PEINCIPLES OF MANURING
PRINCIPLES OF MANURING
C. M. AIKMAN, M.A., B.Sc., F.E.S.E, F.I.C.
PROFESSOR OP CHEMISTRY, GLASGOW VETERINARY COLLEGE;
EXAMINER IN CHEMISTRY, GLASGOW UNIVERSITY;
AUTHOR OF 'FARMYARD MANURE,' ETC.
WILLIAM BLACKWOOD AND SONS
EDINBURGH AND LONDON
SIR JOHN BEMET LAWES, BAKT,, D.C.L, LL.D., F.B.S.,
SIR J. HENRY GILBERT, M.A., LL.D., F.R.S.,
FORMERLY SIBTHORPIAN PROFESSOR OP RURAL ECONOMY,
UNIVERSITY OF OXFORD,
WHOSE FAMOUS INVESTIGATIONS DURING THE LAST FIFTY YEARS
HAVE SO LARGELY CONTRIBUTED TO BUILD UP
THE SCIENCE OF MANURING,
EMBODYING MANY OF THE ROTHAMSTED RESULTS,
WHEN the present work was first undertaken there
were but few works in English dealing with its
subject-matter, and hardly any which dealt with
the question of Manuring at any length. During
the last few years, however, owing to the greatly
increased interest taken in agricultural education,
the demand for agricultural scientific literature has
called into existence quite a number of new works.
Despite this fact, the author ventures to believe that
the gap which the present treatise was originally de-
signed to fill is still unfilled.
Of the importance of the subject all interested in
agriculture are well aware. It is no exaggeration to
say that the introduction of the practice of artificial
manuring has revolutionised modern husbandry. In-
deed, without the aid of artificial manures, arable
farming, as at present carried out, would be impos-
sible. Fifty years ago the practice may be said to
have been unknown ; yet so widespread lias it now
become, that at the present time the capital invested
in the manure trade in this country alone amounts to
millions sterling. It need scarcely be pointed out, there-
fore, that a practice in which such vast monetary
interests are involved is worthy of the most careful
consideration by all students of agricultural science,
as well as, it may be added, by political economists.
The aim of the present work is to supply in a
concise and popular form the chief results of recent
agricultural research on the question of soil fertility,
and the nature and action of various manures. It
makes no pretence to be an exhaustive treatise
on the subject, and only contains those facts which
seem to the author to have an important bearing
on agricultural practice. In the treatment of its
subject it may be said to stand midway between
Professor Storer's recently published elaborate and
excellent treatise on ' Agriculture in some of ' its Re-
lations to Chemistry ' a work which is to be warmly
recommended to all students of agricultural science,
and to which the author would take this opportunity
of acknowledging his indebtedness and Dr J. M.
H. Munro's admirable little work on ' Soils and
In order to render the work as intelligible to the
ordinary agricultural reader as possible, all tabular
matter and matter of a more or less technical nature
have been relegated to the Appendices attached to
The author's somewhat wide experience as a Uni-
versity Extension Lecturer, and as a Lecturer in con-
nection with County Council schemes of agricultural
education, during the last few years, induces him to
believe that the work may be of especial value to
those engaged in teaching agricultural science.
He has to express the deep obligation he is under,
in common with all writers on Agricultural Chemis-
try, to the classic researches of Sir John Bennet
Lawes, Bart., and Sir J. Henry Gilbert, now in pro-
gress for more than fifty years at Sir John Lawes'
Experiment Station at Eothamsted. His debt of
gratitude to these distinguished investigators has
been still further increased by their kindness in per-
mitting him to dedicate the work to them, and for
having been good enough to read portions of the work
in proof. In addition to the free use which has been
made throughout the book of the results of these
experiments, the last chapter contains, in a tabular
form, a short epitome of some of the more important
Eothamsted researches on the action of different
To the numerous German and French works on the
subject, more especially to Professor Heiden's encyclo-
paedic 'Lehrbuch der Dlingerlehre' and the various
writings of Dr Emil von Wolff, the author is further
Among English works he would especially mention
the assistance he has derived from the writings of
Mr E. Warington, F.E.S., Professor S. W. Johnson,
Professor Arrnsby, the late Dr Augustus Voelcker,
and others. He would also tender his acknowledg-
ments to the new edition of Stephens' ' Book of the
Farm/ and he has to thank its editor, his friend Mr
James Macdonald, Secretary to the Highland and
Agricultural Society of Scotland, for having read
parts of his proof-sheets.
It is also his pleasing duty to thank his friends
Dr Bernard Dyer, Hon. Secretary of the Society
of Public Analysts; Dr A. P. Aitken, Chemist to the
Highland and Agricultural Society of Scotland ; Pro-
fessor Douglas Gilchrist of Bangor ; Mr F. J. Cooke,
late of Flitcham ; Mr Hermann Yoss of London ; and
Professor Wright of Glasgow, for having assisted him
in the revision of proof-sheets.
128 WELLINGTON STREET, GLASGOW,
PART I. HISTORICAL INTRODUCTION.
Beginning of agricultural chemistry ...... 4
Early theories regarding plant-growth 4
Van Helmont ......... 4
Duhamel and Stephen Hales ...... 8
Jethro Tull 9
Charles Bonnet's discovery of source of plants' carbon . . 11
Researches of Priestley, Ingenhousz, Se'ne'bier, on assimilation
of carbon H-12
Publication of first English treatise by Earl Dundonald . . 13
Publication of Theodore de Saussure, * Chemical Researches on
Vegetation,' 1804 . . .14
Theories on source of plant-nitrogen . . . . .15
Early experiments on this subject 16
Sir Humphry Davy's lectures (1802-1812) .... 17
State of agricultural chemistry in 1812 . . . . .17
Beginning of Boussingault's researches (1834) .... 21
Publication of Liebig's first report to the British Association . 24
Refutation of " humus" theory ..... 26
Liebig's mineral theory ....... 26
Liebig's theory of source of plants' nitrogen ... 27
Publication of Liebig's second report to British Association . 30
Liebig's services to agricultural chemistry . . .31
Development of agricultural research in Germany ... 32
The Rothamsted Experiment Station ..... 33
Sir J. B. Lawes and Sir J. H. Gilbert, the nature and value of
their experiments 33
Review of the present state of our knowledge of plant-growth 36
Proximate composition of the plant . . . . .36
Fixation of carbon by plants . . . . . .37
Action of light on plant-growth, Dr Siemens' experiments 38
Source of oxygen and hydrogen in the plant . . 39-40
Source of nitrogen in the plant . . . . .40
Relation of the free nitrogen to leguminous plants . 42-44
Relation of nitrogen in organic forms, as ammonia salts,
and nitrates to the plant ..... 46-50
Nitrification and its conditions ...... 51
Ash constituents of the plant ...... 53
Methods of research for ascertaining essentialness of ash
constituents of plants 53
(a) Artificial soils, (6) water-culture .... 53-55
Method in which plants absorb their food-constituents . 55
Endosmosis . . . . . . . . .55
Retention by soils of plant-food ..... 57
Causes of retention by soils of plant-food .... 59
Manuring ......... 60
" Field " and " pot " experimentation .... 60
PART II. PRINCIPLES OF MANURING.
CHAPTER I. FERTILITY OF THE SOIL.
What constitutes fertility in a soil ...... 65
I. Physical properties of a soil . . . . . .66
Kinds of soils ......... 67
Absorptive power for water of soils ..... 67
Absorptive power for water of sand, clay, and humus . 68
Fineness of particles of a soil . . . . . .69
Limit of fineness of soil-particles . . . . .69
Importance of retentive power . . . . . .70
Power of plants for absorbing water from a soil, experi-
ments by Sachs ........ 73
How to increase absorptive power of soils . . . .74
Amount of water in a soil most favourable for plant growth 75
' Hygroscopic power of soils . . . . . .75
Capacity of soils for absorbing and retaining heat . . 76
Explanation of dew ....... 77
Heat of soils 78
Heat in rotting farmyard manure 78
Causes of heat of fermentation . . . . .79
Influence of colour on heat-retaining power ... 80
Power of soils for absorbing gases 81
Gases found in soils . . . . . . .81
Variation in gas-absorbing power of soils ... 82
Absorption of nitrogen by soils ..... 82
Requirements of plant-roots in a soil . . . .83
Influence of tillage on number of plants in a certain area 86
Comparison of English and American farming . . 86
II. Chemical composition of a soil ...... 87
Fertilising ingredients of a soil . . . . . . 87
Importance of nitrogen, phosphoric acid, and potash in a
Chemical condition of fertilising ingredients in soils . 89
Amount of soluble fertilising ingredients in soils . . 90
Value of chemical analysis of soils . . . . .90
III. Biological properties of a soil ... 92
Bacteria of the soil . .... 92
Recapitulation of Chapter I , .96
APPENDIX TO CHAPTER I.
I. Table of absorptive power of soil substances by Schiibler . 98
II. Table of rate of evaporation of water in different soils by
III. Table of hygroscopic power of soils dried at 212 F.
IV. Gases present in soil . . . . . . .100
V. Amount of plant-food in soils . . . . . .100
VI. Chemical composition of the soil 101
VII. Forms in which plant-foods are present in the soil . . 107
CHAPTER II. FUNCTIONS PERFORMED BY MANURES.
Etymological meaning of word manure 109
Definition of manures ....
Different classes of manures ... .111
Action of different classes of manures 113
CHAPTER III. POSITION OF NITROGEN IN
The Rothamsted experiments and the nitrogen question . . 115
Different forms in which nitrogen exists in nature . . .116
Relation of "free" nitrogen to the plant . . . .117
Combined nitrogen in the air . . . . . .118
Amount of combined nitrogen falling in the rain . . 119
Nitrogen in the soil . . . . . . . .120
Nitrogen in the subsoil . . . . . . .121
Nitrogen of surface-soil 121
Amount of nitrogen in the soil . . . . . .123
Soils richest in nitrogen 123
Nature of the nitrogen in the soil . . . . .124
Organic nitrogen in the soil . . . . . .125
Differences of surface and subsoil nitrogen . . .126
Nitrogen as ammonia in soils . . . . . .127
Amount of ammonia in soils ...... 127
Nitrogen present as nitrates in the soil . . . .128
Position of nitric nitrogen in soil . . . . .128
Amount of nitrates in the soil . . . . . .129
Amount of nitrates in fallow soils 129
Amount of nitrates in cropped soils . . . . .130
Amount of nitrates in manured wheat-soils . . . 131
The sources of soil-nitrogen 131
Accumulation of soil-nitrogen under natural conditions . 133
Accumulation of nitrogen in pastures . . . .134
Gain of nitrogen with leguminous crops . . . 1 35
The fixation of " free " nitrogen ..... 136
Influence of manures in increasing soil-nitrogen . . 136
Sources of loss of nitrogen . . . . .137
Loss of nitrates by drainage . . . . . .137
Prevention of loss of nitrogen by permanent pasture and
"catch-cropping". . . . . . . .138
Other conditions diminishing loss of nitrates . . .139
Amount of loss of nitrogen by drainage . . . .140
Loss of nitrogen in form of " free " nitrogen . . .141
Total amount of loss of nitrogen . . . . .142
Loss of nitrogen by retrogression ....
Artificial sources of loss of nitrogen . . . . .144
Amount of nitrogen removed in crops . . . .144
Losses of nitrogen incurred on the farm . . . .146
Loss in treatment of farmyard manure . . . .146
Nitrogen removed in milk . . . . . .147
Economics of the nitrogen question . . . . .147
Loss of nitrogen-compounds in the arts . . . .148
Loss due to use of gunpowder . . . . . .148
Loss due to sewage disposal . . . . . .149
Our artificial nitrogen supply . . . . . .150
Nitrate of soda and sulphate of ammonia . . . .150
Peruvian guano . . . . . . . .151
Other nitrogenous manures . . . . . .152
Oil-seeds and oilcakes . . . . . . .153
Other imported sources of nitrogen ..... 153
Conclusion ......... 153
APPENDIX TO CHAPTER III.
I. Determination of the quantity of nitrogen supplied by
rain, as ammonia and nitric acid, to an acre of land
during one year ........ 155
II. Nitrogen in soils at various depths . . . . .156
III. Nitrogen as nitrates in cropped soils receiving no nitro-
genous manures, in Ib. per acre (Rothamsted soils) . 157
IV. Nitrogen as nitrates in Rothamsted soils . . .157
V. Examples of increase of nitrogen in Rothamsted soils
laid down in pasture ....... 158
VI. Loss by drainage of nitrates ...... 158
VII. Examples of decrease of nitrogen in Rothamsted soils . 159
VIII. Amount of drainage and nitrogen as nitrates in drainage-
water from unmanured bare soil, 20 and 60 inches deep 160
CHAPTER IV. NITRIFICATION.
Process of nitrification . . . . . . . .161
Occurrence of nitrates in the soil . . . . . .162
Nitre soils of India . . . . . . . . .162
Saltpetre plantations . . . . . . .163
Cause of nitrification . . . . . . . .165
Ferments effecting nitrification . . . . .167
Appearance of nitrous organisms . . . . .168
Nitric organism . . . . .169
Difficulty in isolating them 169
Nitrifying organisms do not require organic matter . .169
Conditions favourable for nitrification
Presence of food-constituents . . . . . .170
Presence of a salifiable base . . . . . .171
Only takes place in slightly alkaline solutions . . .172
Action of gypsum on nitrification 173
Presence of oxygen 173
Temperature . . . . . . . . .175
Presence of a sufficient quantity of moisture . . .176
Absence of strong sunlight . . . . . .176
Nitrifying organisms destroyed by poisons . . .176
Denitrification . .177
Denitrification also effected by bacteria . . . .178
Conditions favourable for den itrifi cation . . . .178
Takes place in water-logged soils 179
Distribution of the nitrifying organisms in the soil . . .179
Depth down at which they occur . . . . .180
Action of plant-roots in promoting nitrification . . .181
Nature of substances capable of nitrification . . .181
Rate at which nitrification takes place . . . . .183
Nitrification takes place chiefly during summer . . 183
Process goes on most quickly in fallow fields . . .184
Laboratory experiments on rate of nitrification . . .185
Certain portions of soil - nitrogen more easily nitrifiable
than the rest ........ 187
Rate of nitrification deduced from field experiments . .187
Quantity of nitrates formed in the soils of fallow fields . 188
Position of nitrates depends on season .... 188
Nitrates in drainage- waters . . . . . .188
Amount produced at different times of year . . .189
Nitrification of manures . . . . . . .190
Ammonia salts most easily nitrifiable . . . .191
Sulphate of ammonia the most easily nitrifiable manure . 191
Rate of 'nitrification of other manures . . . .192
Soils best suited for nitrification . . . . .192
Absence of nitrification in forest-soils . . . .193
Important bearing of nitrification on agricultural practice . 193
Desirable to have soil covered with vegetation . . .194
Permanent pasture most economical condition of soil . 194
Nitrification and rotation of crops 195
APPENDIX TO CHAPTER IV.
