become productive. There are thousands of acres of sour soils in the United States, notably in Rhode Island, Massachusetts, New Hampshire, Connecticut, New York, Illinois, Maryland, Virginia, and Alabama. The applica- tion of lime to such soils may do more to make them productive than the use of large amounts of com- mercial fertilisers. THE SOILS THAT NEED LIMING Contrary to the popular notion, soils containing a large amount of humus are not more likely to be sour than upland soils. Soils are sour because the rocks from which they were formed were deficient in lime. Sour soils are very apt to have an abun- dance of sorrel or "sourgrass." When this plant comes into the field and crowds out other plants, it is a fairly reliable indication that lime is needed, although sorrel often grows well on sweet soils. Practically all farm crops, except watermelon, COMMERCIAL FERTILISERS 401 Hungarian grass, red-top, blackberries, and the lupines, do poorly on a sour soil; these seem to prefer it. Indian corn and rye stand it much better than the other cereals. Clover, alfalfa, beets, and timothy are almost sure to fail on sour soils. TESTS FOR SOUR SOILS A simple and fairly reliable method of deter- mining whether a soil is sour, is to test it with blue litmus paper. This can be bought at a drug- store for a few cents. Get several samples of moist soil from different parts of the field, mix them into a paste with water, and insert one end of the litmus. At the end of an hour, if the blue paper has turned red where it came in contact with the paste, probably the soil is sour. The litmus test will usually show with con- siderable accuracy whether a soil is badly in need of lime, but soils which are not actually sour may need it. The best way is to apply lime to a strip of soil and compare the growth of crops on this strip with their growth on unlimed parts of the field. In the fertiliser test previously described, use about 200 pounds of lime on the T^-acre plot. HOW TO SWEETEN SOUR SOILS A sour soil should be limed at the rate of 1,000 to 4,000 pounds per acre; two tons per acre is about the maximum of application. The lime should be applied broadcast in late fall or early spring. The best form of lime to use is the water- slaked. Put stone lime in heaps on the ground and cover it with moist soil. In a few days the 402 SOILS lime will be found powdered and may then be spread. If air-slaked lime is used, the applications stiould be heavier. If lime is used in seeding to grass, apply it ten to fourteen days before seeding, if possible. It is not usually necessary to lime soils oftener than once in four or five years. OTHER AMENDMENTS Land plaster, or gypsum, which is sulphate of lime, has about the same effect upon the soil as common lime. Gypsum was formerly used very largely, especially on clover, Indian corn, and pota- toes. It has been observed to increase the yield of clover 20 to 30 per cent. ; but after a number of years, this benefit is no longer obtained. Its beneficial effect is due largely to the fact that it makes the potash in the soil more soluble, thus causing an increase in the crop. Land plaster is not now used to any extent except as it occurs as a part of acid phosphate, but in this case it has no value for sweetening the soil. It can be used to great advantage, however, on the floors of cow and orse stables and the roosts of hen houses to pre- vent the escape of ammonia. It is also useful, in some cases, for treating alkali soils. Wood ashes are about 35 per cent, lime, and im- prove the soil in all the ways that lime does. Part of the excellent results commonly secured from the use of wood ashes is due to the value of the ashes for correcting acidity and setting free plant food. Marl which is chiefly fossil shells, contains much carbonate of lime and is valuable for dressing land that needs lime. Large areas of land in New Jersey that were formerly unproductive have been COMMERCIAL FERTILISERS 403 made productive by applications of marl. It improves the texture of the soil, sets free plant food and corrects acidity, the same as lime. If a deposit of it is handy, it is certainly worth using. Salt was once used considerably as a fertiliser, especially on asparagus. It makes the soil more moist and assists decay, but its agricultural value is not equal to its cost, which is $4 to $6 per ton. The potash salt, kainit, is one-third common salt. If salt is needed, buy it in this form, because the price of kainit is based solely upon the amount of potash in it. APPENDIX I. ROTATIONS PRACTISED IN DIFFERENT STATES The following remarks on the crop rotations practised in or recommended for the different states are a summary of correspondence between the author and the various authorities quoted. ALABAMA In the cotton states the majority of farmers pay little attention to rotations. Where small grains are grown the following rotation is recommended: First year, corn, with cowpeas planted in May or June between the corn rows. Second year, fall-sown oats or wheat, followed by cowpeas in June. Third year, cotton. The cowpeas after the crop of small grains are usually cut for hay, but may be picked for seed or may be pastured or plowed under in January or February. This can be lengthened into a four-year rotation, in order to put one-half of the arable land of the farm into cotton, by adding cotton as the crop of the fourth year. Director, Alabama Experiment Station. J. F. Duggak. ARIZONA Our soils are still so new to cultivation and so fertile that the need of rotations has not yet been felt. The deficient elements of our soils are nitro- gen and humus. At present, and doubtless largely in the future, these are supplied by alfalfa. Agriculturist, Arizona Agr. Experiment Station. V. A. Clare. ARKANSAS Arkansas is both a cotton and fruit state. Land along the rivers is culti- vated in corn and cotton without reference to rotation. Throughout the state cowpeas grow well and are usually sown after oats and wheat are har- vested, also in the cornfields. Rye is used only for winter pasture. In the orchard belt the usual rotation is corn, wheat, cowpeas; or corn, oats, clover. The rotation of stock farmers is corn (summer), rye (winter), cowpeas or sorghum (forage), wheat (winter and spring). The weak point in the agri- culture of this state is the lack of diversified crops. Professor of Agriculture, University of Arkansas. Geo. A. Cole. CALIFORNIA The course of California agriculture hitherto has been to avoid rotation and to keep the land producing that to which it seems adapted, and for which profitable prices could be had, for an indefinite period. Recently 405 406 APPENDIX the desirability of rotation has become more apparent, especially in connection with sugar beet growing. Our rotations probably will never be like those in the East because it is only occasionally that a certain piece of land is suited to the growth of three different grains. California must devise rotations of her own, as her agriculture advances, and the question will be quite as much what crop will succeed at all, as what crop will be best for the land. Professor of Agriculture, University of California. E. J. Wickson. COLORADO Under ditch the principal rotation is alfalfa for several years, beets or potatoes, followed by grain and again seeding to alfalfa. The tendency is to grow beets several seasons on the same ground on account of the high profit of the crop, but they should be grown only one to two years. Where potatoes are grown the same is true. In the San Luis Valley, where 50,000 acres of peas are grown annually, the rotation is peas, potatoes, grain. The regions outside of both potatoes and beets have no definite rotation. We have under experiment a rotation of alfalfa two years, roots one year, grain one year. Professor of Agronomy, Colorado State Agr. College. W. H. Olin. CONNECTICUT No regular rotation is practised. One of our principal industries is dairy- ing and we must grow large quantities of corn for silo. On fields where corn can be grown with greatest economy it is often the practice to grow corn year after year, using stable manures and commercial fertiliser to maintain the productive power of the soil. A rotation I have found well adapted to our conditions is: First year, corn; second year, potatoes; third year, rye; fourth year, meadow. The rye is put on in the fall after the potatoes are removed, and the grass seeding put on with the rye. Where potatoes are not desired, we sometimes break up the sod and grow corn two years in succession; then seed down either with rye or use grass and clover seeds alone. Director, Storrs Agr. Experiment Station. L. A. Clinton! DELAWARE On most of the soils of Delaware devoted to grain farming, the most common rotation, and probably the best, is corn seeded to wheat the same fall; the wheat cut in June, the stubble clover and weeds cut once or twfce with mowing machine and allowed to fall to the ground; clover, or clover and timothy the next June followed by a second crop of hay; or, more usually, the field is turned out to pasture for the remainder of the year. In other words, a three-year rotation of corn, wheat and clover. Sometimes the field is pastured the second season, making a four-year rotation of corn, wheat, clover, pasture. This rotation in itself is not so good as the three-year rotation, but