Fertilizers

Front matter

Copyright N°_^2/^2

COPYRIGHT DEFOSIT.

Ube IRural Science Series

Chapter I Pages

The Natural Fertility of the Soil and Sources op

Loss oe the Elements op Fertility . . . 1-19

Soil Fertility — Chemical elements needed in plant growth — Fertility as influenced by water, climate and season — The influence of physical character of soil — Location of soil qualifies the term "fertility" — Practical fertility is usable potential fertility . . . 2-6

What Becomes of Our Fertility f 7

Sources of Natural Loss of Nitrogen — Importance of careful culture — Loss of nitrogen by drainage — Escape of nitrogen into the atmosphere .... 8-11

The Natural Loss of the Mineral Elements — Losses due to mechanical means 11-12

Artificial Losses of Fertility — A comparison of the prices received for the fertility elements in different crops — Fertility content of cereals and vegetables — Irrational farm practice — Losses in manures . . 13-19

Chapter II

The Function op Manures and Fertilizers, and the Need of Artificial Fertilizers

The Essential Elements of Fertilizers Natural Manures and Artificial Fertilizers Direct and Indirect Effect of Manures Unavailable and Available Plant-food Danger of Loss from the Use of Soluble Plant-food The Usefulness of a Fertilizer Constituent does not Depend upon Its Original Source .

Use of Fertilizers

v

20-35

22-23

23-25

26 27-28 vi Contents

PAGES

The Need of Artificial Fertilizers — The cost of production to a unit of income is increased — A greater demand for special crops — Farm manures are inadequate

— The growing importance of fruit-growing . . . 28-33 Will it Pay to Use Fertilizers ? 33-35

CHAPTER III Nitrogenous Fertilizers ....... 36-60 What is Meant by Form of Nitrogen ? 36-37

Dried Blood 37-39

Dried Meat or Meal, Azotin, Ammonite, or Animal

Matter 39

Dried and Ground Fish, or Fish Guano . . . 39-40

Tankage 40-41

Garbage Tankage 42

Low-grade Nitrogenous Products — Horn meal or

ground horn — Leather meal — Wool and hair waste . 42-43 Vegetable Nitrogenous Products — Cottonseed meal

— Linseed meal — Castor pomace — Vegetable pomaces 43-44 Natural Guanos — Mechanical Condition should be

considered 44-47

Ammonia Compounds — Sulfate of ammonia — Calcium cyanamid . 47-50

Nitrate Nitrogen — Nitrate of soda — Calcium nitrate

— Potassium nitrate — Ammonium nitrate . . . 50-53 The Belative Availability of the Different Forms of

Nitrogen — Comparative availability of different nitrogenous substances — Conditions which modify availability 53-60

Chapter IV

Phosphates — Their Sources, Composition, and Relative Value ......... 61-80

Phosphate of Lime, or Bone Phosphate — Animal Bone — Raw bone — Fine bone — Boiled and steamed bone — Commercial grades of bone — Bone tankage — Other organic products — Bone-black, or animal charcoal — Bone-ash 62-68 vn

Mineral Phosphates — South Carolina rock phosphates

— Florida phosphates — Canadian apatite — Tennessee phosphate — Recent discoveries in western states — Basic slag — Manufactured phosphates — Artificial basic-slag meal — Wiborgh phosphate — Wolter phosphate — Palmaer phosphate — Phosphatic guanos

Phosphates as Sources of Phosphoric Acid to Plants

— The influence of source of phosphate upon availability

— Influence of fineness of division — The character of soil as a factor influencing availability — Influence of the kind of crop — General considerations

68-75

75-80

CHAPTER V Insoluble Phosphoric Acid 81-82

Soluble Phosphoric Acid 82

Reverted Phosphoric Acid 82-83

How Superphosphates are Made — The difference in the superphosphates made from the different materials — Soluble phosphoric acid chemically identical, from

whatever source derived 83-85

Phosphates and Superphosphates are not Identical . 85-89 Double Superphosphates . . . . . . 89-90

Chemical Composition of Superphosphates — Well-made superphosphates contain no free acid — Phosphoric acid remains in the soil until taken out by plants . . 90-93

