Sere: RRR SSS LTE Ly AAA ADVERTISEMENT. Reversible Coulters. Beware of Imitations. ALL GENUINE “ACME” HARROWS HAVE ‘ FLEXIBLE GANG BARS. DISTRIBUTING DEPOTS. Goods are delivered free on board at—New York.—Co.umpvs, O.—Cuicaco, Inn.—Kansas Crry, Mo.—Mryneaporis, Minn.— Lovisvitie, Ky.—but all communications should be addressed to DUANE H. NASH, SOLE MANUFACTURER, MILLINGTON, MORRIS COUNTY, N. J. eae CULTURE FARM CROPS. OF THE SCIENCE OF AGRICULTURE, AND A HAND-BOOK: OF PRACTICE FOR AMERICAN FARMERS. By HENRY STEWART, Author of “The Shepherd’s Manual,” ‘ Irrigation for the Farm, Orchard and Garden.” Civil Mining and Agricultural Engineer. Member of the Western Society of Engineers. ore Kes YF! TDN OCT 28 ey, Oy. byes vane PUBLISHED BY DUANE HH: NASH, MILLINGTON, Morris County, NEw JERSEY. 1887. Entered, according to Act of Congress, in the pou DUANE H. NASH, — In the Office of the Librarian of Congress at Washi - 4 is : * wn i * . . a oe rac . ~ f 4 ’ 4 a¥ Pt ae bil” Var ge ob a fan - ‘ “00cerseescscncsescscesccarsoonsace CHAPTER VII. RR eae ser TA GSTS MME RE ete ae gc Corin con ss bere ee 166 f s *S Carlycub hay.-..tc:..2:4 Ero awakes A5She ss oe Lh RSM eee oe de Soe 140 ee 6 PeMMRE GUUS roe, salaces 1.50 ce Chloride Of MANGANESE............ceeseeeeeeeeeeeseerene tenses 3.39 TEPOAPIOLE SOG... <000hcscecsnsescsscsncevecces setnecersaccsasens 156.53 TOGIGE OF SOA. 0... .ccecccsocccosasccecsescastasssrenescoronesensces trace Sulphate of potassium. ...........ceeceeeeeeeeeereeeeerrneeeees trace Sulphate of Magnesia.............:scsescceeeseeeestssseeeseeess trace Sulphate Of Lime.............:eessceeeeeeesnneesrseeeeeeenennreres 38.07 Phosphate Of SOM. .......--::sseeeseeeceeeeeesenseneereeeeceeees trace WATHOMAtTC OF LIMC.....-0-.-0.cccssecnvcsoccecccessccnsassavsrsees 48 THE CULTURE OF FARM CROPS. Total in one gallon 13489.17 grains. Per cent. 19.78 _ The water of springs, wells and rivers is thus never pure, but holds in solution more or less of solid substances. Hence we find that land watered by irrigation from rivers produces. much larger crops than that watered by rain; also that land that has been or is periodically overflowed by floods, becomes exceedingly fertile. Even rain water is not pure except in the wettest seasons, when the atmosphere has been washed clean from its impure matter which is brought down by the showers. In this way a large quantity of solid fertilizing matter, as well as of fertilizing gases, is brought within reach of the roots of the plants by the rain which is absorbed by the soil. The water also dissolves matter from the soil and presents it to the roots in such a condition that it can be absorbed and utilized as nutriment. These facts prove how indispensable it is that the soil should be brought by thorough culture, and the use of the most perfect implements, into such a condition of porosity and mellowness that the water may be absorbed and held in itand not flow off from the surface and carry away into the streams, not only all its own burden of rich fertilizing matter but also rob the soil - of a large portion of its own possession. The solvent power of water is increased by heat, in regard to nearly all substences excepting lime and ammonia which are dissolvcd and absorbed by cold water more readily than by warm. This property will be further explained in a future chapter on HEAT. Water has a strong affinity for various substances, indeed it exists in a greater or less proportion in almost all solid bodies and in every crystallized substance; forming in these cases what is known as “the water of crystallization.” When limestone is burned, water and carbonic acid are DECOMPOSITION OF WATER. 49 driven off by the heat and lime remains. (This lime is the oxide of the metal calcium.) When lime is brought into contact with moisture, about one-third of its weight of water is absorbed and the lime, swells, breaks apart and falls into a very fine powder which is perfectly dry. This water is combined with the lime and cannot be expelled at less than a red heat. Gypsum contains in the same manner 21 per cent. of water; alum contains 24 parts of water to two of solid matter ; Epsom salts contain 50.2 per cent. of water; and so on through a long list of crystallized minerals. It has also a strong affinity for clay and all the more so, as the clay is finely pulverized and disintegrated; carbonized veg- etable matter also takes up a large quantity of water; hence the great advantage of securing as large a quantity of de- cayed organic matter, as may be possible in the soil. This is quite distinct from the mechanical grasp upon water exerted by porous substances, which merely hold it in its interstices by capillary attraction, as is the case with a sponge, and give it out again with great facility and with- out any chemical action. The elements of water are held together loosely and are combined with great ease. When hydrogen is burned in the air it combines with oxygen (as has been previously described) and forms water. Ifa piece of zinc is placed in a vessel of water—a glass bowl or a wide mouthed bottle, for instance—and a little sulphuric acid (a few drops) is added, the water is in part decomposed and the hydrogen is set free. As this experiment is a pleasing one and very simple, the chemical operation is here explained. The sul- phurie acid acts upon the zinc and combines with it; but as this acid has only three equivalents of oxygen (S. O3) and zine requires one more equivalent to make the combin- ation as sulphate of zinc (Z. S.O4) this excess of oxygen is taken from the water, leaving the hydrogen free, when it, escapes in bubbles apparently from the surface of the zinc. If the bottle is corked and a glass or rubber tube is put through the cork, the hydrogen gas may be collected. But as it is explosive when mixed with air, great care must be 50 THE CULTURE OF FARM CROPS. exercised in igniting the gas, and the first which is set free should be permitted to escape until the air has been all car- ried off. Water undergoes continual decomposition and recombi- nation in the interior of plants and animals. As a fluid it finds its way into every cell and pore and passes out by transpiration after it has given up to the tissues the matter which is extracted from it. And so slight is the hold which its elements have upon each other, and so strong is their affinity for other elements, that they are ready to separate upon very slight impulses; the oxygen forming compounds with one and the hydrogen with others, as the production of the various substances of which the plants form them- selves, require and demand. And when the nature of chem- ical combinations begins to be understood, there is no more wonderful fact in the study of vegetable physiology than the great variety of changes which are continually going on through the agency of the elements of water and others which it conveys into the tissues of plants and animals. In the state of vapor too, water exerts a very potent in- fluence upon the life and growth of farm crops. Vapor escapes from water into the air, or is absorbed by the air, not only at boiling heat, but at all temperatures. Even at a zero temperature the air takes up water, as is known by the housewife whose linen freezes dry in the cold, crisp, wintry, air. A piece of ice exposed to the air in the coldest weather gradually evaporates and disappears. It is how- ever in the summer that the evaporation of water is most active; and it is then that the effects of the condensation of the at- mospheric moisture is most perceptible and useful. Dew is the product of this condensation. The air charged with the vapor which has been gathered during the heat of the day, is cooled at night by contact with the soil, from which the heat is rapidly lost by radiation. The cooling of the air causes the moisture to condense, forming sometimes visible vapor, seen in the evening and night fogs which prevail in some localities; but always a burden of moisture which is too heavy to be suspended in the air. This moisture then FORMATION OF DEW. 8 falls and settles in fine globules upon the vegetation, the soil, and upon all other objects which have been sufficiently cooled. This process goes on mostly at night, but constantly at other times when the temperature falls, and especially in the soil, in which with the constant circulation of air (prev- jously described) there is always the accompanying mois- ture; which is condensed and deposited in the interstices and so supplies the demands of the plants. The more com- pletely the soil is made fine and pulverized the larger is the deposit of atmospheric moisture. This behavior of water under the beautiful and compre- hensive laws to which it is subject, affords an instance of the provident as well as bountiful operations of nature. Every one of these operations tend towards the good of mankind. It is the cultivator of the soil who reaps the benefits of these universal and beneficent laws. Yet the rewards are not given to all alike. We are told that the rains descend, the _dews are distilled and the sun shines upon the just and the unjust ; upon the industrious as well as the idle and neglect- ful. An impartial and kind Providence offers these bene- fits with an open and generous hand; overflowing with good to mankind. But Providence does nothing more. The farmer who avails himself of these invaluable gifts and does his part by studying the nature of them and their adaptation for his purposes; and thus adapts them with skill and in- dustry to the preparation of the soil and the culture of his crops, gains the highest rewards. The prizes are his; but the blanks in the distribution are for those who neglect these grand provisions and refuse to avail themselves of them. It is “the hand of the diligent which maketh rich:”’ the neglectful careless tiller of the soil has no promise of wealth from the free gifts of nature; these are for the farmer who uses every possible means to secure these gifts by the prac- tice of an intelligent and effective culture of crops. THE CULTURE OF FARM CROPS. gts AE aa sO oe Re Ge HEAT AND COLD.—THEIR INFLUENCE UPON MATTER AND VEGETATION. Heat and cold are merely relative terms. Cold is a low degree or absence of heat, just as darkness is the absence of light, and has not in any sense, or in fact, any specific ex- istence, as separate from heat. It is only quite recently that the nature of heat has been understood. It was for- merly supposed to be an element, a subtle fluid to which the name Calorie was given; and whose entrance into a body produced warmth and whose loss produced cold. As some bodies, such as marble, felt cold and others, as wool, felt warm, it was believed that various substances contained less or more of this fluid stored up in its interstices according to their varying capacities. It was given, in fact, all the properties of a gas with some others which were believed to belong to it specifically. This ancient notion was exploded when it was discovered that heat was simply the effect of motion of the particles of a body, and that the intensity of the motion determines the temperature. It is not the purpose here to discuss the various theories which are held in regard to the nature of heat; these may be studied in special works on the subject such as that of Prof. Tyndall. It is most important for us to consider how it affects those elementary and compound bodies which have a close relation to the growth of plants, and its effects upon germination and plant growth. It will be sufficient here perhaps to repeat the words of Dr. Locke uttered a hun- dred years ago in which the true idea of heat was enuncia- ted. He said, “heat is a very brisk agitation of the insen- sible parts of any object which produces in us that sensation from which we call the object, hot; so that what in our sensations is heat, in the object is nothing but motion.” A LATENT HEAT. 5S familiar instance may be given. If a person slide down from an elevated place by means of a rope held in the hands and he descends rapidly he feels a burning sensation in his hands and the skin is blistered precisely the same as if he held a hot iron rod in his hands. This heat is the re- sult of an intense vibration of the fibers of the muscles and skin of the hands; and is equal in degree exactly to the vi- bration of the particles in an iron rod whose heat would cause precisely the same sensation and result in the hands. To study the relations of heat with intelligence it must not be regarded as a thing, but as a condition of matter and an effect of the change of a condition. The chief source of heat is the sun. All combustion isa source of heat, and as we have seen, combustion is a chemi- cal effect. Mechanical force is also a source of heat; and friction, pressure, or any other result of force is accompanied by heat. Heat once produced is never lost or destroyed: it may disappear but it always exists. The heat of the sun communicated to the earth is absorbed in various ways, that is we use this expression; but in truth we should say the force is communicated to every object brought under its influence. It is absorbed by the waters of the ocean and their particles move and separate more widely apart form- ing vapor. The amount of force (which we call heat) thus commun- icated has been accurately calculated. If we take an ounce of ice at 32 degrees and one of water at 174 degrees and put them together, the ice will be melted and there will be two ounces of water; but the temperature will be only 32 degrees. Where has the excess of 142 degrees of heat which has been apparently lost by the hot water, disappeared? It has not been lost but has become stored up in the water and has become the latent or hidden heat of the liquid. This latent heat can be found again when the water is froz- en, for in the formation of ice precisely 142 degrees of heat are given out by the water in the gradual change of the liquid to a solid. In the same way when water is changed to steam a very 54 THE CULTURE OF FARM CROPS. large quantity of heat is rendered latent in the vapor. Water at 32 degrees absorbs 180 degrees of heat and reaches a temperature of 212 degrees which is the boiling point. But it does boil only slowly and steara is produced very gradually. It is found that if the consumption of one pound of coal will raise a quantity of water from 32 degrees to 212 degrees; 53 Ibs. more will be required to change it all to steam of the same temperature. 53 times 180 or 990 units of heat will then have been expended, but have not been lost; they are stored in the steam and are the latent heat of the vapor of water. And when the vapor of water is condensed into liquid this heat is given out again. And here is another most wonderful instance of the infinite wisdom and beneficent adaptation of the laws of nature to the stability of the universe and the comfort and happiness of mankind. The expansion of water as it changes into ice has been already mentioned. This is one more effect of heat, that is a reduction of it, upon this liquid, and has an intimate connection with this part of our subject. When water reaches its maximum density which is 39 degrees, un- der the influence of the abstraction of heat, it then begins - to increase in bulk until ice crystals form when the total expansion amounts to one-eleventh of the bulk. Conse- quently the ice floats on the surface and after a time it be- comes thick enough to protect the underlying water from the effects of cold. Were it otherwise, ice would sink to the bottom and as the surface water cooled it would also sink and the whole water would soon be changed into ice. The ocean would then become a vast bed of solid ice, which by the very force of this law would remain permanently and re- sist all the heat of the sun to change it. Then the earth would be uninhabitable. No green blade would appear on the surface; no animal would find subsistence; there would be no clouds, no rain; everything would be cold and drear and lifeless; a dead world. Again, were it not for the gradual absorption of heat by the melting ice and the evaporating water, the earth would ‘THE FORCE OF HEAT. 5D be destroyed by the sudden catastrophe of an overwhelming flood at the approach of every spring. The accumulated ice and snow of the winter would be changed to vast bod- ies of water as soon as they reached the temperature of 32 degrees; and when the boiling heat should be reached, the water would change into steam with the force of an ex- plosion and rend everything near it to atoms. _Instead_ of being useful to man it would be a most destructive agent, which men would avoid as they would avoid nitro-glycerine. The contemplation of these thoughts gives a new force and interest to the fact that “the earth was given to man” and truly the gift was perfectly well adapted to his uses, and for his enjoyment. ; It has been shown that the force equivalent to the heat required to produce 9 lbs. of steam at 212 degrees by the union of 8 lbs. of oxygen and 1 lb. of hydrogen is equal to that represented by the fall of a ton weight down a preci- pice 22,320 feet high: to change this vapor into liquid a force is exerted equal to that of the fall of a ton down 2,900 feet; and to change the water into ice the force is equal to the descent of a ton down 433 feet. And yet these enormous forces are going on in the soil and in the tissues of delicate plants, continually, silently, but omnipotently; without any out- ward indication. Prof. Tyndall has remarked of this lat- ent force hidden in a drop of water, “I have seen the wild stone avalanches of the Alps; which thunder and smoke down the declivities with a force almost sufficient to stun the observer. I have also seen snowflakes, descending so softly as not to injure the fragile spangles of which they were composed; yet to produce from aqueous vapor, a quan- tity of that tender material that a child might carry, de- mands an exertion of energy competent to gather up the shattered blocks of the largest avalanche I have ever seen and to pitch them to twice the height from which they i.” Combustion is a source of heat; and the decay of organic substance is a slow combustion. This fact is exemplified in the decomposition of vegetable matter. When the farmer 56 THE CULTURE OF FARM CROPS. makes a heap of manure, or a hot bed, the mass soon begins to heat and in time is changed from its previous condition into a black powdery substance having no resemblance to vegetable tissue. ‘The heat produced by the chemical ac- | tion which has resulted in this change has been precisely equal to that which would have been required to drive off the moisture; set free the gases; and reduce the matter to its mineral, carbonaceous, and nitrogenous elements which remain in the mass. In like manner heat is produced by every chemical change. The union of water with sul- phuric acid is accompanied by violent heat; so is the solu- tion of a piece of copper in nitric acid. And as the decom- position of a vegetable cell in a manure heap is accompanied by heat so is its decomposition in the soil; and its formation in the plant. The effects of heat—and cold—upon the soil are great and varied. It is the sun’s heat, penetrating the soil which causes the germination of the seed. At low temperatures seeds will remain in the soil for many years unchanged. The heat of the sun does not penetrate very deeply and at a very moderate depth the heat of the soil is constant, dur- ing summer and winter. This is caused by the effect of evaporation, as well as by the nonconducting property of the air spaces between the particles of the soil. Seeds of weeds and plants which remain at some depth in the soil are thus kept dormant for many years, starting into growth © whenever they are brought under the influence of the warmth of the sun’s rays. The heat of the sun also causes the evaporation of water from the soil and dries it and makes it fit for the labors of the farmer. But this result has also another effect which is unfavorable. It cools the soil and reduces the temperature, and when the soil contains an excess of water and the evap- oration is copious, this cooling is exceedingly hurtful to the crops. There are soils which are called cold clays; and swampy lands are always cold and unproductive of the bet- ter class of crops, favoring the growth of mosses and ferns and other useless plants. This is due to the constant evap- THE EFFECTS OF VARIATIONS OF TEMPERATURE. 