it means more live stock and, therefore, more forage and grain fed on the farm and consequently more manure. A few farmers get a good crop of corn fully matured every fall following a good crop of crimson clover hay from the same land. Sec. of Delaware State Board of Agriculture. Wesley Webb. APPENDIX 407 FLORIDA There is little or no systematic rotation practised. In the northern part of the state, where corn and cotton are grown, they follow corn with cotton and sow cowpeas in the corn, or a row of peanuts between the rows of corn. Farther south where velvet beans are grown and used for fattening cattle a rotation is: corn the first year, velvet beans the second year, and the velvet beans are pastured off during winter and the ground is again put in corn. In the vegetable section of the state, no rotation is practised unless it is forced by plant diseases which can be killed only by rotation. Professor of Agriculture, University of Florida. Chas. M. Conner. IDAHO There is little systematic rotation of crops here. A few farmers rotate grain with such crops as corn, potatoes, and beans. In some irrigated sections grain is rotated with sugar beets. In older irrigated sections an effort is being made now to rotate grain with alfalfa. Our practice at the Station is a five-year rotation: Two years of grass, one of corn, one of wheat, and one of oats or barley. Director, Idaho Agr. Experiment Station. H. T. French. ILLINOIS Some crop rotations which are being practised to some extent in this state are: THREE-TEAR ROTATION First year, wheat, followed by cowpeas or soy beans as catch crop; second year, corn, with cowpeas or soy beans as catch crop; third year, cowpeas or soy beans (to be followed by wheat). All crops except the wheat should be fed or pastured or used as bedding and all manure returned to the land. If the corn crop is cut and shocked, then a three-year rotation of corn, wheat, and clover is a good one. FOUR- YEAR ROTATION First year, corn, with cowpeas or soy beans as catch crop; second year, cow- peas or soy beans ; third year, wheat (with clover to be seeded in spring) ; fourth year, clover. If well filled, the second crop of clover should be harvested for seed. All other crops, excepting wheat and possibly cowpea or soy bean seed, should be fed and the manure returned to the land. FIVE-YEAR ROTATION This may be the same as the four-year rotation except that timothy may be seeded with clover and the land pastured the fifth year. Professor of Agronomy, University of Illinois. C. G. Hopkins. INDIANA Corn is our principal crop practically all over the state, and forms the basis of every rotation, as it is generally desired to bring in corn as often as possible. The prevailing rotation, whenever any system is followed, is the three-course — 408 APPENDIX corn, wheat or oats, clover. The four-course — corn, oats, wheat, clover, is more or less used in central Indiana; also corn, wheat or oats, clover and grass two years. In southern Indiana we sometimes find a two-course — wheat and clover rotation. For general purposes we consider the three- course rotation best. Most of our farmers claim that they can get a better stand of clover in wheat than in oats. Occasionally we find a four-course rotation, consisting of corn, corn, small grain, clover. Agriculturist, Indiana Agr. Experiment Station. A. T. Wiancko. IOWA Corn is the "money-crop" of Iowa and it is desired to raise as many crops of corn as possible. Clover has thus far been found the most satisfactory leguminous crop for a rotation in this state. In the southern part of the state a common rotation is corn two years; wheat one year; clover one year. This may be extended into a five-year rotation by allowing the land to remain in clover and timothy for two years. Another rotation, practised less extensively, is corn one or two years; oats one year; wheat one year; clover and timothy, one or two years. In the northern portion of Iowa, where winter wheat has not been as successfully grown, the rotation most extensively practised is corn two years; oats one year; clover one year. In many cases it is necessary to sow a catch crop of cowpeas in order to include a leguminous crop in this rotation. Winter wheat is superior to oats as a nurse crop for clover, and is being included in rotations wherever it can be successfully grown. Iowa State College, Dept. of Agr. Extension. A. H. Snyder. KANSAS Less than 10 per cent., and perhaps less than 5 per cent., of Kansas farmers practise rotation of crops. The three main crops are corn, wheat and alfalfa. Many fields can be found in some sections upon which wheat has been grown almost continuously from twenty to thirty years. The same may be said of corn-growing, especially in the eastern part of the state. Alfalfa is often left on the fields for many years. The size of the farms is such that the farmers must resort largely to wheat culture, as it would be impossible to farm them thoroughly with several crops with the small amount of help. In most of the wheat sections the farmers grow some corn, kaffir corn or sorghum, but do not have any definite rotation. Two rotations we are suggesting are: (1) Alfalfa, four years; corn, two years; wheat, one year; and alternating two years of corn with one of wheat for nine years more before seeding again to alfalfa. (2) Grasses and clover, three years; corn, two years; spring grain, one year; wheat with catch crops, one year, repeating the latter three twice before seeding to grass and clover in wheat. Professor of Agronomy, Kansas Agr. College. A. M. Ten Eyck. KENTUCKY There is no very generally adopted rotation, but as the farmers understand the importance of getting humus in the soil, and of using clover or some related plant in order to increase the nitrogen, they generally employ for APPENDIX 409 these purposes, bluegrass, timothy, red clover, cowpeas and soy beans. The cultivated crops alternating with these are hemp, tobacco, corn and wheat. Botanist, Kentucky Agr. Experiment Station. H. G. Garman. LOUISIANA Many sugar planters plant corn and cowpeas after harvesting the last crop of stubble cane, growing a crop of corn and cowpeas one year in three or one year in four. The rice land is sown for two, or sometimes three years, then devoted to cotton or allowed to grow weeds and grass, and then put in rice again. On the prairies of southwestern Louisiana many fields have been devoted to rice for twelve or fourteen years in succession. On a majority of the larger plantations cotton is grown continuously year after year. Corn is practically the only other crop grown so there is little rotation. On the alluvial lands, one year in four or five cotton land is put into corn and cow- peas. In the hill lands a few plant grain or cotton, two years; then corn and cowpeas one year; and sometimes a crop of oats, followed by a crop of cow- peas. A very desirable rotation is oats, cotton and corn, with cowpeas between. The oats are harvested in May and the land put in cowpeas. These are harvested in September or October and the land is fall-plowed and the following year planted in cotton. The cotton is followed with corn, and cowpeas sown in the corn at the last plowing. The corn is gathered in September or early October and the land is plowed and sown to oats. With the addition of a reasonable amount of acid phosphate this builds up the land very perceptibly. Director, Louisiana Agr. Experiment Station. W. R. Dodson. MAINE In many sections of the state no systematic rotation is practised. We have many " patchy farms" ; a man will go to the middle of the field, or to one side, and plow a small area and on this plant any crop. In Aroostook County a three-course rotation, consisting of potatoes, oats or wheat, and clover, is followed. On the college farm, we are practising a four or five-year rotation, potatoes, corn, oats, seeding with the oats to grass, and clover, and allowing the land to remain in grass one or two years. This rotation is frequently followed in dairy sections. Professor of Agronomy, University of Maine. Wm. D. Hurd. MARYLAND The principal crop rotations practised in this state are: Southern Maryland (Tobacco section), (1) tobacco, wheat, red clover; (2) tobacco .wheat, red- top and red clover. Central and eastern Maryland (dairy farming and grain and hay crops), (3) corn, wheat, timothy and clover, timothy; (4) corn, winter barley, timothy and clover, timothy; western Maryland (beef- cattle and grain farming), (5) corn, wheat, clover; (6) corn, oats, wheat, timothy and clover, timothy. Director, Maryland Agr. Experiment Station. H. J. Patterson. 