I. Old theories of nitrification . . . . . .196
II. Nitrification takes place in solutions devoid of organic
III. Oxidising power of micro-organisms in soils . . .197
IV. Effect of urine on nitrification in soils . . . .197
V. Solution used by Professor Frankland in cultivating nitri-
ficative micro-organisms . . . . . .198
VI. Experiments by Boussingault on rate of nitrification . 198
VII. Nitrogen as nitrates in Rothamsted soils after bare fallow
in Ib. per acre ........ 198
CHAPTER V. POSITION OF PHOSPHORIC ACID IN
Occurrence of phosphoric acid in nature 199
Mineral sources of phosphoric acid ...... 200
Apatite and phosphorite ........ 200
Occurrence of phosphoric acid in guanos ..... 202
Universal occurrence in common rocks ..... 202
Occurrence in the soil ........ 203
Condition in which phosphoric acid occurs in the soil* . . 203
Occurrence in plants ........ 204
Occurrence in animals 205
Sources of loss of phosphoric acid in agriculture . . . 205
Loss of phosphoric acid by drainage . . . . .206
Artificial sources of loss of phosphoric acid .... 206
Amount of phosphoric acid removed in milk . . . . 207
Loss of phosphoric acid in treatment of farmyard manure . 208
Loss of phosphoric acid in sewage 208
Sources of artificial gain of phosphoric acid .... 208
APPENDIX TO CHAPTER V.
I. Composition of apatite (Voelcker) 210
II. Percentage of phosphoric acid in the commoner rocks . 211
CHAPTER VI. POSITION OF POTASH IN AGRICULTURE.
Potash of less importance than phosphoric acid . . .212
Occurrence of potash 213
Felspar and other potash minerals 213
Stassfurt salts . . . . . . . . .214
Occurrence of saltpetre 215
Occurrence of potash in the soil . . . . . .215
Potash chiefly in insoluble condition in soils . . . .216
Percentage of potash in plants and plant-ash . . . .216
Occurrence of potash in animal tissue . . . . .217
Sources of loss of potash 217
Amount of potash removed in crops . . . . .218
Amount of potash removed in milk . . . . . .218
Potash manures ....... .218
APPENDIX TO CHAPTER VI.
I. Amount of potash in different minerals .... 220
II. Quantity of potash obtained from 1000 Ib. of different
kinds of vegetation in the manufacture of potashes . 220
PART III. MANURES.
CHAPTER VII. FARMYARD MANURE.
Variation in its composition ....... 223
Made up of three classes of constituents ..... 224
Its nature 224
Difference in composition of the solid excreta of the
different farm animals ...... 224
Causes of this difference ...... 225
Percentage of manurial ingredients in solid excreta of
different animals . . . . . . .226
Its nature 228
Variation in its composition 229
Causes of this variation ....... 229
Manurial value of the urine of the different farm animals 230
Percentage of the organic matter, nitrogen, and mineral
substances in the food, voided in the solid excreta and
Comparison of manurial value of total excrements of the
different farm animals ...... 234
Nature of changes undergone by food in process of
digestion . . . 235
Its uses 236
Straw as litter, and its qualifications . . . .237
Composition of different kinds of straw .... 238
Loam as litter 239
Peat as litter 240
Comparison of properties of peat-moss and straw . . 241
The bracken-fern as litter . . . . . .241
Dried leaves as litter . . . . . . . 242
Manures produced by the different animals
Amount produced ........ 243
Its nature and composition ...... 243
Amount of straw used for litter ..... 244
Sources of loss on keeping 245
How to prevent loss ....... 245
Use of " fixers," and the nature of their action . . 245
Amount produced ........ 248
Its nature and composition ...... 248
Amount of straw used as litter ..... 248
Sources of loss on keeping ...... 249
Advantages of short dung ...... 249
Amount produced ....... 250
Its nature and composition ...... 250
Amount of straw used as litter . . . . .251
Amount produced ....... 251
Nature and composition ...... 251
Amount of straw used as litter ..... 252
Methods of calculating amount of manure produced on the
farm 252, note
Fermentation of farmyard manure
Action of micro-organic life in producing fermentation . 255
Two classes of bacteria active in this work, aerobics and
anaerobies ......... 255
Conditions influencing fermentation
Openness to the air . . . . .256
Dampness . . . . . . . . . 257
Composition of manure ....... 257
Products of fermentation ....... 257
Analyses of farmyard manure
Dr Voelcker's experiments 259
Variation in composition - . . . . . . . 259
Amounts of moisture, organic matter (containing nitrogen),
and mineral matter . . . . . . .260
Its inanurial value compared with nitrate of soda, sulphate
of ammonia, and superphosphate . . . . .260
Comparison of fresh and rotten manure
The nature and amount of loss sustained in the process of
Ought manure to be applied fresh or rotten ? . . . 262
Relative merits of covered and uncovered manure-heaps . . 263
Methods of application of farmyard manure to the field
Merits and demerits of the different methods . . .265
Setting it out in heaps . . . . . . .265
Spreading it broadcast, and letting it lie . . . . 266
Ploughing it in immediately . . . . . .267
Value and function of farmyard manure
As a supplier of the necessary elements of plant-food . 268
As a " universal " manure . ...... 269
Proportion in which nitrogen, phosphoric acid, and potash
are required by crops . . . . . . .269
Proportion in which they are present in farmyard manure 270
Farmyard manure poor in nitrogen . . . . .270
Lawes' and Gilbert's experiments . . . . .271
How it may be best reinforced by the use of " artificials " . 271
Indirect value of farmyard manure as a supplier of humus
to the soil 273
Its influence on soil-texture ...... 273
Its influence in setting free inert fertilising matter in the
soil .......... 274
Rate at which farmyard manure ought to be applied . . 275
Lasting nature of farmyard manure ..... 276
Its economic value . . . . . . . . .276
APPENDIX TO CHAPTER VII.
I. Difference in amount of excreta voided for food con-
sumed ... 279
II. Solid excreta voided by sheep, oxen, and cows . .279
III. Urine voided by sheep, oxen, and cows . . . 280
IV. Percentage of food voided in the solid and liquid ex-
crements ........ 281
V. Pig excrements 281
VI. Manurial constituents in 1000 parts of ordinary foods . 282
VII. Analyses of stable - manure, made respectively with
peat-moss litter and wheat-straw .... 283
VIII. Analyses of bracken ' . 283
IX. Analyses of horse-manure ...... 283
X. The nature of the chemical reactions of ammonia
11 fixers" 284
XI. Analyses of cow-manure ...... 286
XII. Composition of 'fresh and rotten farmyard manure . 286
XIII. Comparison of fresh and rotten manure . . . 288
XIV. Lord Kinnaird's experiments . . . . .289
XV. Drainings of manure-heaps ...... 290
XVI. Amounts of potash and phosphoric acid removed by
rotation from a Prussian morgen (.631 acre) . . 290
XVII. Composition of farmyard manure (fresh) . . . 291
XVIII. The urine (quantity voided) 291
CHAPTER VIII. GUANO.
Importance in agriculture ....... 293
Influence on British farming . . . . . . .294
Influence of guano not wholly good ...... 295
Value of guano as a manure ....... 296
Origin and occurrence of guano ...... 297
Variation in composition of different guanos .... 299
I. Nitrogenous guano
(a) Peruvian guano 300
Different deposits of Peruvian guano . . . 301
Appearance, colour, and nature of Peruvian guano . 303
Composition of Peruvian guano .... 304
(b) Other nitrogenous manures : Angamos, Ichaboe . 306
II. Phosphatic guanos
Occurrence of phosphatic guanos ..... 308
Inequality in composition of phosphatic guanos . . 309
" Dissolved " phosphatic guano ..... 310
" Equalised " or " rectified " guano ..... 311
The action of phosphatic guauos as manures . . .312
Proportion of fertilising constituents in guano . . 314
Mode of application of guanos . . . . .315
Quantity of guano to be used ...... 317
Adulteration of guano . . . . . . .318
Value of fish-guano 322
Meat-meal guano ........ 324
Value of meat-meal guano ...... 324
Bat guano 325
Pigeon and fowl dung 325
APPENDIX TO CHAPTER VIII.
I. Peruvian guano imported into United Kingdom, 1865-
II. Guano deposits of the world ...... 327
III. Composition of concretionary nodules . . . .328
IV. Table showing gradual deterioration of Peruvian guano,
V. Composition of different guanos ..... 329
VI. Liebig's theory as to the action of oxalic acid in guano . 330
VII. Analyses of dung of fowls, pigeons, ducks, and geese . 331
CHAPTER IX. NITRATE OF SODA.
Amount of exports . . . . . . . . .332
Date of discovery of nitrate deposits ..... 333
The origin of nitrate deposits . . . . . . .334
Forbes and Darwin on the theory of their origin . . .335
Source of nitric acid in nitrate of soda ..... 337
Guano theory of origin of nitrate of soda ..... 337
Nitric acid in nitrate of soda probably derived from sea-weed . 339
Appearance of nitrate-fields .... ... 340
The method of mining the nitrate of soda . . . .341
Composition of caliche . . . . . . .342
Extent of the nitrate deposits ....... 342
Composition and properties of nitrate of soda . . . .343
Nitrate applied as a top-dressing . . . . . .344
Nitrate of soda encourages deep roots ..... 344
Is nitrate of soda an exhausting manure ? 345
Crops for which nitrate of soda is suited . . . . .346
Method of application of nitrate of soda ..... 347
Importance of having a sufficiency of other fertilising con-
stituents .......... 348
Conclusions drawn ......... 349
APPENDIX TO CHAPTER IX.
Total shipments from South America, 1830-1893 . . .351
Total imports into Europe and United Kingdom, 1873-1892 . 351
CHAPTER X. SULPHATE OF AMMONIA.
Value of ammonia as a manure ...... 352
Sources of sulphate of ammonia ...... 353
Ammonia from gas-works ....... 353
Other sources .......... 354
Composition, &c., of sulphate of ammonia .... 355
Application of sulphate of ammonia . . . . .356
APPENDIX TO CHAPTER X.
Production of sulphate of ammonia in United Kingdom,
CHAPTER XI. BONES.
Early use of bones ......... 359
Different forms in which bones are used ..... 360
Composition of bones ........ 362
The organic matter of bones . . . . . . .363
The inorganic matter of bones ....... 363
Treatment of bones ......... 364
Action of bones ......... 365
Dissolved bones ......... 368
Crops suited for bones ........ 368
Bone-char or bone-black ........ 369
APPENDIX TO CHAPTER XI.
I. Analysis of bone-meal 371
II. Analysis of dissolved bones 371
III. Composition of bone-ash ....... 372
IV. Composition of bone-char 372
CHAPTER XII. MINERAL PHOSPHATES.
Coprolites .......... 373
Canadian apatite or phosphorite . . . . . .374
Estremadura or Spanish phosphates 375
Norwegian apatite . . . . . . . . .376
Charlestown or South Carolina phosphate . . . .376
Belgian phosphate ......... 377
Somnie phosphate . . . . . . . . .378
Florida phosphate 378
Lahn phosphate . . . . . . . . .379
Bordeaux or French phosphate ...... 379
Algerian phosphate . . . . . . . . .379
Crust guanos .......... 379
Value of mineral phosphates as manures 380
APPENDIX TO CHAPTER XII.
Imports of phosphates . . . . . . . .381
CHAPTER XIII. SUPERPHOSPHATES.
Discovery of superphosphate by Liebig ..... 382
Manufacture of superphosphate 383
Nature of the reaction taking place ...... 385
Phosphates of lime ......... 385
Reverted phosphate . . . . . . . .389
Value of reverted phosphate . . . . . . .391
Composition of superphosphates ...... 391
Action of superphosphates . . . . . . .392
Action of superphosphate sometimes unfavourable . . . 395
Application of superphosphate . . . . . . .395
Value of insoluble phosphates ....... 396
Rate at which superphosphate is applied 397
APPENDIX TO CHAPTER XIII.
I. The formulae, and molecular and percentage composition,
of the different phosphates ...... 398
II. Reactions of sulphuric acid and phosphate of lime . . 398
III. Table for conversion of soluble phosphate into insoluble
IV. Action of iron and alumina in causing reversion . . 399
V. Relative trade values of phosphoric acid in different
manures ......... 400
CHAPTER XIV. THOMAS-PHOSPHATE OR
Its manufacture ......... 401
Not at first used 403
Discovery of its value as a manure 403
Composition of basic slag ....... 404
Processes for preparing slag ....... 406
Solubility of basic slag . . . . . . . .408
Darmstadt experiments with basic slag . . . . . 410
Results of other experiments . . . . . . .413
Soils most suited for slag . . . . . . .414
Rate of application . . . . . . . . .414
Method of application . . . . . . . .416
APPENDIX TO CHAPTER XIV.
Analysis of basic slag . . . . . . . .417
CHAPTER XV. POTASSIC MANURES.
Relative importance . . . . . . . .418
Scottish soils supplied with potash . . . . . .419
Sources of potassic manures . . . . . . .419
Stassfurt potash salts . . . . . . . .420
Relative merits of sulphate and muriate of potash . . .421
Application of potash manures ....... 422
Soils and crops suited for potash manures .... 423
Rate of application ......... 423
CHAPTER XVI. MINOR ARTIFICIAL MANURES.
Shoddy and wool-waste ........ 427
CHAPTER XVII. SEWAGE AS A MANURE.