57 oration from the surface. To change the water into vapor, has been shown to require a large expenditure of heat; and precisely the same heat is drawn from the soil when vapor rises from it as is imparted by the fuel of a fire which pro- duces the same amount of evaporation. This heat drawn from the soil necessarily reduces its temperature. An ex- periment which exemplifies this result may be made as follows: A few drops of ether are placed upon the skin; and the breath is blown upon it. The current of air evap- orates the volatile ether quickly, and causes a large absorp- tion of heat. The abstraction of the heat from the skin to supply this requirement of the evaporation causes a sensa- tion of cold upon the skin. This is precisely the effect up- on the soil, when the warm air blowing over wet clay or swampy land causes copious evaporation and is all the greater as the evaporation is excessive. This effect operates to relieve persons from the results of excessive heat. When the temperature rises to 90 degrees and over, the animal system becomes oppressed. The blood whose normal heat is 98 degrees, rises in temperature and produces serious disturbance of the nervous system, which if not relieved quickly ends in what is known as sunstroke, and speedy death. But the evaporation of the water of the system in the form of perspiration relieves the oppression; carries off the heat; cools the blood and theskin; and prevents the fatal results of the unrelieved heat. When an incau- tious person suddenly plunges into cold water, or drinks cold water to excess, the pores of the skin are closed in the one case and a chill is produced in the other; either of which checks the perspiration; and prevents the escape of the internal heat; when fatal results are often produced. So the wearing of wet clothes abstracts heat from the body and thus produces pernicious effects; while the use of wet sheets in which fever patients are wrapped; rapidly cools the parched skin; induces natural perspiration; and saves the sufferer. The abstraction of heat by evaporation is so great under some circumstances that water can be frozen by it. This 58 THE CULTURE OF FARM CROPS. may be shown by a simple experiment. A shallow vessel containing sulphuric acid is placed in another containing water and both are placed under the receiver of an air pump. When the air is exhausted the vapor of the water. is so rapidly absorbed by the acid that the water is frozen. By using liquid sulphurous acid which evaporates with in- tense force, and pouring it into a red hot vessel, and then adding water, the water is suddenly frozen into ice under the intense cold produced by the rapid evaporation of the acid. The lowest degree of cold ever produced; 220 degrees. below zero; was by means of the vaporization of liquid pro- toxide of nitrogen mixed with bisulphide of carbon in a va- cuum. These examples however are not of practical interest. to the farmer further than to exemplify the vast and varied changes produced in matter by heat and cold. The same kind of result may be produced by the sudden liquefaction of solids. Thus a mixture of salt and ice causes the rapid melting of the ice and a sufficient reduction of temperature to freeze water. In this case both the solids. are liquefied and the effect is intensified. The cold thus. produced is 40 below zero. Four ounces of sal ammoniae: and the same quantity of saltpetre, finely powdered and dis- solved in 8 ounces of water, will cause a reduction of 40: degrees of temperature; and powdered Glauber’s salts, drenched with hydrochloric acid, will sink the temperature: from 50 degrees to zero. These mixtures are in common use as the so called freezing mixtures. The newly intro- duced ice machines by which ice is produced at a cost of one dollar per ton, are operated by the vaporization’ of am- monia in the gaseous form from its solution in water. A very useful practical application of the liberation of heat by freezing is that often used to evade the freezing of the contents of cellars in very cold weather, by placing a. pail full of water in the cellar. The water freezes more eas- ily than any other liquid or solid containing liquid; as fresh vegetables and fruits; and in the act of freezing gives out. the latent heat of the water which actually warms the cel- EFFECTS OF EVAPORATION ON CLIMATE. 5D lar. For the same reason the coolness of the early winter is subdued and greatly modified by the heat given out by large bodies of water in the act of freezing; and in this way lakes and rivers, as well as the ocean, have a very import- ant influence upon the climate of adjacent localities. Late frosts are avoided and the intense cold is delayed until later: in the winter. This fact has given rise to the common adage, “As the days begin to lengthen, the cold begins to strengthen,” by which is meant that the cold does not be- come severe until the beginning of the new year, when the waters and the ground have become frozen and all their latent heat has been given out. The heats of the summer are also much reduced in in- tensity by the excessive evaporation from bodies of watér and from cultivatedsoil. Ithasbeen found that the climate of the great western plains has been favorably modified by the in- troduction of irrigation and the breaking up of the vast areas of dry prairie which have been brought under tillage. Evaporation of the water thus used, or gathered in the por- ous soil by the rains, which are absorbed instead of flowing as heretofore, from the dry hard surface in vast sheets and floods to the nearest stream, both cools and moistens the air; supplies tke vapor for clouds which shade the soil and temper the sun’s rays, and which in turn descend again to. the soil whence they came in genial cooling showers. This is a remarkable instance of how man’s industry modifies climate by changing the natural conditions prevailing and so fits the earth for his occupation and use. THE CULTURE OF FARM CROPS. CHAPTER XX. CARBONIC ACID.—ITS PROPERTIES AND FUNCTIONS IN PLANT GROWTH. Carbonic acid is one of the three materials which together form the starting point of vegetable growth; the others be- ing water and nitric acid. This acid is formed of carbon and oxygen in the proportion of one part of the former to two of the latter chemically combined. It is a colorless gas, having an acid taste and smell; is soluble in water; weighs one-half more than air and can be poured from one vessel to another, as a liquid may be; 100 parts of water dissolve 106 parts of this gas, and it is from this source that the roots of plants derive the needed supplies of it. It is produced by the combustion of carbon in the atmos- phere; when it unites with oxygen in the proportions men- tioned. An easy way to produce it is to burn charcoal on an open hearth. In a close room this combustion takes the oxygen from the atmosphere and fills the whole space with carbonic acid. ‘This necessarily is a dangerous proceeding and at times causes fatal results, by the keeping of char- coal fires, or even coal fires, in poorly ventilated apart- ments. This gas is wholly unable to support life and when exist- ing in an excessive proportion in the air not only destroys animal life, but is also fatal to vegetable existence. Neither will it support combustion. Fire is extinguished by it; but when mixed with certain proportions of hydrogen it be- comes inflammable, and even explosive when mixed with air. It forms a large proportion of the rocks in combina- tion with various mineral elements. One of the most com- mon of the rocks,—limestone, and of which marble is one form, contains 44 per cent. of it and can be separated from it by the action of an acid or by burning. If asmall quan- y CARBONIC ACID A FOOD FOR PLANTS. 61 tity of powdered marble be placed in any vessel and strong vinegar, or any acid, is poured upon it, active effervescence ensues and the carbonic acid is given off copiously. Chalk is a common form of this combination of lime and carbonic acid, the union of which forms carbonate of lime. One cubic inch of marble or chalk will yield 4 gallons or near- ly half a cubic foot of this gas; and the burning of one bushel _ of charcoal will produce 2,500 gallons. It is also produced. by fermentation. When cider is suffered to ferment; or any other liquid which contains sugar; bubbles of carbonic acid gas are evolved from it and rise through it and es- " cape at the surface. ‘This is caused by the change of the sugar into aleohol by which carbonic acid is formed. The same result happens when a solution of malt or glucose is fermented for the manufacture of beer: the foam which appears upon the fresh beer being caused by the escape of carbonic acid from the liquid during its confinement in the barrel or bottle. The foaming of sparkling wines is due to the same cause. It is also produced by the decomposition of solid sub- stances which contain starch, or other vegetable matter. The carbon of the starch, or cellular substance, is slowly consumed by the low heat of the decomposition, and unites with oxygen, giving off carbonic acid in the process; the residue left after final decay being mostly all mineral matter. Carbonic acid is the principal food of plants and con- tributes largely to that portion of their substance, which is derived from the atmosphere. The supply of this nec- essary compound is derived both fromthe atmosphere, and from the water, which are always present’in the soil. These entering into the substance of the plants, the for- mer by the leaves and the latter by the roots, are taken in- to the circulation in the sap and elaborated into the solid cellular tissue, starch, sugar, and gum, which are com- pounds of carbon oxygen and hydrogen; or carbon and water; asthe oxygen and hydrogen exist in these sub- stances in precisely the proportions which go to form water. 62 THE CULTURE OF FARM CROPS. ‘Thus starch consists of 12 parts of carbon; 20 parts of hy- ‘drogen and 10 parts of oxygen; while it has been seen that water, consisting of 2 parts of hydrogen and 1 part of oxy- gen, the 20 parts of hydrogen and 10 of oxygen in the starch are equivalent to precisely 10 parts of water. But it is not certain that starch is made up of carbon and wat- er; it is more probable that the three elemeuc: exist in ‘starch in other forms of combination. It is certain however that carbonic acid is the source from which the carbon of the vegetable substance is procured: because carbon is in- soluble in water and is a solid substance, and plants cannot take any solid matter into their circulation and their food _ must always be in solution in water. This part of our ‘subject however will be more fully treated in a future chap- ter and under its appropriate head. The air contains one part of carbonic acid in 2,500 and this proportion seems to be the most suitable for the health- ful growth of plants. The sun light has a great influence upon this nutritive function of this acid. When plants are exposed to the sunshine, it has been found that they grew more vigorously in an artificial atmosphere containing one- twelfth of its bulk of carbonic acid; but when this propor- tion was increased the plants were injured. When the carbonic acid amounted to one-half the atmosphere, the plants perished in 7 days; and when the proportion was two-thirds, the plants stopped growth immediately. Inthe shade, any increase of the carbonic acid above the normal amount in the atmosphere viz one twenty-five hundredth (.0004) proved to be injurious. This fact is of im- portance; for the reason that although an _ increase in the quantity of carbonic acid in the air, might stimu- late vegetable growth, yet it would seriously and even fatally disturb the balance of nature, because the air would then be unfit for the respiration of animals; and moreover al- though plants would grow more luxuriantly in such an at- mosphere, in perpetual sunshine, yet they would suffer in the shade; and would also certainly require a proportion- -ate increase in the supply of other food, to complete their ACTION OF CARBONIC ACID. 63 growth; for it is a well established law of vegetable growth that plants will not and cannot take into their circulation, * to any considerable extent, any larger proportion of any one element of their structure than the normal quantity as found existing in them upon chemical analysis. Thus wheat plants contain certain elements in their composition, and these are found to be constant under all circumstances; and notwithstanding that the soil might contain an excess- ive quantity of any one of these elements, yet no more than the normal proportion would be taken up by the wheat. If one is increased, every one must be, and thus an increase of one would necessitate an increase of all. If then the at- _ mosphere should contain an excessive quantity of carbonic acid and the growth of vegetation should be greatly stimu- lated thereby, it would lead to a very rapid exhaustion of the soil by the removal of the necessary mineral elements. This principle is a fundamental one, and applies generally to the growth of farm crops and should therefore be kept in constant remembrance by every farmer. Carbonic acid unites with all the alkaline minerals in the soil: as lime; magnesia; potash; soda; also with ammonia; as the carbonates of these substances. Its solution in water gives this liquid an increased solvent power over mineral substances; thus common carbonate of lime is practically insoluble in pure water; but when the water contains car- bonic acid, it is able to dissolve a considerable quantity of it, and this property applies to other mineral substances as well. This gives a practical importance to the functions of this acid which is of the greatest interest to cultivators of the soil. A simple experiment will illustrate this behavior of carbonic acid. A current of this gas passed through lime water will produce a milky appearance in it by the forma- tion and precipitation of carbonate of lime. After a short time the cloudiness will disappear by the solution of the carbonate thus formed, in the acid water. By heating the water the carbonic acid is driven off and the carbonate of lime is again precipitated and appears. The carbonic acid of the air is produced from a variety 64 THE CULTURE OF FARM CROPS. of sources. It is given off copiously by the lungs of ani- mals during respiration: it is formed during the process of fermentation, andthe decomposition of all organic sub- stances. But its absorption and reproduction in. nature seem to be perfectly balanced. It exists primarily in the air to the extent named and is equally diffused throughout the mass of it. Plants spring up and grow and form their substance by its absorption from the atmosphere both di- rectly and through the water which dissolves it. Plants de- cay and return their carbonic acid to the atmosphere. Animals feed upon the vegetation, convert the carbon into carbonic acid in their system by the production of vital heat, which is a true process of combustion; and exhale the gas from their lungs. Men dig coal from the bowels of the earth or cut timber from the forests and use these for fuel; in the combustion enormous quantities of carbon stored up in these substances are changed into carbonic acid, and are discharged into the air, in which it isimmediately diffused. The succeeding generations of plants take this new supply and convert it to their uses and thus a grand routine is completed and the precise balance is maintained. This is but one of the niany beautiful instances of the operation of a set of natural laws, the effects of which produce what. is called the balance of nature; or the conservation of force. Both of these terms are well applied, and strictly correct, for as every operation of nature consumes force, it is the balance of these forces which maintains the equilibrium of the universe, preserving order and regularity of motion, which goes on undisturbed as generations come and go and centuries roll around; typifying the eternity of matter and the indestructible nature of elements. THE SOURCES OF NITRIC ACID. fe APT ER XI. NITRIC ACID.—ITS COMPOSITION, AND USES IN THE GROWTH OF CROPS. Nitrogen itself is wholly inert and has no positive action in nature. Its office is wholly negative. But when com- bined with oxygen as nitric acid, or with hydrogen as am- monia, it becomes endowed with the most active properties. and enters into the most interesting and useful combina~ tions in the structure of organic matter. Nitrogen forms’ one-sixth part of the animal tissues and the same propor~- tion of the so called nitrogenous, or albuminoid portions of plants. But there is no evidence to prove that the nitro- gen so combined in organic substance Is derived directly from this element as it exists in the atmosphere; but on the contrary abundant reason to believe that it enters into the composition of plants in the form of nitric acid, which is a combination of nitrogen and oxygen. Moreover we are at a loss to know how this nitric acid enters into the compo- sition of plant tissue; the general drift of the evidence gained by the most careful experiments going to show that it is carried into the plants in solution in the water of the soil, and is derived from the ammonia which is abundantly evolved from decaying organic matter in the soil and only to a very small extent from the contributions drawn from the atmosphere. The sources of nitric acid are threefold; first; from the atmosphere in which it exists as a product of the decompo- sition of organic matter and from which it is washed by the rains which dissolve it; second; from a peculiar fermenta- tion of organic matter, in the soil or in manure; which is produced by the agency of a low form of plant life; agerm or fungus which grows and spreads through the mass and causes the oxidation of the nitrogenous matter in it; or it 66 THE CULTURE OF FARM CROPS. may be that it acts upon the nitrogen left free by the with- drawal of the oxygen from it and so induces its combina- tion with oxygen; and, third; nitric acid is formed in the atmosphere by the action of electrical discharges by which the oxygen and nitrogen are brought into combination; in the manner previously mentioned. The atmospheric sources of nitric acid are not sufficient to account for the large quantity of it which is found in any ordinary crop. Various experiments have been made for the purpose of ascertaining the amount of combined nitrogen, in either of its forms, which is gathered by plants from the atmosphere. The average of all the determina- tions which have been reached, give the quantity at about 10 pounds per acre. But the average consumption by the crops equals 44 lbs. per acre. So that this atmospheric supply is wholly inadequate for the growth of farm crops. This is one of seeming anomalies of nature, that while no less than nearly 20,000 tons of nitrogen, as it exists in the atmosphere, rest over one acre of surface, a crop cannot procure the small quantity of 44 lbs. per acre from all this vast atmospheric store. But this is quite consistent with the regular course of natural operations. The elements form combinations, as has been shown of an infinite num- ber and variety, and it is only in these combined forms that they serve their ends. The elementary carbon can provide plants with their supply of carbon, only through its combination with oxygen; and in like manner the ele- mentary nitrogen requires a certain preparation to fit it for assimilation by plants. The small quantity of nitric acid which is procured from the atmosphere by the crops, is however sufficient for all the practical needs of the intelligent farmer. He does not de- pend upon the air to supply his crops with this scarce and most valuable nutriment. By a wise course of economical management he accumulates a large amount of organic matter rich in nitrogen, the decay of which he aids by his skillful methods, and so provides an abundant stock of food for his crops. Ifthe atmosphere then contributes a fourth HOW NITER IS FORMED IN THE SOIL. 67 of what his crops need, he is the gainer by so much, and by his abundant