Potash Salts — The importance of potash as a constituent of fertilizers — Forms of potash — Kainit — Hardsalt — Carnallit — Muriate of potash — High-grade sulfate of potash — Double manure salt — Potash manure salt — Double carbonate of potash and magnesia — Potassium carbonate — Potassium nitrate — Feldspar and other minerals as a source of potash — Seaweeds as a source of potash — Fixation of potash .... 93-101

CHAPTER VI Miscellaneous Fertilizing Materials

Tobacco Stems and Stalks — Tobacco salts — Crude fish scrap — Wool and hair waste — Sewage — Muck and

102-118 viii Contents peat — King crab, mussels and lobster shells — Seaweed

— Wood-ashes and Tanbark-ashes — Coal-ashes — Cotton-hull-ashes — Corn-cob-ashes — Cocoa shells — Green sand marl — Agricultural salt — Powder waste — Gas lime — Gypsum or calcium sulfate — Phosphorus powder — Calcium carbide waste — Oxy-acetylene residue — Purchase and use of miscellaneous materials . 118

CHAPTEE VII

Farmyard Manures — Variations in manures — Manure produced by different animals — Composition of stable manure — Solid and liquid portions — Sources of loss in manures — Care of manures — Manure preservatives — The improvement of manures — Application of yard manure — Poultry and pigeon manure — Composts 119-128

Green-manures — "Nitrogen gatherers" and "nitrogen consumers ' ' — The most useful crops — Green-manure crops that consume the nitrogen in the soil — Mixtures are advisable — Precautions in the use of green-manures 128-134

CHAPTER VIII Occurrence of Lime 136

Forms on the Market — Caustic lime — Ground limestone — Calcium-magnesium lime — Ground burned lime — Hydrated lime — Air-slaked lime — Oyster shell

lime — Shell marl 136-140

Action of Lime on Soils — Mechanical effects of lime

— Chemical effects of lime — Lime supplies a necessary base — Lime assists the decomposition of organic matter

— Lime makes soil potash available — Lime makes soil phosphates available — Less plant-food required — Injurious chemical effects — Effects of gypsum . . . 140-145

Biological Effects of Lime — Biological effects may be harmful 145-146

IX

The Use of Lime — Do soils need lime ? — The application of lime — When and how to apply lime — The form of lime to use — Distribution of lime — Analysis and guarantee

146-152

CHAPTER IX Standard High-grade Materials 154-155

Fertilizing Materials Variable in Composition . . 155-156 High-grade and Low-grade Fertilizers — The "unit" basis of purchase — The " ton " basis of purchase — The necessity of a guarantee — Laws alone do not fully protect — Method of statement of guarantee sometimes misleading — Discussion of guarantees — Raw materials — Mixed fertilizers — The advantages and disadvantages of purchasing raw materials and mixed fertilizers . . 156-167 Home Mixtures — Formulas — The cost of handling

"make-weight " 167-173

General Advice 173-174

CHAPTER X Chemical Analyses of Fertilizers

The Interpretation of an Analysis The Agricultural Value of a Fertilizer The Commercial Value of a Fertilizer Calculation of Commercial Values The Uniformity of Manufactured Brands

CHAPTER XI Conditions which Modify the Usefulness of Fertilizers

191-211

— Derivation of soil a guide as to its possible deficiencies

— Physical imperfections of sandy soils — Physical imperfections of clay soils — The influence of previous treatment and cropping — The influence of character of crop — The kind of farming, whether " extensive " or

" intensive " 191-199

Plants Vary in their Power of Acquiring Food — Characteristics of the cereal group — Characteristics of grasses and clovers — Root crops — Market-garden crops

— Fruit crops 199-204

Systems of Fertilizing Suggested — A system based

upon the specific influence of a single element — A system based upon the necessity of an abundant supply of the minerals — A system based on the needs of the plants for the different elements as shown by chemical analysis

— A system in which the fertilizer is applied to the "money crop" in the rotation — An irrational system 204-210

Summary 210-211

CHAPTER Xn

Fertilizers for Cereals and Grasses .... 212-236 Experiments to Determine the Lacking Element — A scheme for plot experiments — Results that may be attained 214-219

The Importance of System in the Use of Fertilizers — Indian corn exhaustive of the fertility elements — Oats

— Barley — Wheat — Rye — Clover — Timothy — A gain of fertility by the rotation system — The necessity of adding more plant-food than is required by a definite increase in crop — The system should be modified if no

farm manures are used 219-231

Fertilizers for a Single Crop Grown Continuously . 231-233

Fertilizers for Meadows 234-235

Will this System of Fertilizing Pay?. . . . 235-236

CHAPTER Xni

Fertilizers for Potatoes, Early Crop — The time and method of application — The amount to be applied —

Form of the constituents 238-243

Late Potatoes 243-244

Sweet Potatoes — Fertilizer constituents contained in an average crop — The application of the fertilizers . 244-248

XI

Tomatoes — Field experiments with fertilizers for tomatoes — Fertilizers for the early crop for different conditions of soil — The use of fertilizers with yard manures — Fertilizers for late tomatoes

Peppers and Eggplant

Peas and Beans ....