410 APPENDIX MASSACHUSETTS Massachusetts fanning is largely devoted to specialties. Fertilisers or manures or both are used very freely and there is less dependence upon rota- tians than in many other states. Some of the most important money-crops, especially onions and tobacco, are grown year after year on the same land. In some parts of the state a four-course rotation, (1) turnips, barley, clover and oats, is practised, most of the manure being applied to the corn, not to the grass. In parts of the state where dairying is prominent and where the potato is a money-crop, a common rotation is (2) potatoes, one year; corn, two years (the second for ensilage); grass and clover three years. There are several modifications of this rotation. On our light soils the follow- ing three rotations are common: (3) Potatoes, winter rye, clover; (4) corn, potatoes, rye, clover; (5) corn, potatoes, rye, grass and clover two years. Succession cropping is practised with much skill and success by our market gardeners. Director, Massachusetts Agr. Experiment Station. W. P. Brooks. MICHIGAN A rotation valued at the college is corn, wheat, oats or barley, clover or clover and timothy, pasture. In most cases we spread manures upon pasture. We seed always with a grain crop. In Wexford County the following rotation is used successfully: Clover, potatoes, wheat; seeding to clover with the wheat. Many farmers believe that it is not possible to secure a good stand of clover or clover and timothy with oats, and therefore grow wheat or barley. Professor of Agronomy, Michigan Agr. College. Joa. A. Jeffeby. MISSISSIPPI As a rule our farmers do not practise crop rotation. Our best rotation for the general cotton farmer is: Fall oats, followed by cowpeas; cotton; corn, laid by in cowpeas. The above rotation has for i*s principal object the maintenance of soil fertility. Professor of Agriculture, Mississippi Agr. College. E. R. Lloyd. MISSOURI Missouri farmers are just beginning to rotate crops. In north Missouri and part of Missouri the common rotation has been corn for several years, then grass for a few years and back into corn. In the wheat-growing section it has been mostly wheat for several years, then into grass, and back again into wheat; although some of the farmers have practised a rotation of (1) corn, wheat and clover, or clover and timothy. A rotation used in north Missouri is ("-2) corn, oats, clover or clover and timothy. Farmers are beginning to sow cowpeas to some extent, using (3) corn, cowpeas, wheat, or (1) corn, cowpeas, wheat, clover; or in some cases simply wheat and cowpeas. In southeast Missouri some farmers harvest wheat, turn the land quickly and put in cowpeas, harvest the cowpeas for seed or hay and Eut the land back into wheat in the fall. Some farmers in northeast Missouri ave a rotation of (5) corn, oats, wheat, clover, in some cases following the clover with timothy. Professor of Agronomy, University of Missouri. M. F. Miller. APPENDIX 411 MONTANA But one rotation is followed to any great extent — two years in clover and two years in grain; wheat or oats being usually grown after the second crop of clover, and oats orbarley the succeeding year. On dry bench lands above the irrigation ditch a common practice is to summer-fallow one year followed by a grain crop the next. On the watered land, in some sections, summer- fallow is followed by two or three grain crops. In a few instances, peas are followed by two crops of grain. Sometimes this is made peas, potatoes and grain two years. Some are planning the following rotation: Alfalfa, four or five years; wheat, sugar beets, or other cultivated crops, two years; then one or two seasons of grain. Director, Montana Agr. Experiment Station. F. B. Linfield. NEBRASKA Crop rotation is not carried out systematically by many Nebraska farmers. Corn is the main crop throughout the eastern third of the state; frequently it is grown continuously on the same field. Recently farmers have begun to realise the necessity for some change on account of the corn root-worm and other difficulties, and it is now quite common to alternate corn with oats. Where anything like a systematic rotation is attempted it generally consists of corn for perhaps two years, followed by oats put in on the corn stubble without plowing, followed by winter wheat drilled in on the plowed oat stubble. In the central part of the state, corn and wheat are alternated by drilling in wheat between the corn rows. In the extreme western part of the state the occasional complete failure of crops takes the place of a rotation so far as its effect on the land is concerned. A rotation at the Nebraska Experiment Station consists of corn two years, oats, wheat, alfalfa, or mixed grasses. If seeded down it is left for four years. Professor of Agriculture, University of Nebraska. T. L. Lyon. NEVADA There is no prevailing crop rotation in this state. More often than other- wise two crops of grain follow alfalfa. Potatoes usually follow alfalfa and are followed by grain. The length of time that land is kept in alfalfa de- pends largely upon the stand. It is seldom less than four years. Some alfalfa fields in the state are twenty years old. Professor of Agriculture, Nevada State University. Gordon H. True. NEW HAMPSHIRE There are only a few farms which contain arable land in large enough fields to practise a definite system of rotation. The fields on many farms remain in grass for twenty-five years, or even longer. The fields on which the sod is poorest are plowed in late summer and either seeded down again at once to grass or planted to corn or potatoes for a year or two, and then seeded to grass. Perhaps the following is the most common rotation: Corn; potatoes; oats, or oats and peas; clover; clover and timothy; timothy. Prof. J. W. Sanborn practises the following eight-year rotation on his 412 APPENDIX upland farm: Corn (for husking and ensilage); oats and peas; clover; potatoes; Hungarian; timothy; timothy; pasture. Professor of Agriculture, New Hampshire College. T. W. Taylor. NEW JERSEY We have a large number of rotations because of the many crops grown. In general farming the rotations are about as follows: (1) Corn, oats, wheat, clover; (2) corn, oats, wheat, clover and timothy mixed, timothy; (3) corn, wheat or rye, clover. In dairy, potato and market garden sections the rotations are: (1) Corn, oats and peas and cowpeas, rye or wheat, clover; (2) corn, wheat, potatoes, clover or timothy or mixed; (8) corn, potatoes, hay; (4) corn, tomatoes, sweet potatoes, white potatoes, clover. This is not a regular rotation, but these are used as conditions seem to warrant. Director, New Jersey Agr. Experiment Station. E. B. Voorhees. NEW MEXICO But little crop rotation is practised in this territory. Alfalfa, in most cases, is grown continuously on the same land. There is but one arrangement of crops that can be classed as a rotation, that is wheat and corn, which are usually grown in alternation. Assistant in Irrigation, New Mexico College of Agriculture. A. C. Martenbower. NEW YORK One of the best rotations where wheat is grown is: Clover, corn or potatoes, oats or barley, wheat with seeding. In this case the hay is usually harvested but one season. A rotation more generally used in the southern tier of counties where wheat is not grown is : Clover and timothy, two or more years, corn or potatoes, oats with seeding. A rotation considerably used in the northwestern part of the state where buckwheat is much grown, is: Buck- wheat, oats with seeding, meadow as long as the yield is satisfactory, then buckwheat again. It is generally recognised that buckwheat has peculiar value for mellowing heavy soils. Advantage is sometimes taken of this to improve such soils for potato growing. The meadow is cut, the land immediately plowed and sown to buckwheat. This is followed by potatoes, then oats with seeding. There are a large number of other rotations found on different farms. Assistant Professor of Agronomy, Cornell University. J. L. Stone. NORTH CAROLINA We have found the following a very good three-year rotation for a cotton farmer: First year, (a) wheat, oats, or rye, followed by cowpeas, (b) cotton followed by rye, (c) corn with cowpeas; second year, (a) cotton followed by rve, (6) corn with cowpeas, (c) wneat, oats, or rye, followed by cowpeas; third year, (a) corn with cowpeas, (6) wheat, oats, or rye followed by cowpeas, (c) cotton followed by rye. The peas are sown after the small grain crops and harvested; the rye in the cotton and the cowpeas in the corn are sown at the last cultivation. APPENDIX 413 A good four-year rotation for a tobacco farmer is: First year, clover, corn, tobacco, wheat; second year, corn, tobacco, wheat, clover; third year, tobacco, wheat, clover, corn; fourth year, wheat, clover, corn, tobacco. An excellent rotation for corn on the fine, sandy loam-soil of eastern North Carolina is, corn followed by bur clover. Sow 4 or 5 bushels of clover in bur just before the last plowing of corn. The clover is plowed under in spring and a volunteer crop appears in the fall. Another promising rotation is: Peanuts followed by wheat, wheat followed by cowpeas, corn with cowpeas, cotton. Director, North Carolina Agr. Experiment Station. B. W. Kilgore. NORTH DAKOTA Wheat is our money-crop. It is grown chiefly with a barren summer fallow every fourth or fifth year, and sometimes with a change to barley and millet occasionally, which is quite desirable. The summer fallow exhausts the soil and gives no return that season. In the flax districts, flax and wheat alternate and the two crops are sometimes replaced by barley or millet. A rotation of three wheat and flax crops and one of corn, potatoes, or other cultivated crops is beginning to find favour instead of summer fallow. This gives as good returns as fallow and forces the feeding of more provender to live-stock. North Dakota farmers are now just beginning to grow clover and timothy and to put them into the rotation. Professor of Agriculture, North Dakota Agr. College. J. H. Sheppabd. OHIO The most common rotation in this state is corn, wheat, and a timothy and clover mixture, with a variation in the number of years given to each crop. In some parts of the state a very common rotation is corn, two years; wheat, one year; timothy and clover, three years. In some localities where wheat is not profitable oats are substituted for it in this rotation. Alfalfa is now being used considerably in place of the timothy and clover mixture of the above rotation. Potatoes, wheat, and clover have been found a very satisfactory rotation by our Experiment Station. Professor of Agronomy, Ohio State University. A. G. McCall. OKLAHOMA No well-defined systems of rotation have been adopted in this new country. When this state was first opened, the one-crop system prevailed: wheat, Indian corn, and cotton. Gradually other crops have been introduced; we have now reached a point where rotations can be adopted. The following general rotation could be used in northern and eastern Oklahoma: Corn; cowpeas seeded at time corn is laid by; oats, followed by' cowpeas for green manure; Kaffir corn; cowpeas, harvested; fall wheat, followed by cowpeas for green manure. This general plan could be followed in other sections of the state but it would be necessary to substitute other crops, as broom corn in the northwestern counties, and cotton in the southern counties. Agronomist, Oklahoma Agr. Exper. Station. L. A. Moorehouse. 