provision in the form of manure and fer- tilizers, his fields are yearly increasing in fertility. The formation of nitric acid and nitrates in the soil by the ac- tion of the special ferment alluded to is of paramount im- portance to the farmer. The manner by which this result may be produced artificially, and has been effected for the production of saltpeter, is as follows. A mass of soil rich in organic nitrogenous compounds, as urine, animal excre- ments, vegetable and animal matter of any kind, is put in- to a heap and mixed with a quantity of quicklime. The heap is put up loosely so that the air can penetrate easily through the mass. In course of time the mass is leached, and the liquid, highly charged with nitric acid, is neutral- ized with carbonate of potash; the solution is then evapor- ated and nitrate of potash or saltpeter is produced. These heaps are known as “niter beds” and the process was for- merly used extensively for procuring saltpeter for the man- ufacture of gunpowder for warlike purposes, before the great natural deposits of niter in South America were dis- covered. These natural deposits are now the chief source whence saltpetor of commerce is procured, and yield thou- sands of tons yearly of nitrate of soda for use as a fertilizer. It is a probable supposition that the origin of these deposits was similar to that of the artificial niter beds. A vast mass of organic matter rich in nitrogen, such as fish, or plants of some kind, had accumulated in shallow lagoons of the ocean, and had been covered with mud by gradual deposition. The action of the atmosphere in the hot arid climate of Western South America favored the nitrification of the mass and the nitric acid formed, combined with the soda of the salt from the sea water to form nitrate of soda. One of the frequent convulsions of nature common to that coast eleva- ted the surface of the land, gradually, during the formation of the deposit, and the gradual rise has left the niter beds in their present position at a distance from the ocean. The compost heaps made by the farmer, in such a manner as to favor this process of nitrification, form a source whence a 68 THE CULTURE OF FARM CROPS. large supply of this indispensable plant food may be pro- cured. It is quite possible, not to say probable, that the oxida- tion of nitrogen may occur directly in these beds. A large quantity of free nitrogen is necessarily left in the mass by the consumption of oxygen in the decomposition of the or- ganic matter. This nitrogen is dissolved to some extent by the water in the heap, the water is decomposed by the chemical action, and in the aggregate result of the vigorous chemical actions and reactions going on there is no violent assumption in the conclusion that the free nitrogen is seized upon to some extent by the omnipotent oxygen and reduced to nitric acid. The possibility or probability of this is all on the side of the farmer who may avail himself of it as far as possible, by providing the means for it and securing the results of it if there are any. The earth is a great magnet and electrical disturbances are constantly going on, through its mass and upon its sur- face. Every spark of electricity, from the lightning flash, to the tiny discharge from weak currents in the soil, cause a union of the elements of the air and produce nitric acid. It is quite possible, and even probable, that many vexed questions in regard to the source of the nitrogen gathered by such plants, as clover, from the soil, may in time find their solution in this direction. So far we know that a crop of clover gathers an enormous quantity of nitrogen from some source. All we know of the subject tends to point out the soil as the source of it. A fertile soil may contain from two to three tons of nitrogen to the acre, and of this a crop of clover will gather in its roots and stubble and leave upon the soil from 150 to 180 Ibs.; while no other crop could ex- tract from it enough to supply the needs for any profitable yield. The clover has procured this nitrogen in some hid- den way; how we know not; but we know the fact. This is sufficient for the purposes of the farmer, who may specu- late upon the causes of it, while he avails himself of the re- sults. It may be however that a large portion of this gathered nitrogen has been brought up from great depths EFFECTS OF ELECTRICITY. 69 in the soil by the long tap roots of the clover plants and to which the roots of other plants cannot reach; and that some of this organic nitrogen, at least, may have been procured from nitric acid produced in the deeper soil by the action of electrical currents. Perhaps this source is over estimated; but it is certain that the action of electrical discharges through the soil, which are quite as frequent as those through the air, and from cloud to cloud, have as yet not been con- sidered to any extent, if at all, in the discussions and inves- tigations of this exceedingly important question: “where do plants procure their nitrogen?” THE CULTURE OF FARM CROPS. Crear TER XT AMMONIA.—ITS COMPOSITION, PROPERTIES, AND RE- LATION TO VEGETABLE GROWTH. Ammonia has been previously mentioned as a compound of nitrogen and hydrogen gases. It has some very inter: esting and important properties in regard to organic mat- ter, and has been made the subject of much study and ex- periment by agricultural physiologists. It is a colorless gas, but offers in its other remarkable properties, an instance of the wonderful changes in matter made by chemical com- bination. Its primary elements have neither taste nor odor, but when combined, this product has a most powerful penetrating odor; a burning acrid taste: extinguishes flame; is not combustible as hydrogen is; instantly suffocates ani- mals; kills living vegetables, and corrodes their substance. It is absorbed in large quantities by porous substances; charcoal absorbs 95 times its own bulk of it; peat takes up a large amount of it, varying with its own condition; decay- ing vegetable matter also takes up and holds it in its mass; porous soils, clay, and iron oxide mixed in the soils of a red color, are capable of absorbing and retaining it within their pores, when it is brought into contact with them. But water absorbs ammonia to a far greater extent than any other substance. Ifa bottle filled with the gas is in- verted in water, the water will instantly rush up and fill the bottle, absorbing and dissolving the ammonia and occu- pying its place. The solution of ammonia in water is lighter than water to the extent of one-eighth; and has the same properties as the gas itself. Ammonia is an alkali and combines with acids; changes vegetable red colors to blue, and in combining with some acid gases forms solid substances; as for instance when carbonic acid gas is mixed with it, the two gases combine INFLUENCE OF AMMONIA UPON VEGETATION. Ti and form solid carbonate of ammonia, in the form of mi- nute particles appearing as a white cloud. A feather dip- _ ped into diluted hydrochloric acid, or in vinegar, and held over a bottle of ammonia water, or any substance from which ammonia is escaping, is soon covered with a white downy substance, which in the one case is chloride of am- monia, and in the other is acetate of ammonia. ‘This test. of the presence of ammonia is an easy method of distin- euishing it where its escape from decomposing substances is suspected. This gas is only little more than half the weight of air (59 hundredths); hence it ‘rises and is diffused in the air with ease. It consists of 14 parts by weight of nitrogen (82.545 per cent.) and 3 parts by weight of hydrogen (17.455 per cent.). In nature it exists in large quantity. It is almost uni- versally diffused throughout the atmosphere and in the surface soil and the waters of the atmosphere and the earth; but itis not known to enter into any of the mineral com- pounds of which the earth is composed. One exception may be noted and this is guano; a substance supposed by some to consist of the decomposed excrements of sea birds, and by others of infusorial matter, having some relation to mineral substance. But in either case guano would be of organic origin and a product of the decomposition of or- ganic matter. This substance when free from earthy mat- ter contains a large proportion of ammonia, both free and combined, and is the most valuable and costly fertilizer known. Ammonia chiefly exists in a state of combination as carbon- ate, but also asa chloride, and anitrate. Asit combines very freely with acids, and most easily with carbonic acid, it is rarely found free in the atmosphere, and then only tempor- arily; but it is as easily separated from its combinations, on account of its volatile character which makes it readily subject to the influence of heat. The influence of ammonia upon the growth of plants is exceedingly active. It not only promotes the growth with re THE CULTURE OF FARM CROPS. rapidity and luxuriance, but it appears to exercise a con- siderable control over the functions of vegetable life. In this regard there are several special properties of this com- pound which should be clearly understood, by the farmer and student of agriculture. First.—It has a powerful affinity for acid substances, and unites with them with great facility as it escapes into the atmosphere, or meets with them in the soil. Hence when formed or liberated in the stables; in the cattle yard; man- ure and compost heaps and in other places where organic matter is in a process of decay; it unites with such acid sub- stances and forms salts or saline compounds. And these salts appear to exert a considerable influence upon the growth of crops. Second.—This affinity for acid substances however, is much less active and strong than that possessed by other al- kaline compounds, as potash, lime, soda and magnesia. Hence if any one of these alkaline substances is brought in- to contact with a salt of ammonia, this is at once decom- posed and its acid is taken up by the stronger alkali, while the ammonia is separated and set free in its gaseous state. If a small quantity of sal-ammoniac (chloride of ammon- ium) is powdered and is. mixed with twice its weight of powdered quicklime, the ammoniacal gas is liberated, and the chlorine unites with the lime. This is one of the several methods of procuring pure ammonia, and is an instance of one of the very many useful functions performed by lime in the soil for the benefit of farm crops; especially upon lands which have been made rich in organic matter by liberal manuring, or which are naturally well supplied with decay- ing vegetable matter, as reclaimed swamps or peat bogs. It also shows the injurious effect of mixing lime with man- ure of any kind in which ammonia exists, or can be devel- oped by the decomposing agency of the lime, unless at the same time, the lime is used in moderate quantity and a con- siderable amount of soil or other matters which absorb am- monia are used to counteract this result of the lime. Third.—The salts and saline compounds which are formed AMMONIA ABSORBED BY THE SOIL. te by the union of the ammonia with acids, are like the gas itself, exceedingly soluble in water. Two results of this property follow. The carbonate of ammonia which is formed in the atmosphere by the union of the ammonia and the carbonic acid, is readily dissolved, and is washed down and brought to the earth by the rains and dews; the soil is thus supplied with most useful food for the crops, while the air is freed from a noxious substance and is purified for the use of mankind and animals. Also whatever combina- tions of ammonia are formed in the soil, are dissolved and diffused through it by the rains, or other moisture derived by condensation, and are carried everywhere in all direc- tions by the movements of this moisture among the fine particles of the soil. Fourth.—As this gas is readily absorbed by porous earthy matter, it is readily taken up by the soil and held in reserve to be yielded up to the roots of plants with the water of the soil which draws upon this source for asupply. Hence the ammonia yielded by the decomposing organic matter of the soil, is held safely but loosely among the finest particles of the soil as an intermediate deposit, to be drawn upon for future use as it may be required by the crops. This prop- erty of fine dry soil is of great importance to the farmer for it is exerted to a large extent. All porous substances— as. has been previously explained—have, among other proper- ties, that of oxidizing organic matter. Hence it has been found that the dry earth used as an absorbent in the do- mestic earth-closets and urinals, so rapidly and effectively oxidize these matters which are rich in nitrogen, and in which the nitrogen is easily converted into ammonia, that they wholly disappear, and the dry earth after having been used repeatedly nine times in the closet, with alternate pe- riods of rest, still gives no indication of having been used for this purpose in the slightest offensiveness, or appearance of containing any disagreeable substance. The organic mat- ter has disappeared; having evidently been resolved by ox- idation into its elements and the gases having been absorbed and held by occlusion in the interstices of the porous earth. 74 THE CULTURE OF FARM CROPS. This fact is full of significance to the farmer who may per- ceive in it a proof of the necessity of a thorough pulverization of the soil for the maximum growth and yield of his crops. Fifth.—In the state of carbonate,—in which it mostly ex- ists, because of its affinity for this acid and the abundance of it in the atmosphere—ammonia decomposes gypsum (sulphate of lime) and changes acids with it; forming sul- phate of ammonia and carbonate of lime. This action only goes on however when moisture is present. The beneficial action of gypsum (the common agricultural ‘‘plaster”) upon clover, corn and other crops has been ascribed to this single property. But popular impressions are easily formed and take a firm hold upon the popular mind, whica does not stop to think and reason, or take pains and time to observe closely; hence the opinions thus formed are too often only superficial and partial and are not substantial enough to base a rule or principle upon. No doubt some of the favora- ble results of an application of “plaster” to the soil, in some cases, may be due to this mutual action of gypsum and car- bonate of ammonia, or of gypsum and free ammonia upon each other; but there are other principles involved in the subject which must be referred to in a more appropriate place hereafter and to which much of the effect of gypsum is undoubtedly due. Nevertheless as it is a fact that gyp- sum and carbonate of ammonia do exert this mutual reac- tion upon each other, and under favorable circumstances the result may be conspicuously marked upon the growth of the crops. For 100 lbs. of common finely ground gyp- sum—a comparatively small quantity to be spread over an acre of land—will fix or unite with nearly 20 lbs. of am- monia, containing 16% lbs. of nitrogen;—a comparatively large quantity of this scarce and invaluable plant food, for it is equivalent to about 60 Ibs. of nitric acid and nearly 100 lbs. of nitrate of soda, which is considered a very lib- eral use of this most active fertilizer. And this fact is one to be studiously considered and judiciously applied by every intelligent ‘farmer. Sixth.—The presence of ammonia in a soil which contains DECOMPOSITION OF AMMONIA. 75 decaying animal and vegetable matter, induces this matter to attract oxygen from the air with greater rapidity and abundance. That is, in simple words, ammonia assists in and hastens the decomposition of organic substances, and the result of this is that compounds are formed which react upon the ammonia, combine with it and form ammoniacal salts. When these are in their turn decomposed by lime or other substances in the soil, they become more available plant food, being more advanced towards a fit condition for this purpose and for assimilation into the circulation and cellular tissue of vegetables. Seventh.—The most important property of ammonia, and that consequently of the greatest interest to farmers, is the ease with which it undergoes decomposition, in. the air, the soil, and the interior of plants. In the atmosphere it is intimately mixed with a large quantity of oxygen and it also comes into close contact with this gas in the soil. By certain influences already referred to it undergoes a slow and constant decomposition, or oxi- dation, its hydrogen being converted into water, and its ni- trogen, wholly or in part, is changed into nitric acid. This change certainly goes on within the soil and most probably within the substance, or in the sap, of plants. That some- thing of this kind goes on within the plants, as well as in the soil, seems to be clearly indicated by the extraordinary effect of a small quantity of ammonia or of its compounds; in a remarkably short period of time; upon the condition of vegetation. This is very conspicuously seen, in the sim- ple experiment of growing plants in pots where the condi- tion of the soil can be controlled and the effects of plant food noted. A few drops of ammonia added to the water used for the plants, will be seen to change the color of the leaves in a very short time; producing a deep vivid verdure, where before a pale yellowish color prevailed. Investiga- tions are in progress to decide this question but a speedy solution is not likely to be reached. The conditions under which plants exist and the reactions of the compounds of which they are made up upon each other are so varied, that 76 THE CULTURE OF FARM CROPS. a judicious student hesitates to form conclusions, and pas tiently repeats and verifies his experiments; and at the last when he is himself convinced of the truth of any result, he is slow to declare it to the world, but watches it and tries it in other ways until doubt has no longer any existence. Hence the slow progress of knowledge in the true science of agriculture and the caution with which farmers who are following up the experiments of professional students, should watch the results, and form practical conclusions therefrom. But the peculiar action of ammonia upon plant growth, and the analogy which exists between its action and that of other compounds, lead us to believe that ammonia enters in- to the circulation of plants, and that the hydrogen of which it contains so large a proportion, there separates from the nitrogen, and combines with other organic elements which enter by the roots or leaves and thus aids in producing the various solid substances of which plants are constructed and made up. The nitrogen is then fixed in the flowers, helping to produce the bright coloring matter and the agreeable odors; and to form the gluten and albumen of the seeds, and other parts. These and other important considerations will be more fully considered in another chapter. It may be exceedingly interesting to note here, the results of some careful tests made by a German agricultural chem- ist and experimenter, in regard to the effects of ammoniacal manures upon the yield of grain and the proportion of the nitrogenous substances contained in it under varying cir- cumstances. A number of experimental plots were treated as follows, and were sown with wheat. Then from 100 parts of the produce of these plots the various amounts shown of gluten and starch, and the increased product, were estimated. Gluten. Starch. Produce. WVHEMOUE THATIUUCY. 5... ase. aveaciabntesteusey DOLE 66.7 3 With rotted vegetable matter only.. 9.6 65.94 5 SOW AOU NG. Consens cccenousdccecconerenetees MLO 62.3 7 PLOESOVOUIIUE ccc vo tan date oshese eather a 61.64 10 IVES PUNE ss fccewceaserdaactaceaeaeneseeeeeat eet 42.8 12 INS UDISOLL sid css cens cease swowdecenaseeeennion! Mm ODMLE 41.44 14 DrigdWOLOO 4b: sccdaneoosansics ccocudk fees ICE 41.3 14 rieR PING Saris, siedeveecateieucas: ce oe 39.3 at: EFFECT OF AMMONIA UPON WHEAT. rie These facts seem to show that as the ammonia in the man- ures increase, the yield of the crop grown is larger, and the more nitrogen is contained in the produce. Similar results have occurred in the ordinary operations of the farm and the facts have led farmers to use artificial manures rich in ammonia for the express purpose of procuring more valua- ble grain and a larger yield of it. Millers knowing these facts have taken special pains to acquaint farmers with them, with the purpose to procure a better quality of grain for making more valuable flour. THE CULTURE OF FARM CROPS. COA PO eek THE SOURCES OF THE CARBON OF PLANTS.