Irrigation .......... 431
Effects of continued application of sewage .... 433
Intermittent irrigation . . . . . . . .434
Crops suited for sewage . . . . . . . .434
Treatment of sewage by precipitation, &c. .... 436
Value of sewage sludge ........ 439
CHAPTER XVIII. LIQUID MANURE .... 442
CHAPTER XIX. COMPOSTS.
Farmyard manure a typical compost . . . . .446
Other composts ......... 447
CHAPTER XX. INDIRECT MANURES.
Antiquity of lime as a manure . . . . . .449
Action of lime ......... 449
Lime a necessary plant-food ...... 450
Lime of abundant occurrence ...... 452
Lime returned to the soil in ordinary agricultural practice 452
Different forms of lime 453
Caustic lime ......... 453
Lime acts both mechanically and chemically . . .455
I. Mechanical functions of lime ...... 455
Action on soil's texture ....... 455
Lime renders light soils more cohesive . . . .457
II. Chemical action of lime ....... 457
III. Biological action of lime . ' . . . . . .459
Action of lime on nitrogenous organic matter . .460
Recapitulation . . . . . . . . .461
CHAPTER XXL INDIRECT MANURES GYPSUM,
Gypsum ........... 462
Mode in which gypsum acts . . . . . .462
Antiquity of the use of salt . . . . . . 465
Nature of its action ........ 465
Salt not a necessary plant-food . . . . . .466
Can soda replace potash ? . . . . . . .466
Salt of universal occurrence . . . . . .467
Special sources of salt . . . . . . .468
The action of salt 468
Mechanical action on soils . . . . . . .470
Solvent action . . . . . . . . .470
Best used in small quantities along with manures . .472
Affects quality of crop . . . . . . .472
Rate of application 473
CHAPTER XXII. THE APPLICATION OF MANURES.
Influence of manures in increasing soil-fertility . . .474
Influence of farmyard manure on the soil . . . .475
Farmyard manure v. artificials ....... 476
Farmyard manure not favourable to certain crops . . . 477
Conditions determining the application of artificial manures . 477
Nature of the manure . . . . . . .478
Nitrogenous manures . . . . . . . .478
Phosphatic manures . . . . . . . .480
Potash manures ......... 480
Nature of soil .......... 481
Nature of previous manuring . . . ... . . 482
Nature of the crop ......... 483
Amounts of fertilising ingredients removed from the soil by
different crops ......... 484
Capacity of crops for assimilating manures .... 486
Difference in root-systems of different crops . . . 488
Period of growth 489
Variation in composition of crops . . . . .490
Absorption of plant-food ....... 490
Fertilising ingredients lodge in the seed .... 491
Forms in which nitrogen exists in plants 491
Bearing of above on agricultural practice .... 492
Influence of excessive manuring of crops . . . . .492
CHAPTER XXIII. MANURING OF THE COMMON
Cereals ........... 493
Especially benefited by nitrogenous manures . . . 494
Power of absorbing silicates . . . . . .494
Period of growth ....... 495
Most suitable soil ....... 496
Farmyard manure not suitable 497
Importance of uniform manuring of barley . . 497
Norfolk experiments on barley 497
Proportion of grain to straw . . . . .498
Rothamsted experiments ....... 500
Continuous growth ....... 500
Flitcham experiments . . . . . . .500
A very hardy crop ....... 502
Require mixed nitrogenous manuring . . . .502
Arendt's experiments 503
Aveniue ......... 503
Quantities of manures ...... 504
Effect of manures on herbage of pastures . . . .505
Influence of farmyard manure . . . . . .506
Influence of soil and season on pastures .... 507
Manuring of meadow land ...... 508
Baiigor experiments . . . . . . .508
Norfolk experiments . . . . . . 509
Manuring of permanent pastures ..... 509
Influence of manure on composition . . . .512
Nitrogenous manures increase sugar 512
Amount of nitrogen recovered in increase of crop . .513
Norfolk experiments 513
Manure for swedes . . . . . . .514
Highland Society's experiments 515
Manuring for rich crops of turnips . . . .516
Experiments by the author on turnips . . . .516
Highland Society's experiments . . . . .518
The Rothamsted experiments . . . . . .519
Effect of farmyard manure ..... 520
Manuring of potatoes in Jersey 521
The influence of manure on the composition . . 521
Leguminous crops ......... 522
Leguminous plants benefit by potash .... 523
Nitrogenous manures may be hurtful .... 523
Clover sickness ........ 524
Alternate wheat and bean rotation ..... 524
Beans . . .525
Manure for beans ....... 525
Relative value of manurial ingredients . . ' . 526
Gypsum as a bean manure ...... 526
Effect of manure on composition of crop . . . 527
APPENDIX TO CHAPTER XXIII.
Experiments on bean-manuring . . . . . 530
CHAPTER XXIV. ON THE METHOD OF APPLICATION,
AND ON THE MIXING OF MANURES."
Equal distribution of manures ....... 531
Mixing manures ......... 532
Risks of loss in mixtures ........ 533
Loss of ammonia ........ 533
Effects of lime on ammonia . . . . . .535
Loss of nitric acid ........ 536
Reversion of phosphates . . . . . . .537
Manurial ingredients should be applied separately . . . 538
CHAPTER XXV. ON THE VALUATION AND ANALYSIS
Value of chemical analysis ....... 539
Interpretation of chemical analysis . . . . . .539
Nitrogen . . . . . . . . . . 540
Phosphoric acid ......... 541
Importance of mechanical condition of phosphate . . 542
Other items in the chemical analysis of manures . . . 543
Fertilisers and Feeding Stuffs Act ...... 543
Different methods of valuing manures . . . . . 544
Unit value of manurial ingredients ...... 544
Intrinsic value of manures ....... 545
Field experiments 545
Educational value of field experiments ..... 547
Value of manures deduced from experiments .... 548
Value of unexhausted manures ...... 549
Potential fertility of a soil 549
Tables of value of unexhausted manures ..... 551
APPENDIX TO CHAPTER XXV.
I. Factors for calculating compounds from manurial in-
gredients . . . . . . . . . 553
II. Units for determining commercial value of manures and
cash prices of manures 554, 555
III. Manurial value of nitrogen and potash in different sub-
stances .......... 556
IV. Comparative manurial value of different forms of nitrogen
and potash ......... 557
V. Lawes' and Gilbert's tables for calculating unexhausted
value of manures ........ 559
CHAPTER XXVI. THE ROTHAMSTED EXPERIMENTS.
Nature of experiments on crops and manures . . . .561
Soil of Rothamsted 561
Table I. List of Rothamsted field experiments . . .562
Unmanured plots 562
Wheat grown continuously on same land (unmanured) . 562
Table II. Results of first eight years . . .562
ii III. Results of subsequent forty years . . 562
Table IV. Wheat grown continuously with farmyard man-
ure (14 tons per annum) .... 564
ii V. Wheat grown continuously with artificial man-
Table VI. Experiments on the growth of barley, forty years,
it VII. Experiments on the growth of oats, 1869-78 . 567
ii VIII. Experiments on root crops Swedish turnips 568, 569
ii IX. Experiments on mangel-wurzel . . . 568, 569
.. X. Experiments with different manures on permanent
meadow-land, thirty-six years, 1856-91 . . 570
.1 XI. Experiments on the growth of potatoes average
for five seasons, 1876-80 571
u XII. Experiments on growth of potatoes (continued)
average for twelve seasons, 1881-92 . . . 572
MANUKES AND THE PEINCIPLES
AGRICULTURAL CHEMISTRY, like most branches of nat-
ural science, may be said to be entirely of modern
growth. While it is true we have many old specu-
lations on the subject, they can scarcely be said to
possess much scientific value. The great questions
which had first to be solved by the agricultural
chemist were, What is the food of plants ? and,
What is the source of that food ? The second of
these two questions more easily admitted of answer
than the first. The source of plant-food could only
be the atmosphere or the soil. As the composition
of the atmosphere, however, was not discovered till
the close of last century, and the chemistry of the
soil is a question which is still requiring much work
4 HISTORICAL INTRODUCTION.
ere we shall be in possession of anything like a full
knowledge of it, it will be at once obvious that the
very fundamental conditions for a solution of the
question were awanting. The beginning, then, of a
true scientific agricultural chemistry may be said to
date from the brilliant discoveries associated with
the names of Priestley, Scheele, Lavoisier, Cavendish,
and Black that is, towards the close of last century.
Early Theories on Source of Plant-food.
While this is so, and while we must regard the
early attempts made towards solving this question as
being, for the most part, of little scientific value, it
is not without interest, from the historical point of
view, to glance briefly at some of these old interesting
The Aristotelian doctrine, regarding the possibility
of dividing matter into the so-called four primary
elements, /ire, air, earth, and water, which obtained
in one form or another till the birth of modern
chemistry, had naturally an important influence on
these early theories.
Van Helmont s Theory.
Among the earliest and most important attempts
made to solve the problem of plant-growth was that
by Jean Baptiste Van Helmont, one of the best known
of the alchemists, who flourished about the beginning
of the seventeenth century. Van Helmont believed
VAN HELMONT'S THEOKY. 5
that he had proved by a conclusive experiment that
all the products of vegetables were capable of being
generated from water. The details of this classical
experiment were as follows :
" He took a given weight of dry soil 200 Ib. and
into this soil he planted a willow-tree that weighed
5 Ib., and he watered this carefully from time to time
with pure rain-water, taking care to prevent any dust
or dirt falling on to the earth in which the plant
grew. He allowed this to go on growing for five
years, and at the end of that period, thinking his
experiment had been conducted sufficiently long, he
pulled up his tree by the roots, shook all the earth
off, dried the earth again, weighed the earth and
weighed the plant. He found that the plant now
weighed 169 Ib. 3 ounces, whereas the weight of the
soil remained very nearly what it was about 200 Ib.
It had only lost 2 ounces in weight." l
The conclusion, therefore, come to by Van Helmont
was that the source of plant-food was water. 2
1 The History of the Chemical Elements. By Sir Henry E. Ros-
coe, F.K.S. (Wm. Collins, Sons, & Co.)
2 Van Helmont's science was, however, of an extremely rudimentary
nature, as may be evidenced by the belief he entertained that the
smells which arise from the bottom of morasses produce frogs, slugs,
leeches, and other things ; as well as by the following recipe which
he gave for the production of a pot of mice: " Press a dirty shirt
into the orifice of a vessel containing a little corn, after about twenty-
one days the ferment proceeding from the dirty shirt, modified by the
odour of the corn, effects a transmutation of the wheat into mice."
The crowning point ill this recipe, however, lay in the fact that he
6 HISTORICAL INTRODUCTION.
Some fifty years later an extremely interesting book
was published bearing the following title : ' A Dis-
course concerning the Vegetation of Plants, spoken
by Sir Kenelm Digby, at Gresham College, on the
23d of January 1660. (At a meeting of the Society
for promoting Philosophical Knowledge by Experi-
ments. London : Printed for John Williams, in Little
Britain, over against St Botolph's Church, 1669.) '
The author attributes plant-growth to the influence
of a lalsam which the air contains. This book is
especially interesting as containing the earliest rec-
ognition of the value of saltpetre as a manure. The
following is an extract from this interesting old
" The sickness, and at last the death of a plant,
in its natural course, proceeds from the want of that
balsam ick saline juice ; which, I have said, mak'es it
swell, germinate, and augment itself. This want may
proceed either from a destitution of it in the place
where the plant grows, as when it is in a barren soil
or bad air, or from a defect in the plant itself, that
hath not vigour sufficient to attract it, though it be
within the sphere of it ; as when the root has become
asserted that he had himself witnessed the fact, and, as -an interest-
ing and corroborative detail, he added that the mice were born full-
grown. See 'Louis Pasteur: His Life and Labours.' By his Son-
in-law. Translated by Lady Claud Hamilton. (Longmans, Green,
& Co.) P. 89.
DIGBY'S THEORY. 7
so hard, obstructed and cold, as that it hath lost its
vegetable functions. Now, both these may be renie-
dy'd, in a great measure, by one and the same physick.
. . . The watering of soils with cold hungray springs
doth little good ; whereas muddy saline waters brought
to overflow a piece of ground enrich it much. But
above all, well-digested dew makes all plants luxuriate
and prosper most. Now what may it be that endues
these liquors with such prolifick virtue ? The meer
water which is common to them all, cannot be it;
there must be something else enclosed within it, to
which the water serves but for a vehicle. Examine
it by spagyric art, and you will find that it is nothing
else than a nitrous salt, which is dilated in the water.
It is this salt which gives foecundity to all things :
and from this salt (rightly understood) not only all
vegetables, but also all minerals draw their origine.
By the help of plain salt-peter, dilated in water and
mingled with some other fit earthy substance, that
may familiarize it a little with the corn into which
I endeavoured to introduce it, I have made the bar-
renest ground far out-go the richest, in giving a pro-
digiously plentiful harvest. I have seen hemp-seed
soaked in this liquor, that hath in due time made
such plants arise, as, for the tallness and hardness
of them, seemed rather to be coppice-wood of fourteen
years' growth at least, than plain hemp. The fathers
of the Christian doctrine at Paris still keep by them
for a monument (and indeed it is an admirable one)
8 HISTORICAL INTRODUCTION.
a plant of barley consisting of 249 stalks, springing
from one root or grain of barley ; in which they
counted above 18,000 grains or seeds of barley. But
do you think that it is barely the salt-peter, imbibed
into the seed or root, which causeth this fertility ?
no : that would be soon exhausted and could not
furnish matter to so vast a progeny. The salt-peter
there is like a magnet, which attracts a like salt
which fecundates the air, and gave cause to the
Cosmopolite to say there is in the air a hidden food
of life." 1
DuJiamel and Hales.
The names of the French writer, Duhamel, and of the
English, Stephen Hales, may be mentioned in passing
as authors of works bearing on the question of veg-
etable physiology. Both of these writers flourished
about the middle of the eighteenth century. The
writings of the former contained much valuable in-
formation on the effects of grafting, motion of sap, and
influence of light on vegetable growth, and also the
results of experiments which the author had carried
out on the influence of treating plants with certain
substances. ' Statical Essays, containing Vegetable
Staticks ; or an Account of some Statical Experiments
on the Sap of Vegetables, by Stephen Hales, D.D.' (2
1 He then goes on to relate a number of experiments by Cornelius
Drebel and Albertus Magnus, showing the refreshing power of this
balsam, and then those of Quercitan with roses and other flowers,
and his own with nettles.