414 APPENDIX OREGON In the western portion of the state, on farms where general agriculture is practised, the rotation is usually with the cereals and clover or vetch; for instance, wheat, oats, clover for two years, or a crop of winter vetch. In the dairying districts corn is grown in a rotation with clover and cereals. In the Columbia River basin in eastern Oregon, the practice is grain growing exclusively; usually wheat, bare fallow, and wheat again. In sections where the rainfall is greater, some farmers follow wheat with barley, then the bare fallow. Director, Oregon Agr. Experiment Station. James Withycombe. PENNSYLVANIA Probably corn, oats, wheat, grass, the latter including more or less clover, is the most common rotation. In some parts of the state another year of of grass is added. In the southern part, notably in the Cumberland Valley, the common rotations are: Corn, oats, wheat, wheat, grass; and corn, wheat, wheat, grass. In the tobacco districts various short rotations are practised according to the soil conditions best adapted to the growth of this crop. Professor of Agriculture, Pennsylvania State College. G. C. Watson. RHODE ISLAND The usual practice is to break up sward land and plant potatoes and corn, sometimes reversing the order of these two, sometimes introducing a crop of millet or oats for another season, and then seeding either with or without winter rye or oats. The land is allowed to continue in grass upon most farms so long as there is anything worth cutting. The following rotations are in progress at the Experiment Station: (1) Oats sown in the spring, with common red clover; clover; potatoes, and winter rye sown after the potatoes are harvested; winter rye cut green and followed by Hubbard squashes; onions. (2) Winter rye; timothy and red top seed sown with rye and common red clover sown on the surface the following March; clover and grass; grass; grass; Indian corn; potatoes. (3) Winter rye; common red clover (seed sown in March of the previous year); potatoes. Director, Rhode Island Agr. Experiment Station. H. J. Wheeler. SOUTH CAROLINA Very little rotation is practised here. The main crops raised are corn and cotton. The bottom lands are usually planted to corn year after year and the uplands planted year after year to cotton. Cotton can be contin- uously grown on the same land without diminishing the yield provided the seeds are returned on the soil. But the continuous growing of cotton on uplands diminishes the fertility rapidly; chiefly because the clean cultivation that is required for this crop permits the soil to wash badly. We recom- mend a rotation of corn with cowpeas, and a cover crop of rye; wheat or winter oats; cowpeas, with a rye cover crop; cotton. We have a small section in which tobacco is grown; for this crop we recommend tobacco, with a rye cover crop; corn and cowpeas; oats; cowpeas; rye, with a cover crop; cotton. Director, South Carolina Agr. Experiment Station. J. N. Hakpeb. APPENDIX 415 SOUTH DAKOTA No very definite methods of rotating crops have yet been adopted. In the dryer central and western portions of the state it is important, if not essential, that small-grain crops be alternated with cultivated crops or with summer fallow handled to conserve moisture. In the eastern and south- eastern portions of the state, where moisture is more plentiful, a sod crop is needed in the rotation. Some suggested rotations are: (1) Wheat, brome hay three years, flax, wheat, corn. (2) Barley, millet, wheat. (3) wheat, corn, oats. (4) Wheat, corn (manured), wheat, oats. (5) Wheat, oats, corn, flax, millet. Agronomist, South Dakota Agr. Experiment Station. J. S. Cole. TENNESSEE A rotation often followed is corn, alone or with cowpeas, wheat, grass or grass and clover. This rotation is adapted to east and middle Tennessee, and parts of west Tennessee. Short rotations of wheat and clover, and of wheat and cowpeas are also practised to advantage. A good rotation for cotton is: Cotton; corn, and peas; a cereal (usually oats); cowpeas. Two de- sirable pasture rotations for sheep and hogs are; (1) Barley, (sown in August); sorghum; rape; cowpeas. (2) Clover, either red or alsike. sown in August or early in September; rape or barley or spring oats, followed by soy beans or cowpeas. Professor of Agronomy, University of Tennessee. Chas. A. Mooers. TEXAS The common rotation in this state is corn and cotton. In a considerable portion of the state, notably the black-land section, alfalfa and cowpeas are added to this rotation. We have no grass crops that can come into our rotations; therefore, for the most part, our soils are covered with intertillage crops. In some sections peanuts are grown, in other sections potatoes have a place. Nearly all the legumes are grown with considerable success. In the north Texas black-land country is a four-course rotation of corn, wheat, oats, and cotton. Professor of Agriculture, Texas Agr. College. F. S. Johnston. UTAH There is little systematic rotation of crops, largely because our soil is still nearly virgin. Among sugar-beet growers a common rotation is: Beets, manure applied in the fall and plowed; beets; alfalfa, with oats for a nurse crop; alfalfa, third crop plowed under as a green manure; beets. Sometimes an oat crop follows alfalfa previous to seeding the beets. A better rotation is: Sugar beets, manure applied in the fall and plowed under; beets; field peas with or without oats; sugar beets; corn or potatoes; alfalfa and oats; alfalfa, with third crop plowed under; sugar beets. Where it is desired to grow such crops as tomatoes and possibly wheat, or any other main crops, they can be supplied in place of oats, potatoes, or sugar beets, in this rotation. In dry farming the usual method at present is to grow wheat two years out of three, the land being summer-fallowed one year in three. Occasionally wheat is followed by barley or oats. A better system is : Wheat, potatoes if possible, or corn; wheat; field peas; barley; summer fallow; wheat. Agronomist, Utah Agr. Experiment Station. W. M. Jardine. 416 APPENDIX VERMONT Corn, potatoes, grass; or corn, oats, grass are about the only rotations practised in this state, grass occupying the major time. Director, Vermont Agr. Experiment Station. J. L. Hills. VIRGINIA The most common rotation is corn, one year; wheat, two years; grass for three to five years. Two years of wheat are put in because the farmers do not consider that they get their land in proper condition for grass following the corn with one year of wheat, especially when they expect to mow it for one or two years. Agronomist, Virginia Agr. Experiment Station. John Fain. WASHINGTON There have not been, as yet, any well-defined rotations established. In the extreme eastern part of the Palouse country, there is just beginning to be considerable alfalfa and brome grass grown, but where these are grown the farmers usually put them in for permanent meadow or pasture, rather than inserting them as crops in a rotation. Through all the wheat belt the common practice is to alternate grain with summer fallow, with two years of grain to one year of summer fallow in the more moist parts of the wheat belt and alternate grain and summer fallow in the drier portions. In the more moist portions the practice is rapidly developing of growing corn, potatoes, or sugar beets on these summer fallows and this is giving excellent results wherever tried. The objections to summer fallowing are too well known to need mention. In our irrigated sections cropping is becoming highly specialised, alfalfa continuously in one place, hops in another, fruit in another. On the west side of the state specialisation is also marked, though dairying is beginning to be a permanent factor and farmers are seeking to work out some sort of a rotation and some system of soiling. There are no established rotations as yet in the state of Washington. Assistant Agriculturist, Washington State College. Geo. Severance. WISCONSIN