—HOW IT ENTERS INTO THEIR CIRCULATION AND SUBSTANCE It is obvious to the cultivator of the soil that the various plants of which his crops consist, are supported by the earth and the air, both. It is necessary to the intelligent culture of farm crops then to learn how much plants owe «0 each of these; and for which of their elements they are indebted to the soil and for which to the air. As carbon contributes the larger part of their substance to plants this element de- mands the first consideration. Carbon is a solid substance and is therefore incapable of entering directly into the structure of plants. It must then present itself to the roots of plants in the soil, in solution in water; and to the leaves in a gaseous form; for it is a law of plant growth that no solid substance can enter into the roots; and no liquid or solid substance can enter the leaves or any other portion of the plant which is above the ground. Therefore the sources of all vegetable carbon must be the soil in which the roots of plants exist, and through which they penetrate; and the air in which the stems and leaves of plants are constantly bathed. There is always a large quantity of vegetable matter in a decaying state in the soil, and which is made up of the remains of previous vegetation ; and the farmer is continually adding to this by the manure which he applies to the land for the purpose of feeding his crops. And it has been shown that about one-half of this matter consists of carbon. The question then arises; is this carbon of the soil, the source from which plants derive their supply; and do they feed upon it by and through their roots; or do they derive it from the air, in which we have learned that a vast amount of carbonic acid exists in the form of an evenly diffused mixture. It is not usual for far- WHENCE DO PLANTS DERIVE THEIR CARBON. 79 mers to consider this question with much interest, if at all; giving more attention to the other elements of plant growth and leaving the carbon to take care of itself. But it is a question which should be carefully considered, because of its importance and because other questions which draw atten- tion from it, may become more prominent than they deserve. We know that there was a time when no vegetable mat- ter existed in the soil and when vegetation first covered the earth’s surface. Then the first plants must have grown and matured without the aid of any vegetable or animal matter in the soil and could have derived their carbon from no other source than the atmosphere, directly; or indirectly, by its presence in the water in the soil. It is also known that soils which have been perfectly arid and have produced no vegetation, or very little previously, yield abundant ‘crops when brought under culture by irrigation, and that plants are often grown in water and in some cases grow lux- uriantly without having any connection with the soil. Further it is a common practice for farmers, when their lands are unable to produce maximum crops, to seed them to grass or clover and to leave them for years to recuperate and become enriched by the gradual accumulation of veg- etable matter in the soil; and when these lands are again plowed a rich black soil filled with carbon is found, where but little organic matter existed previously. This also ap- plies to lands under forest growth, and to the rich prairies of the west, where the dark vegetable mold lies many feet in thickness and contains an inexhaustible supply of carbon; as well as to the peat swamps in which enormous quantities of carbon have been accumulated. We may also take into consideration the vast beds of coal which have been made up of accumulations of vegetable matter, the luxuriance of which, proved by its remains, still to be recognized in the coal, almost surpass imagination; and may then ask, whence did all this vegetable growth procure its carbon, which has gradually accumulated in the soil to this vast extent; and which we can perceive still accumulates under our own personal observation ? 80 THE CULTURE OF FARM CROPS. Any reasonable person will be impelled to reply, the atmos- phere must have been the first source of it; that all these plants must have existed upon such carbon as they could gather from the air, and that as they perished, they left a supply in the soil which was not fit to nourish succeeding generations, and hence accumulated during the vast periods of time which have elapsed since vegetable growth first began. | This reasoning is plausible and seems free from objection, and would seem to justify us in concluding that plants de- rive their carbon directly from the atmosphere. In some cases this must be certainly true, for there is no other ex- planation to be given of the circumstances. But as regards the culture of farm crops it would not be safe to conclude that the vegetable matter of the soil has no relation to the growth of plants, and that the carbon existing in the soil does not contribute to the carbonaceous substance of vege- tables. For facts prove otherwise. Just now the public interest is in a lively condition of agitation in regard,to the question, whence do plants gather their nitrogen, and the equally important question in regard to carbon is neglected. Farmers are actively engaged in procuring nitrogen in va- rious forms at very considerable expense, believing this to be the chiefly indispensable agent in fertilizing their crops. But a few farmers of intelligence, and used to closely ob- serve what is going’ on in their fields, have not lost sight of the importance of a large supply of combined carbon, and are adding to their fields as large a quantity of carbona- ceous matter as they can procure, with such nitrogen as may seem to be adequate, and are thus avoiding the ex- treme to which the popular belief seems to have turned. In considering this question in the light of present expe- rience, it may be considered that at first only a very poor and weak growth of inferior plants covered the soil; or that. by reason of the exceedingly active chemical changes which were then occurring, the soil was highly charged with carbon in such forms as were available for plant food. In the one case vegetable growth would proceed slowly to fill CARBON DRAWN FROM THE AIR. 81 the soil with decomposing matter and prepare it for a bet- ter product; and plants procuring a portion of their carbon from the air and gradually finding an increased supply in the soil from the decomposed organic matter, there would, in time, be a surplus, and this surplus would constantly in- crease, and gradually accumulate and fill the soil. In the other case the vegetation would be developed on an enor- mous scale, just as we have reason to suppose it was at the period when the carbonaceous matter which supplied the materials for the vast coal beds was deposited. Climate necessarily would have much to do with this, as it has now; for in tropical regions the vegetation is exceedingly luxu- riant, forming dense jungles through which it is impossible to pass without laboriously cutting a way with axes, over an enormous deposit under foot of the tangled and decompos- ing remains of previous luxuriant growth. We are forced to believe from the evidence that plants may derive a large portion of their carbon from atmospheric sources, and that they derive a considerable portion of it from the soil. That they are fitted by nature to draw sus- tenance from either source or from both; and that the pro- portion of their food which is derived from either source depends upon a variety of circumstances; such as the nature of the plant; the period of its growth; on the soil; on the abundance of provision furnished by the soil; upon cli- mate; season; and other circumstances; so that the most reasonable conclusion would be, that plants, like animals, have a power of adapting themselves, to a certain extent, to the conditions in which they are placed, and of finding aliment, and supporting life, and of making growth, by the help of such nutriment as they may most easily reach. Just as sheep, which are herbivorous animals, under cer- tain conditions are known to live upon fish, and to thrive as well to all appearances upon this unusual diet, as upon the pastures. But supposing that plants derive the whole of their car- bon from the air, or are able to do so; then knowing that no other compound of this element is found in the atmosphere 82 THE CULTURE OF FARM CROPS. to any appreciable extent, than carbonic acid, and that this compound is everywhere diffused throughout the atmos- phere and is always found in solution in water, the con- clusion cannot be avoided, that it is from carbonic acid that the carbon of plants is derived, primarily. This con- clusion is supported and confirmed by the knowledge that plants absorb carbonic acid through their leaves inthe sun- shine, and that they will die in an atmosphere from which carbonic acid is wholly excluded. Again supposing that plants derive their carbon wholly from the soil or are able to do so, then, knowing that the most abundant product of the decay of vegetable matter is carbonic acid; and that in a well manured soil filled with decaying vegetable matter, this gas must be quite abun- dant; and that water dissolves it freely, we must be satisfied that it is from this carbonic acid, absorbed with the water of the soil by the roots that the carbon of plants is derived. In either case it is the carbonic acid which supplies the car- bon, and it is most probable that this enters the plant both by the roots, and leaves. Thus whether from the earth or the air, this gas furnishes an unfailing supply of food for plants from which their carbon is derived. But when water passes through the soil it takes up what- ever soluble substance it may meet—potash; soda; lime; magnesia; silica; &c.; and conveys them into the plants by the medium of their roots. Do the roots exercise a super- vision over the absorbed waters and reject every soluble form of carbon but that of carbonic acid? This is a ques- tion of interest too to the farmer and applies directly to the practice of manuring the land. This subject is out of place as yet, but the question is pertinent to the present enquiry. It is known that plants do not exercise such a watch and have no discretionary power over the water which they ab- sorb; for various coloring matters as madder and the juice of poke root berries have been absorbed into the circulation of plants and have imparted their color to the flowers, and other parts. These coloring matters then undergo a chem- ical change in the plants and even afford nutriment. Sugar CARBONIC ACID A FOOD FOR PLANTS. 83 sum and gelatine have been thus fed to plants, with the ef fect of making them grow vigorously. A great variety of organic substances containing carbon may therefore be ab-~ sorbed into the plants and afford nourishment. Practical farmers act on this principle and it forms the basis of many of his operations and daily labors as he accumulates a stock of organic substances in the form of manures as food for his crops. THE CULTURE OF FARM CROPS. Siar L yh + TV.. SOURCES OF THE NITROGEN OF PLANTS.—ITS COM- POUNDS AND THEIR EFFECTS UPON THE GROWTH OF PLANTS. While the quantity of nitrogen contained in plants is small as compared with that of other elements, yet its office in the structure of plants, and especially of their seeds, is so important that careful and patient study of the character and changes of this element is well worthy of the time em- ployed. It is not always the most abundant elements in nature that are the most worthy of regard. The chief pur- pose of many farm crops is the seed, and although this part of their substance may be quite insignificant in quantity, yet it is often the most precious and highly valued; and it is in the seed that the nitrogen of plants is most abundantly stored. Again while the nitrogen in the more bulky crops may be but 1 to 2 per cent., this element isthe most impor- tant for the profitable feeding of farm stock: as it contrib- utes largely to the formation of the muscular tissue and supplies the waste of it by muscular exertion. Moreover, any substance is to be valued according to the difficulty of obtaining it. A diamond is so highly valued as it is, because a whole year’s labor of several men may be spent in the vain search for one, and its enormous price in commerce merely represents the labor spent in its success- ful discovery. Nitrogen is the most costly substance the farmer is obliged to procure for the purpose of feeding his crops, and although it is the most abundant constituent of the atmosphere, yet it is so inert and passive and submits to combination with other elements so unwillingly, that na- ture supplies only a small portion of what the soil requires of it, to produce a profitable crop. It is a most serious fact in regard to this point, that the greater part of the farmers THE IMPORTANCE OF NITROGEN. 85 labor and his largest expenditures for fertilizing matter, are made necessary for the purpose of supplying his field with an adequate amount of nitrogen for the growth of good crops. Does he spend labor and care in the preparation of the soil? it is that nitrogen compounds may be developed in it. Does he feed his cattle with rich food purchased at great cost? it is that the manure may be enriched with as large a quantity as possible of this valued element. Does he laboriously gather organic matter and lime, and compost these with his manure, and sedulously watch over the de- cay of these materials? it is that the nitrogen developed may not be lost, but preserved for use to supply the never satisfied needs of his crops. And thus his thoughts by day, and his reflections by night; his labors; studies; and ex- penditures; all center upon this one most important, but otherwise inconsiderable element of vegetable matter. With regard to an element so difficult to be procured, it is a serious fact that its consumption in the soil is compara- tively large. A crop of hay takes 60 Ibs. of it from one acre of the soil; a crop of clover removes 180 lbs. ; wheat carries off 45 lbs. Hereafter this subject will be pursued to its completion, here it is the purpose to consider the sources from which plants can procure their supply rather than the amount of it which they need. When we come face to face with this question we are met with the fact, that the only source from which any large quantity of nitrogen can be obtained is the atmosphere. Nitrogen does not exist in the rocks excepting in those of an organic origin as coal; the atmosphere is the great store- house of it. Organic matter contains a considerable quan- tity of it, and its decay in the soil furnishes the crops with a large part of their demands; but the first plants which covered the soil must have procured their supply, as they procured their carbon; viz, from the atmosphere, primarily. But in coming to this conclusion it by no means follows that the nitrogen of the atmosphere is directly absorbed by plants and made subservient to their growth; or that it is absorbed in an uncombined state through any other me- 86 THE CULTURE OF FARM CROPS. dium. Though the leaves of plants are continually sur- rounded by nitrogen, and the roots may be bathed in water containing it in solution, yet there is no evidence to show that any plant is so constituted as to avail itself of this supply. Indeed there is’a good deal of evidence to prove that the leaves do not absorb nitrogen and that if any uncombined nitrogen at all is contributed by the at- mosphere and used by plants, it is through the roots that it must enter into their circulation. But that even this oc- curs is a matter of opinion only, with no evidence to sup- port it. It is an essential part of good farming to break up the land and reduce it by thorough tillage, by means of the most effective implements, to a loose and mellow condition, so that the air can have access to the decaying organic mat- ter in the soil; as well as to the living roots which permeate the earth in all directions to considerable depths below the surface. When the air is thus admitted to the roots, it is not. impossible that some of the nitrogen, as well as some of the oxygen, may be absorbed and made use of by the plant di- rectly; but in the changes in the organic matter which oc- cur, it is known that nitrogen is disengaged in a form in which it can be appropriated by plants; and it is probable that some atmospheric nitrogen may also be seized upon and converted into plant food at the same time. To what. extent this may happen however we have as yet no certain re- sults from which any definite knowledge has been reached. If any nitrogen enters the roots of plants in solution in wa-_ ter, the quantity is very small and. uncertain. When water is exposed to the air it gradually absorbs both oxygen and nitrogen; as has been previously men- tioned. The whole quantity of these mixed gases thus tak- en up amounts to about 4 per cent. of the volume of the water and in rain water about two-thirds of this quantity consists of nitrogen. A hundred cubic inches of rain water will therefore carry into the soil 2 inches of this gas. But this water in passing through the soil dissolves also- other substances; carbonic acid and various solid matters and in THE NITROGEN DERIVED FROM THE AIR. 87 doing so gives off a portion of the other gases which it had previously taken up and absorbed from the air. Butif the water should actually carry to the roots and take with it into the circulation of the plants 2 per cent. of its bulk of nitrogen, the whole amount of this nitrogen would be quite inadequate to supply the requirements of a crop. For the whole rain fall in this country, during the season when a crop of hay, wheat, or oats is grown, amounts to about 8 inches; and of this at least one-half is evaporated very soon after it has fallen. Ifwe suppose the quantity left in the soil during this period amounts to 6 inches there would be 864 cubic inches of water fall upon a square foot, contain- ing of nitrogen about 17 cubic inches, or about 5 grains in weight. This would give something over 30 lbs. to the acre of nitrogen carried into the soil. But it would be un- reasonable to suppose that more than one-third of this quan- tity would be carried into the roots and be transpired by the leaves of any growing crop. There would then be about 10 pounds of nitrogen carried into the circulation of the plants, which is only one-sixth part of that which is contained in a crop of hay, and one-eighteenth part of that removed from the soil in a crop of clover. This is a rough estimation, but it affords convincing proof that plants cannot depend upon the atmosphere for their supply of this element; but that they draw their chief sup- ply of it from its combinations with oxygen and hydrogen. If it is asked how the first plants grown upon the soil, the origin of vegetable growth upon the earth, gained the nitrogen they required to build up their tissues, it may be replied, that in this case, the earliest plants grown were not of that highly organized character which demanded a large proportion of nitrogen. In the coal beds, which were form- ed of vast deposits of vegetable matter accumulated during lengthened periods of time, are found plants of a far lower character than those grown as farm crops. Mosses, ferns, and semi-aquatic plants made up the larger bulk of them, and as these died and decayed, the little nitrogen they pos- sessed gradually accumulated in the soil in the mass of de- 88 THE CULTURE OF FARM CROPS. cayed matter which remained. This process continually repeated, laid a foundation for a higher character of vege- table growth ; until in time the soil became well supplied with organic matter; and fitted for the occupation of man, who afterwards appeared upon the scene, and entered into possession of a soil abounding in accumulated fertility. We know of our own knowledge that the soil we cultivate, however rich it may be at the first, is very quickly ex- hausted of nitrogen, and that a renewed supply is indispen- sable to the growth of crops. This exhaustion is so rapid that there connot be any material addition to the supply, from the atmosphere. The most important combination of nitrogen is that with hydrogen, known as ammonia; and that this gas enters into the circulation of plants is rendered probable by a variety of circumstances. It is known that ammonia exists in the sap of many plants; as in the beet, birch, and maple, in which it is asso- ciated with cane sugar; in the leaves of tobacco, in elder flowers, in various fungi and in other plants. A species of chenopodium actually exhales ammonia from its leaves; it also appears in ‘the odorous exhalations of many other plants and flowers. Ammonia can be procured from nearly all vegetable sub- stances by distillation; and many vegetable extracts are found to contain it. When wood is distilled in retorts for the manufacture of acid, ammonia is produced. These and other facts of similar bearing are in no wise proofs that ammonia is the form in which nitrogen enters into the substance of plants; either through the roots or the leaves; because there are ways in which it could be pro- duced in the plant by the same converting power which produces sugar and starch in the interior of the plant from carbonic acid and water; and while ammonia is easily pro- duced from coal and wood, yet we know that it does not actually exist in these substances in their natural condition. In the case of tobacco, the production of ammonia by means of a high temperature may be illustrated by a simple ex- EFFECT OF AMMONIA UPON VEGETATION. 