JETHKO TULLS THSOBY. 9
vols.), was published in London in 1738 ; and contain-
ed, as will be seen from its title, records of experiments
of very much the same nature as those of Duhamel.
Jethro TulVs Theory.
Some reference may be made to a theory which
created a considerable amount of interest when it was
first published viz., that of Jethro Tull. The chief
value of Tull's contribution to the subject of agricul-
tural science was, that he emphasised the importance
of tillage operations by putting forward a theory to
account for the fact, universally recognised, that the
more thoroughly a soil was tilled, the more luxuriant
the crops would be. As Tull's theory had a very
considerable influence in stirring up interest in many
of the most important problems in agricultural chem-
istry, and as it contained in itself much, the value of
which we have only of late years come to understand,
a brief statement of this theory may not be without
According to Tull the food of plants consists of the
particles of the soil. These particles, however, must
be rendered very minute before they become available
for the plant, which absorbs them by means of its root-
lets. This pulverisation of the soil goes on in nature
independently of the farmer, but only very slowly, and
the farmer has therefore to hasten it on by means of
tillage operations. The more efficiently these opera-
tions are carried on, the more abundant will the supply
10 HISTORICAL INTRODUCTION.
of plant -food be rendered in the soil. He conse-
quently introduced and advocated the system of horse-
hoe husbandry. This theory, he informs us, was sug-
gested to him by the custom, which he had noticed on
the Continent, of growing vines in rows, and hoeing the
intervals between these rows from time to time. The
excellent results which followed this mode of cultiva-
tion induced him to adopt it in England for his farm
crops. He accordingly sowed his crops in rows or
ridges, wide enough apart to admit of thorough tillage
of the intervals by ploughing as well as by hand-
hoeing. This he continued until the plant had reached
maturity. As to the exact width of the interval most
suitable, he made a large number of experiments. At
first, in the cultivation of wheat, he made this interval
six feet wide; but latterly he adopted an interval
of lesser width, that finally arrived at being between
four and five feet. He likewise experimented on each
separate ridge as to which was the best number of
rows of wheat to be sown, latterly adopting, as
most convenient, two rows at ten inches apart. The
great success which he met with in this system of
cultivation induced him to publish the results of
his experiments in his famous work, ' Horse-Hoeing
While Tull's theory was based on principles at
heart thoroughly sound, he was carried away by his
personal success into drawing unwarrantable deduc-
tions. Thus he came to the conclusion that rotation
DISCOVERY OF THE SOURCE OF PLANTS' CARBON. 11
of crops was unnecessary, provided that a thorough
system of tillage was carried out. Manures also, ac-
cording to him, might be entirely dispensed with
under his system of cultivation, for the true function
of all manures is to aid in the pulverisation of the
soil by fermentation.
The first really valuable scientific facts contributed
to the science were made by Priestley, Bonnet, Ingen-
housz, and Senebier.
Discovery of the Source of Plants Carbon.
To Charles Bonnet (1720-1793), a Swiss naturalist,
is due the credit of having made the first contribu-
tion to a discovery of very great importance viz.,
the true source of the carbon, which we now know
forms so large a portion of the plant - substance.
Bonnet, who had devoted himself to the question of
the function of leaves, noticed that when these were
immersed in water bubbles were seen, after a time,
to collect on their surface. De la Hire, it ought
to be pointed out, had noticed this same fact about
sixty years earlier. It was left to Priestley, how-
ever, to identify these bubbles with the gas he had
a short time previously discovered viz., oxygen.
Priestley had observed, about this time, the interest-
ing fact that plants possessed the power of purify-
ing air vitiated by the presence of animal life. 1 The
1 Priestley, however, did riot realise that carbonic acid gas was a
necessary plant-food ; on the contrary, he considered it to have a
12 HISTOKICAL INTRODUCTION.
next step in this highly interesting and important
discovery was taken by John Ingenhousz (1730-1799),
an eminent physician and natural philosopher. In
1779, Ingenhousz published a work in London entitled
* Experiments on Vegetables.' In it he gives the
results of some important experiments he had made
on the question already investigated by Bonnet and
Priestley. These experiments proved that plant-
leaves only gave up their oxygen in the presence of
sunlight. In 1782 he published another work on
'The Influence of the Vegetable Kingdom on the
Animal Creation/ l
The source of the gas, which Bonnet had first
noticed to be given off from plant-leaves, Priestley had
identified as oxygen, and Ingenhousz had proved to be
only given off under the influence of the sun's rays,
was finally shown by a Swiss naturalist, Jean Senebier 2
(1742-1809), to be the carbonic acid gas in the air,
which the plant absorbed and decomposed, giving out
the oxygen and assimilating the carbon.
deleterious action on plant -growth. Percival was really the first to
point out that carbonic acid gas was a plant-food.
1 It is recorded as an instance of the scientific enthusiasm of the
man, that he was wont to carry about with him bottles containing
oxygen, which he had obtained from cabbage-leaves, as also coils of
iron wire, with which he could illustrate the brilliant combustion
which ensued on burning the latter in oxygen gas.
2 For a full account of Senebier's researches, see l Physiologic
vegetale, contenant une description des organes des plantes, et une
exposition des pheuomenes produits par leur organisation, par Jean
Senebier.' (5 tomes. Geneve, 1800.)
TREATISE ON AGRICULTURAL CHEMISTRY. 13
Publication of First English Treatise on Agricultural
In 1795, a book dealing with the relations between
chemistry and agriculture was published. This work
was written by a Scottish nobleman, the Earl of
Dundonald, and possesses especial interest from the
fact that it is the first book in the English language
on agricultural chemistry. The full title is as follows :
* A Treatise showing the Intimate Connection that
subsists between Agriculture and Chemistry/
In his introduction the author says : " The slow
progress which agriculture has hitherto made as a
science is to be ascribed to a want of education on
the part of the cultivators of the soil, and to a want
of knowledge, in such authors as have written on
agriculture, of the intimate connection that subsists
between the science and that of chemistry. Indeed,
there is no operation or process not merely mechanical
that does not depend on chemistry, which is defined
to be a knowledge of the properties of bodies, and of
the effects resulting from their different combinations."
In quoting this passage Professor S. W. Johnson
remarks : l " Earl Dundonald could not fail to see that
chemistry was ere long to open a splendid future for
the ancient art that had always been and always will
be the prime supporter of the nations. But when he
1 How Crops Grow. By Professor S. W. Johnson. Macmillan &
Co. (Introduction, p. 4.)
14 HISTORICAL INTRODUCTION.
wrote, how feeble was the light that chemistry could
throw upon the fundamental questions of agricultural
science ! The chemical nature of the atmosphere was
then a discovery of barely twenty years' standing.
The composition of water had been known but twelve
years. The only account of the composition of plants
that Earl Dundonald could give was the following:
' Vegetables consist of mucilaginous matter, resinous
matter, matter analogous to that of animals, and some
proportion of oil. . . . Besides these, vegetables con-
tain earthy matters, formerly held in solution in the
newly-taken-in juices of the growing vegetables.' To
be sure, he explains by mentioning in subsequent
pages that starch belongs to the mucilaginous matter,
and that on analysis by fire vegetables yield soluble
alkaline salts and insoluble phosphate of lime. But
these salts, he held, were formed in the process of
burning, their lime excepted; and the fact of their
being taken from the soil and constituting the indis-
pensable food of plants, his lordship was unacquainted
with. The gist of agricultural chemistry with him
was, that plants ' are composed of gases with a small
proportion of calcareous matter ; for although this dis-
covery may appear to be of small moment to the prac-
tical farmer, yet it is well deserving of his attention
and notice.' "
The year 1804 witnessed the publication of by far
the most important contribution made to the science
SOURCE OF PLANT-NITROGEN. - 15
up till this time. This was ' Eecherches Chimique sur
la Vegetation/ by Theodore de Saussure, one of the
most illustrious agricultural chemists of the century.
De Saussure was the first to draw attention to the
mineral or ash constituents of the plant; and thus
anticipate, to a certain extent, the subsequent famous
" mineral " theory of the great Liebig. The French
chemist maintained that these ash ingredients were
essential; and that without them plant-life was im-
possible. He also adduced fresh experiments of his
own in support of the theory, based on the experi-
ments of Bonnet, Priestley, Ingenhousz, and Senebier,
that plants obtain their carbon from the carbonic
acid gas in the air, under the influence of the sunlight.
He was of opinion that the hydrogen and oxygen of
the plant were, probably, chiefly derived from water.
He showed that by far the largest portion of the
plant's substance was derived from the air and from
water, and that the ash portion was alone derived from
the soil. To Saussure we owe the first definite state-
ment on the different sources of the plant's food. It
may be said that the lapse of nearly a century has
shown his views to be, in the main, correct.
Source of Plant-nitrogen.
There was one question, which, even at that remote
period in the history of the subject, engaged the atten-
tion of agricultural chemists viz., the question of the
source of the plant's nitrogen a question which may
16 HISTORICAL INTRODUCTION.
be fitly described at the present hour as still the burn-
ing question of agricultural chemistry. 1
As soon as it was discovered that nitrogen was a
constituent of the plant's substance, speculations as to
its source were indulged in. The fact that the air
furnished an unlimited storehouse of this valuable
element, and the analogy of the absorption of carbon
(from the same source by plant-leaves), naturally sug-
gested to the minds of early inquirers that the free
nitrogen of the air was the source of the plant's
nitrogen. As, however, no direct experiments could
be adduced to prove this theory, and as, moreover,
nitrogen was found in the soil, and seemed to be a
necessary ingredient of all fertile soils, the opinion
that the soil was the only source gradually supplanted
the older theory. Little value, however, must be
attached to these early theories, as they can scarcely
be said to have been based on experiments of serious
value. Indeed it may be safely affirmed, in the light
of subsequent experiments, that it was impossible for
this question to be decided at this early period, from
the fact that analytical apparatus, of a sufficiently
delicate nature, was then wholly unknown. Indeed
it is only within the last few years that it has been
possible to carry out experiments which may be re-
garded as at all crucial. A short sketch of the
development of our knowledge of the relation of
nitrogen to the plant will be given further on.
1 See p. 40 to 45.
Cress, experiments with, 41.
Crimea, bones from, 360.
Cropped soils, nitrates in, 157 lost
by drainage in, 141.
Crops, capacity of, for assimilating
manures, 486 ; difference in root-
sy stems of, 488 ; manuring of com-
mon farm, 493 - 530 ; period of
growth of, 489 ; potash removed
in, 218 ; suited for sewage, 434 ;
variation in composition of, 490.
Crusius on phosphoric acid removed
from the farm, 207.
Crust guanos, 308, 379.
Cura?ao phosphates, 308, 330, 379.
Darmstadt experiments with basic
Darwin on origin of nitrate-fields, 335.
Daubeny on mineral sources of phos-
phoric acid, 200.
Davy, Sir Humphry, lectures of, on
agricultural chemistry, 17-19 ; on
heat and water absorbing and re-
taining properties of soils, 57 ; on
hygroscopic power of soils, 99.
Deherain, on nitrification, 52 ; on
nitrification in sulphate of am-
monia, 191 ; on rate of nitrification.
Denitrification, 177 ; conditions fav-
ourable for, 178 ; effected by bac-
Derby, Lord, introduction of Peruvian
guano by, 301.
Detmer on humus in soil, 47.
Dew, action of, on guano, 300 ; ex-
planation of, 77 ; most abundant
in summer, 78.
Dicalcic phosphate, 387 ; formula of,
398; molecular composition of,
398 ; percentage composition of,
Digby, Sir Kenelm, on value of
nitrates to plants, 45 ; theory of,
on plant-food, 6-8.
Diorite, phosphoric acid in, 202, 211.
Direct manures, 113.
Dissolved-bone compound, 372.
Dissolved bones, 368; composition
Dissolved guano, 310.
Dolerite, phosphoric acid in, 202, 211 .
Dolomite, phosphoric acid in, 202,
Downton experiments on sewage-
Drainage, average of thirteen years,
160 ; nitrates in, 160 ; nitrates lost
by, 140 ; phosphoric acid lost by,
206 ; potash lost by, 217.
Drainings of manure-heaps, analysis
Dried blood, 424 ; composition of,
424 ; manure for sugar-cane, 425 ;
potash in, 219 ; rate of nitrification
in, 192 ; source of nitrogen, 152 ;
suited for horticulture, 425.
Dried flesh, 425 ; nitrogen in, 425.
Dried leaves, as litter, 242 ; compo-
sition of, 242 ; nitrogen in, 242 ;
phosphoric acid in, 242 ; potash in,
Ducks' dung, analysis of, 331.
Duhamel and Hales, theory of, on
Dundonald, Earl, treatise by, on agri-
cultural chemistry, 13.
Dung and urine, composition of,
Dutrochet on absorption of plant -
Dyer, Dr Bernard, analyses of stable
manure by, 283 ; experiments on
peat as litter, 240 ; on nitrate of
soda as manure for mangolds, 349.
Earth, an adulterant of guano, 319 ;
composition of solid crust of, 102.
Ecuador, guano deposits at, 327.
Egyptian guano, nitrogen in, 329;
phosphoric acid in, 329.
Elbe, waters of, phosphoric acid in,
206 ; potash in, 217.
Elm-tree, water transpired by, 71.
Enderbury Island guano, 309, 328;
phosphoric acid in, 328.
English farming, 86.
Equalised guano, 311.
Essex, coprolites from, 374.
Estremadura phosphate, 375.
Ethylamine, nitrification in, 182.
Evaporation from soil, 71, 72, 98.
Excreta, amount of nitrogen in, 149,
292 ; composition of, 226, 292 ; dif-
ference in amount of, for food con-
sumed, 279 ; liquid, in farmyard
manure, 224 ; solid, in farmyard
manure, 224 ; solid, undigested
food in, 224 ; solid, voided by cows,
280, 292 ; solid, voided by horse,
292 ; solid, voided by oxen, 280 ;
solid, voided by sheep, 280, 292.
Factors for calculating manurial in-
gredients into their different com-
Falkland guano, 308 ; nitrogen in,
330 ; phosphoric acid in, 330.
Fallow-fields, nitrates formed in, 188.