In central Wisconsin clover is sown with barley, and the barley harvested ; the second year the clover is clipped after reaching the height of about six inches and the full crop retained for seed; the third year the land is plowed and run to corn, followed with clover sown with barley. The most common rotation is clover and timothy sown with barley, oats, or wheat as a nurse crop. First year, harvest the grain. The next year the crop is clover largely, getting as a rule two cuttings. The ground is then manured quite heavily in the fall and winter. As a rule some clover and a good crop of timothy will be secured the third year. As soon as the hay is cut the land is usually pastured until fall. The fourth year the sod is turned and corn planted. Some farmers add a fifth year in which the ground is pastured. Agronomist, Wisconsin Agr. Experiment Station. R. A. Moobe. APPENDIX 417 WYOMING ♦ h HeK Sre n° Cr°P stations in general use. In the older farming districts n/nl Tf I'" f^^ ad°ptiDg the rotation common in north^Colorado St7' • ? fr" ^ars1'1 Potatoes, grain and seed down to alfalfa tS fn lv • LPr°bably une-relled f°r the arid regions where potatoes are success! fully raised as a general crop. At higher altitudes an excellent rota"Ln is ha^) M^X^ (%bC ^ kmbS thr°Ugh ^^er^Tnot narvested) , followed by gram. Farming without irrigation consists in fallow one year and gram or some other crop the next. Our soils ar 'rich mnS tahfaTeg^mT m mtr°gen ^ hUmUS' S° "V — essfufrSon muTcon Director, Wyoming Agr. Experiment Station. B. C. Buffum. II. ANALYSES OF SOILS comp^ro?gfaZtlls0f * '*" T^M™ s<^ *-W the general ANALYSIS OF ADOBE SOIL FROM SANTA FE, NEW MEXICO Silica . . PerCent. Alumina . . . [ 66-69 Ferric oxide ...... 14,16 Manganese oxide 4-38 Lime . . . . ; 0.09 Magnesia - 2.49 Potash . . 1-28 Soda ...!!!;;; L21 Carbonic acid ... ®'%J Phosphoric acid ..... °"77 Sulphuric anhydride . . . °,"29 Chlorine . °-41 Water ....'.'.' °-34 Organic matter 4-94 2.00 ANALYSIS OF LOESS FROM DUBUQUE, IOWA Silica . Per Cent- Alumina .'.'.'.'..'. 72-68 Iron sesquioxide ...... 12.03 Iron protoxide . 3-^53 Titanum oxide. . . . °'96 Phosphoric anhydride ..." °,'7~ Manganese oxide . °-23 Lime .... 9-06 Magnesia . t.59 Sodl . 1.H Potash . . ' 1-63 Water ...'.'...'.[ 213 Carbon dioxide ... 2-^9 Sulphurous anhydride . . . .... 0.39 Carbon . 9-51 0.09 418 APPENDIX ANALYSIS OF SOIL FBOM YAKIMA COUNTY, WASHINGTON Per Cent. Insoluble matter 71.67 \ „« „a Soluble silica 5.11 J70'78 Potash 1.07 Soda 0.35 Lime 2.00 Magnesia 1.34 Brown oxide of manganese 0.04 Peroxide of iron 6.88 Alumina 7.91 Phosphoric acid 0.13 Sulphuric acid 0.02 Water and organic matter 2.82 Total 99.33 Humus 4.10 Hygroscopic moisture 4.98 ANALYSIS OF SWAMP SOIL IN CARTERET COUNTY, NORTH CAROLINA Per Cent. Silica (insoluble) 1.52 Silica (soluble) 0.00 Alumina 0.39 Oxide of iron 0.15 Lime 0.36 Magnesia 0.14 Potash 0.06 Soda 0.13 Phosphoric acid 0.06 Sulphuric acid 0.38 Chlorine 0.02 Organic matter 87.25 Water 9.60 APPENDIX 419 HI. NATIVE PLANT FOOD IN FARM SOILS The analyses given below show the large amounts of plant food that are in most farm soils, and the wide variation in these amounts. o ©.Ed o.H c a o.5_c c +J *l-i jj 4J co a"* « b""" CO " Where from OU J2 a a rj 8ST: a O 'S >* Phosphoric Acid Name of Substance H o v CUB- 0>jJ 33 is a O V Plwsphoric Acid Fertilisers 4.12 1.70 2.60 1.67 0.76 7.85 .... 2 .... 1 .... 5 13.09 4 £ .... S .... 1 2.29 5.56 6.66 10.52 7.25 13.25 4.50 10.44 4.04 15.75 2.30 12.12 ... 1 ... 1 2.61 ... 1 3.80 . 3.54 0.46 5.19 2.02 . 1.60 . 3.50 6.65 6.44 5.50 . 1.10 . 1.12 . 1.62 0.45 2.20 0.40 6.70 8.28 1 3.53 7.55 1 8.36 0.60 2 1.60 ... 3 3.05 6.30 5.22 4.07 4.33 6.90 7.43 3.60 5.00 5.20 36.08 7.00 4.60 7.47 35.89 28.28 Bone-black (dissolved) Bone meal 17.00 23.50 Bone meal (from glue factory) 29.90 17.60 18.90 Cuban guano 24.27 12.52 7.60 7.31 14.81 1.50 7.33 3.20 2.00 1.93 6.31 1.25 4.75 7.25 10.61 9.00 9.98 6.86 12.50 12.75 10.17 7.27 12.09 7.40 1.25 6.00 8.54 13.35 Mona Island guano 21.88 Nevassa phosphate 34.27 Orchilla guano 26.77 Peruvian guano 15.26 S. Carolina rock (ground) .... S. Carolina rock (dissolved) . . Potash Fertilisers Kainit 28.03 27.20 15.20 35.00 8.50 Muriate of potash Nitrate of potash Spent tan-bark ashes 1.61 Sulphate potash (high-grade) . . Sulphate potash and magnesia Sylvanite Tobacco stems 0.60 Wood ashes (unleached) Nitrogen Fertilisers Castor pomace 1.85 1.40 2.16 Cottonseed meal 1.45 Dried blood 1.91 Dried fish 8.25 Horn and hoof waste Lobster shells 1.83 3.52 Meat scrap 2.07 Malt sprouts 1.70 Nitrate of soda Nitrate-cake Oleomargarine refuse . 0.88 422 APPENDIX V. Analyses of Commercial Fertilising Materials — Continued Name of Substance Nitrogen Fertilisers Sulphate of ammonia Tankage Wool waste Miscellaneous Materials Ashes (anthracite coal) Ashes (bituminous coal) . . . Ashes (corn-cob) Ashes (lime-kiln) Ashes (peat and bog) Gas lime Marl (Massachusetts) Marl (North Carolina) Muck (fresh) Peat Pine needles Shell lime (oyster shell) Soot Spent tan bark Spent sumach Sugar-house scum -so So. 1.00 13.20 9.27 15.45 5.20 4.40 18.18 1.50 76.20 61.50 7.80 19.50 5.54 14.00 30.80 50.20 20.50 6.82 5.64 0.30 0.30 0.75 0.30 0.20 1.00 2.10 ■S5 o V <0, 02 3 c 23 C V HO. 11.25 0.29 0.10 0.40 1.18 0.50 1.05 0.56 0.20 0.20 0.04 0.10 VI. ANALYSES OF FARM MANURES Name of Substance L. S 9 V go '4 5 So, eg .- u zc a P.O. Phosphoric Acid Per Cent. Cattle (solid fresh excrement) .... 73.27 0.29 0.58 1.63 0.44 1.55 0.80 0.55 1.95 0.50 0.60 0.43 0.10 0.49 0.85 0.35 1.50 0.30 0.15 2.26 0.60 0.13 0.83 0.17 1.54 Horse (solid fresh excrement) 0.17 1.40 Sheep (solid fresh excrement) 0.31 0.01 0.30 Swine (solid fresh excrement) 0.41 0.07 1 APPENDIX 423 VII. FERTILISING MATERIALS IN FARM PRODUCTS Name of Substance Hay and Dry Fodders Alfalfa Carrot tops (dry) Clover (alsike) Clover (crimson) Clover (mammoth red) Clover (medium red) Clover (white) Corn fodder Corn stover Cowpea vines Hungarian grass (brome) Italian rye-grass June grass Meadow fescue Meadow foxtail Millet (common) Mixed grasses Orchard grass . .'. Perennial rye-grass Red-top Salt hay Serradella Soja (Soy) bean Tall meadow oat grass Timothy hay Vetch and oats Yellow trefoil Green Fodders Alfalfa Clover (crimson) Clover (red) Clover (white) Corn fodder Corn fodder (ensilage) Cowpea vines Horse bean Meadow grass (in flower) Millet . Oats Peas Rye grass Serradella >- c 6.26 9.76 9.93 16.4 11.41 10.72 28.24 9.00 7.15 8.29 9.79 9.75 11.26 8.84 9.13 7.71 5.36 7.39 6.30 7.52 11.98 75.30 8.15 80.00 81.00 72.64 71.60 78.81 74.71 70.00 62.58 83.36 81.50 70.00 82.59 2.07 3.13 2.33 1.95 2.23 2.09 2.75 1.80 1.12 1.64 1.16 1.15 1.05 0.94 1.54 1.28 1.37 1.31 1.23 1.15 1.18 2.70 2.32 1.16 1.26 1.37 2.14 0.72 .43 0.53 0.56 0.56 0.36 0.27 0.68 0.44 0.61 0.49 0.50 0.57 0.41 1.46 4.S8 2.01 1.17 1.22 2.20 1.81 0.76 1.32 0.91 1.28 0.99 1.46 2.01 2.19 1.69 1.54 1.88 1.55 1.02 0.72 0.65 1.08 1.72 1.53 0.90 0.98 0.45 .26 0.46 0.24 0.62 0.33 0.31 1.37 0.60 0.41 0.38 0.56 0.53 0.42 0.53 0.61 0.70 .36 0.55 0.44 0.52 0.51 0.30 0.53 0.35 0.55 0.37 0.34 0.44 0.49 0.35 0.41 0.56 0.36 0.25 0.78 0.67 0.32 0.46 0.53 0.43 0.15 .08 0.13 0.20 0.28 0.14 0.98 0.33 0.15 0.19 0.13 0.18 0.17 0.14 424 APPENDIX VII. Fertilising Materials in Farm Products — Continued Name of Substance ■go 2U '3 *> +3 u 0.40 86.11 0.24 85.35 0.44 80.00 0.50 13.08 1.01 13.25 0.72 15.00 0.80 16.00 1.30 12.09 0.50 11.50 0.23 15.00 0.80 14.30 0.64 28.70 0.29 16.65 1.36 2.29 1.04 77.00 0.49 15.40 0.24 92.65 0.35 89.80 0.30 14.80 0.91 10.50 1.01 15.00 0.54 10.36 0.82 87.73 0.24 84.65 0.25 90.60 0.19 90.02 0.14 87.29 0.19 79.75 0.21 87.82 0.21 87.20 0.22 15.42 2.06 4.10 14.10 1.44 10.88 1.82 10.00 1.46 12.20 2.62 11.80 3.20 ■gS* 2< w Green Fodder Sorghum Vetch and oats White lupine Young grass Straw, Chaff, Leaves, etc. Barley chaff Barley straw Beech leaves (autumn) Buckwheat straw Corn cobs Corn hulls Oak leaves Oat chaff Oat straw Pea shells Pea straw (cut in bloom) Pea straw (ripe) Potato stalks and leaves Rye straw Sugar beet stalks and leaves Turnip stalks and leaves , Wheat chaff (spring) , Wheat chaff (winter) Wheat straw (spring) , Wheat straw (winter) , Roots and Tubers Beets (red) ; Beets (sugar) , Beets (yellow fodder) Carrots Mangels Potatoes Rutabagas Turnips , Grains and Seeds Barley Beans Buckwheat Corn kernels Corn kernels and cobs (cob meal) Hemp seed Linseed 0.32 0.79 1.73 1.16 0.99 1.16 0.36 2.41 0.60 0.24 0.15 1.04 0.88 1.38 2.32 1.01 0.07 0.76 0.16 0.24 0.42 0.14 0.44 0.32 0.44 0.29 0.46 0.54 0.38 0.29 0.50 0.41 0.73 1120 0.21 0.40 0.44 0.97 1.04 0.08 0.09 0.35 0.22 0.27 0.15 0.24 0.61 0.06 0.02 0.34 0.20 0.11 0.55 0.68 0.35 0.06 0.19 0.07 0.13 0.25 0.19 0.18 0.11 0.09 0.08 0.09 0.10 0.09 0.07 0.13 0.12 0.95 1.16 0.44 0.70 0.60 1.75 1.30 APPENDIX 425 VII. Fertilising Materials in Farm Products— Continued Name of Substance Grains and Seeds Lupines Millet Oats Peas Rye Soja (Soy) beans Sorghum Wheat, spring Wheat, winter Flour and Meal Corn meal Ground barley Hominy feed Pea meal Rye flour Wheat flour By-products and refuse Apple pomace Cotton hulls Cottonseed meal Glucose refuse Gluten meal Hop refuse Linseed cake (new process) Linseed cake (old process) Malt sprouts Oat bran Rj'e middlings Spent brewer's grains (dry) Spent brewer's grains (wet) Wheat bran Wheat middlings Dairy Products Milk Cream Skim milk . .' Butter Butter-milk Cheese (from unskimmed milk) . . Cheese (from half-skimmed milk) Cheese (from skimmed milk) . . s£ 13.80 13.00 20.80 19.10 14.90 18.33 14.00 14.75 15.40 13.52 13.43 8.93 8.85 14.20 9.83 80.50 10.63 8.10 8.53 8.98 6.12 7.79 10.28 8.19 12.54 6.98 75.01 11.01 9.18 87.20 68.80 90.20 13.60 90.10 38.00 39.80 46.00 5.52 2.40 1.75 4.26 1.76 5.30 1.48 2.36 2.83 2.05 1.55 1.63 3.08 1.68 2.21 0.23 0.75 6.52 2.62 5.43 0.98 5.40 6.02 3.67 2.25 1.84 3.05 0.89 2.88 2.63 0.58 0.58 0.58 0.12 0.64 4.05 4.75 5.45 1.14 0.47 0.41 1.23 0.54 1.99 0.42 0.61 0.50 0.44 0.34 0.49 0.99 0.65 0.54 0.13 1.08 1.89 0.15 0.05 0.11 1.16 1.16 1.60 0.66 0.81 1.55 0.05 1.62 0.63 0.17 0.09 0.19 0.09 0.29 0.29 0.20 0.87 0.91 0.48 1.26 0.82 1.87 0.81 0.89 0.68 0.71 0.66 0.98 0.82 0.85 0.57 0.02 0.18 2.78 0.29 0.43 0.20 1.42 1.65 1.40 1.11 1.26 1.26 0.31 2.87 0.95 0.30 0.15 0.34 6.15 0.80 0.80 0.80 426 APPENDIX VIII. SCHEDULE FOR THE VALUATION OF FERTILISERS The following is the schedule of prices adopted by agreement by the Experiment Stations of the states of Connecticut, Massachusetts, New Jersey, and Rhode Island, to be used in the valuation of fertilisers for the year 1906: Cents per pound Nitrogen in ammonium salts 17.5 Nitrogen in nitrates ... 