89 periment. The sap and dried leaves of this plant contain nitrate of potash (saltpeter) and a small quantity of am- monia. When the dried leaves are burned ammonia is given off in sensible quantities with the smoke, and can be detected by bringing a piece of reddened litmus paper into contact with the smoke when the color will be changed to a blue; or by using a feather dipped into vinegar or any weak acid, the white cloud of carbonate of ammonia will appear. (Litmus paper is used for testing the presence of acids and alkalies. It is absorbent paper steeped in a red or blue vegetable coloring matter, as the juice of red cabbage, of the red beet, or of the berries of the poke root. Litmus is a red color obtained from some species of lichens, and is changed to blue by ammonia. An alkaline liquid or vapor will change the red to blue, and an acid will change the blue to red again. This test can be used by farmers in a variety of ways; in detecting the escape of ammonia from manure, or acidity in milk). In this case however the ammonia may be in part pro- duced by the combustion, which decomposes the water con- tained in the tobacco—to the extent of 14 per cent. in its usual air dry condition—and thus disengages hydrogen, which can easily combine with the nitrogen disengaged in the combustion of nitrate of potash present in the leaves, and so form ammonia. But there are other circumstances which tend to favor the belief, in a much stronger manner, that ammonia does enter into the circulation of plants in many cases. Experience has shown that plants grow most rapidly and luxuriantly when liberally supplied with manures con- taining animal substances. Dried blood; fish scrap; guano; the dung of fowls; decomposed urine and night soil; are all rich in ammonia and are the most efficacious of manures. The same is true of the salts of ammonia. These substances are used when in a state of decomposition and when the evolution of ammonia is in most active progress. [lowering plants also grow with greater luxuriance when a small quantity of ammonia is added to the water given to them. In 90 THE CULTURE OF FARM CROPS. the writers garden at the present time is a bed of red cab- bage; through the center of which flows a drain from the yard in which the manure from the horse stable is kept. On both sides of this drain, for about'3 feet, the red cabbages are blue: and their growth is far more luxuriant than that. of other plants distant from the drain. Is not this a dis- tinct illustration of the fact that the ammonia from the li- quid manure; in which it is shown to be abundant by the litmus paper test; is absorbed by the cabbages and acts up- on the coloring matter with its usual effect? In all these cases however the proof is not decisive; but. it is quite sufficient to make it appear that the probabilities are all in favor of the belief that ammonia does enter into: the tissues of plants when brought in solution in water to the roots and to justify us in holding this belief. But ac- tual proof is wanted before this can be asserted as a fact. The changes which occur in nature are so involved; so in- tricate; so sudden; and so unexpected when experience is at fault; that we should hesitate to found a belief upon any but the strongest evidence, or to base a principle, or a law for our guidance, upon anything but accurate and well de- termined knowledge. So far as the question under consid- eration is concerned this knowledge is wanting; but a mass. of observed facts tending thereto is all that we possess. Other soluble conipounds of nitrogen are formed during the decay and oxidation of animal substances and actually ex- ist in the liquid manures of the stable and yards, and they are likely to be absorbed by the roots. of plants when ap- plied to the soil. Thus urea, a compound of carbon, hy- drogen, nitrogen and oxygen, and containing about one- third of its weight of nitrogen, exists abundantly in urine, and by its decomposition produces carbonate of ammonia. Being very soluble this substance may enter with water in- to the roots of plants and be decomposed within the tissues and made to give up its nitrogen. The same may be ap- plied to other compounds of nitrogen ; so that while the fact that animal manures are very beneficial to the growth of plants, may be considered as favoring the probability that. EFFECTS OF NITRIC ACID UPON VEGETATION. 91 the ammonia contained in such manures enters into the. substance of plants and yields up nitrogen to them, it must also be considered that a portion of the nitrogen contained in plants and procured from decaying animal substances, may be obtained from other compounds of it than ammonia, and in which ammonia may not exist. Nitric acid is invariably present in the juices of plants in combination with potash, soda, lime, and magnesia. Therefore all the evidence afforded by the facts above noted are also applicable to the belief that this acid is one of the sources, at least, from whence the nitrogen of plants is de- rived. This acid has been detected in tobacco, and the sun- flower, and in the grain of barley in the form of nitrate of soda. If we were therefore to infer from these facts that this acid really enters the roots of plants we might draw a certain conclusion. Like other compounds of nitrogen, it may have been formed in the interior of plants during the many changes there effected, and hence its presence proves no more in regard to a solution of the question at issue than the presence of ammonia. The same uncertainty would still exist. But the most recent investigations go to show that of all the forms in which nitrogen enters into plants, nitric acid is the most probable one. It exerts a powerful in- fluence upon growing crops of grass and grains. It changes the color of the leaves to an intense green in a short time; and largely increases the quantity of nitrogenous matter in grain, as well as the yield of the crop. For instance it has been found that a dressing of nitrate of soda has increased the amount of gluten in wheat from 19 to 252 per cent. reducing the starch from 55% to 493 per cent. Many other similar instances are recorded, all tending to show the fav- orable effect of nitric acid upon the growth of vegetation. Heretofore a still more striking instance has been given of similar results from the use of manures rich in ammonia. But recent researches of the leading investigators espec- ially those at the Rothampstead farm in England under the supervision of Sir J. B. Lawes, aided by a most efficient 92 THE CULTURE OF FARM CROPS. corps of assistants, have shown that there is much reason to believe that ammonia is oxidized and changed to nitric acid and in this form it is that the nitrogen enters into the circulation of plants. To sum up the conclusions in regard to this question, of such surpassing interest to farmers, which are presented by a consideration of the facts known in this connection, the following propositions result. First—That uncombined nitrogen of the atmosphere may enter into the circulation to a small extent, either in its natural form of a gas or in solution in water ; and this prob- ably does happen. But the quantity so gained by plants is very small and is wholly insufficient for their needs and only a small proportion of that which vegetables actually contain. Second.—That ammonia has the power of entering into plants and of yielding nitrogen to them to a very large ex- tent and actually in excess of their necessities so that the normal quantity of nitrogen in the product is largely in- creased; and it does appear, but is not proved, that plants do derive nitrogen from this source. Third.—That in like manner nitric acid has the power of entering into plants and of yielding nitrogen to them to a larger extent than they need to produce a normal product and there is reason to believe that plants do derive the largest portion of the: nitrogen they contain from this source. Fourth—But there is also reason to believe that ammo- nia is changed to nitric acid in the soil, and perhaps in the plants, and in this combination it is that nitrogen enters the roots of plants and contributes to their substance. THE INORGANIC ELEMENTS OF PLANTS. PART SECOND. ee = yas er ie eV THE INORGANIC ELEMENTS OF PLANTS. When any vegetable substances are burned in the air, the whole of the crganic elements disappear, and a small quantity of ash remains. The proportion of the substance which has disappeared varies from 88 to 99 per cent. This. has all been derived from the air, and is made up of the four elements which have occupied our attention up to this point. The small remnant left after complete combustion constitutes the inorganic elements of plant growth. These are now to be studied. The results of recent investigations have wholly exploded the notions which formerly prevailed, to the effect that this. inorganic matter was of no serious importance to the crops, and was a mere accidental circumstance, and might be ab- sent without any serious detriment to the growth of the plants. It was discovered in course of careful experiments that this ash of the plants represented exactly the various mineral substances which were taken from the soil, and that these, to the smallest proportion, were of vital necessity to the plants. The results of long continued study, finally gathered into systematic order, showed that on whatever soil a plant might be grown and mature its seed fully, the quantity and char- acter of the ash is nearly the same; and that though grown on the same soil, plants of different species and character leave an ash entirely unlike; the ash varying characteristi- ‘94 THE CULTURE OF FARM CROPS. cally with the species. Moreover it was found that when a plant was grown out of the soil; and with its roots envel- oped only in water; it grew with equal luxuriance as if grown in the soil, provided that the water held in solution the same mineral substances which were found in the ash of the same species, together with the needed quantity and variety of its organic elements. Thus the soil was found to possess functions of more importance to plant growth than the mere mechanical support for its roots, and really sup- plied to the plant a number of constituents. without which, or any one of which, the growth was enfeebled or wholly failed. Hence there was no longer any doubt that the ash of plants represented really essential portions of their nutri- ment, and the farmer then was able to understand the whole secret of the art of manuring; viz; that to grow abundant crops every constituent part of the plants must be present in the soil, or if not, they must be supplied to it in the form of manures or fertilizers. This discovery necessarily modi- fied the notions held by farmers, and regulated the prac- tices of agriculture in every branch. One of the most use- ful reforms in thought and practice was to abolish the idea which was prevalent among unintelligent farmers, viz, that books and other literature were totally useless to them, and that the only way to become good farmers was to spend a life time in copying the ways and methods of older men, and learning from them what they knew of their art. We have now learned that while this is all useful, there is some- thing else which is pre-eminently necessary; viz; to study the laws of plant growth and with the knowledge thus gained from books and other sources to give careful and in- telligent consideration to the nature of the soil; the princi- ples upon which its proper culture are based; the most perfect machinery for this culture; the ait of manuring; the nature and use of artificial fertilizers; and the produc- tion of manure, made richer in the needed elements of plant growth by feeding cattle. And for the purpose of encouraging this study and of spreading abroad the neces- sary information for it; a special literature devoted to agri- THE FEEDING FUNCTIONS OF PLANTS. 95 culture, consisting of books and periodical journals, sprang into existence, and was eagerly procured and read; and lastly special schools for teaching the science and art of farming were established jointly with farms and laboratories for experimental culture and chemical investigations. Thus step by step the art of growing farm crops became an intelli- gent industry, and farmers are respected in proportion to the importance and dignity of their vocation. For all this we are indebted to numerous pains-taking men, who with unusual self-denial, patience, and _per- severance, have spent their lives in industrious retirement; heard of by few and known by less; busy in their fields and experimental plots, or hidden in their laboratories; gradually building up, fragment by fragment, the grand edifice of knowledge which now represents what every man who desires, may know of the culture of farm crops. One very important point of this knowledge is the fact that vegetables feed—that is, absorb and assimilate or build up their substance—upon mineral substances, as well as up- on the remains of vegetable matter. That while these re- mains in the shape of completely decomposed farm manure, or animal matters, contain the various inorganic compounds which are found in the ashes of plants, and which are known to be necessary to their growth, yet the same com- pounds drawn from a mineral origin, are equally serviceable as plant food. Thus, lime procured from the lime kilns; potash from the rocks of which it forms a part; gypsum or plaster; phosphate of lime; soda in the form of salt, or as nitrate of soda; sulphate of magnesia; and other mineral substances; when finely ground, and made soluble, produce precisely the same results when used as fertilizers as the same substances in the ashes of plants, or in their decayed remains. They are absorbed by plants with equal facility, and are utilized in the same way and to the same extent, in forming the tissues of the plants. They are in fact plant food. Hence the common idea that these fertilizing sub- stances are stimulants only, and merely encourage the crops to put forth some unusual effort, so to speak, by which 96 THE CULTURE OF FARM CROPS. some unnatural and excessive product is yielded, is a wholly wrong and mistaken one. Wrong terms and ideas are in- jurious, notwithstanding that a name has no effect in chang- ing the nature of anything; for they lead to wrong prac- tices and grave errors in the management of the crops, and these cannot fail to result in loss. The inorganic substances upon which plants feed and which they extract by their roots from the soil, have been mentioned in a previous chapter, but they may be conven- iently repeated. They are lime; potash; soda; magnesia; sulphur and sulphuric acid; phosphoric acid; silica and chlorine. These, with the exception of sulphur and chlor- ine, which are elements, are the oxides of metals which are elementary substances. The first four are usually found in the ashes of plants combined with carbonic acid as carbon- ates; lime however is found as a sulphate being combined with sulphuric acid in the ashes of clover and a few other plants. There are a few other substances of inorganic ori- gin which are occasionally found in plants, such as iron, manganese, iodine, &c. but these are evidently accidentally absorbed with the water in which they happen to be in sol- ution, and being innoxious do not interfere with the devel- opment of the plants, but are not strictly plant food. The proportion of the various mineral elements of plant. growth varies greatly in the different species of vegetables; so much so as to become a leading characteristic with them. Thus there are what may be called potash plants; lime plants; soda plants, &c.; and these dominant elements will be found to have a considerable bearing upon the question of fertilizing crops, to be hereafter treated. Thus on refer- ence to the tables given in the next chapter, it will be seen that the ash of the stems and leaves of potatoes contain from 39 to 46 per cent. of lime and 16 to 22 per cent. of mag- nesia; pea straw cantains 38 per cent. of lime; but wheat: straw only 6 per cent.; and the tubers of potatoes only 2+ per cent.; while the ash of the last mentioned contains 60 per cent. of potash; that of turnips 50 per cent., clover 35 to 50 per cent.; of young grass 56 per cent.; and of tobacco THE LAWS OF PLANT GROWTH. 97 273 per cent. The dried tobacco plant has 24 per cent. of ash while the whole wheat plant has but 33 per cent. It must not be supposed that these peculiarities are of no im- porfince to the farmer, and that the fact that the ash of beets, turnips, and carrots, including leaves and roots to- gether, contains from 12 to 243 per cent. of soda, and from 6 to 11 per cent. of chlorine; while that of most other plants contain a very insignificant quantity of these sub- stances; or that the ash of clover contains along with the large quantity of lime a considerable amount of sulphuric acid, and that this acid exists in the ash of turnips, cabbage, rape and kohl-rabi, mustard and other plants of the Cru- cifere family to the enormous extent of from 8 to 164 per cent. For these facts explain the reason why an applica- tion of salt (chloride of sodium) and of gypsum (sulphate of lime) furnishes these elements to the crops mentioned, and thus supplies necessary food without which they could not grow. It results, in fact, that the soil must contain all these substances, which are found in their ashes, in such quantity and in such form as to yield easily to each crop as much of each, as the plant specially requires. This is the first grand law which controls the culture of farm crops. The second is that the soil must be brought into such a proper condition by tillage, as to enable the roots of plants to avail themselves of the needed food which it contains. A special study should be made of the tables given in the next chapter and specially placed by themselves that they may attract the notice which they demand. For a third law controlling the growth of plants is, that ¢f one of these necessary substances is wanting in the soil, or is existing there . in deficient quantity, the crop will prove a failure; it will either be weak and diseased (for itis the weak and ill nour- ished plants—and animals equally—which are subject to disease) or it will fail to grow at all. The intelligent farmer will then naturally ask what are these mineral or inorganic substances upon which plants depend for their successful growth, and in what proportion do they require them; and further, in what proportions do 98 THE CULTURE OF FARM CROPS. these needed mineral substances exist in the soil; and when any of them are deficient, how can they be supplied in the easiest, most advantageous and most economical manner? The first of these questions will be answered by the tables given in the next chapter and the others will be considered in their turn. THE ASH, OR MINERAL PARTS OF PLANTS. CHAPTER: XVI. THE ASH OF CULTIVATED PLANTS AND ITS VARIED COMPOSITION. In the following tables collected from various sources in which the results of thousands of experiments by the most noted agricultural chemists and investigators have been published, will be found the average composition of the ash of the plants named. These plants have been gathered from the crops grown under ordinary circumstances, and when there has been any unusual variation in any samples, a large number of analyses have been made and an average taken. These analyses have been verified so often by more recent examinations that they have been accepted as the standard, and are used for all purposes, and for reference in all recent agricultural study. They may therefore be ac- cepted by students with the utmost confidence and reliance. They are given in full because hereafter frequent allusions and references will be given to them in future chapters. CoMPOSITION OF THE ASH OF AGRICULTURAL * PRODUCTS. S as a S) Lge WAR eles Oe Nak UGE Re Substances. S% re) A eg a3 a § See gi oe CRRA nO asta wane Sia oO I ie oD) o HAY AND GRASS. Ordinary hajy................... 7-78 25.6 7.0 4.9 11.6 62. B14 29-6) .60 YOUNE STASS........csceeceseoeee 932 562. LS 28> 107-105 0 103° ;2.0 FEIDG AY 5 0 csesk- ce cscs cceesent a. 76. 