Field Beans ....

General Considerations

248-257 257

257-258 258 269

CHAPTER XIV Green Forage Crops 260-282

Cereals and Grasses — Maize (corn) forage — Silage corn — Wheat and rye forage — Spring rye — Oats — Oats and peas — Barley and peas — Millet — Orchard grass — Italian rye grass — Bermuda grass . . . 260-269

Clovers and Other Legumes — Japan clover — Cowpea and soybean — Spring vetch — Hairy or winter vetch — Alfalfa or lucerne — Sweet clover — Need of lime for legumes — Fertilization of soiling crops . . 269-277

The Cabbage Tribe — Rape — Cabbage — Kohlrabi . 277-279

Boot Crops — Fertilizers for fodder-beets, sugar-beets and carrots — Turnips and swedes .... 279-282

Tuber Crops 282

CHAPTER XV

The Yield and Quality Dependent upon Continuous and Bapid Growth — A basic fertilizer for market-garden

crops — The different kinds of vegetables . . . 283-289

Boot Crops — Beets and turnips — Carrots . . 289-291

Bulb Crops 291-293

Cole Crops 293-294

Pot Herbs 294-295

Salad Crops — Celery — Lettuce .... 296-296

Pulse Crops 296-297

Solanaceous Crops — Eggplant — Peppers — Tomatoes 297-299

Vine Crops 299-300 xii Contents

Miscellaneous Crops — Asparagus — Rhubarb —

Sweet corn— Okra 300-306

Condimental or Sweet Herbs 306-307

CHAPTER XVI

Fruit Crops differ from General Farm Crops . . 308-309 The Specific Functions of the Essential Fertilizing

Constituents . 310

The Character of Soil an Important Consideration . 311-312

The General Character of the Fertilizing . . . 312-313

The Application of Fertilizers for Fruits . . . 314 The Fertilizing of Apples and Fears — The amounts

to be applied 314-318

Peaches — The need of fertilizers — Methods of fertilizing 318-325

Plums, Cherries, and Apricots 325

Citrous Fruits 325-326

Small Fruits — Strawberries — Raspberries and

blackberries — Currants and gooseberries — Cranberries 326-330

Grapes 330

CHAPTER XVII Fertilizers for Various Special Crops .... 332-357 Cotton — Fertilizers for cotton — Formulas for cotton fertilizers — Method of application .... 332-338

Tobacco — The influence of fertilizers on the quality of the crop — The conclusions from Connecticut experiments — Form of the constituents — Amounts to apply 338-343 Sugar-beets — The demands of the crop for plant-food

— The influence of previous deep cultivation of soil . 343-346 Sugar-cane — The needs of the plant as indicated by

the Louisiana experiments — The application of fertilizers 347-350

Flax ' 351

Miscellaneous Crops — Sorghum — Buckwheat — Peanut — Roses, and other flowering plants — Lawn grasses

— Forcing house crops 351-357

LIST OF ILLUSTRATIONS

Plate I. Fig. 1. Coke-oven Plant, Gary, Indiana, where ammonium sulfate is an important by-product opposite 32

Plate II. Fig. 2. Cylinder Experiments at the New

Jersey Agricultural Experiment Station . " 54

Plate III. Phosphate Mining " 70

Fig. 3. Phosphate Pit, Dunnellon, Florida. Fig. 4. Mining Phosphate Eock by Means of Floating Dredge.

Plate IV. Mining and Composting " 98

Fig. 5. Mining Phosphate Eock by Hydraulic Pressure.

Fig. 6. The Manure Spreader is a Labor-saving Device

which secures an Even Distribution .... 125

Plate IV. Mining and Composting .... opposite 98 Fig. 7. Unloading and Composting New York Stable Manure in South Jersey.