16.5 Organic nitrogen in dry and fine-ground fish, meat, and blood, and in mixed fertilisers 18.5 Organic nitrogen in fine bone and tankage 18.0 Organic nitrogen in coarse bone and tankage 13.0 Phosphoric acid, soluble in water 4.5 Phosphoric acid, soluble in ammonium citrate 4.0 Phosphoric acid in fine-ground fish, bone, and tankage ... 4.0 Phosphoric acid in coarse fish, bone, and tankage 8.0 Phosphoric acid in mixed fertilisers, if insoluble in water and in am- monium citrate 2.0 Phosphoric acid in cottonseed meal, castor pomace, and wood ashes 4.0 Potash in high-grade sulphate, and in forms free from muriate (or chlorids) 5.0 Potash as muriate 4} INDEX Abrasive effects of sand, 19 Absorbent capacity of soils, 95 Acid, phosphoric, forms of, 370 Acids secreted by plant roots, 9 Adaptability of soils, 24 Adobe soils, composition of, 63 where found, 64 Air fertilises the soil, 37 Air, fertility in, 29, 37 Air in soils, 24 Alabama, rotation in, 405 Alfalfa, value as a soil improver, 340 Alkali soils, contents of, 66 cost to reclaim, 67 deep tillage for, 68 deficient in nitrogen, 69 how to treat, 67 two types of, 66 Alluvial soils, 17, 48 Ammonia is not nitrogen, 369 Analyses of commercial fertilising materials, 421-422 of farm manures, 422 Analysing soils at home, 71 Analysis of adobe soil from Santa Fe, N. M., 417 of loess from Dubuque, la., 417 of soil from Yakima Co., Wash., 418 of swamp, soil in Carteret Co., N. C, 418 Angleworms, service of, 14 Animal excretions, value of, 316 Animals as soil builders, 12 enrich soils, 21 obstruct drains, 228 Ants as soil builders, 13 Arid land, cost of levelling, 267 should be level, 266 water needs of, 265 Arizona, rotation in, 405 Arkansas, rotation in, 405 Artesian wells, available for irriga tion, 244 Artificial fertilisers, are made of, 366 growth of trade in, 365 Ashes, cotton hull, 384 hardwood, 384 lime-kiln, 3S4 softwood, 384 unleached, wood, 384 use of, 62 wood, for muck soils, 62 Bacteria do not thrive on sour or wet soils, 337 each crop has different, 335 in manure, 348 in the soil, 40, 43, 334 Barley, temperature of soil for, 32 Beam wheel, plow, 133 Blood, dried, contents of, 378 Bogs, drainage of, 201 Breaks, how to construct, 293 necessary to good farming, 294 Brush drag, 173 Burrowing animals soil builders, 13 California, rotation in, 405 Capacity of soils to hold water, 80, 93 Capillary action, 89, 96 Catch crops, how to use, 331 Chemical changes in the soil, 44 Chemical vs. mechanical analysis, 71 Clay, 52 loams, 58 test for, 72 to separate from sand and silt, 73 Clay soils are cold, 33 composition of, 56 crops for, 59 needs of, 389 properties of, 52 treatment of, 57, 126 value of, 57, 93 Cleansing properties of commercial fertilisers, 321 427 428 INDEX Clevis, plow, 133 Clover, crimson, a soil improver, 340 red, is best green-manuring crop, 338 red, when to sow, 338 temperature of soil for, 32 Cold, effect on rock, 6 Cold soil, drainage helps, 33 Colorado, rotation in, 406 Commercial fertilisers, 364 a poor soil improver, 345 are made of, 366 when to apply, 395 Composition of soils, 51 Conglomerates, 5 Connecticut, rotation in, 406 Cottonseed meal, contents of, 378 Coulter, disk and knife, 132 Cover crop adds humus to soil, 331 how to use, 331 checks erosion, 293 use in fruit growing, 331 Cow manure, plant food value, 349 Cowpea, value as catch crop, 339 value as soil improver, 339 Crimson clover a valuable soil im- prover, 340 Crop alternation in U. S., examples of, 307-310, 319 Cropping impairs fertility, 312 Crop rotation checks "club-foot," 303 fungous diseases, 304 insect and disease injury, 303 potato scab, 303 weediness, 302 Crop rotation for "Corn Belt," 308, 310 for dairy farm, 308, 309 for hay and grains, 310 why beneficial, 300 Crop rotations practised in different states, 407-419 Crops, catch and cover, how to use, 331 choosing for a rotation, 305 clovers, including all legumes, need of, 393 cotton, needs of, 394 different rooting habits of, 301 early, best slope for, 34 forage, need of, 393 Crops, for loam soils, 59 for sandy loams, 55 for sandy soils, 54 for sour soils, 401 fruit, needs of, 394 gradual decrease in yield, 285 due to exhaustion of soluble plant food, 286 how often to irrigate, 268 Indian corn, needs of, 393 market garden, needs of, 394 needs of different, 392 learned by study 393 root and tuber crops, needs of, 394 rotation, a law of Nature, 300 rotation of, 299 sweet and Irish potatoes, needs of, 394 Cultivate, how often, 165 how deep, 166 Cultivating, 142 to kill weeds, 157 Cultivation to save water, 163 Cultivators, broad-tooth, assist ero- sion, 295 called "horse hoes," 152 definition of, 152 hand, 183 shovel-tooth, or coulter, 153 spike-tooth, 153, 184 spring-tooth, 154 Cultivators, sulky, 155 types and use of, 144, 152-156 Culture, level, advantage of, 168 Dairy farm rotation, 308, 309 Delaware, rotation in, 406 Deodoriser, soil is a, 39 Disk plow, 139 Ditch digging, 224 tools used for, 224 Ditches, cement-lined, 252 cost of filling, 229 fix grade and depth, 203, 214 how to dig, 202, 224 open, 200, 202 when practicable, 201 how to fill, 226 Ditching spade, 225 Diversified farming, 315 Diversity of soils, 49 Do plants excrete? 318 Draft in plowing, 127 INDEX 429 Drag, brush, use of, 173 Drainage capacity of tiles, 223 direct benefits of, 193 ditch, how to dig, 202 for special crops, 195 natural, 194 poor, signs of, 190 signs of need, 191 warms the soil, 33 when needed, 190 Drainage system, avoid abrupt curves, 217 cost of, 229 how to plan, 208 map and drawing, 208 outlet for, 209 planning, 207 Draining, effect on soil, 196 farm soils need, 194 first cost large, 196 lowers water-table, 198 makes soil more moist, 197 pot holes, 230 practical results from, 199 promotes aeration, 197 reclaims swamps, etc., 193, 231 slope an aid to, 195 to improve texture, 192 Drains, box, 230 brush, 230 fall of, 211 grade for, 207, 210 kind to use, 200 mole, 230 pole, 230 stone, 229 surface, 200, 202 tile, 201, 205, 217, 225 Dried blood, contents of, 378 Drift soils, how made, 12, 48 Drumlins, 12 Dry farming, 105 crops under, 108, 238 methods, 107 secret of, 108 Early crop, best slope for, 34 Earth being slowly levelled, 4 Earthworms as soil workers, 14 Electricity of the soil, the, 39 increases yield, 39 Elements in rocks, 27 Elements in soils, 27 Engines to pump water, 248 cost of, 248 Erosion causes loss of fertility, 286 checked by deep plowing, 295 directing water, 29 1 side-hill ditches, 291 terracing, 291 underdrainage, 294 methods of checking, 2S8 on slope lands, 288 prevented by woodlands, 289 trees prevent, 2S9 Erosive action of sand, 19 Eucalyptus trees aid drainage, 78 Evaporation of water, 88, 93 Excretions, animal, value of, 316 Excretorv theory of soil fertilitv, 318, 321 Fallowing and soil fertility, 296 methods of, 298 to get rid of weeds, 298 to set free plant food, 297 to store water, 297 Fall plowing, 134 Farming, diversified, 315 dry, 105, 238 improvident, 343 single-crop, 310, 315 Farm irrigation, 233 Farm manures, 346 analyses of, 422 Farm products, fertilising materials in, 423-425 Farm soils, leading types of, 53 native plant food in, 419 test of water capacity, 93 Fertile air, 29 Fertilisers, amount to apply, 397 advantages of home-mixed, 376 artificial, are made of, 366 growth of trade in, 365 bill of American farmers ex- cessive, 364 calculating value of, from analysis, 373 commercial, as soil cleansers, 321 commercial, when to applv, 395 common way of testing, 390, 391 cost of, 375 430 INDEX Fertilisers, crude fish scrap, 386 green manures not complete, 332 how to apply, 396 indirect, benefit the soil, 399 low grade, expensive, 375 many brands of, 367 new theory as to action, 319, 320 nitrogen, quickly soluble, 396 quantivalence of, 370 raw materials can be bought, 377 seaweed, 386 tags, studying, 368 guarantees on, 368 tobacco stems and stalks, 386 trade in, State supervision, 367 valuation of, schedule for, 426 value based on amount of f)lant food contained, 373 ue of, 373 what kinds to use, 388 when complete and incom- plete, 366 when it pays to use, 398 wool and hair waste, 386 Fertilising materials in farm pro- ducts, 423-425 