29° Bay 19. 22 . O07 Gah) OF BTTIMI@UIDY, asncvne~ceo=4-2-s ess ereee Tel 98.8 2.7 3.7. 94 108 .39 %.6 5.0 PU PATI 25.0255. 85--.s sew eeees 7.23 37.4 8.00 MES) Se a6. 25.0> Oe CLOVER AND FODDER PLANTS. ath OY Ol ese,s0-0 5020 008000-eae 672 34.5 16 122 340 99 30 27 3.7 White Clover..............+--++ "16-175 78 100 322 141. 88 45. 32 WUC CEM scconceinidgaves von dee ons o22e 714 Oa dy Gee C4 8b. 61 (2.0. £9 Alsike Clover.........2-: e+. -s0+ BS) Se8 ocbibe dae -st:9- 104 40 12) 28 Green pea (in flower)...... 7A0* 40.8 0.2. $2 28.7 13.2 3.5 26 1.8 GTEEM TAPEC.........0eeeeee ee eeees Sa7 73S 2 ae get 8.7 16.8. 3.2-) yhG Co ST CO NT OV MNOWDORUOG ft © © Sr Se) SU Ores Sok wWwhbonb Uta 5.4 24.0 8.7 100 THE CULTURE OF FARM CROPS. ROOT CROPS (Roots.) Potstoes 1.5, sis is ett 8.74 59.8 16 4.5 io 1958. Betsy. .c..esesiks. Gash eseeeaceeee 6:86 63.1 14:8 5.1 46 9.6 Sugar beets. 1. cvsecigoceeses 435 494 96 8.9 6.8 14.3 TULIPS Hts; isc ndesasaieeeess 8.28 39.3 114 3.9 10.4 13.3 Re DASAS ict steeeeae NBO oleae | 0. to). 260 9:7 15.3 OBITO a coccse est teree? ae ee bt Susb ee DIS | 107 12.5 ROOT CROPS (Leaves and Stems.) Potatoes (green)... onic agdsee 257 168) 39:0 6.1 decay Civ? eter ee eae ais 5A «6.8 OB 22.6 « 46.2 - 5.5 TAGOUS scaibecesied. andasaace saeuaass 190 2OAk 2A0: GET 1A 4.8.1. SMP HTD CCiStsesncsstevscicsineg LESOw Sol, 168, ABS AS7 7s4 SEAN aot dapasstivennatstts 13:68 22.9 7.8 45 324 89 EATNOUS SH cicesdecsartessesgaatuies 13.57 14... 233b 4:6: 33:0 4.7 0°) 0) 00: I eae Re ese ne re 10.81 48.6 3.9 3.8 15.3 15.8 STRAW. / Winter wheat.................. ASG INS *2.9° 256 6.2 5.4 MIIET! THOS So cswceovianceee MeSHP Sel ce) teed: 7.000 4.7 MIPTIME TV C\. va co'cscats veciesoenoess 5.59 23.4 2.8) - 3.9 G5 IONS sis tcdeevstneeeteventns AO “SEG? 4h Se ie eS (2 i nl ee ae, Se 5.12 2210: 53) 40 92) 4 Corn DAS” 38.3" 1.2" “bb AON 6 S8al! TRIE Ss cnsijeastts wsvaccnum asians shaver Hid 21 Bt (5S We) BRO “76 Bains: oo Sa Rea 1.12 444° 33 “8 230948 Buck wheat. cciscsccsccssscveecass 6:15) 46:6; 22° 316 18.4 =1139 TDA Gctnesecenne scascndidigtoes fem 4.58 25.6 10.3 5.7 265 7.0 CHAFF. WORE evisinetivtd on sectoentngs mis 9. LS 12 - 1.9: se DROS ices etvasnecaccbente’s an Mos, 127 O08 18 14. (28 RiGee, ccotagereeet cane acres 9:22 Tal) 438" “286 8.9 02 Corn (CODS) i005. se daalea Tests 0.56471. 12 42 -34. 44 FIBER PLANTS. Sax (CMTC). oes isz.tenve yore 4.30 32 4.8 9.Q 15.5 23.0 Hemipy So viesccesseusteesen te 4:60. 1875 SIS" OG 8 aay “146 MURS (fo aa sen ise dake ves 0.87 26.2 - 3.8- 5.8:" 36.0 121 "TAHACCO:.0.0<0ssecsesse sntpisaee 24.08 27:4 3.7 “10.5 8710. 3.6 LITTER. Heath 458 1.2 6.3) 84 (188 .b1 GTN ye ov civet itus ccs ezeccas ene veres ks ADS A. Veneer OT SOR“ WOGUS v.21 cicensnasedeseecves 14.39 14:5 240. 95 18:9 ‘32 Beech Jeaves..............0 6.75)5:2. 016 6.0). 44:9" 4 Oak : ME ~ © Se Soteteesd cred 4:0 35 ‘06 4.0 48.6 ~S1 White pine “ 1.40 10.1 99 414 16.4 | 5G 00) Sad ae eee ee Ee 5.82 1.5 2:3) Ap)’ 82 Salt Diack grass... .ccc.:2...0c 5.30 36.6 66 64 95 - 64 Salt marsh grass............... S08: SER Ss VAD eo hy GRAINS AND SEEDS. Boye SEE, omer St pee 2.07 311 35 122 3.1 46.2 Rye.. 2.03 30.9 1.8 10.9 2.7 47.5 Barley Zoo 2G 28 33 2.5 32.8 Oats 3:07 159 38 73 3.8. 207 GIT senidens ssn dec desc nasedscdeece 1.42 27.0 1.5 146 2.7 44.7 Ll 2.3 3.3 3.0 2.4 0.5 2.0 8.0 4.2 4,8 3.1 3.8 5.6 1.2 66.3 58.1 59.9 53.8 48.7 38.0 5.9 2.5 4.6 4.5 2.1 10.2 LOA 0.4 4.4 14.2 5.6 COMPOSITION OF FARM CROPS. 101 RIC Giese oe so oe serie ssaanneeere 7.84 18.4 45 8.6 Bly 47:20 06 0.6 AVE iee enea.- cecauceaswas oeeean 46 4.49 TO. 10. 8:4 WO Zee Oy © Ses SOR SIN occa wees eensnsa se 1.86 23.0 3.3 14.8 1.3: 50:9 1S PUICIAWHEAE . woceassdeaswseennas LOT 2351 ~ 6.2) 13.4 3.5, 48.0 2.1 ay PERRI ca enaeiocatedeersnes sxescedenss Asod 98he al 1252) 13:8) A319: (3.6 th Os SO OSUEITD Spice dec amdoncedscacsovecese 780 37.42 836 1610 3:0 33:16 0.27 2.8 0.2 IFRS coos sate nome naapionease eciee SG aoe on aS BLD 8.4 40.4 Lil Ta Ok ig (200 0h Oe eee ore Sas OO Lea Gaon) eee oo.o ~O.2). 12.8. 0:3 SMISHRIG 55... 2c taSecee tos onewce 4:30 15:9 5:8 10:2 188 39:0. 4.7 2.4 0.4 Aan ont) CORE SRS eee ore OS) SEO) SS deh ADD (ZO1 0.7 COATT Olisvags digacuscccsss evweewateens $50 195 “48. 6:7 88:8 15.8 6:6 Bidie Oise PRR oa ctiewedastaicicnsasoen set mnes 2:81 --40;4 S27 8.0 4.2 36.3 3.5 0:9 238 SEIS cis s abewanns Suaaen smeanne Sib: AOS. Ae. 16,7 m2 39:2. bil 2 + 2D MONIO Ti con avduakoconsancaeneers ice Ald shee ORG a ole 2 6.2 33.5 -4.7 24. ks WOOD. RGU EIVC)- oe ncehs pas apadcakxs -saare Rib 2058 16:7) 6:8. B78 alee) | 27 0.8 0.8 ES EU GUN 2s Sascnsseeindeacveedsaveesy 6 Ql 11-6, 5.8 . 3:9 600" 8:5. 1013 48 0.6 MOO.) nt cctin Scaeccanon tacks S25 16:1) --2:7 14,0) -60:2. 8.07 AO 5.4 O21 MM ete ee aC cut cet Gosh cid c's wasauh M21 7100 3:6!) 48. 73.6. bb) We i Oe MV HUMGWG is bocedes cosa svesns ccadecsiee 0450 135°) 5:6: JOu 50:8) 216-4-- 3 OF7) 0:6 WPL Tiee-seoce ae fonts wesesasess seers PES 24 St 0.0) 379 S86" «b:4 6.2 6.7 WAP os oo ss adagea socsedas LAR 35:89 6:0, 4.2. 20.9" 14:9) "5:8 2s ee ES eae ae 10 0 16 87 TAO 46 28. 218 02 HRC UAC ss, ca cb naaden naps > done ses 0:35: -b.2 26:8 - 6:2 47:9; 6.1. » 3.0 2.0 40 VV GIGS JOUING. 8.0.22 mer escnes sees O28) 15.35 °9:9 5:9 50 5.5" «3.0 6:0: 0.2 ES ISSEHIWMTIT: ook 29 aos = 2a ‘ oa PNG GIUUWIN 535: 855 Sone gacessoescseseee ees 14°33. 6:2 (9.7) 26:3" ~41éa eas sf OS FL MMERY OOS fc coses ccoste once coattodac 15.0 “7.0 -TET = 21:9) SAG ees “s ad UTE oe Soccecnesccuvnsussteecencaneesuse 16.0° “7-0 I3.b- 19:3. --40.4° "S20 Rbd. Clover, POOP: 200s, -DeiG eeee MOGUGT WiVG ss iciccsisetsuecicdnceesccumewseosus cccszaeeos 143 '5.1 104 23.1 445 28 ERD OGEU See tap a ea'e wos cok wraev dena cee oareae tone 14.3°°4.5) Ovi 227 49.82 3.0 DtaliamcRye Grass, cas: occ. seca cess saseacatevoceectex: 14.3. 4.8 12" 22.9 .40:6)9 oe Amelia dey C2 GLASRs ns ..esecsocs dodvetncveatevedeared sas 14.3 6.5 “10:2: 180.2 36. ar PreneCn eye MRASS 1, oo.nes Cocksoen feeeac eee staeetes 34:3) 9:9 WE OSs GB2.6 ae Upland Grasses, A&verage.........c..sssccecceeseeees 14:3.. 5.8 « 9.5. 28:7 ~ 39. — 2:6 PUN Paris Grass..\.couscatsetetcorceecne ented eeeeeeat 18:4. ° 5:7 10:8" > 294 > 88:5: 22 “Pan COMPOSITION OF FODDER PLANTS, GREEN FODDER. Grass just before DlOOM.............ccccceseeeee eee eeee 75.0 ABU GEASS s+ 5. sresececeensansscssasevssecucertidesesevesa 80.0 IG HEP ASiINC GTASNe.. dethansc acanteartcacdsacrsenteseJols 78.2 DUAL ATA ER VE TORS. os cnslivesaenveenes2 casnneoSatacaes onnana 73.4 PCS EV Cs GLASS x 2sccaae-=c0 82.0 Lucerne, Quite YOUNG. .........cccccserccresrsersereeees 81.0 ee at beginning of blossom................. 74.0 Sand Lucerne, at beginning of blossom....... 78.0 ESPATSette ........scsecceeersecseesecscsssseeesessseeseneees 80.0 BUN eices ccs cewsacee once cote ebanctadues cieneascoaeasns rece 81.5 Hp CLOVCL...........scscceceesesssnsenecesnssesscecens cneees 80.0 ROEM Tae oe eens wavdes spew deve oeaeaenes seestmacunctten 80.0 Lupine, MeCGiUM...........cceeeeeeeeeeeeeeeeeeteeeeeeeees 85.0 4 WEY EMO soda seapet seven dis eve-soac ncese- 028 85.0 Field Beans at beginning of blossom............ 87.3 Fodder vetch at beginning of blossom.......... 82.0 Hodder Peas in DIOSSOM. ...22....500655.0..d0000 senses 81.5 Bek WHat MO WIOSBOML, ..2.2.52..-.0sscceensessea5ss>- 85.0 GYEEN RAPe..........2--cscosecesescsnseseecoessecnsenrncoees 87.0 NG GOT OM DAE Cre. c-scceseac-osceesenccravaesessseececess 84.7 NV TTL CED DARE. 2... .vcc--ncasecnvecesesscceses tenons coesse 89.0 Cabbage Stems..............ccceseeeseeceeeceeeeeenes cenees 82.0 Potato Tops, OCLODET............cccccseseeeeceeeeeeseees 78.0 MOREY ENT IESUCBiuace cen eet ennai taser cers stance Dmecdeucenw eres 82.2 Fodder Beet leaves. ..........:ssccssccceeees Banas 90.5 Rutabaga leaves..........cccecceceeeseeeeeeseeseneeeees 88.4 TOO MIATANOE LOAVES. co5.s00- 20s cane nes aes soc eee cnccesvar anaes 85.0 Artichoke Tops...............000--.ccseesscceesrneeeceeees 80.0 Fermented hay from Maize............:.:c0esee 83.5 « Pe UITUTICY. cha caperods ss oee= 79.9 - ss 5 Beet leaves............... 80.0 ag x ‘ Potato, Tops:.....2. 2... 77.0 es 6 ME Red CLOVE...2.. sseeerees 79.2 STRAW. EATEN LIGAEN s sidetce vos neacatoscc~s en nea sresisVusascoansens 14.3 Winter Rye...........cscscccssssscresccesnescccsevecseecsees 14.3 Witter Barley i...c.1c-0.2.c.c05.eccvecansacreecevsedeoenese 14.3 Summer Barley.......... papssh octch cine aetbackoesssamenaee 14.3 Ostia; Diaseveseatuaes Ractreuas daccstawewensta cusstess Srareses 14.3 3.1 2.0 2.2 2.8 2.0 2.2 PALE 1.6 1.4 1.0 1.0 EE 1.8 1.5 1.5 1.3 2.0 1.5 1.8 L7 2.0 His, 1.5 1.6 1.5 1.8 0.7 0.7 1.0 1.8 1.5 1.4 1.6 1.6 1.2 1.9 3.0 3.6 1.8 2.3 1.8 2.7 Pt 2:9 4.1 5.3 2.1 4.6 4.1 5.5 4.1 4.0 3.0 3.0 4.5 3.6 3.6 3.4 3.4 3.3 2.3 12 1.8 2.5 3.1 4.6 3.3 3.0 3.5 3.3 3.3 4.5 4.5 4.0 3.2 2.7 3.5 3.0 3.1 4,2 2.8 3.5 3.2 2.4 29 2.0 1.5 ita! 2.3 3.2 139 2.1 2.8 2 Oo. 1.2 3.1 3.0 2.9 4.2 3.0 3.0 3.3 3.5 4.0 6.0 4.0 4.0 Wed 10.6 8.0 10.1 7.9 6.5 4.7 4.4 6.7 8.5 2.8 4.5 5.8 6.0 4.5 6.0 5.0 9.5 8.0 6.5 6.2 6.0 5.2 5.1 4.5 3.5 5.5 5.6 4.2 4.2 2.4 2.0 2.8 6.0 3.0 1.3 1.6 1.4 3.4 5.3 6.8 PE | 4.7 5.9 40.0 44°0 43.0 40.0 39.5 a Ts) 7.5 36.9 39.3 32.5 36.7 36.2 103 0.8 0.8 1.0 1.0 1.0 Tat 1.0 0.8 0.5 0.5 0.5 0.7 0.7 0.9 0.7 0.6 0.8 0.6 0.6 0.6 0.8 0.8 0.6 0.7 0.8 12 0.4 0.4 0.3 0.6 0.6 0.6 0.6 0.7 0.4 0.3 1.0 1.0 0.5 0.5 0.8 0.8 0.9 0.8 1.2 2.6 2.2 1.2 1.3 1.4 1.4 2.0 104 THE CULTURE OF FARM CROPS. Summer Grain Straws medium.................... WSs 41 3.8 394 a= Ly " rk AES EIT OME Scie sso Sush saan 1438 6.7 69 386.7 229 25 Winter sp OCs AUT OG) TNM e aces eaten sas 02 14.3 48 42.0 349 13 * - iS: a a ne 14.3 5.3 37.8 36.7 124 JEL C ORS Net yeh 12) i 1 Le ee ee sell, Ca eg ee ea 16.0 4.5 43:0. 29:0\ 4:0 38:0 340. 0 34:0 ‘34.2 “Wp Straw of Legumes, medium...............002sseceee 16.0 4.5 . 38.0 32.4 1.0 AN ee . MET BOO. ninsscearka hanes 160 65.1 10.2 #45 “32 ae I STIURUS Sorc a sence asa taaktnuveuuacacke nesta eaee tee eae 16:0 6:5 14:0 .33:6 279. 220 METOUIIG) oi 500 7apsae- so tecongdescaitac senna sanent se aban tea 160 41 5:9 408 adios CE COLO VOI nos siia esc acetsis or anpldon ce shes senen aes tees 16:0 66 94 20 2 20 EONS Fcce sale ob ehav atv eWateoanieomolunor sbanbacsehemeenetereees 140 42 35 40.0 354 190 OGRE 2.5 akc on stole ane enh ae ae eee ae 1510, 4.2 310° 40:0 3627. io CHAFF, HULLS, ETC. 4 RI Sic ces no ve cae ca ate ones ane doemee races 143) OiO'2) A238. BBD (B40) Ss MG Coo eens Soh ce vas oa ic es op Oe eee 143 "7.51. (36) A4S35% 29:9) Le DES ences Frans bea ee « San eae ae oe eee 14:3 10.0%. 420) } 34,0). (36:2), oe WOE Yie So oan Gries acshicne ssadeca dons mest ossectemeasarse 14:3. 13:0 < 230) 5880s. 3B2— 1S NCH Te) 1 gee eet ann Marae fea ene te ea rye ert 15:0), <8i0 ASke i S320) 3575.42 A o.2 7 a ie a ee aie SOIREE, OER THSL SAR Ne 15.0. 60> BA So) ~ 36:9. ew GT ha she ee ear ee oe Sa Ss eas anes aoc 15.0.) ‘9:b,, 10:5: ses 2340) 20 RA UUs sy os ec co Os ca a desea es 143, 3:5 45 300 30:0 > ee WO Reh Sah Be cas yeptecee wastegate 14.0 .85 °40) -406> (313s Wir OS Es Re se ees ee eee 140: <2.8: 5 d4 SSeS. TAR, oat me oo no ~I a tn ty = oO — Q ow iq") ~ 5 _ a So — for) nono a em bo ol POLS EGGS ok ea coen as ae wee veh owes en enet cee aeumenencs an 75:0) 0:9). 24% Tele SOB = a0 WET GCIGICES cites oc seeteavec wane gushes meee ees meneame ees 80:0" 1,0 © (2:0) “AGS, dsb Oe Wed Ger Bee tae or oo ea cette teanade sencreoteeeens 83:0 0:5° 1 1.09 91 308 Si aPB Cts tec oss tereee art oes ssc oes seaesapeneaspessecnee 81:5 0.7. 1:0). 43) do, 10 CATO Sacco cae Lae ha ness ee da wale Se tee pemaeneaw caeeaeas 85i0:, 0/9) dao) La, IOUS ieee Giant Carrots...........0205 ceceeserceeseeere cee se eee een sees 87.0. .0:5) see a ae 9:6; 02 FRYERS EAS ooo ooo his Jc nen ba clsnc sont cds'de-ntstngeeyiences | OPE» geet eee 9:5- Om GPT IPB sacs po? ons seen vaca cnepn caw dco ssetacaccieze nus acunts OREO” LI SE Tees oe eee PPT SIA YG 5a. cenlesd aos ASotee voraevucedegsusobecen stewensuszages OOVG) UMD, CaSO (0 RIR oe mia ea GRAINS AND FRUITS. Wrheatncc ee Aa eh hhc ni een che A TO, CO Gee BEGG cc lhccn ge Fe tvan ee absasicts apne doe one pantensacceavod dete Serna EES” MAREE 74 2:0 RIGO G 2s oc ak dacinte ons Fen dauiscnchs ont vsceceiteeiks aud xsavciecy sus eege eeeemea aL) Aaa IMR as Osis. 2586 ik i Reni cla vadisas dooeneats MARS OST Oe ORT acta /rammene Minize 8 oe che cdi ees eas ce tee LO” LO aed ee Nae Ge ee ae Se ect seeks eke OO 7, Seed ee ee Back wheats ke coc cssces ali ccdalecs beckebccoesssacbecceasss LAOS PACS 7 0010s SEO) 5 aie s7 alec Bibe, delle. so ia, hon. hens ke et Apis scoecsunsnciseneee eae IO, Org) ne) PPO 25 Fn chs ex ssc betwen beni wea od code Gewcerdee ewe deo.esneeey Lae Reger ae nO ees ela ee BHEVG VBCAIIS beak f522i5ehececctoccence boc ges anc ace lev sious cus veal EEE E) EMME aT etaee Ol ngUcae we ected area 5S 211 1 ee ODS Rie Se me PO pn Ree Mee | i IE RMN UT TO RESTS Us | 711 ee ee a ey a en RE Bory Deringer EEE? FST GS oy lone PS el Taare VODOW <.. ....2000sevees ensahs 3:2 DE Rp Ape USSTPCMIN oc asasce sas specs guosdanescuonvcsyatice Sees vemeead toeceeeee case ses 12 pe G2 lab" <5: 7° 58.6). Ab PES AIS Eg oo ccks Sho lemdd st Roonaan merctpossetarcagpoebaes huss 12, BonipOm 50% 43.7.. 30.0 22.5 Linseed Meal, N€W PLoCeSs........0..0...sesessceseeees OTe ete: .e6! (saul. 2)3 Cotton Seed, whole Meal........:..ccccecscsssccescesss it, Ot (25:60 22:0- 30a) Gi ‘Cotton Seed Meal, without hulls................... DOS eo aao. O2es 195° 13:7 The above figures show precisely what imorganic, or min- eral substances, plants draw from the soil. They also show that the quantity of inorganic matter contained in the same weight of different crops varies greatly. Thus while the grain of corn contains only 1.42 per cent. of inorganic mat- ter; peas contain twice as much; oats two and a half times as much; and rice five and a half times as much. Also the’ quantity contained in the various parts of the same plant varies in a similar manner. Wheat grain has but 2.07 per cent of ash but the straw has more than twice as much and the chaff has over five times as much. Barley shows a still greater difference in this way and so on through the whole tables. The same facts apply to trees and their bark and leaves. Another important point is peculiarly worthy of notice; this is the difference between plants in an early stage of growth and when they are mature. Young grass for in- stance contains considerably more ash than ripe hay and this ash consists of much more important elements of vege- table growth. The large quantity of potash and phosphoric acid shown to be needed by such grass as is used for pastur- ing, seems to disappear as it grows older and to be replaced by silica. What becomes of these two substances, so valua- ble and indispensable in the aliment of animals, and which gives to the young stock the materials for building up their growing muscles and bones; and how is it that the mature grass has so large a quantity of silica which is of no use as aliment to animals? But we see a purpose in this, although it operates to the disadvantage of the farmer. The first law ») 106 THE CULTURE OF FARM CROPS. of nature is the survival of all living things, and the most perfect fulfillment of its purpose in creation. And we see an instance of the perfect order and wise adaptation of means to ends in nature, in this excess of silica in the stem of a ripe herb, for it requires stiffness and strength to enable it to hold up the seed until it ripens. Were it not for this silica in ripe hay and the straw of the grains, the stems. would not have strength enough to stand upright and would fall and rot on the ground and the seed would perish. These variations are not accidental, for they exist every- where, on all soils and in all climates. They must there- fore originate in some natural and universal law. That they are so, inures to the advantage of the farmer and makes agriculture possible. For otherwise, there would be no certainty that after he had prepared the soil and had sown his seed, he would reap the crop he desired; or that what his land produced would suit the purpose for which he intended it, either for the subsistence of mankind or for feeding his animals. But being based upon a universal law, the farmer has a safe and constant rule for his guid- ance, and may be able to furnish his crops with precisely what they need, when he has by long use lessened the orig- inal fertility of the soil to the point of impoverishment. Moreover by this law the farmer can find a reason why various trees preponderate in the forest and learn from it sufficient of the character of the land under the surface soil to guide him in the choice of afarm. When he sees the land covered with plants of the heath family, the huckleberry; cranberry; &e.: or with a forest of balsam fir; or with birch or beech timber; he can as safely judge that the soil is light and sandy, as if it were all exposed to view; and on the other hand where oaks, elms, maples and basswood flourish and grow to a large size, he may be sure that the land is rich in potash, lime, and phosphoric acid; the most. important elements of plant food; and that with judicious. cultivation of such soil his labor will be rewarded with abundant crops. | & INORGANIC ELEMENTS OF PLANTS, CharT hh AV IL. THE COMPOUNDS OF THE INORGANIC ELEMENTS OF PLANTS. The inorganic elements of plants, viz. potash; soda; magnesia; lime; phosphoric acid; sulphuric acid; silica. and chlorine, exist in combination; and never in their original elementary condition as simple substances. It has been shown that the organic substance of plants contains four elementary substances ; oxygen, hydrogen, carbon, and nitrogen in various proportions; and that the inorganic part of them is made up of eight elements; mentioned in a previous chapter; and rarely of a very small portion of a few others chiefly, aluminium, iron and manganese. These eight elements are chiefly in combination as shown in the following enumeration of them. Name In combination with Forming Potassium Oxygen Potash “ Chlorine Chloride of Potassium Sodium Oxygen Soda ee Chlorine Salt Magnesium Oxygen Magnesia Calcium Oxygen Lime Phosphorus Oxygen Phosphoric acid Sulphur Oxygen Sulphuric acid Silicon Oxygen Silica Chlorine Metals Chlorides With the exception of sulphur these elementary bodies. are not known to exist on the surface of the globe in their simple uncombined state, but in combination as above men- tioned they form the greater part of the mass of the earth and of the soil upon its surface. It is these combinations which are of interest to the farmer in his study of the prin- ciples and laws of vegetable growth. POTASSIUM AND ITS COMPOUNDS. PotassIvumM is of most importance in its form of CARBONATE OF PorasH, 108 THE CULTURE OF FARM CROPS. a combination of potash with carbonic acid. This is the form in which potash exists in wood ashes; and in the pot- ash and pearl ash of commerce. It has a most important influence upon the growth of plants, as may be seen by reference to the tables in the previous chapter. Its use for this purpose as a fertilizer dates back to the time of the ancient Hebrews, Egyptians, and Romans, and the value of wood ashes as a fertilizer has been mentioned by several of the ancient writers. Moreover it is well known that wood ashes are more favorable to some plants than to oth- ers, “bringing in,” as it is termed, plants like the clovers which are rich in potash, and so crowding out useless weeds, and improving the land at the same time. PorasH is extremely caustic, destroying all vegetable and animal matter very rapidly. It is easily produced as fol- lows. 12 parts by weight of carbonate of potash are dissolv- ed in water and boiled with half the weight of newly burned (or quick or caustic) lime slaked in water, the lime takes the carbonic acid from the potash and settles to the bottom, leaving the potash in solution in a caustic state. Caustic potash so readily absorbs water, from the atmos- phere, that it can only be kept dry with difficulty. It is not known that potash in this form is of any service in the growth of plants, but it is thought possible, because of the action of lime upon the carbonate; and when lime is ap- plied to the soil, as it frequently is, it is quite possible that it may exert this effect upon the soluble carbonate of pot- ash with which it comes in contact. PorasstuM, may be obtained by mixing the dry caustic potash, procured by evaporating the solution above de- scribed to dryness, with powdered charcoal and iron filings, and submitting the mass to intense heat in a closed retort. The potash is decomposed; its oxygen combines with the iron, and the metal potassium is left pure in the form of a vapor which is distilled over and appears, on cooling, in the form of white silvery drops. This process was one of the remarkable discoveries of Sir Humphrey Davy to whom we are indebted for much that is known of agricultural * POTASH COMPOUNDS. 