Fanning Island guano, 328 ; phos-
phoric acid in, 330.
Farmyard manure, 223-292 ; action
of, on soils, 273 ; ammonia in, 258 ;
amount produced on farm per year,
252 ; analyses of, 259, 286 ; appli-
cation of, 264 ; ash of, 287, 288 ;
carbonic acid gas in, 258 ; classes
of constituents of, 224 ; compared
with artificials, 476; composition
of, 259 ; denitrification in, 179 ;
depth to plough to, 267 ; effect of,
on potatoes, 520 ; fertilising matter
in, 270 ; fire-fang in, 264 ; fresh,
composition of, 286, 288 ; functions
of, 268 ; heat in fermentation of,
78, 253 ; humates in, 259 ; hurnic
acid in, 258 ; inadequate source of
nitrogen to soil, 271 ; indirect in-
fluence of, 273 ; influence of, on
soil, 475 ; Lawes, Sir J ohn, on
composition of, 291 ; Lord Kin-
naird's experiments with, 289 ;
marsh-gas in, 258 ; mineral matter
in, 260 ; moisture in, 260 ; nitric
acid in, 259 ; nitrogen in, 260 ;
ratio of, to ash ingredients, 271 ;
organic matter in, 260 ; phosphor -
etted hydrogen in, 258 ; phosphoric
acid in, 260 ; potash in, 260 ; pro-
ducts of decomposition of, 257 ;
rate of application of, 275 ; re-
trogression of nitrogen in, 142 ;
rotten, composition of, 287, 288
value of, 261 ; rotting, effects of, on,
262 ; solid excreta in, 224 ; sul-
phuretted hydrogen in, 258 ; sup-
plemented with nitrogen, 271 ;
supplemented with phosphoric acid,
272 ; temperature, effect of, on soil,
79, 274 ; typical compost, 446 ;
ulmates in, 259 ; ulmic acid in,
258 ; unfavourable to certain crops,
477 ; urine in, 228 ; value of, 268 ;
variation in composition of, 223 ;
water in, 258.
Fatty acids in guano, 305.
Felspars, 103 ; albite, 103 ; composi
tion of, 103 ; labradorite, 220 ;
oligoclase, 103, 214, 220; ortho-
clase, 103, 214, 220; phosphoric
acid in, 211 ; potash manures, 213;
potash in, percentage of, 213, 220.
Ferment, aerobic, 173, 255 ; anaerobic,
Fermentation, ammonium carbonate
formed during, 245 ; in bones,
365 ; heat of, 79 ; of farmyard
manure, 253 ; of guano, 299 ; tem-
perature of, 256.
Fern, bracken, as litter, 241.
Ferric chloride, test for sulphocyan-
Fertilisers and Feeding Stuffs Act, 543.
Fertilising ingredients, amount of
soluble, in soil, 90 ; amounts re-
moved by different crops, 484, 485 ;
chemical condition of, in soil, 89 ;
lodge in seed, 491 ; in soil, 87.
Fertility, of the soil, 65-97 ; poten-
tial, of soil, 214, 549 ; properties
necessary for, 66 ; supply of oxy-
gen necessary for, 81.
Field experiments, 545, 548 ; educa-
tional value of, 547 ; on rate of
Finger-and-toe prevented by lime,
Fire-fang in farmyard manure, 264.
Fischer on absorption of plant-food,
Fish-guano, 320-323 ; application of,
323 ; consumption of, 152 ; manu-
facture of, 321 ; nitrogen in, 321 ;
phosphoric acid in, 321 ; production
of, 322 ; source of nitrogen, 152 ;
value of, 322.
Fixers, 246 ; chemical reactions with,
Fleece, potash in, 217.
Fleischer, Professor, on solubility of
Flint Island guano, 309.
Flitcham experiments on growth of
Floated bones, 362, 365.
Florida phosphate, 378.
Fluorapatite, composition of, 210.
Food, consumed by pigs, 281 ; dry
matter of, voided in dung, 228 ;
percentage of, in excrements, 281.
Food-constituents, plant, necessary
for nitrification, 170. .
Forbes, David, on nitrate - fields of
Forest-soils, absence of nitrification
Fowl-dung, 320, 326; analysis of,
Fownes on phosphoric acid in rocks,
Frankland, P. F., experiments on
nitrification, 52, 167, 198.
Franklin, Benjamin, experiment of,
with gypsum, 462.
Frey Bentos, meat-meal guano from,
Gallopagos Islands, guano deposits
Garden earth, absorptive power of,
98 ; ammonia in, 128.
Gas-liquor, ammonia in, 353.
Gas-works, ammonia from, 353, 358.
Gases, absorbed by soils, 81 ; present
in soil, 100.
Gazzeri on retention by soil of plant -
Geese-dung, analysis of, 331.
Geic acid in humus, 47.
Gelatin, nitrification in, 182 ; from
Germany, agricultural research in,
32 ; bones imported from, 360 ;
manufacture of meat-meal guano
Germination, influence of temperature
on, 76 ; oxygen necessary for, 81.
Gilbert, Sir J. Henry, on barley-
manuring, 496 ; on Liebig's mineral
theory, 28 ; on manuring of po-
tatoes, 520 ; Presidential address
of, 61 ; and see Lawes and Gilbert.
Glauber on artificial production of
Glycin, assimilated by plants, 47.
Glycocoll, experiments with, 46.
Gneiss, 106 ; phosphoric acid in, 207.
Grandeau, Professor, on forms of
plant-food in soil, 107 ; on loss of
phosphoric acid, 207.
Granite, 105 ; in guano, 303 ; phos-
phoric acid in. 202, 211 ; potash in,
Grass, Bangor experiments on, 508 ;
effect of manure on, 505 ; influence
of farmyard manure on, 506 ; man-
uring of, 504-510.
Gray, Asa, on transpiration by plants,
Great Cayman guano, 379.
Green manures, 113.
Grouven on guano, 313.
Guanape Island guano, 302, 327 ;
nitrogen in, 329 ; phosphoric acid
Guanine, 304 ; experiments with, 46.
Guano, 293-331 ; action of, as a man-
ure, 312 ; adulteration of, 318 ; ap-
plication of, 315 ; bat, 325 ; com-
position of, 305, 329 ; crust, 308 ;
deposits of the world, 327 ; dis-
solved, 310; equalised, 309; fer-
mentation of, 299 ; fertilising con-
stituents in, 314; fish, 320-323;
importance of, in agriculture, 293 ;
inequality in composition of, 309 ;
influence of, on farming, 294 ; meat-
meal, 324 ; mode of application of,
315 ; nitrification in, rate of, 192 ;
nitrogenous, 300-308 ; origin of,
297; Peruvian, 300-306; phos-
phatic, 308 ; quantity to apply,
317 ; rectified, 311 ; so-called, 320 ;
source of phosphoric acid, 202 ;
source of potash, 219 ; value of, as
a manure, 296 ; variation in com-
position of, 299.
Gulf of Mexico, guano deposits at,
Gulls, guano from, 297.
Gunning on sources of plant-nitrogen,
Gunpowder, exports of, 149 ; nitrogen
lost in, 149 ; production, annual,
of, 149 ; saltpetre in, 149, 333.
Gypsum, 462-464 ; absorptive power
of, 98 ; action of, mode of, 462 on
nitrification, 173 ; an adulterant of
guano, 319 ; as a fixer, 246, 247,
285 ; decomposes double silicates,
463 ; favourable to clover, 464 ;
as an oxidising agent, 464.
Hales, Stephen, theory of, on plant-
Hampe, Dr, on nitrogen in plants, 46.
Harting on sources of plant-nitrogen,
Heat, of soils, 76-78 ; of fermenta-
Heiden, Dr, on application of farm-
yard manure, 265 ; on fixation of
bases and acids by soil, 59 ; ou loss of
ammonia from dung, 249 ; on per-
centage of food voided by animals,
253 ; on straw as litter, 244, 249.
Hellriegel, on amount of water in
soils, 75 ; on barley, 498 ; on ni-
trogen in plants, 44.
Helmout, Van, theory of, on source
of plant-food, 4.
Henslow, Professor, on coprolites,
Heraus on organisms in soil, 95.
Herbage, effect of manure on, 505.
Herrings as manure, 321.
Herve-Mangon, experiments on action
of light on plants by, 38.
Hilgeustock on tetracalcic phosphate,
Hippuric acid, experiments with, 46 ;
in farmyard manure, 257.
Hire, De la, on evolution of gases by
Hofmeister on horse excrements,
Hoof-guano, source of nitrogen, 152.
Hoofs and horns, manure from, 425.
Hops, manuring of, 528 ; potash re-
moved by, 217 ; slow-acting man-
ures benefit, 528.
Horn, capable of nitrification, 182 ;
as manure, 425 ; nitrogen in, 426 ;
phosphoric acid in, 426.
Horse-dung, alkalies in, 226 ; com-
position of, in dry state, 227 ; hot,
225 ; nitrogen in, 225, 226 ; phos-
phoric acid in, 226 ; water in, 225,
Horse-manure, 242 ; amount produced
per day, 243 ; amount produced per
year, 243 ; analyses of. 283 ; dry
matter in, 243 ; dry nature of, 245 ;
fermentation rapid in, 245 ; mineral
matter in, 243; nitrogen in, 243,
Horse-urine, alkalies in, 230 ; com-
position of, in dry state, 231 ; fer-
tilising ingredients in, 232 ; nitrogen
in, 230 ; phosphoric acid in, 230 ;
water in, 230.
Hosaus on assimilation of ammonia,
Howland Island guano, 309, 328 ;
phosphoric acid in, 330.
Huanillos, guano from, 302, 327 ;
nitrogen in, 330 ; phosphoric acid
Hueppe on organisms in soil, 95.
Hughes, John, on bracken-fern as
litter, 241 ; on composition of
Humates in farmyard manure, 259.
Humboldt, A., discovery of Peruvian
guano by, 300.
Humic acid in farmyard manure,
258 ; in humus, 47.
Humin in humus, 47.
Humus, absorptive power of, 68, 98 ;
evaporation from, 99 ; nature of, in
soil, 47 ; soils improved by addi-
tion of, 273.
Huou Island guano, 309, 328 ; phos-
phoric acid in, 330.
Huxtable and Thompson on retention
of plant-food by soil, 57.
Hydrated silicates, 107, 459.
Hydrochloric acid as a fixer, 245.
Hydrogen, amount of, in plants, 40 ;
source of, in plants, 40.
Hygroscopic power of soils, 75.
Ichaboe guano, 307 ; nitrogen in,
329 ; phosphoric acid in, 329.
Independence Bay guano, 302, 327 ;
nitrogen in, 329 ; phosphoric acid
India, nitre soils of, 162.
Indirect manures, 113, 114, 449-473.
Ingenhousz, John, experiments by, on
nitrogen in plants, 41 ; on oxygen
evolved by plants, 12.
Insoluble phosphate, 386; value of, 396.
Iodine, in ash of plants, 55 ; in
nitrate of soda, 340, 342.
Iquique, nitrate of soda from, 333.
Iron in ash of plants, 54 ; necessary
for plant-growth, 55 ; reversion in
superphosphates caused by, 390,
Iron-works, ammonia from, 353, 355,
Irrigation, 431 - 433 ; intermittent,
434 ; subsoil, 432.
Jamieson, Professor, experiments
with coprolites, 380.
Jarvis Island guano, 309, 328 ; phos-
phoric acid in, 330.
Jersey, manuring of potatoes in, 521.
Johnson^ Professor S. W., on appli-
cation of superphosphate, 395 ; on
Earl Dundonald, 13 ; on nitrogen
in buffalo-horn shavings, 426 ; on
nitrogen in soils, 123 ; on solubil-
ity of basic slag, 408 ; value of
organic nitrogen to plant, 46.
Jurgensen on nitrogen in excreta, 234.
Kainit, as a fixer, 247 ; potash in,
percentage of, 214, 220, 421 ; rate
of application of, 423.
Kaolin clay, analysis of, 104.
Karmrodt/ analysis of Chincha Island
guano, 305 ; of concretionary nod-
Karnallite, potash in, 220.
Kellner, experiments on nitrification
Kelp, potash in, 420.
Kinuaird, Lord, experiments by, with
farmyard manure, 289.
Kitchen-garden soil, nitrogenous mat-
ter in, 122.
Knop on condition of nitrates in
Koosaw River, phosphates from, 376.
Kreatin assimilated by plants, 47.
Kuria Muria guano, 309, 328.
Labrador, guano deposits at, 328.
Labradorite, 214 ; potash in, 220.
Lacepede Island guano, 309, 328 ;
phosphoric acid in, 330.
Lahn phosphate, 379.
Lava, phosphoric acid in, 202, 211.
Lawes, Sir J. B., and Gilbert, early
researches of, at Rothamsted, 34 ;
experiments with farmyard man-
ure, 271 ; experiments with Per-
uvian guano, 301 ; inauguration of
Rothamsted experiments by, 33 ;
on composition of farmyard man-
ure, 291 ; on manuring of wheat,
483 ; on motion of plant's sap, 56 ;
on percentage of food in excreta,
233 ; on rate of nitrification, 186 ;
on sources of plant-nitrogen, 43 ;
on sulphate of ammonia, 356 ; on
unexhausted manures, 550, 557-559.
Lawes, Sir J. B., experiments with
guano by, 301 ; manufacture of
superphosphate by, 382 ; on ap-
plication of superphosphate, 395 ;
on bones, 359 ; on composition of
farmyard manure, 291 ; on farm-
yard manure, 477 ; on loss of ni-
trates, 142 ; on sources of nitrogen,
Leather, as manure, 428 ; nitrogen
Leaves, dried, as litter, 242; nitro-
gen in, 242 ; phosphoric acid in,
242 ; potash in, 242.
Legrange, Charles, on extent of ni-
Leguminous plants, benefited by basic
slag, 414 by potash, 523 ; fixation
of free nitrogen by, 42 ; gain of
nitrogen with, 135 ; manuring of,
522-527, 530 ; nitrogenous manures
hurtful to, 523.
Lehmann on ammonia as plant-food,
Leipzig, bones from, 361.
Leones, guano deposits at, 327.
Leucite, potash in, 220.
Lias chalk, phosphoric acid in, 211.