Fertility, influence of plant food on, 281 ■ lost in cropping, 312 loss by erosion, 286 maintenance,conflicting views on, 281 of soil, to maintain, 280, 311 selling, 311 soil, new theory of, 318-321 Film water, 30 as plant food, 25, 30 held by soils, amount of, 81 movement of, 87, 90 need of, 31 to prevent loss of, 90 Fineness of soil, 25 Fire-fang or ferment, 349 Flooding, in irrigation, 254 Florida, rotation in, 407 Flume, how to build, 252, 258 Forest, preserve on hill crests, 289 Forests, influence on water supply, 84 Free water, rainfall is, 29 Fresh manure best for heavier soils, 360 Frost a soil refiner, 21 Furrow irrigation, 257-260 Gang plow, 139 Garden irrigation, 258 Gases absorbed by the soil, 38 German potash salts, sources of, 385 Germination of seeds, 99 Germ life in the soil, 40 Glacial soils, 49 Glaciers deposit soil, 11 Good texture, how Nature secures, 323 humus insures, 323 what is meant by, 322 Grade of tile drains, 210 to be uniform, 211 to establish, 212, 214 Gravelly loams, 59 Green manure benefits poor soils most, 336 darkens soil, 35 red clover the best, 338 two kinds of, 329 Green-manuring and worn-out soils, 322 Green-manuring for impaired soil, 330 Green manures from non-legum- inous crops, 341 not complete fertilisers, 332 when to plow under, 337 Guarantees, fertiliser, points for study of, 372, 373 Gullies, clay soils most liable, 294 growth checked by breaks, 294 Gypsum alleviates stable odours, 356 Hand cultivators, 184 Hand tools, 183 Harrowing, objects of, 142 Harrow, Acme, 148 cutaway, 149 disk, 149 kinds and use, 144-152 Meeker, the, 150 plank, 179 rolling, 149 smoothing, 147 INDEX 431 Harrow, spading, 149 spike-tooth, 145, 146 spring-tooth, 147, 148 Hay an exhausting crop, 313 salt, 65 Heat, effect on rock, 6 Hoes, scuffle, 184 styles of blades, 182 wheel, 184 Hoeing, good and poor, 181 purpose of, 179 to kill weeds, 180 Hog manure, plant food value, 349 Horses, heavy vs. light for plowing, 128 Horse manure, value of, 349 How deep to cultivate, 166, 168 How often to cultivate, 165 How plants drink, 77 Humus, 53 enables soil to hold moisture, 328 increases water capacity of soils, 83 darkens the soil, 35 test for, 72 value of, 8, 83, 92 Ice has made soil, 11 Idaho, rotation in, 407 Idle land unprofitable, 332 Illinois, rotation in, 407 Improvident farming, 343 Indiana, rotation in, 407 Infertility caused by poor texture, 283 Influence of sun on soil, 34 Inoculating with old soil, 334 artificial cultures, 334 Inoculation of soils, bacterial, 40, 43, 334 Insect pests, control of, 303 Iowa, rotation in, 408 Irrigation, alfalfa, 271 afternoon best time for, 269 by well and spring water, 244 directing the flow, 269 extent of, 233 frequency and time of, 267 from artesian well, 244 hydrant water for, 244 in foreign countries, 233 in humid regions, 239, 242 in the East, 241 Irrigation in United States, 233-236 market-garden, 241, 245 National aid in, 275 objects of, 236 of meadows, 271 orchard, 271 of small fruits, 273 of potatoes, 273, pumping water for, 246 sources of water for, 244 supply of water for, 243 of tree fruits, 271 of vegetables, 274 when necessary, 237 winter, 268 Japanese pea, value as a soil im- prover, 341 Jointer, plow, 132 Joints of tile drains, 226 Kainit, effect of, 403 enriches manure, 357 source of and contents, 385 value of, 385 Kansas, rotation in, 408 Kentucky, rotation in, 408 Land reclaimed by drainage, 231 enriched by irrigation, 237 Land plaster, as aid in saving manure, 357 or gypsum, effect on soil, 402 for treating alkali soils, 402 Land, when to ridge, 169 Landside plow, 137 Legume, what it is, 329 benefit poor soils most, 336 Leguminous plants renovate soil, 330, 334 Level culture, advantage of, 168 Level, home-made, to construct 213 how to use, 213 spirit, use of, 216 Lime and land plaster called indirect fertilisers, 399 Lime, air-slaked, how used, 402 effect on light soil, 399 leachy soil, 399 clay soil, 399 how to apply, 401 water-slaked best form to use on sour soils, 401 when to apply, 402 432 INDEX Liming, benefits of, 399, 400 benefits acid soil, 338 Litmus tests for sour soils, 401 Live-stock excrements, value of, 316 Loams, sandy, 55 clay, 58 Loam soils, value of, 59, 93 Loams, gravelly and stony, 59 Loess soils, composition of, 62, where found, 63 Louisiana, rotation in, 409 Lupines grown for green-manuring, 341 Maine, rotation in, 409 Mains, rules for estimating size of, 223 Manure, green, darkens soil, 35 two kinds, 329 horse, cow, and hog, value of, 349 horse, value of, 349 how it benefits the soil, 346 improve texture of the soil, 347 pits, 355 quality of, 350 rotted, best for lighter soils, 360 sheep and poultry, 350 spreaders, 363 Manures and fertilisers as soil cleansers, 319 Manures, animal, value of, 316 amount made on the farm, 358 excel in nitrogen, 362 farm, analyses of, 422 average values of, 350 green feeds aid production of, 858 how much to use, 361 how to apply, 363 how to care for, 354 how wasted, 351 injury from heating, 353 loss from escape of urine, 354 loss from fermentation, 353 loss from leaching, 352 new theory as to action, 319, 320 plant food in, wasted, 352 spreading in winter, 360 the real value of, 346 to estimate plant food in, 359 Manures to prevent loss by heating, 356 when to apply, 360 Marl, effect of, 402 Marshes, drainage of, 201 Maryland, rotation in, 409 Massachusetts, rotation in, 410 Measuring water, methods of, 262 Meal, cottonseed, contents of, 378 Mechanical vs. chemical analysis, 71 Michigan, rotation in, 410 Mineral contents of soil, 26, 28 Miner's inch, definition of, 263 Mississippi, rotation in, 410 Missouri, rotation in, 410 Modules, 263 Montana, rotation in, 411 Morains, 12 Mosaic law as to fallowing, 296 Moss, sphagnum, 47 Mouldboard, plow, 131 Moving water, action of, 16 Muck, crops for, 62 soils, 60 wood ashes for, 62 Mulch, definition of, 91 in dry farming, 107 prevents loss of soil water, 91 Mulches, the most effective, 91 Muriate of potash, contents of, 385 value of, 385 Native plant food in farm soils, 421 Nebraska, rotation in, 411 Nevada, rotation in, 411 New Hampshire, rotation in, 411 New Jersey, rotation in, 412 New Mexico, rotation in, 412 New York, rotation in, 412 Nitrate of soda, Chili salt-petre, con- tents of, 378 Nitric acid ferment, 40 Nitrification of soils, 40 Nitro-culture, bacteria, 335 Nitrogen fertilisers quickly soluble, 396 Nitrogen-fixing bacteria, 40 process of, 329, 334 Nitrogen in soils, value of, 41 most costly plant food, 377 sources of, 377 Non-leguminous plants as soil im- provers, 341 North Carolina, rotation in, 412 INDEX 433 North Dakota, rotation in, 413 Northern slope vs. southern slope, 34 Oats and buckwheat as soil im- provers, 342 Obstructions in drains, to prevent, 228 Ohio, rotation in, 413 Oklahoma, rotation in, 413 Oregon, rotation in, 414 Peat and muck soils, needs of, 390. Peat, formation of, 47 Peat soils, 60 crops for, 62 Pebbles as plant food, 25 Pennsylvania, rotation in, 414 Phosphoric acid, available, 370 cost of, 383 forms of, 370 insoluble, 371 phosphate meal, 381 reverted, 372 soluble, 370 sources of, 379 acid phosphate, 383 basic slag, 381 bone boiled and steamed, contents, 380 dissolved bone, 382 dissolved boneblack, contents, 380 dissolved rock, 383 phosphate slag, con- tents of, 381 plain superphosphate, 383 raw bone, contents,379 rock phosphates, con- tents of, 381 superphosphates, 382 Thomas slag, contents of, 381 Pine barrens, 51 Pits, cement, to save manures, 355 Planker, how to make, 178 use of, 179 Planking, benefit of, 178 Plant food, 25, 45 air as, 29 available only in certain forms, 283 Plant food drawn from the soil by average yields of different crops, 420 film water as, 25 in arid lands ineffective with- out water, 283 locked up in soils, 283 loss in seepage water, 85 loss of under different systems of farming, 314 native, in farm soils, 419 not fertility, 281 pebbles as, 25 soils exhausted of, 284 soil a storehouse of, 282 stones as, 25 value of different manures, 349 trade value of, 375 Plants as soil builders, 7, 8, 10, 53 do they excrete, 318 enrich soils, 21 excrete poisonous wastes from roots, 320 how they drink, 77 leguminous, definition of, 329 for soils lacking nitrogen, 329 used for green manures, 329, 334 soil-building, check erosion, 29 Bermuda grass, 292 brome grass, 293 Lespedeza, 293 sanitation by, 320 water needed by, 76 what they feed upon, 45 Plow across slopes to check erosion, 295 beam, 131 beam wheel, 133 clevis, 133 coulter, 132 disk, 139 early American, 115 essentials of a good, 131, 133 evolution of the, 114-117 gang, 139 how deep to, 122 jointer, 132 landside, 137 mouldboard, 131 point, 133 share, 133 434 INDEX Plow, the modern, 116 subsoil, 125 sulky, 138 swivel, 137 trenching, 224 when to, 134-136 Plowing, a soil cooler, 36 deep, 121, 123, 124, 126 deep, vs. shallow, 126 draft in, 127 fall, 134 flat-furrow, 118 for fruit trees, and root crop, 123 heavy teams for, 128 in heavy soils, 121 in the South, 126 lap-furrow, 119 leguminous crop grown for, 329, 334 objects and methods, 114-131 overlapping-furrow, 118 power for, 129 rolling-furrow, 118 spring, 135 steam power, 130 to drain soil, 122 to establish a mulch. 