109 science. This metal can be kept only in some liquid which contains no oxygen, hence it is immersed for keeping in pure turpentine, or in naphtha, which are compounds of carbon and hydrogen. When exposed to the air it is quick- ly oxidized; when it is thrown upon water, it floats and ab- sorbs oxygen from this fluid, so rapidly that it takes fire and burns. A curious experiment in this direction may be made by placing a small piece of the metal upon ice, when it at once inflames by combining with the oxygen of the ice. Hydrogen gas is of course liberated in the decom- position of the water. The oxide of potassium thus formed is caustic potash, and weighs one-fifth more than the potas- sium; the increase being due to the oxygen combined. CHLORIDE OF PorTAssIUM, is very useful as a fertilizer, furnishing to plants not only potash, but chlorine. It ex- ists In sea water along with common salt; it is found mixed with salt in the salt mines and is extracted in large quan- tities from the salt mines of Germany, from whence it is. brought as “muriate” (chloride) of potash to this country and sold as German potash salts. It consists of potassium combined with chlorine. It can be easily produced by dis-- solving pearl ash in hydro-chloric acid, until effervescence ceases and evaporating to dryness. It is extensively used in the manufacture of alum which is a double sulphate of alumina and potash. ‘This salt of potash is found in the ash of nearly all plants, and in large quantities in sea weeds; salt marsh grasses; and sedges. SULPHATE OF PorasH, consists of potash and sulphuric: acid and is a most useful and cheap form from which pot-. ash may be furnished to the crops. It may be formed by dissolving the carbonate of potash in sulphuric acid until gas (carbonic acid) is no longer given off, and evaporating: the solution. It exists in considerable quantities in wood ashes, and in the ashes of plants; and forms 18 per cent. of the weight of common alum. This salt has been found to act beneficially upon clovers; peas; beans; cabbages; tur- nips; rape and other plants: all of which will be found,, on reference to the preceding tables to contain both potash 110 THE CULTURE OF FARM CROPS. and sulphuric acid in notable amounts. Hence the favor- able result of its use as a fertilizer for these crops. NirratE OF PorasH or saltpeter is a well known sub- stance and consists of potash and nitric acid, and can be formed by dissolving pearl ash (carbonate of potash) in nitric acid and evaporating. It exists in large beds in South America and is generally diffused in the soil in small quantities, being produced wherever potash and decaying vegetable matter happen to be in conjunction in the soil, by the action of the nitrifying organism which exists in the soil and is supposed to aid in the production of nitric acid. This salt exerts a most remarkable effect upon plants; con- taining as it does two of the most important elements of plant growth and being extremely soluble. As little as 50 lbs. per acre, applied when the soil was damp has exerted a marked effect upon the vegetation in the course of a sin- gle night. OXALATE OF PotTasH.—Oxalic acid has not been men- tioned heretofore, but it deserves a passing notice here be- cause it exists in many plants which are known by their agreeable acidity. Sorrel, and the common garden rhu- barb, owe their sourness to this acid; itis also found in the chick pea; several varieties of the rumex family (to which rhubarb belongs) as the docks; also in tormentilla; bistort; gentian; saponaria; and many others. Lichens and va- rious mosses also contain this acid in combination with lime and soda. It is also noteworthy because it is closely akin to carbonic acid, being a derivative from the element car- bon, ecnsisting of two parts of carbon and three of oxygen, and can be easily formed in a plant by the addition of one equivalent of carbonic oxide (C. O.) to one of carbonic ac- id (C. Oz); forming together(C2O3) oxalicacid. This acid is very readily changed to carbonic acid by heat: thus when oxalate of potash is heated in a capsule over a lamp, it is decomposed and carbonic acid is left. It has been supposed that this salt of potash exists freely in plants and trees, and that this change occurs in their combustion, and the formation of the ashes. It may therefore perform an SODA COMPOUNDS. 111 important part in the changes which occur in the interior of plants, although its direct agency in this direction has not hitherto been distinctly understood. TARTRATES AND CITRATES OF PorasH, exist in many fruits; the citrates abound in the citrus class of fruits, oranges, lemons, shaddocks, and limes; and the tartrates in grapes. ‘These salts are easily decomposed by heat as the oxalate of potash is, leaving carbonate of potash. Few experiments have been made in regard to these compounds of potash; probably because of the slight difference between them and the carbonate and the ease with which they can be interchanged in the process of growth of plants. SODIUM AND ITS COMPOUNDS. Sodium is never found uncombined and of necessity has no relation to vegetation. It is of some interest however as being the base of various compounds which are inti- mately connected with the growth of plants. Like potas- sium it is a soft silvery white metal, light enough to float upon water, and like it will oxidize and burn on contact with this fluid. It is produced from soda in precisely the same manner. Its compounds are first CHLORIDE OF SopIuM,or common salt. This substance is universally diffused. It forms 2% per cent. of the weight of the ocean and isfound more or loss in all soils; it also’ exists as a rock in enormous beds among the strata of the earth’s crust, some of these being considerably over a thou- sand feet in thickness. It formsa portion of the substance of all plants and animals, and hence is of great interest to farmers, as being a most important manure for crops; for which purpose it has been used from the earliest ages. It consists of sodium and chlorine. — It is so well known that its properties need no further consideration at this time. SopA, is the oxide of sodium, and resembles very strongly the corresponding oxide of potassium; although its proper- ties are not so strongly marked. It is extremely caustic and absorbs moisture from the air. The sodium compounds seem to be everywhere diffused, being found everywhere, 12 THE CULTURE OF FARM CROPS. and even in the particles of atmospheric dust. But although their presence is universal, they possess a less marked im- portance in vegetable growth than the potash compounds; appearing in much less quantity in the ashes of plants. With the exception of salt, none of these compounds are used in agriculture, excepting incidentally as impurities in the more costly potash fertilizers. These consist of sulphate of soda and chloride of scdium chiefly, and are mingled to a considerable extent with magnesia salts in the so called German potash salts from the Strassfurth salt mines. The universal diffusion of these compounds in nature sup- plies all the needs of the farmer for the growth of his crops, and if any one is thought necessary, salt will serve every pur- pose. This will be considered at greater length when the subject of manures is under consideration. CALCIUM AND ITS COMPOUNDS. Catcivm, like the preceding two metals is silver white in color, and by its union with oxygen forms lime. It is not. known to exist in an uncombined state in nature and there- fore has no direct action upon vegetation. LiMg, is the oxide of calcium, and has so very great an affinity for water and for carbonic acid that it only remains in its pure state a short time. It is prepared from the com- mon limestone, the crystallized form of which is known as marble, by burning it ina kiln. The carbonic acid is driv- en off in the combustion, leaving the lime in a caustic con- dition, or as it is termed quick lime, and loses 44 per cent. of its weight in the burning. Lim, is by far the most important mineral constituent of plants and forms the greater part of the ash of the major- ity of them. Its relation to plant growth, and its action in many ways upon the soil, gives it a high position in the es- timation of farmers, both as a direct fertilizer, and an indi- rect aid in the preparation of the soil for the growth of crops. It has an exceedingly destructive action upon all organic matter, quickly decomposing it and reducing it to its origi- nal elements, and preparing it for plant food. It has also LIME COMPOUNDS. Ts a solvent action upon silica, decomposing combinations of it with potash, and soda, and forming silicates of these sub- stances which are soluble; thus forming a most important: addition to the plant food in the soil. It gradually absorbs carbonic acid from the air, and from any decomposing or- ganic matter brought into contact with it, and thus slowly returns to its condition of a carbonate of lime, in which it is inert, excepting when it is dissolved in water. Its many valuable properties will be more fully detailed in the chap- ter on manures. CHLORIDE OF CALCIUM, is the well known chloride of lime, of daily use as a disinfectant. It has no important relation to plant growth although it has a most useful effect. in various ways in purifying the air about farm build- ings, manure yards and drains. SuLPHATE OF Live or gypsum, is an exceedingly val- uable compound of lime and deserves special study. It is composed of 523 parts of lime, 462 of sulphuric acid, and 21 of water; the water existing as water of crystallization which is driven off when the gypsum is exposed to a heat of 300 degrees. This substance is atranslucent, yellowish or white, soft, rock; which is easily ground into a fine powder. It is inert and exercises no action upon other substances, but is easily decomposed when its constituents enter into other combinations, as will be hereafter described. It is a most valuable fertilizer, supplying the crops with sulphuric acid and lime, and enters in its combined form into some plants. It is soluble in 400 times its bulk of water. It is largely and beneficially used as an absorbent of ammonia in stables and manure heaps; exercising this action by the ease with which it parts with its sulphuric acid; giving this up to the ammonia, from which it takes in exchange car- bonic acid; thus forming carbonate of lime and sulphate of ammonia. NirrateE oF Limf, is little heard of in agricultural lit- erature and yet it undoubtedly has a most interesting rela- tion to plant growth. The production of nitric acid, arti- ficially, in the so called “niter beds,” has been already 114 THE CULTURE OF FARM CROPS. referred to, but may be usefully recalled in this connection, because nitrate of lime is formed as a result of the combina- tions. This compound rapidly absorbs water, and is never found as a solid in its natural condition, but always in so- lution as a liquid. It is supposed to exist in all fertile soils, and to furnish most valuable plant food; but being extreme- ly soluble and being rapidly changed to carbonate of lime by a low heat, it escapes detection in the analysis of soils or vegetable substances, while its constituents have entered in- to other combinations. PHOSPHATE OF Lime, formed by the combination of lime with phosphoric acid is an exceedingly important ele- ment of vegetable and animal substance. It forms 57 per cent. of the dried bones of an animal and exists to some ex- tent in every part of its body. ‘It is largely contained in the seeds of plants, and in all the grasses. Next to nitro- gen it is the most valuable constituent of manures and fer- tilizers, and its sufficient supply to the soil gives the farmer much care and anxiety in regard to the culture and perfec- tion of his crops. It exists naturally in the rocks as apa- tite, or mineral phosphate of lime, and thus consists of 543 per cent. of lime, and 452 per cent. of phosphoric acid; bone phosphate of lime, containing 512 per cent. of lime, and 483 per cent. of phosphoric acid. A bi-phosphate of lime is found in animal manures, chiefly in the urine, in which there are 712 per cent. of phosphoric acid and 28% per cent of lime. The phosphate of lime and bones, furnish the basis for the manufacture of superphosphate of lime which is one of the most valuable fertilizers. MAGNESIUM, is a metal having many points of similar- ity to those above mentioned. It is white, easily inflamma- _ ble, and when burned in the air unites with oxygen form- ing a compound or earthy oxide known as magnesia. It is of no direct interest in relation to vegetable growth. Its compounds enter into vegetable and animal substance, at times to a considerable extent. CHLORIDE OF MAGNESIUM, exists in the water of the ocean to a larger extent than chloride of sodium and gives MAGNESIA COMPOUNDS. 1 Tee to it its bitter taste. It is met with in the ash of plants, and also mixed with salt in the water of salt springs and in rock salt. It therefore forms a constituent of the German potash salts in which it exists in a considerable proportion; although it is not estimated at all in the market value of these fertilizers. SULPHATE OF MAGNESIA, is the common Epsom salts. It has been used as a substitute for gypsum in the same manner, and for the same kinds of crops, but it is too costly for this purpose. It has been considered as injurious to crops by some farmers, and as it exists abundantly in al- most all soils, and is an ingredient of widely distributed rocks, but little interest is afforded by its consideration. CARBONATE OF MAGNESIA, is found abundantly in many kinds of marble and other limestone as an impurity, and is not considered of any value. PHOSPHATE OF MAGNESIA, exists in the blood and tis- sue of all animals and in the ash of nearly all plants. It is in this form that it chiefly enters into the substance of plants; but as it exists in the soil in sufficient quantities it has never been brought to the notice of farmers as necessary fcr the growth of crops. No doubt there are conditions under which the soil may be beneftted by an application of some form of magnesia, but this can easily be given indi- rectly with the potash salts or with lime. It forms a con- stituent of nearly all commercial fertilizers, in some com- bination or other. PuospHorvus.—This element does not exist in a free or uncombined state in nature, this being impossible because of its extreme inflammability. It is a soft, colorless, trans- lucent, wax-like substance which takes fire on the slightest friction and burns with much violence; emitting dense white fumes of phosphoric acid. It is insoluble in water. It was discovered by Brandt more than 200 years ago, and because of its intensely inflammable character, was much dreaded by the uninformed alchemists, who termed it “the Son of Satan.” It exists in vegetable and animal substance; being a constituent of albumen and fibrin, and of the ner- 116 THE CULTURE OF FARM CROPS. vous substance. It is a far more abundant element in organic nature than sulphur, which resembles it in many respects. PuospHoric ActD, is the form in which this element is of the greatest interest to farmers; because of the universal and most important relation which this compound bears to vegetable and animal life. This acid is exceedingly sour; is readily soluble in water, and is corrcsive to vegetable and animal substances. It does not exist ina free state, although it is frequently mentioned as a constituent of the ash of all plants; but is always found in combination; chiefly with potash, soda, lime, and magnesia. In these forms it is uni- versally diffused through nature and it is in these combina- tions that it is of interest in the study of its relation to plant growth. SULPHUR, is too well known to need any detailed de- scription. It is only of interest in its combined form as sul- phuric acid and this in its state of combination with other substances. Alone, this acid isthe most corrosive substance known, dissolving or decomposing all organic and many — inorganic substances. When in combination with metals or alkaline substances it forms sulphates. These exist abundantly in nature and some of them, as sulphates of potash and lime are useful to vegetation, while others, as sul- phate of ircn or:sulphate of alumina are hurtful. SILICON, exists only artificially as a dark brown powder prepared with great difficulty by a tedious chemical process. In its oxide as Sinica, it is one of the most abundant substances, form- ing the larger part of almost all minerals; being almost the sole constituent of the most common rocks and a part of al- most every one of others. Its character is that of an acid, as it combines with alkalies, and forms silicates, as silicate of lime; of potash; of soda &c. It exists in the ash of all plants without exception, and quite largely in many, form- ing the outer coverings of the stems and seeds; thus pro- viding support for the plant, and protection for the germ, or vital portion of the seed. These silicates are soluble in water or are easily decomposed by water containing some THE SILICATES. TIF caustic alkali, as lime, in solution; and the silica is then made available as food for plants. The insoluble silicates of potash, lime, soda and magnesia exist in many mineral substances. The transparent glassy mineral known as mica, and often wrongly called “isin- glass” and which is used for the windows of stoves, is a sili- cate of alumina and potash, being composed of 46.3 per cent. of silica; 36.8 per cent. of alumina; 9.2 per cent. of potash, with a little iron; the very common mineral, feldspar, is another silicate of alumina, containing 16.95 per cent. of potash: another abundant mineral, prehnite, contains 26 per cent. of lime in combination with silica and alumina; other similar minerals have soda instead of potash, and some have magnesia in their composition. As these minerals which form vast rocks, and mountain masses, are slowly de- composed by the action of the atmosphere and the carbonic acid contained in it and by the rains; or are broken up by the frosts of repeated winters, the debris is carried down and borne to the lower grounds and forms the richest soils. The glistening specks of mica which are seen so abundantly in the soils over extensive areas, all tell the story of inex- haustible stores of potash, and soda, held safely until the slow action of the weather, the effective labors of the farmer, and the chemical agency of the manures and fertilizers he applies to the soil, unlock them from the close embrace of the silica and release them to become aliment for the crops, and bring comfort and wealth to mankind. These silicates are a subject for most interesting study, and although silica is rarely considered by farmers as of any value to them, it is really one of the most important of the inorganic elements. But it exists so abundantly in nature, and in such a readily available form, that like the air and the water which come to us unbidden, this really precious plant food is furnished as a free gift, without money or price and is lavished most abundantly upon us, so that the farmer is in no way concerned in regard to it. CHLORINE, is a gas of a most pungent and offensive char- acter; of a greenish yellow color; and is one of the elements 118 THE CULTURE OF FARM CROPS. which, combined, form hydro-chloric acid ; commonly called muriatic acid. This element fortunately does not exist in a free state but is quite abundant in combination; forming 60 per cent. of common salt; (chloride of sodium). It is easily produced by decomposing salt by means of the black oxide. of manganese, mixed with it, and placed in a bottle or jar and pouring sulphuric acid upon the mixture. The chlo- rine is separated from the salt and is given off in the form of the gas described. It is a most characteristic element. It extinguishes fire; but it causes phosphorus; gold (in the form of “leaf’’); potassium; sodium; and many other met- als, to take fire when immersed in it, and burn; combining with them and forming chlorides. It is 43 times heavier than air, and may be poured from one vessel to another. Animals cannot breathe it, and when unmixed it destroys. all living vegetables. Yet its solution in water promotes. the germination of seeds. It exerts astrongly destructive effect upon organic matter, and hence is employed as a disinfecting agent, to decompose: the noxious gases which emanate from putrid vegetable and animal matter. It also quickly destroys colors, and on this account is used for bleaching cotton goods. It is extensive- ly distributed in nature as may be seen by its universal pres- ence in the ash of plants, in some combined form. It is also present in all the secretions and other fluids of animals, and forms, as hydro-chloric acid, a portion of the gastric fluid of the stomach. This acid is composed of chlorine and hy- drogen. We have thus enumerated and described, as far as may be useful, the inorganic elements of plants, and those parts of them which are derived from the soil. The nature of the soil itself next claims our careful consideration. md THE SOIL. Cherlin eV ELT, THE SOIL.