Plate V. Fertilizers and Wheat .... " 120

Figs. 8 and 9. Continuous Wheat Cropping with and without Green-manures, New Jersey Experiment Station.

Plate VI. Wheat and Potatoes .... " 140

Fig. 10. Wheat Grown as a Winter Cover-crop Preceding Potatoes, Freehold, New Jersey.

Plate VII. Fertilizers and Eye . . . . " 158

Figs. 11 and 12. Eye with One-half Ton of Lime and without Lime, xiii

XIV

List of Illustrations

Plate VI. Wheat and Potatoes ....

Fig. 13. Making an Application of One and One-half Tons of Quicklime to the Acre for Alfalfa after Potatoes.

Fig. 14. Grain Drill with Fertilizer Sower

Plate VIII. Wheat and Timothy ....

Fig. 15. Thirty-five Bushels of Wheat to the Acre, Mechanicsburg, Pennsylvania.

Fig. 16. Early Spring Top-Dressing with Commercial Fertilizer High in Available Nitrogen Greatly Increases the Yield of Timothy.

Plate IX. Lima Beans and Potatoes

Fig. 17. Ninety-acre Field of Lima Beans for Canning, Freehold, New Jersey.

Fig. 18. The Potato-planter with Fertilizer Attachment, which distributes Fertilizer evenly in the Kow

PAGE

opposite 140

. 213 opposite 178

Plate IX. Lima Beans and Potatoes

Fig. 19. One Ton of High-grade Fertilizer Used upon Early Potatoes is the Common Practice among Growers in New Jersey.

Plate X. Fertilizers and Tomatoes .... Fig. 20. Early Tomatoes Grown in Light,

Sandy Soil, Thorofare, New Jersey.

Fig. 21. Growth of Clover along Tomato Rows

Heavily Fertilized the Preceding Year,

Moorestown, New Jersey.

Plate XL Peppers and Red Clover ....

Fig. 22. Peppers Grown under Field Conditions, Thorofare, New Jersey.

Plate XII. Fig. 23. Oats and Canada Field Peas respond to Good Fertilization

Plate XL Peppers and Red Clover ....

Fig. 24. Excellent Second Growth of Red Clover on Heavily Fertilized Potato Land, Freehold, New Jersey.

opposite 202

260 234

List of Illustrations xv

PAGE

Plate XIII. Fig. 25. Dwarf Essex Rape mixed with Soybeans and Sweet Clover, and Heavily Fertilized, makes a Luxuriant Forage . opposite 278

Fig. 26. Garden Fertilizer Sower 284

Fig. 27. Garden Fertilizer Sower with Hoe to work

Fertilizer into Surface Soil 288

Plate XIV. Cabbage and Watermelons . . . opposite 294 Fig. 28. Cabbage Heavily Fertilized, Freehold,

New Jersey.

Fig. 29. Watermelons, Peppers, and Corn Fertilized with Basic Fertilizer, Clarksboro, New Jersey.

Plate XV. Fertilizers for Peaches .... " 318

Figs. 30 and 31. Views of the Vineland Experimental Peach Orchard, New Jersey Experiment Station, showing (Fig. 30) Effect of Nitrogen in Addition to Minerals; Fig. 31, below, Minerals Only, No Nitrogen.

Plate XVI. Fig. 32. Tobacco, Lancaster area,

Pennsylvania " 338

Chapter I

NATURAL FERTILITY OF THE SOIL, AND SOURCES OF LOSS OF THE ELEMENTS OF FERTILITY

There is no one question of greater importance to the farming industry than that of soil fertility. In order that the industry may be successful, it is not enough to produce crops; it is necessary that their production shall result in a genuine profit. That is, it is not enough to produce crops which bring more than they cost in the way of labor and manures, without taking into consideration the effect of their growth upon the future productive capacity of the soil. The relation of the outgo and income of the fertility elements is an important factor in determining profits, and must be considered. The farmer who secures crops that bring more than they cost, and who, at the same time, maintains or even increases the productive capacity of his soil, is, other things being equal, the broadly successful farmer. Many farmers are able to accomplish this object because of the knowledge they have acquired through long years of experience, rather than because they possessed in the beginning of their work a definite knowledge of the fundamental principles involved in crop production, and upon the observance of which their success depended. One of the first needs, therefore, in the use of commercial fertilizers is a more or less definite knowledge of what constitutes fertility, and of the principles which underlie crop production.