Liebig, criticism of humus theory by,
25 ; dissolved bones discovered by,
361 ; first report to British Associ-
ation, 24 ; manufacture of super-
phosphate from bones by, 359 ;
mineral theory of, 26-29 ; on am-
monia as a manure, 352 ; on im-
portation of bones by Britain, 360 ;
researches of, in agricultural chem-
istry, 23-32 ; services of, to agri-
cultural chemistry, 31 ; theory of
manures by, 29 ; theory of, on ro-
tation of crops, 29.
Light, action of, on plant-growth, 38.
Lime, 449-461 ; abundant occurrence
of, 452 ; action of, 461 contradic-
tory, 450 not thoroughly under-
stood, 449 on nitrogenous organic
matter, 460 on soil's texture, 455 ;
antiquity of, as a manure, 449 ;
binding effect of, 457 ; biological
action of, 459 ; caustic, 453 ; chem-
ical action of, 457 ; decomposes
minerals, 458 ; different forms of,
453 ; effect of, on soils, 112 ; fixed
by soils, 58 ; in ash of plants, 54 ;
mechanical functions of, 455 ; mild,
453 ; necessary for nitrification,
171, 459 for plant-growth, 55,
450 ; neutralises acidity in soils,
458 ; phosphates of, 385-388 ; pig
excrements contain, 281 ; prevents
clay puddling, 456 ; returned to
soil, 452 ; soils contain, 450-452.
Limestone, analyses of, 106 ; evapora-
tion of water from, 99 ; occurrence
Linseed, imports of, 153 ; manurial
constituents of, 282.
Linseed-cake, manurial constituents
Liquid manure, 442-444.
Lithia in ash of plants, 55.
Litter, loam as, 239 ; peat as, 240 ;
straw as, 236 ; uses of, 236.
Lloyd on fattening animals, 253.
Loam, as litter, 239 ; evaporation of
water from, 99 ; poor in fertilising
Lobos, guano deposits at, 327.
Lobos de Afuera guano, 302, 327.
Macabi Island guano, 302, 327 ; ni-
trogen in, 329 ; phosphoric acid in,
Maercker, Professor, on destruction
of nitrifying organisms, 177.
Magnesia, fixed by soils, 58 ; in ash
of plants, 54 ; in pig excrements,
281 ; necessary for nitrification,
171; necessary for plant -growth,
55 ; sulphate of, as a fixer, 246, 285.
Maize, absorbs ammonia, 352 ; fer-
tilising ingredients removed from
soil by, 485 ; manurial constituents
in, 282 ; source of nitrogen, 153.
Maiden Island guano, 309, 328 ;
phosphoric acid in, 330.
Malpighi on importance of atmo-
spheric air for germination, 39.
Malt-dust, manurial constituents in,
Manganese, oxide of, in ash of plants,
Mangels, fertilising ingredients re-
moved from soil by, 485 ; guano a
manure for, 318 ; mauurial con-
stituents in, 282 ; manuring of,
346, 511, 513, 514 ; Rotham-
sted experiments on growth of,
Manitoba soils, nitrogen in, at various
depths, 156 ; rate of nitrification
Manure, cow, 247 ; farmyard, 223-
292 ; horse, 243 ;' liquid, 442-444 ;
meaning of word, 109 ; pig, 250 ;
sewage, 430-441 ; sheep, 251 ; stable,
from peat-moss, 283 wheat-straw,
Manures, action of, 61 ; analysis of,
interpretation of, 539-544 ; appli-
cation of, 474-492 ; method of, 531-
538 ; cash prices of, 555 ; equal
distribution of, 531 ; functions of,
109 ; increase soil - fertility, 474 ;
intrinsic value of, 545 ; lasting
effects of, 483 ; methods of valuing,
544 ; minor artificial, 424 - 429 ;
mixing of, 531-538 ; nitrogenous,
293 - 359 ; phosphatic, 359 - 417 ;
potassic, 418 - 423 ; quantities of,
applied to oats, 504 ; unexhausted,
549-552, 558 ; units for determining
commercial value of, 554 ; valuation
of, 539-559 ; value of, deduced from
experiments, 548 ; various classes
Manurial constituents of various
Manurial ingredients, unit value of,
Manuring of, barley, 495-498 ; beans,
525-527, 530 ; cabbages, 528 ; cere-
als, 493-504 ; clover, 524 ; common
farm crops, 493-530 ; grass, 504-
510 ; hops, 528 ; leguminous crops,
522-528 ; mangels, 511, 513, 514 ;
oats, 493 - 504 ; peas, 527 ; pota-
toes, 517-522 ; roots, 510 - 517 ;
turnips, 510, 511, 513-517 ; wheat,
Maraeaibo guano, nitrogen in, 330 ;
phosphoric acid in, 330.
Marl, phosphoric acid in, 211.
Marsh -gas from farmyard manure,
Meadow -hay, fertilising ingredients
removed from soil by, 485 ; man-
urial constituents in, 282 ; Roth-
amsted experiments on manuring
Meadow-land, benefited by basic slag,
414, 508 ; manuring of, 508 ; Nor-
folk experiments on, 509.
Meat-meal guano, 320, 324 ; com-
position of, 152 ; imports of, 324 ;
manufacture of, 324 ; nitrogen in,
324 ; phosphoric acid in, 324 ; rate
of nitrification in, 192 ; source of
nitrogen, 152 ; value of, 324.
Mechi on liquid manure, 442.
Mejillones guano, 309, 327 ; phos-
phoric acid in, 330.
Mene, on sources of plant - nitrogen,
Menhaddo. guano manufactured from,
Mexico phosphate, 308, 328.
Mica, analysis of, 105 ; potash in,
Micro-organisms, convert ammonia
into nitrous acid, 167 ; convert
nitrous acid into nitric acid, 168 ;
effect fermentation, 80 ; effect fix-
ation of free nitrogen, 44 ; effect
nitrification, 161 ; oxidising power
Mild lime, 453.
Milk, nitrification in albuminoids of,
182 ; nitrogen removed in, 147 ;
phosphoric acid removed in, 207 ;
potash removed in, 218.
Mineral phosphates, 373-381 ; value
of, as a manure, 380.
Mineral salts necessary for nitrifica-
Minor artificial manures, 424-429.
Mixing manures, 532-538 ; ammonia
lost in, 533 ; nitric acid lost in,
536 ; phosphates reverted in, 536.
Moisture, atmospheric, action on
guano, 300 ; in farmyard manure,
260 ; in manures, 543 ; necessary
for nitrification, 52, 176.
Mona guano, 309.
Mond, Ludwig, on nitrogen in coal,
Monks guano, 327; phosphoric acid
Monocalcic phosphate, 386 ; formula
of, 398 ; molecular composition of,
398 ; percentage composition of,
398 ; reversion of, with iron and
alumina compounds, 399 with
tricalcic phosphate, 399.
Mulder on humus in soil, 47, 126.
Miiller, A., on nitrogen in soil, 121,
Munro, Dr J. M. H. , on nitrification,
52 ; on sewage-sludge as manure,
439 ; on urine voided, 292.
Muntz, on ammonia in air, 118 ; on
nitrifying organisms in soil, 180 ;
on oxidising power of micro-organ-
Muriate of potash, application of,
423 ; forms calcium chloride, 422 ;
harmful effects of, 421 ; more con-
centrated than sulphate, 422.
Navassa phosphate, 308, 328, 379.
Nesbiton composition of guano, 301,
New Granada, guano deposits at, 327.
New Zealand, meat-meal guano from,
Nile, nitrates in waters of, 159.
Nitrate - fields, appearance of, 340 ;
origin of, 334.
Nitrate of soda, 332 - 351 ; amount
exported from Chili, 151, 332, 351 ;
amount imported into Britain, 151,
351 ; appearance of fields of, 340 ;
application of, 347 ; Chili and Peru
chief source of, 161 ; composition
of, 343 ; crops suited by, 346 ; dis-
covery of deposits of, 333 ; extent
of deposits of, 342 ; encourages deep
roots, 344 ; formation of fields of,
334-340 ; method of applying, 347 ;
method of mining, 341 ; nitric acid
in, source of, 337 ; nitrogen in,
percentage of, 343 ; not an exhaust-
ing manure, 345 ; origin of fields of,
334 ; properties of, 343 ; quantity
to apply, 348 ; shipments of, 351 ;
soils benefited by, 348 ; source of
nitrogen, 150 ; top - dressing with,
Nitrates, amount lost by drainage,
140 ; amount produced at different
times, 189 ; amount in soil, 129 ;
conditions diminishing loss of, 139 ;
constantly formed in soil, 138 ; in
barley -soils, 158 ; in cropped soils,
130, 157 ; in drainage-waters, 160,
188 ; in fallow-soils, 129 ; in man-
ured wheat-soils, 131, 157 ; in soil,
129, 162 ; lost by drainage, 137 ;
most formed in summer, 139 ;
nitrogen as, in Rothamsted soils,
198 ; position of, in soil, 188 ;
quantity formed in fallow -fields,
Nitre, beds, 163 ; occurrence of, 162 ;
soils of India, 162.
Nitric acid, amount of, supplied to
soil by rain, 155 ; derived from sea-
weed, 337 ; formed from ammonia,
118 ; formed from nitrous acid, 168 ;
in farmyard manure, 259 ; in soil,
128 ; lost in mixing manures, 536 ;
most important nitrogen compound
for plants, 161 ; relation of, to
plants, 50 ; source of, in nitrate
of soda, 337.
Nitrification, 51, 52, 161-198 ; action
of gypsum on, 173 ; alkalinity
necessary for, 172 ; in asparagin,
182 ; bearing of, on agriculture,
193 ; in bones, 182 ; cause of, 165 ;
conditions favourable for, 170 ;
deuitrification, 177 - 179 ; effected
by micro-organisms, 51, 167 ; in
ethylamine, 182 ; in fallow-fields,
184 ; food - constituents necessary
for, 170 ; field experiments on rate
of, 187 ; in gelatin, 182 ; in horn,
182 ; laboratory experiments on
rate of, 185 ; in manures, 190, 192 ;
in milk albuminoids, 182 ; mineral
salts necessary for, 52 ; moisture
necessary for, 52, 176 ; old theories
on, 196 ; organic matter not neces-
ary for, 169, 196 ; oxygen necessary
for, 52, 173 ; plant-roots promote,
181 ; in rape-cake, 182 ; rate of,
183 ; rotation of crops, bearing of,
on, 195 ; soil best suited for, 192 ;
in subsoils, conditions favourable
for, 181 ; substances capable of, 181;
in summer, 183 ; sunlight, effect
of, on, 176 ; temperature necessary
for, 52, 175 ; in thiocyanates, 182 ;
hi urea, 182 ; in wool, 182.
Nitrifying organisms, depth found
at in soil, 180 ; distribution of, in
soil, 179 ; effect of poisons on, 176 ;
organic matter not required by, 169.
Nitrogen, 115-160 ; absorbed by soil,
81, 131 ; accumulates in pastures,
134 ; in air, 116 ; as ammonia in
soils, 127 ; amount of, in plants,
40; amount of, in soil, 123; arti-
ficial supply of, 150 ; in bat guano,
325 ; in bones, 363, 364 ; combined,
in air, 118 ; combined, in rain, 119,
155 ; condition of, in manures, 540 ;
converted into nitrates in soil, 51 ;
in cow - dung, 226 - 228 ; in cow
excrements, 278 ; in cow - urine,
230 ; difference between surface and
subsoil, 126 ; different forms of, 45,
116 ; dissolved in rain, 131 ; in
dried blood, 424 ; in farmyard
manure, 260; in fish -guano, 321;
fixation of free, 136 ; forms of, in
plants, 491 ; free, relation of, to
plant, 117; gain of, with legumin-
ous crops, 135 ; in guanos, 329 ;
in hoofs and horns, 426 ; in horse-
dung, 226 - 228 ; in horse - man-
ure, 243 ; in horse - urine, 230 ;
importance of, in soil, 88 ; in lean
flesh, 424 ; in leather, 428 ; least
abundant of manurial ingredients
in soil, 271 ; loss of, artificial sources
of, 144 ; loss of, by crops, 144 ;
loss of, on farm, 146 ; loss of,
sources of, 137-150 ; loss of, total
amount of, 142 ; lost in the arts,
148; lost in free condition, 141;
lost in treating farmyard manure,
146; lost in milk, 147; lost by
retrogression, 142 ; in Manitoba
soils, 156 ; in meat - guano, 324 ;
nature of, in soil, 124 ; as nitrates
in soil, 128 ; as nitrates in cropped
soils, 130, 157 ; as nitrates in Eoth-
amsted soils, 198 ; as nitrates
in wheat - soils, 157 ; in nitrate of
soda, 343 ; nitric, in soil, 128 ;
organic, absorbed by plants, 47 ;
organic, in soil, 125 ; original
source of, m soil, 133 ; in oxen
excrements, 280 ; in pasture-lands,
158 ; peat-soils richest in, 123 ; in
Peruvian guano, 302, 306, 307, 329 ;
in pig-dung, 226-227 ; position of,
in agriculture, 115-160; relative
manurial value of, 556; Rotham-
sted experiments on, 115 ; in
scutch, 427 ; in sewage, 431 ; in
sewage-sludge, 439 ; in sheep -dung,
226 - 228 ; in sheep excrements,
280 ; in sheep-urine, 230 ; in soil,
120 ; in soil, portion of, easily
nitrifiable, 187 ; in soils at various
depths, 156 ; in soot, 428 ; source
of, in plants, 15, 16, 40-52 ; sources
of soil, 131-137 ; in straw, 237, 243 ;
in subsoil, 121 ; in surface - soil,
121 ; in swine-urine, 230 ; in wool-
len rags, 427.
Nitrogenous guano, 300-308, 329.
Nitrogenous manures, application of,
478 ; benefit cereals, 494 ; hurtful
to leguminous crops, 523.
Nitrogenous organic substances, in
Chincha guano, 305 ; in concretion-
ary nodules, 328.
Nitros omon as, 167.
Nitrous acid, converted into nitric
acid, 168 ; formed from ammonia,
Nobbe, on fixation of free nitrogen,
136 ; on potash in soil, 108.
Nollner on origin of nitrate - fields,
Norfolk, coprolites from, 374 ; experi-
ments on barley, 497 on meadow-
land, 509 on turnips, 513.