—ITS ORIGIN AND FORMATION. A study of the principles of geology will be found very useful and instructive to the farmer, for they explain how the soil which he prepares for his crops, and from which the subsistence of man is procured was formed; from what ma- terials it was derived; and how it came to be available for his purposes. The earth was once “without form and void and water covered the great deep.” This is the testimony of inspira- tion as given in the Scriptures and it is the testimony given by the rocks themselves. Everything in relation to the rocks and the soil which has been derived from them, prove the combined agency of great heat and of water, in their construction. The solid earth is composed in greater part of a few elements only; the larger part of the 64 which are known to exist, are found only in small quantities; and when we enumerate the 8 inorganic substances already men- tioned as contributing the mineral elements of vegetation and add to them the single one alumina which is chiefly represented by clay, we have all the elements which make up the vast bulk of the globe and form the soil which cov- ers its surface. The solid rocks which form what we call the crust of the earth are of two kinds, viz: those which give evidence of haying been erupted from a molten mass and of having been cooled into a solid state, and those which give evidence of having been deposited by the agency of water. It may per- haps best explain our subject by giving a short history of what is believed to have been the manner in which the earth was brought into its present condition. The condensation of the gaseous materials of which the earth is composed, at its original formation, produced a heat 120 THE CULTURE OF FARM CROPS. incomprehensible to our minds in its intensity, and of which we have an example in the present condition of the sun. In course of ages the gases became condensed to fluids and by a gradual process of cooling the-various elements became plastic and more adherent; separating from each other by molecular attraction and forming layers or masses, which formed a crust around the central portion, still fluid from the retained heat. At this period of the earth’s history it was surrounded by a dense atmosphere of steam ; produced by the vaporization of the water by the heat. Upon still further gradual cool- ing the watery vapor became condensed, in part; and the heated masses of plastic rock were enveloped in an ocean of boiling water, above which floated the dense volumes of steam. Here was indeed chaos, and the darkness which covered the waters and the earth. As the cooled crust hardened, it shrank, and as the pressure of the molten mass within it burst the thin shell, it was vomited forth into the ocean, causing explosions and outbursts of steam, which as- cending, became cooled and fell in tremendous torrents of rain, into the ocean. A seething, boiling, tumultuous ocean, thus enveloped the globe; while vast eruptions from beneath it forced mountain masses of plastic rock far above its surface, and these were washed with the descending rain ‘torrents. The soft rock was thus broken down into mud which flowed into the depressions, forming vast beds at first horizontally spread out. All this went on during vast ages; a period of terrible commotion and chaotic disturbance. As the gradual cooling proceeded, the disturbances became less frequent. At times the pressure from below the hard- ened crust lifted this slowly, breaking it into fissures and throwing up the rocks upon their edges, or into vast waves. These waves of rock were sometimes burst at their summit, when melted matter flowed over them and filled the depres- sions between them; or one side of the broken crust would fall back to a lower level leaving a precipitous wall of rock on the other side. The ocean beating upon these heated rocks, quickly wore them down into mud or sand; and THE FORMATION OF THE SOIL. 1a these spreading out under the great depths were soon pressed and hardened into the slates or the sandstones which we know so well. The hot water holding silica in solution gave up its burden as it cooled, and gradually added it to these beds furnishing the cement which bound them into a firm mass; or it filled the fissures and formed the quartz beds and veins so prominent among the existing mountain masses. Then came long periods of rest. The ocean cooled and + no longer gave forth the vast clouds of steam which hid the sun. Then came the light, and the day and night. The dry land was formed by the lifting up of the earth’s crust along continuous lines; the rocks being broken and tilted on their edges, and higher in places than in others, formed lines of islands through the enveloping ocean. Thus were formed the great chain of the Rocky mountains, and the lesser chain of the Blue ridge and Appalachians which stretch from Georgia to the north into lower Canada, and of which the White mountains and the Adirondacks are a part. A great broad valley was formed between these mountain chains, anda gradual slope on either side down to the depths of the ocean. By gradual shrinking of the still cool- ing crust, the mountain chains were lifted up and great de- pressions were formed into which the ocean withdrew, leav- ing broad continents stretching from the south to the north poles. All these changes of course were accompanied by - vast floods which washed the loose materials into depres- sions and formed layers of gravel, sand, clay and earth, much as we find them to-day when we excavate the banks of earth on the hill sides. . Then came the ice period. Everywhere over half the earth’s surface were vast beds of ice. These spread from the mountain tops down their sloping sides to the valleys. As the lower portions melted, the pressure of the enormous masses above, forced these beds of ice downwards, slowly but continuously; as the glaciers of the present age move down the mountain sides. The tremendous pressure ground down the rocks into powder; wearing away thousands ~of feet from the top, cutting off the crests of huge bends and 122 THE CULTURE OF FARM CROPS. waves: andas the ice melted under the heat of the pressure and friction, great floods emerged from under the glaciers and carried the broken down rock, sand, and mud, with them, and spread them in the valleys; forming broad shallow lakes. which eventually dried up and left wide areas of soil. Thus were formed the broad plains and prairies; the gently swelling vales and the broad valleys; and the hills and mountains were left to give birth to the rivers which cut their ways through the soil, on their passage to the source from which the all powerful beams of the sun first. drew them. Then came the first plant; a humble moss or lichen, covy- ering the soil in the first ages of vegetation, and gradually gathering from the atmosphere the carbon, nitrogen, oxy- gen, and hydrogen; and the various inorganic elements which have been described; furnished by their death and decay the sources from which future ages of life might spring. And by the gradual accumulation of stores of carbon and nitrogen in the soil, a better and richer vegetation was evolved, until the time came when the sweetly odorous flowers; the verdant meadows; the glorious forests; the teeming fruits and the nutritious grains covering the prolific soil; made a fit home for man; and the earth was given to him for his eternal heritage and dominion. Thus was the soil formed and man became a tiller of the eround. THE ROCKS THE ORIGIN OF SOILS. Cite? Tee xX Ex. THE ROCKS.—THEIR COMPOSITION AND INFLUENCE UPON THE SOIL. Rocks are divided by geologists into two great classes; one termed primary ; igneous; or unstratified; such as gran- ite; quartz, &c: the other, secondary; stratified; or sedi- mentary; as sandstones slates &c.; by which is meant that the latter has been formed from the debris of the former as has been explained in the previous chapter. One other class is termed, generally, the tertiary or third formation; and this consists, of the water worn pebbles; gravels; marl beds; clays and sandstones which have been formed by the later changes'on the earth’s surface and since animals of the kinds which now exist appeared on the globe. For this class of rocks are distinguished by the frequency of animal remains in them, which are similar to or identical with species which now exist. These three classes are divided into various sub-classes called systems and these again into formations; each of these having some common resemblance, which shows that _ they were deposited under nearly the same general physi- cal conditions of the earth’s surface. Thus there is the car- boniferous system, consisting of a series of limestones; sand- stones; iron stones; and beds of coal; which contain animal and vegetable remains of the same species, and are thus shown to have been formed at one special era of the earth’s history. From the characteristics and formation and order of deposition of these beds, the geologist or an attentive intelli- gent student, can formas clear an idea of what occurred during the age in which these plants grew and these ani- mals lived, and these rocks were deposited and formed, as if he had the open volume before him in which he might read the history. This is a study of the most intense inter- 124 THE CULTURE OF FARM CROPS. est to the farmer, who plows the soil and reaps his crops from the land made rich by the remains of past ages of veg- etable and animal life; and the history of which is recalled as he turns up in his fields the fossil or stony remains cf creat- ures which existed, we know not how many ages ago. The composition of the various rocks is of great interest to the student, because, as the soil is formed from the rocks, and its character is recognized by fragments of the prevail- ing rocks of which it is made up, the nature of the soil is necessarily similar to that of the rocks of which it consists. This knowledge of the rocks is indispensable to farmers, for without it they cannot know what they should of their soils, and the adaptability of these to the crops which they grow. For there are wheat lands; corn lands; grass lands; soils for fruit; for the vine; for the dairy; for sheep; and for other special crops as hops, tobacco, &c., and a right choice of land for a special purpose is indispensable to successful agriculture. Granite is the foundation rock of the globe. It is the basis of the oldest mountain ranges whose granite peaks, bare and rugged, point their pinnacles to the noon-day sun and defy the foot of man to reach them. This rock is of great importance in the formation of the soil; for it contains the most indispensable elements for vegetable growth; viz: silica; potash, alumina and soda; and in veins which are contained in it, lime; magnesia; phosphoric acid; sulphur and chlorine are found. Thus from this one rock and its accompanying minerals may be furnished to the soil, every inorganic element needed for the successful growth of crops. It is made up of crystals of quartz, feldspar, and mica, ce- mented together most compactly and making a rock of ex- treme hardness. The quartz is the clear, glassy, white, mineral; which makes up the larger portion of the ordinary sand; the feldspar is a flesh colored, or white, milky col- ored substance, softer than the quartz, and is usually in the form of square or rhomboidal crystals; the mica is in white yellow or black scales. There are no richer soils than those derived from granite, FERTILITY OF GRANITE SOILS. 125 the component parts of which contribute every necessary element for abundant and vigorous vegetable growth; while the large proportion of silica existing in them, with the alumina and magnesia, give them a loose open texture which makes them easy of cultivation and permeable to water. These soils produce wheat and all the grains, grasses, fodder crops, and fruit, to perfection. They may be readily dis- tinguished by the glistening of the small bright particles of mica which glitter in the sunlight, and by their loose open mellow texture. They bear a forest growth of oak, hick- ory, elm, basswood and white pines of the largest dimen-. sions and finest quality; and having a deep surface soil with an open subsoil rarely require artificial drainage. The principal constituents of the feldspar of which these soils largely consist are silica, alumina, potash, and soda; the soda feldspar is called albite; the potash feldspar is. called orthoclase. ‘These minerals have the following com- position. Orthoclase, Albite. SHR ITCCL? ty Rape RE. Sie Wes Bee 65.21 69.09 AG) PLYTUNTV EY ic ane conan aanngosess cusands 18.13 19.22 PS REISE che tatoo tenes Covanees panases 16.66 RRM ED Sauercerpanate Gravnvecs ceacasaaaaeneots ee 11.69 100.00 100.00 The mica contained in the granite has a varied composi- tion, one kind containing magnesia in considerable propor- tion. The following are analyses of these two kinds. Potash Mica. Magnesia Mica. SD BRR ee aaa Se ose tes ca ba chara 46.10 40.00 PAMAITVAUE cee teccncnwavacwasaccncdsscse 31.60 12.67 REA CLEVOFE IPOM Gs ocisct. ccc cssiwescsess 8.65 19.03 REGUS Nieto. aap sae ds dodadnaneaccach sa 8.39 5.61 LN: ee 1.40 16.33 PORMOPTCNANCN soo oc cccccecesscees aces T12 2.10 Muisitiesteectcn ti. ahectcscks ds osucps anatoueens 1.00 — MEMTIAC BOI. cvatasseensaveonces +230 a 1.63 98.26 97.37 When the granite contains hornblende in place of mica it is called Syenite. Hornblende is a black glassy mineral, very tough and hard; and contains the following substances.. 126 THE CULTURE OF FARM CROPS. Basalt Hornblende. Syenite Hornbdlende. SUGAR eavdeccescutasticrivadisdeseacs 42,24 45.69 cA VURTTUTTNG ease seseevantarees eure sanvcsas 13.92 12.18 ATOR ce eae dca chia i Poach opce 12.24 13.83 IW AGTIONIH cv evainecsotesrecdessseqreses 13.74 18.79 OMIDGOE TOU s. neces evseesovceess 14.59 7.32 Oxide of Manganese............. 0.33 0.22 IREGOEIG CIO sc ceterssessvecuscarseuens —— 1.50 97.06 99.53 This variety of granite is distinguished by the absence of potash and the presence of lime in notable quantity. Granite also contains a number of other minerals in veins, or scattered through the mass. Among the most important of these are apatite or phosphate of lime; marble or crys- tallized carbonate of lime; tourmaline; epidote and cryso- lite. These furnish to the soil the phosphoric acid, which is indispensable for vegetable life and growth, and contrib- ute lime, magnesia, potash and soda as well. Where these minerals abound, the soil is fertile and bears abundant crops. The greater parts of New England; northern New York; eastern Canada; Pennsylvania, parts of New Jersey, West Virginia and southward along the mountains and eastward to their feet, are covered with soil produced by the decom- position of this class of rocks and prove by the high culture and value of the soil, how well it is furnished with the ele- ments of plant food. The same may be said of all the other rocks of this class; which consist of similar minerals varying more or less in proportion. This variation naturally has an effect upon the character of the soils derived from these rocks. For when phosphoric acid is deficient, no surplus of other ele- ments will make up a fertile soil; and when the lime or potash has been washed from the soil on the higher lands into the valleys, the sandy land which remains has no good quality to attract the husbandman. The most fertile soils are those derived from the decom- position of limestone rocks. When the traveller across the continent passes the Appalachian mountains, he enters the grand valley of the Mississippi and Missouri rivers, and traverses a vast region of the utmost fertility, renowned as VALUE OF LIMESTONE LANDS. 127 the granary of the world and surpassingly rich in cattle. The blue grass region of Kentucky, Missouri, Ohio and Iowa; the inexhaustible bottoms of the Ohio rivers; the “loess” soils of Nebraska and Kansas and the rich prairies and forests of the north western states, are all underlaid with limestone rocks and covered with a limestone soil of unsur- passed fertility. These lands have made the United States the richest and most powerful nation of the world; for they have attracted the many millions of industrious enterprising immigrants which have covered these lands with fertile farms, the produce of which has given employment to the great railroads and fleets of steamships which carry abroad millions of tons of grain and provisions and bring back more of the wealth of muscle and brain, which makes up the strength and power of this great nation. The following ta- ble exhibits the character of the soils referred to. 1 2 3 From Kentucky From the From blue grass region. Ohio valley. Nebraska. Silica and fine sand............. 76.20 85.14 80.51 PAUUUUTTNITY Ocak cates wav epieesngnshe verse 8.51 5.66 6.81 ORAMEOL, ANON: 2 sescaesncassecesssce 2.59 aloes 0.31 NAUUTT ES ees decbcsauvsuaueteatesrscsseaeed 3.92 1.56 4.40 PEM ESA Sc cesseoncescconeasataces 1.68 -ol 1.16 HEHE ceeskvetinees on standensscsee: 2+ 1.14 48 2.13 OE coeaac cisco cees- veers soaseeleeesaccn 0.64 .02 ai PHOSpHOrig ACI... 5.026.002. as, 65 1.60 1,22 MSPS ca ccaxseesaeeanychshpaeecusecs SOL 02 .09 CUNVOTAIVE hoc canettense oasbehaccauecacs .O1 .03 .03 MEY HGMICURCIG...2.x0c