122 Plowing under a green manure, 337 when dispensed with, 136 Plows, adjustment of, 140 various types of, 137 Potash, sources of, 384 Poultry manure, of highest value, 350 Power for plowing, 129 electricity used, 130 steam, 130 Pumpkins, temperature of soil for, 32 Pumps for irrigating purposes, 246 cost of, 248, 250 hydraulic rams, 250 steam and gasoline engines, 248 water-wheels, 249 windmills, 247 Quantivalence of fertilisers, 370 Questioning the soil, 390 by experiment with fertilisers, 390, 391 Rainfall, general, map of, 236 insufficient, 78 soil storage of, 79 Rainfall, supplies free water, 29 unevenly distributed, 78 Rape a good soil improver, 342 Raw materials, actual mixing easily done, 388 cheaper to buy, 388 mixing the, 387 Reclamation Act of 1902, 243, 276 Reclamation of alkali soils, 67 Red clover excels as a soil improver, 338 Reducing and fining process cease- less, 4 Reservoirs, for water storage, 243 small, how to build, 245 Rhode Island, rotation in, 414 Ridging crops promotes erosion, 296 land, 168 Rock becoming soil, 3, 27 elements in, 27 erosion of, 19 split by roots and stems, 9 weathering of, 3 Rollers, kinds and use, 177 Rolling, to assist germination, 171 benefits of, 173-176 Roots, fertilising value of, 332 plant, secrete acids, 9 split rocks, 9 Rotating crops, rules for, 305 Rotation, few systems of, in U. S., 307-310, 319 for "Corn Belt," 308, 310 for hay and grains, 310 of sown and tilled crops, 303 typical systems of, 307 Rotations practised in different states, 407-419 Rye improves soil when plowed under, 341 Salt an indirect fertiliser to small extent, 399 Salt hay, 65 Salt, little used as fertiliser, 403 marshes, drainage for, 65 marsh soils, 64 how formed, 65 crops for, 65 Sand, 51 abrasive effects of, 19 dunes, 50 test for, 72 toseparatc from silt and clay, 73 INDEX 435 Sandy loams, 55 soils, 54, 93 soils are warm, 33 soils, needs of, 389 treatment of, 55, 123 value of, 55 Seaweed, as fertiliser, 386 Sedentary soils, 46 Seedlings, tree, 290 Seeds of quick-growing trees, to sow, 290 Seeds, to germinate well, 99 Seepage, loss of water by, 84 water, loss of plant food in, 85 Selling fertility, 311 Separating sand, silt, and clay, 73 Shallow soils, 30 are dryest, 82 Share, plow, 133 Sheep manure, a good plant food, 350 Silt, 52 test for, 72 to separate from clay and sand, 73 Single-crop farming, 310, 315 is ruinous, 311 Slope of land desirable, 34, 195 Sod land, to retain water in, 170 Soil, a chemical laboratory, 45 acid, benefit of liming, 838 alluvial, 17, 48 analysis a guide to fertilising, 389 bacteria, 334 becoming rock, 5 building, history of, 7 built by wind, 18, 50 chemical changes in the, 44 cleansers, manures and fer- tilisers, 319 cold, drainage helps, 33 contains air, 24 elements in, 27 evolution of, 7 experts, figures by, 24 fertilised by air, 37 fertility, excretory theory of, 318, 321 fertility, new theory of, 318-321 fine, water capacity of, 81, 83 fineness of, 23 fineness is richness, 25 formation, example of, 5 Soil, germ life in the, 40 how plants make, 8 how water is held in, 29 influence of exposure, 34 influence of sun on, 34 inoculation, bacterial, 334 inoculation with bacteria, 40, 43 is a deodoriser, 39 keep it busy, 304 left by glaciers, 11 made by ice, 11 made by rocks, 3, 27 mineral contents of, 26 moved by water, 16 must be moist, 30 must be warm, 31 nature of, 22 particles, number of, 23 renovation, how to begin, 344 vs. subsoil, 69 survey, U. S., 74 temperature, 31 temperature, influence of til- lage on, 36 teems with life, 20 tests, 72 to improve ventilation of the, 37 value as a mulch, 91 ventilation of, 37, 111 water, seepage of, 85 can be prevented, 87 water, to maintain supply, 75 when ready to harrow, 151 yeast cake, action of, 835 Soils, absorbent, 95 absorb various gases, 38 activity of, 3, 20, 21 adaptability of, 24 adobe, 63 alluvial, 17, 48 analysing at home, 71 average depth of, 48 capacity to nold water, 80, 93 cause of infertility, 320 clayey, 56 composition of, 3, 51 dark-coloured, 35 distribution of, 49 diversity of, 49 drift, 48 exhausted of plant food, 284 farm, leading types of, 53 436 INDEX Soils, farm, mostly incomplete, 4 native plant food in, 419 test of water capacity, 93 glacial, 49 now to manage, 46, 123 kinds of, 46-50 light-coloured, to make dark, 35 treatment of, 35 loess, 62 native richness of, 281 peat and muck, 60 salt marsh, 64 sandy, 54, 123 sedentary, 46 shallow, 30 sour and wet, unfavourable to bacteria, 337, 401 test of water-moving ability, 95 tests for, 72 that need liming, 400 transported, 47 unproductive because mis- managed, 344 value of, 50 value of testing, 73 water capacity of, how to increase, 83 why they are sour, 400 worn-out, and green-manur- ing, 322 Soja bean a good soil improver, 341 Sour soils, crops for, 401 how to sweeten, 401 tests for, 401 what to plant in, 401 why so, 400 South Carolina, rotation in, 414 South Dakota, rotation in, 415 Soy bean a good soil improver, 341 Spade, ditching, 225 Sphagnum moss, 47 Spring plowing, 135 Stock-feeding and soil fertility, 345 Stones as plant food, 25 heaved up, 5 Stony loams, 59 Streams underground, 85, 243 Stubble, fertilising value of, 332 Sub-irrigation, 260 cost of, 260 Sub-Irrigation, of soils, 260 pipes for, 261 tiles for, 261 Subsoil, influence on water capacity of soils, 82 what it is, 69 Subsoiling, 124, 125 Succession cropping, profits of, 311 Sulky plow, 138 Sulphate of ammonia, 378 nitrogen contents of, 378 of potash, 386 high grade, cost of, 386 low grade, cost of, 386 Sun, influence of, on soil, 34 like a pump, 89 Superphosphate, enriches manure, 357 Swivel plow, 137 Sylvinit, a crude potash salt, 385 Tags, fertiliser, guarantees on, 368 repetitions in, 369 studying, 368 Temperature changes, results of, 5 Temperature of different soils, 32 of the soil, 31 for barley, 32 for clover, 32 for pumpkins, 32 for tomatoes, 32 Tennessee, rotation in, 415 Tests for soils, 72 Texas, rotation in, 415 Texture, soil, manure improves, 347 Tile drains, cost of laying, 228 kinds of tiles for, 221 need close joints, 226 obstructions in, 227 size of tiles for, 217 to fix grade, 212, 214 to lay, 206, 216, 221, 225 round are best, 221 use of, 205 Tiles, 3-inch best for drains, 217 cost of, 229 drainage capacity of sizes, 223 glazed, 222 how to lay, 225, 261 how to select, 222 kinds of, 221 relative capacity of sizes, 223 round, most in use, 221 special forms of, 221 INDEX 437 Tillage after irrigation essential, 270 benefits of, 97, 105, 112 deep, increases water capacity of soils, 83 good, value of, 36 influence on soil temperature, 36 present emphasis on, 97 promotes fertility, 110 to kill weeds, 101 to prepare seed bed, 98 Tomatoes, temperature of soil for, 32 Tools, a variety needed, 186 extravagance in, 1865 farm, selection of, 185 hand, 183 Transported soils, 47 Tree seeds, 290 Trees an aid to drainage, 78 hardwood preferable, 290 how to transplant, 290 quick-growing, to check erosion, 290 Tree roots obstruct drains, 228 seedlings, how to set out, 291 Under-drainage, philosophy of, 205 cost of, 229 to lower water-table, 83 benefits of, 192 deepens shallow soils, 192 for clayey soils, 192 Under-drains, action of, 205 cost of laying, 228 depth of, 219, 220 distance between, 218 kinds of tiles for, 221 to estimate size of, 223 Underground streams, 85, 243 Unproductive soils have been mis- managed, 344 Utah, rotation in, 415 Value of testing soils, 73 Ventilation of the soil, 37, 111 Vermont, rotation in, 416 Vetches, smooth and hairy, soil im- provers, 341 Virginia, rotation in, 416 Washington, rotation in, 416 Water absorbed from air, 31 amount needed by plants, 76, 264 Water, amount required to produce crops, 238 capacity of soils to hold, 80 93 contents of soil, 29 distribution for irrigation, 250 ditches and flumes, 251 duty of, 264 film, 30 amount held bv soils, 81 movement of, 87 to prevent loss of, 90 for irrigation, sources of, 244 free, to remove excess, 204 held in the soil, 29 irrigation, best way to use, 254 by flooding, 254 by furrows, 257 contour check system, 255 filling the checks, 255 how to apply, 253 on slopes, 255 wild flooding, 256 loss by evaporation, 88, 93 loss by seepage, 84 measurement, acre inch, 263 for irrigation, 262 how to regulate, 262 miner's inch, 263 modules, 263 moving, action on soil, 15 pipes, 252 required for arid soils, 265 right, cost of, soil, cultivation to save, 163 maintenance of, 75 supplv, influence of forests on, 84 units in measuring, 263 Water-built soils, 17 Water-moving ability of soils, 92 Water-moving ability of soils, test of, 95 Water-table, 29 height of, 82 Water-wheels, as pumps, 249 Weathering of rocks, 3, 5 Weeders, types and use of, 156 Weeds, best time to kill, 159 cultivating to kill, 157 Weeds, definition, 101 discourage laziness, 103 438 INDEX Weeds, friendly words for, 102 hoeing to kill, 180 injury done by, 157 in sown crops, 163 recipes for, 101 seeds of, 160 when they thrive, 160 Weight of soils, 26 Wet soils are cold, 33 When to plow, 134-136 White mustard improves light sandy soils, 342 White sweet clover a soil improver, 341 Wild flooding, irrigation by, 256 Willow trees aid drainage, 78 Wind as soil builder, 18, 50 Windbreaks, hedges and trees as, 278 Wind-built soils, 50 Windmills, use and cost, 247 Wisconsin, rotation in, 416 Wood ashes benefit muck soils, 62 ashes, effect of, 402 Worn-out soils in special need of humus, 344 how to restore, 342 Wyoming, rotation in, 417 DATE DUE * lo. 6 ' r 1 < MAR 1 8 1969 ? im MAR kAR ? (0T2tli OCT 2 0 Rem Kctfj U r, P APR APJ??4 Mt-2-JiL.. 8 RECO #0V 2