North America, guano from, 298, 328.
Norwegian apatite, 375.
Oak-tree, water transpired by, 71.
Oat-straw, composition of, 238 ; man-
urial constituents in, 282.
Oats, Arendt's experiments with, 503 ;
avenine in, 503 ; fertilising ingre-
dients removed from soil by, 485 ;
hardy crop, 502 ; manurial con-
stituents in, 282 ; manuring of,
501-504 ; nitrogen removed in crop
of, 148 ; require mixed nitrogenous
manures, 502 ; source of nitrogen,
153 ; Rothamsted experiments on
growth of, 567.
Ohlendorff, introduction of dissolved
guano by, 311.
Oilcakes, imports of, 153 ; source of
Oil-seeds, source of nitrogen, 153.
Oligoclase felspars, 103, 214 ; com-
position of, 103 ; potash in, 220.
Organic matter, in bones, 363 ; in
dung, 228, 260 ; in manures, 543 ;
not necessary for nitrifying organ-
Orthoclase felspars, 103, 214 ; com-
position of, 103 ; potash in, 220.
Ox-dung, fertilising ingredients in,
for food consumed, 228.
Ox-urine, fertilising ingredients in,
Oxalic acid in guano, action of, 330.
Oxen, excrements of, 280 ; food aided
by, 280 ; solid excreta voided by,
280 ; urine voided by, 280.
Oxidation, 79 ; products of, 79, 80.
Oxygen, absorbed by plant-roots, 81 ;
absorbed by soil, 81 ; evolved by
plants, 11 ; necessary for fertility,
81 ; necessary for nitrification, 52,
173 ; percentage of, in plants, 39 ;
source of, in plants, 39.
Pabellon de Pica, guano from, 298,
302, 327; nitrogen in, 330; phos-
phoric acid in, 330.
Pacific Islands, guano from, 298.
Pacific Ocean, sea-weed in, 339.
Palagonite as potash manure, 213.
Palm-kernel meal, manurial constit-
uents in, 282.
Pasteur, on fermentation in urine,
255 ; on nitrification, 166.
Pastures, accumulation of nitrogen in,
134 ; benefited by basic slag, 414 ;
deficient in lime, 451 ; effect of
manure on herbage of, 505 ; nitro-
gen in, 158 ; permanent, 138, 194
manuring of, 509 ; season influ-
ences, 507 ; soil influences, 507.
Patagonian guano, 308, 327 ; nitrogen
in, 330 ; phosphoric acid in, 330.
Patent phosphate meal, 405.
Patillos, guano deposits at, 327.
Patos Island, guano deposits at, 328 ;
phosphoric acid in, 330.
Patterson on superphosphate, 399.
Payen and Boussingault on composi-
tion of dried flesh, 425.
Peas, mamirial constituents in, 282 ;
manuring of, 527 ; phosphorus in,
205 ; source of nitrogen, 153.
Peat, absorbing properties of, 239 ;
adulterant of guano, 317 ; analysis
of stable-manure from, 281 ; litter,
239 ; nitrogen in, 240 ; retaining
properties of, 240 ; soils, 123.
Pelicans, guano from, 297.
Penguin Island guano, 330 ; nitrogen
in, 330 ; phosphoric acid in, 330.
Penguins, guano from, 297.
Percival on carbonic acid in plants,
Peru, guano deposits in, 327 ; guano
first used in, 297 ; nitrate of soda
from, 161, 162.
Peruvian guano, 300-306 ; appearance
of, 303 ; composition of, 304-306 ;
deposits of, 301 ; imports of, 151,
297 ; source of nitrogen, 151.
Peters and Eichhorn on solvent power
of salt, 471.
Petzholdt on sources of plant's nitro-
Pfeffer on action of light on plant -
Phoenix Island guano, 309.
Phosphate of iron in Chincha guano,
Phosphate of lime, in Algerian phos-
phate, 379 ; in apatite, 374 : in
Belgian phosphate, 377 ; in bones,
364 ; in Cambridge coprolites, 374 ;
in Carolina phosphates, 376 ; in
crust guanos, 379 ; in Estremadura
phosphate, 375 ; in Florida phos-
phate, 378 ; hi French phosphates,
379 ; in Lahn phosphates, 379 ; in
Somme phosphate, 378 ; reverted in
mixing manures, 537.
Phosphates of lime, 385-388, 398 ; im-
portance of mechanical condition
Phosphates, mineral, 373-381 ; imports
of, 381 ; value as a manure, 380.
Phosphatic guano, 308, 330.
Phosphatic manures, application of,
Phosphoretted hydrogen in farmyard
Phosphoric acid, 199-211 ; in ash of
plants, 54 ; in basic slag, 404 ; in
bat guano, 325 ; in bones, 363 ;
condition of, in soil, 203 ; in cow-
dung, 226-228; in cow excre-
ments, 280 ; in cow-urine, 230 ; in
farmyard manure, 260 ; in fish-
guano, 321 ; fixed by soils, 58 ; gain
of, 208 ; in guano, percentage of,
329, 330 ; guano a source of, 202 ;
in hoofs and horns, 426 ; in horse-
dung, 226-228; in horse - nrine,
230; importance of, 88; loss of,
artificial sources of, 206 by drain-
age, 206 in farmyard manure, 208
in milk, 207 in sewage, 208
sources of, in agriculture, 205 ; in
meat-guano, 324 ; mineral sources
of, 200; necessary for plant-growth,
55 ; occurrence of, in animals, 205
in nature, 199 in plants, 204 in
soil, 203 ; in oxen excrements, 280 ;
in pig-dung, 226, 227 ; in pig excre-
ments, 281; in pig-urine, 230; po-
sition of, in agriculture, 199-211 ;
relative trade values of, in manures,
400 ; in rocks, 202, 211 ; in sewage-
sludge, 441; in sheep-dung, 226
228 ; in sheep excrements, 280 ;
in sheep-urine, 230; statement of,
in analyses of manures, 541.
Phosphorite, 201, 374.
Phosphorus, in albuminoids, 205; in
animals, 205; in beans, 205; in
peas, 205; in plants, 204; in pig-
Physical properties of soils, 66-87.
Pichard on action of gypsum on ni-
Pig-dung, composition of, 226 ; in dry
Pig excrements, 281 ; composition of,
Pig-manure, 250; amount produced
per day, 251 ; mineral matter in,
251 ; nitrogen in, 251 ; poor in
Pig-urine, composition of, 230 in dry
Pigeon-dung, 320, 325; analysis of,
Pigs, excrements of, 281; food con-
sumed by, 281.
Pisagua, nitrate-fields at, 340.
Plant, action of light on, 38 ; amount
of hydrogen in, 40 nitrogen in,
40 oxygen in, 40 ; ash constituents
of, 53-55; carbon fixed by, 37, 38;
food, absorption of, by, 55; phos-
phoric acid in, 204 ; potash in, 216 ;
proximate composition of, 36; re-
lation of ammonia to, 48-50 ; source
of hydrogen in, 40 nitrogen in,
40-52 oxygen in, 39, 40.
Plant-food, absorption of, 490; amount
of soluble, in soil, 100 ; early theories
on source of, 4; retained by soil,
Plant-roots, grow downwards, 84;
nitrification promoted by, 181;
openness required by, 83; room
required by, 85; soil in relation
Pliny, on lime as a manure, 449 ; on
salt as a manure, 465.
Pockets a source of phosphoric acid,
Poisons, effect of, on nitrifying organ-
Polstorff on ash constituents of plants,
Polyhallite, potash in, 220, 420.
Porphyry, in guano, 303 ; phosphoric
acidX 202, 211.
Potash, 212-220, 418-423; in ash of
plants, 54 ; in barilla, 420 ; chloride
of, 218 ; condition of, in soil, 216 ;
in cows' excrements, 280 ; in drain-
age-waters, 217 ; in farmyard man-
ure, 260 ; in felspars, 220 ; in fleece,
217 ; fixed by soils, 58 ; importance
of, in soil, 88; in kelp, 420; less
important than phosphoric acid,
212 ; manures, 218, 418-423 ; muri-
ate of, 218, 421 ; necessary for nitri-
fication, 171 ; necessary for plant-
growth, 55; occurrence of, 213; in
ocean, 213; in oxen excrements,
280; in pig excrements, 280; in
plants, 216 ; position of, in agricul-
ture, 212-220; relative manurial
value of, 556; Scottish soils sup-
plied with, 419 ; in sheep excre-
ments, 280; soda replaces, 466;
sources of loss of, 217 ; in Stassfurt
salts, 214 ; statement of, in analyses
of manures, 542 ; in sugar-beet ref-
use, 219 ; sulphate of, 218, 421 ; in
wood-ashes, 218, 220, 419.
Potash manures, 218, 418-423 ; appli-
cation of, 422, 480 rate of, 423;
barilla , as, 420; crops suited for,
423 ; relative importance of, 418 ;
soils suited for, 423; sources of,
419 ; Stassfurt salts as, 420 ; wood-
ashes a source of, 419.
Potassium phosphate in concretionary
Potassium sulphate, in Chincha guano,
305 ; in concretionary nodules, 328.
Potatoes, effect of farmyard manure
on, 520 ; fertilising ingredients re-
moved from soil by, 485; grown
with covered manure, 289 ; High-
land Society's experiments on, 518 ;
manurial constituents in, 282 ; man-
uring of, 517-522 in Jersey, 529
influences composition of, 521 ; po-
tash removed in, 217 ; Rothamsted
experiments on, 519, 571.
Precipitated ammonium phosphate in
concretionary nodules, 328.
Precipitated phosphate, 330, 387.
Precipitation, treatment of sewage by,
Priestley, discovery of evolution of
oxygen by plants, 11 ; on nitrogen
in plants, 40.
Prussiate of potash, manufacture of,
Pugh on sources of plant-nitrogen,
Punta de Lobos guano, 302 ; nitrogen
in, 303 ; phosphoric acid in, 303.
Punta de Patillos, guano deposits at,
Pyroxene, potash in, 220.
Quartz, evaporation of water from,
Queensland, meat-meal guano from,
Quercitan, experiments of, with
Rape -cake, capable of nitrification,
182 ; manurial constituents in, 282.
Rape-seeds, imports of, 153.
Raza Island guano, 328 ; phosphoric
Rectified guano, 311.
Relative trade values of phosphoric
Resin in guano, 305.
Retentive power of soils for water,
Retrogression, nitrogen lost by, 142.
Reverted phosphates, 389-391 ; deter-
mination of amount of, 391 ; for-
mation of, 387 ; value of, 391.
Rhine, nitrates in waters of, 158.
Rice-meal, an adulterant of guano,
319 ; manurial constituents of, 282.
Rocks, phosphoric acid in, 202.
Roots, influence of manures on com-
position of, 512 ; manuring of, 510-
522 ; Norfolk experiments on, 513 ;
potash removed in, 217.
Rotation of crops, bearing of, on
Rotations, phosphoric acid in, 290 ;
potash removed in, 290.
Rothamsted, alternate Avheat and
bean rotation at, 524 ; ammonia in
rain at, 49 ; barley experiments at,
566 ; Broadbalk Field, alteration in
composition of, 159 manuring of,
159 produce of wheat on, 159 ;
early experiments at, 33-36 ; ex-
periments, 560 - 572 ; experiments
with nitrate of soda at, 347 ; ex-
periments on nitrogen question at,
115 mangel - wurzel, 568 oats,
567 potatoes at, 519 value of
nitrogen in farmyard manure, 271 ;
increase of nitrogen with manures
at, 137, 513 ; nitrates in barley-
soils of, 158 ; nitrates in cropped
soils of, 130, 157 ; nitrates in drain-
age of, 189 ; nitrates in wheat-soils
of, 131, 157 ; nitrogen as nitrates
in soils of, 129, 198 ; nitrogen, de-
crease of, in soils, 159 ; nitrogen in
pasture at, 126 ; pasture, increase
of nitrogen in, 158 ; retrogression
of nitrogen at, 142 ; soil, nature of,
561 nitrogen in, at various depths,
156 ; total amount of nitrogen lost
at, 142 ; turnip experiments at,
568 ; unmanured fallow-land loses
nitrogen by drainage at, 141 ; wheat
experiments at, 500, 562-565.
Roy on sources of plant-nitrogen, 42.
Rubidia in ash of plants, 55.
Ruffle, John, on superphosphate, 388.
Rye, manurial constituents in, 282.
Rye-grass suited for sewage, 435.
Rye-straw, summer, composition of,
238 ; winter, composition of, 238.
St Helena, experiments at, with
Peruvian guano, 301.
Saldanha Bay guano, 328 ; nitrogen
in, 329 ; phosphoric acid in, 329.
Salm - Horstmar, Prince, on water-
Salt, 465-473 ; action of, on crops,
472 ; adulterant of guano, 319 ;
amount applied, 473 ; antiquity of
use of, 465 ; an antiseptic, 468 ;
application of, 472 ; clarifies water,
470 ; coagulates clay, 470 ; decom-
poses minerals, 470 ; a germicide,
468 ; indirect action of, 468 ; me-
chanical action of, 470 ; nature of
action of, 465 ; not a necessary
plant -food, 466 ; occurrence of,
467 ; prevents rapid fermentation,
471 ; quantity to apply, 473 ; sol-
vent action of, 470 ; sources of, 468.
Saltpetre, formation of, 164 ; occur-
rence of, 215 ; plantations, 163.
Sand, absorptive power of, 68 ; an
adulterant of guano, 319 ; cal-
careous, absorptive power of, 98 ;
siliceous, absorptive power of, 98.
Sandy soils deficient in lime, 451.
Sandwich Islands, guano deposits at,
Saragossa Sea, sea-weed in, 339.
Saussure, De, on absorption of gases
by soil, 81 ; on nitrogen in plants,
41 ; researches on plant-food by, 15.
Sawdust an adulterant of guano, 319.
Scheibler, Professor, on basic slag,
Schloesing and Muntz, on nitrifica-
tion, 51, 166 ; experiments on rate
of nitrification by, 185 ; on denitri-
fication, 179 ; on ferments effecting
nitrification, 167 ; on fixation of
free nitrogen, 42 ; on ammonia in
air, 119, 132 ; on nitrogen absorbed
by soil from air, 132 ; on tempera-
ture favourable for nitrification,
Schoenite, potash in, 220.
Schlibler, on absorptive power of
soils, 98 ; on retentive power 'of
Schulze on fixers, 246.
Scutch, 427 ; manufacture of, 427 ; ni-
trogen in, 427.
Sea- weed, nitric acid in, 339.
Seals, guano from, 297.
Seed, fertilising ingredients lodge in,
Seine, nitrates in waters of, 158.
Senebier, Jean, on carbon in plants,
12 ; on nitrogen in plants, 41.
Sewage, 430-441 ; charcoal a filter for,
437; crops suited for, 434; de-
nitrification in, 179 ; dry matter
in, 431 ; effects of continued appli-
cations of, 433 ; filters for, 437 ;
irrigation with, 431-433 ; nitrifica-
tion in, 166 ; nitrogen lost in, 149 ;
phosphoric acid lost in, 149 ; puri-
fied by soils, 435 ; treatment of, by
precipitation, 436 ; value of, as a
Sewage-sick land, 433.
Sewage-sludge, 438-441 ; as a manure,
experiments with, 438 ; nitrogen in,
439 ; phosphoric acid in, 439 ; pro-
fitable treatment of, 441 ; value of,
439 ; water in, 438.
Shale -works, sulphate of ammonia,
Shark's Bay guano, 309, 328.
Sheep, excrements of, 280, 281 ; solid
excreta voided by, 280 ; urine voided
Sheep-dung, alkalies in, 226 ; com-
position of, in dry state, 227 ; most
valuable excrement, 227 ; nitrogen
in, 226 ; phosphoric acid in, 226 ;
water in, 226.
Sheep-manure, 251 ; amount produced
per day, 251 per year, 252 ; dry
matter in, 252 ; mineral matter in,
252 ; nitrogen in, 252.
Sheep-urine, alkalies in, 230 ; com-
position of, in dry state, 231 ; most
valuable urine, 231 ; nitrogen in,
230 ; phosphoric acid in, 230 ; water
Shoddy, 427; production of, 152,
425 ; nitrogen in, 152, 427.
Sicily, bones from, 360.
Sidney Island guano, phosphoric acid
Siemens, Dr, experiments by, with
light on plants, 38.
Silica, in ash of plants, 55 ; in Chincha
guano, 305 ; jelly, 169 ; necessary
for plant-growth, 55.
Silicates, 102 ; absorbed by cereals,
Silicic acid fixed by soils, 58.
Simon on humus in soil, 47.
Slaked lime, 454.
Slugs killed by lime, 461.
Smut prevented by lime, 461.
Soda, in ash of plants, 54 ; fixed by
soils, 58 ; necessary for plant-
growth, 55 ; nitrate of, 332 - 351 ;
in salinas. 335 : replaces potash,
Sodium chloride in Chincha Island
Sodium phosphate in concretionary
Sodium sulphate in concretionary
Soil, 65-108 ; absorptive power of, for
water, 67, 98 ; acids fixed by, 58-
60 ; action of lime on, 453 ; am-
monia absorbed by, 81 ; amount of
soluble plant - food in, 100 ; arti-
ficial, 54 ; barley, nitrates in, 158 ;
bases fixed by, 58-60 ; best suited
for nitrification, 192 ; biological
properties of, 92-96 ; capacity for
heat, 76-78 ; carbonic acid absorbed
by, 81 ; chemical composition of,
87 - 92, 101 - 107 ; colour of, 80 ;
cropped, nitrates in, 157 ; denitri-
fication in, 177 ; evaporation from,
71, 72 ; farmyard manure, action of,
on, 272 ; fertilising ingredients in,
87 ; fertility of, 65-108 ; fineness of,
69-70 ; gases in, 100 ; hygroscopic
power of, 75-76, 99; improved by
humus, 272 ; innueiice of farmyard
manure on, 475 ; on nitrification,
180 ; manures increase fertility of,
474 ; nitrates in, amount of, 128-
131 ; nitrifying organisms in, 179 ;
distribution of, 179 ; nitrogen ab-
sorbed by, 81, 82, 131 ; nitrogen
accumulates, 133 ; nitrogen in,
amount of, 120-128 ; nitrogen least
abundant of manurial ingredients
in, 270 ; nitrogen at various depths
in, 156 ; oxygen absorbed by, 81 ;
phosphoric acid in, 203 condition
of, in, 203 occurrence of, in, 203 ;
peat, 123 ; possesses power of fixing
ammonia, 57 ; potash in, 215 con-
dition of, in, 216 ; potential fertility
of, 549 ; power of, for absorbing
gases, 81 ; relation of, to plant-
roots, 84 ; retention of plant-food
by, 57 ; retentive power of, for
water, 70-73 ; sewage purified by,
435 ; shrinkage of, 74 ; variation in
absorbing powers of, 82 ; varieties
of, 67 ; virgin, 133 ; water in, most
favourable amount of, 75 ; water-
logged, 179 ; wheat, nitrates in, 157.
Soluble phosphate, 386.
Sombrero phosphate, 308, 328, 330,
379 ; phosphoric acid in, 330.
Somme phosphate, 378.
Soot, 428 ; application of, rate of,
429 ; crops suited by, 429 ; nitro-
gen in, 428.
South America, guano deposits in,
327 ; meat-meal guano from, 324.
Starbuck Island guano, 309, 328;
phosphoric acid in, 330.
Stassfurt salts, 214 ; potash in, 215,
Stead and Eibsdale on formation of
basic slag, 407.
Stoeckhardt, on composition of solid
excreta, 226 ; on composition of
Storer, Professor, on composition of
birds' dung, 331 ; on composition of
leaves, 242 ; on fish - guano, 323 ;
on nitrogen removed in milk, 147.
Straw, composition of, 238 ; imports
of, 153 ; as litter, 236, 248 ; mineral
matter in, 238, 243 ; nitrogen in,
237, 243 ; variation in composition
Subsoil, conditions favourable for
nitrification in, 181.
Suffolk coprolites, 374.
Sugar-beet refuse, potash in, 219.
Sulphate of alumina, a precipitant of
Sulphate of ammonia, 352-358 ; am-
monia in, 355 ; application of, 356 ;
composition of, 355; a concentrat-
ed nitrogenous manure, 356 ; con-
verted into nitrates, 356 ; from
gas-works, 353 ; from iron-works,
355 ; from shale-works, 354 ; manure
for cereals, 356 ; most easily nitri-
fiable manure, 191 ; production of,
151, 358 ; properties of, 355 ; source
of nitrogen, 149 ; sources of, 353,
354, 358 ; sulphocyanate of ammonia
Sulphate of lime a fixer, 246.
Sulphate of magnesia, an adulterant
of guano, 319 ; as a fixer, 246.
Sulphate of potash, application of,
422 rate of, 423 ; compared with
muriate, 421 ; sources of, 218, 420.
Sulphuretted hydrogen from farm-
yard manure, 258.
Sulphuric acid, action of, on bones,
382 on guano, 311 on tricalcic
phosphate, 398 ; in ash of plants,
54 ; as a fixer, 245, 285 ; necessary
for plant -growth, 55; superphos-
phate manufactured with, 384, 388.
Superphosphate, 382-400; action of,
392-395 sometimes unfavourable,
395 ; application of, 395 rate of,
397 ; composition of, 391 ; discovery
of, 382 ; hastens early growth, 394 ;
high -class, 392 ; low -class, 392 ;
manufacture of, 383 - 385 phos-
phates suitable for, 384 ; medium-
class, 391 ; production of, 382 ;
reversion in, 389, 399, 400 causes
of, 389, 390 ; reverted in soil, 392.
Surprise Island guano, 328.
Swan Island guano, 328.
Swedes, fertilising ingredients remov-
ed from soil by, 485 ; manurial con-
stituents in, 282 ; manuring of, 514.
Swine-dung, alkalies in, 226 ; com-
position of, 227 ; nitrogen in, 226 ;
phosphoric acid in, 226 ; water in,
Swine-urine, alkalies in, 230 ; com-
position of, 231 ; nitrogen in, 230 ;
phosphoric acid in, 230; water in,
Sydney Island guano, 309.
Syenite, 106 ; phosphoric acid in, 202,
Sylvin, potash in, 220.
Tamarugal, Pampa de, nitrate deposits
Tarapaca, nitrate deposits in, 340.
Temperature necessary for nitrifica-
tion, 52, 175.
Tetracalcic phosphate, 387 ; occur-
rence of, 387, 405 ; solubility of,
Thaer on application of farmyard
Thiocyanates, nitrification in, 182.
Thomas - Gilchrist process of steel-
Thomas-slag. See Basic slag.
Tillage increases number of plants, 86.
Timor Island guano, 309.
Tobacco, potash in, 217.
Torrefied horn, 426.
Torrefied leather, 428.
Tortola guano, 309.
Trachyte, phosphoric acid in, 202, 211.
Transpiration, by elm-tree, 71 ; by
Trees, as pumping-engines, 76 ; water
transpired by, 71.
Tricalcic phosphate, 386, 398.
Tubercles on roots of plants, 44.
Tull, Jethro, theory of, on plant-
growth, 9-11, 69, 109.
Turkey, dung produced by, 331.
Turnips, fertilising ingredients re-
moved from soil by, 485 ; manurial
constituents in, 282 ; manuring of,
510, 511, 513 - 517 ; Kothamsted
experiments on growth of, 568.
Twigs, potash in, 217.
Tyrosin, assimilated by plants, 47.
Ulmates in farmyard manure, 259.
Ulmic acid, in farmyard manure, 258 ;
in humus, 47.
Ulmin in humus, 47.
Uncovered farmyard manure, 263,
Unexhausted manures, valuation of,
Unit value of manurial ingredients,
Units for determining commercial
value of manures, 554.
Urate of ammonium in Chincha Is-
land guano, 305.
Urea, assimilated by plants, 46 ; in
farmyard manure, 257 ; nitrification
Uric acid, experiments with, 46 ; in
Chincha Island guano, 305.
Urine, 228 ; amount voided, 291 ;
composition of, varies, 228 ; con-
tains digested manurial ingredients,
228, 232 ; devoid of phosphoric acid,
205 ; and dung, composition of,
234 ; influence of food on, 229 ;
nitrification in, 197 ; nitrogen in,
292 ; potash in, 292 ; voided by
cows, 280 ; voided by oxen, 280 ;
voided by pigs, 281 ; voided by
Uruguay, meat-meal guano from, 324.
Valuation of manures, 539-559.
Vegetation, desirable to have soil cov-
ered with, 194.
Venezuela, guano deposits at, 327.
Ville, Georges, on assimilation of
ammonia, 50 ; theory of, on source
of plant-nitrogen, 41.
Vine, potash removed by, 216.
Virgin soils, 133.
Voelcker, Dr, analysis of apatite, 210
of farmyard manure, 259 ; on
action of superphosphate, 395 ; on
fresh and rotted dung, 261, 286 ; on
guano, 316 ; on salt as a manure,
Voss, Hermann, on manures used,
Wagner, Professor, on, application of
basic slag, 416 ; assimilation of
organic nitrogen, 46 ; experiments
with basic slag, 408-413 ; fineness
of basic slag, 409 ; manures, 412 ;
relative manurial value of nitrogen
compounds, 556 ; solubility of basic
Wallace, Dr, on sewage purification,
Walruses, guano from, 297.
Warington, E., on ammonia in rain,
49 ; on appearance of nitrous organ-
isms, 168 ; on conditions favourable
for nitrification, 181 ; experiments
on rate of nitrification, 186 ; on
composition of farmyard manure,
260 ; on manufacture of superphos-
phate, 383 ; on manurial constitu-
ents of foods, 282 ; on nitrification
in alkaline solutions, 197 ; on ni-
trogen in excrements, 233 ; on ni-
trogen in soil, 122 ; on potash in
wool, 227 ; researches of, on nitrifica-
tion, 35, 52, 166-168, 180, 186.
Water, absorbed by plants, 73 ;
amount of, transpired by plant-
leaves, 56 ; an adulterant of guano,
319 ; a carrier of plant-food, 55 ;
in cow-dung, 226 cow-urine, 230 ;
from decomposition of farmyard
manure, 257 ; in horse-dung, 226
horse - urine, 230 ; necessary for
plant, 67 ; in pig-dung, 226 pig-
urine, 230 sheep - dung, 226
sheep - urine, 230 ; transpired by
elm-tree, 71 oak-tree, 71.
Water-logged soils, 179.
Waterloo, bones from, 360.
Way, Thomas, on retention of plant-
food by soil, 57, 59 ; on sewage, 437.
West Indies, guano from, 298.
Whales, guano from, 322.
Wheat, fertilising ingredients removed
from soil by, 485 ; Flitcham experi-
ments on, 500 ; manurial constitu-
ents in, 282 ; manuring of, 499-501 ;
nitrogen removed in crop of, 145 ;
requires nitrogenous manures, 499 ;
Rothamsted experiments on, 500,
562-565 ; a source of nitrogen, 153.
Wheat-soils, nitrates in, 157.
Wheat-straw, analysis of stable man-
ure made from, 283 ; composition
of, 238 ; manurial constituents in,
White clover, growth of, promoted by
Wiegmann on ash constituents of
Wilfarth on nitrogen in plants, 44.
Winogradsky, on nitrification, 52,
167, 169, 197 : on organisms in
Wolff on, analysis of manure - heap
draiiiings, 290 ; composition of
fresh and rotten dung, 288 ; assimi-
lation of organic nitrogen by plants,
47 ; relative manurial value of
manurial compounds, 556 ; urine,
Wood-ashes as potash manure, 218,
Woodhouse, researches of, on nitrogen
in plants, 41.
Wool, capable of nitrification, 182 ;
potash in, 217.
Wool-waste, 427 ; nitrogen in, 427.
Wooluey, on organisms in soils, 93,
95 ; on water in soils, 75.
Wrightson, Professor, on application
of basic slag, 414.
Yorkshire, bones first used in, 359.
Zeolites, potash in, 220.
PRINTED BY WILLIAM BLACKWOOD AND SONS.
IVERSITY OF CALIFORNIA LIBRARY
Return to desk from which borrowed.
This book is DUE on the last date stamped below.
MAR 5 1948
UNIVERSITY OF CALIFORNIA LIBRARY