SOIL FERTILITY

The full meaning of the term "soil fertility" is not easily expressed, since many conditions are involved, all of which exert more or less influence. The potential fertility, which is measured by the total content of the food elements contained in a soil, is made practicable, or usable, in proportion as the conditions are favorable. The more important of these influencing conditions are here briefly discussed. In the first place, it is of the utmost importance that a soil should contain those elements found in the plant; hence, it is almost self-evident that a fertile soil must contain a maximum quantity of those particular elements or constituents which are removed from the land in maximum amounts by the crops grown. The removal of crops rapidly exhausts the soil of these elements, and finally reduces the quantity contained in the soil to so low a point as to make profitable cropping impossible.

Chemical elements needed in plant growth.

Careful studies and experiments have shown that plants actually take from the soil at least ten chemical elements which are required for their normal growth and development: viz., nitrogen, potassium, phosphorus, magnesium, sulfur, sodium, iron, chlorin, silicon and calcium. Besides these elements, others are often found, including manganese. It is not to be inferred that all of these elements are required by all plants. There are many plants which grow to maturity without sodium, silicon and chlorin, but all of the others must be present for normal growth. Carbon, hydrogen and oxygen are also found in plants, but these elements are secured from air and moisture.

The number of soil constituents liable to rapid exhaustion is limited in many cases to three, and at most to four, which are nitrogen, phosphoric acid (phosphorus), potash (potassium), and lime (calcium), the latter only in exceptional cases. These are liable to be exhausted because they exist in larger amounts than the others in the plants that are grown, and in smaller amounts than the others in even the most fertile soils. It has also been proved that it is the one element of these which exists in the smallest amount which measures the crop-producing power, or fertility, in this respect, as one element cannot substitute or exert the full functions of another. That is, there may be a relative abundance in the soil of potash and of phosphoric acid, but practically no nitrogen, in which case good crops of cereals, for instance, could not be grown, because no other element can substitute the nitrogen required by the plant, and it can be obtained by it from no other source than the soil ; and the soil, for all practical purposes, is quite as unproductive, lacking in productive fertility, as it would be if it contained much smaller amounts of the mineral elements mentioned, and thus be poorer in potential fertility.

Fertility as influenced by water, climate and season.

In the second place, there are soils that are so rich in all of these elements that if productiveness depended upon them alone, maximum crops might be grown for centuries without exhausting them, while actually they are now incapable of producing a single profitable crop of cereals, grasses, fruits or other products of the farm, because certain other conditions which are essential, in order to bring them into activity, are absent. For example, it may be that water, which is absolutely essential both for the solution of these food elements in the soil, as well as for their distribution in the plant after they have been acquired, cannot be obtained, or that the temperature of the soil and of the surrounding air is either too low or too high, thus preventing or interrupting the progress of those changes which must go on, both in the soil and in the plant, in order that normal growth and development may be accomplished. With a full supply of the fertility elements in the soil, the climatic and seasonal conditions exert an important influence upon its productive power.

It is evident, therefore, that the chemical elements of fertility in themselves are not sufficient to constitute what we understand by the term. Fertility is not measured by them alone ; associated with them there must be other conditions. That is, while crops cannot be grown without these elements, it is the conditions which surround them that, in a large degree, determine the power of the crop to secure them.

The influence of physical character of soil.

In the third place, the physical character of a soil is also a factor in determining actual fertility. This has reference, first, to the original character of the rocks from which the soil particles were derived, whether hard and dense in their mineral character, thus resisting the penetration and the solvent effect of air and water and other agencies, or whether soft and friable, and freely permitting their entrance and action; and secondly, whether, in the formation of the soil, the particles were so fine and so free from vegetable matter as to settle in hard and compact masses, impervious to water, air and warmth; or whether they were coarse, and not capable of close compaction, thus giving rise to an open and friable soil, freely admitting the active natural agencies, such as we find to be the case in sandy soils. In addition to these properties of soils, which have a distinct place in determining fertility, there are many other minor ones which together constitute what is understood as "condition."

Location of soil qualifies the term "fertility."

Furthermore, fertility, even in this true sense, may be useless because of the location of the soil which possesses it. For example, there are many places on this continent where sugar-producing plants will grow and develop perfectly, since the soils are very rich in the fertility elements, and since the surrounding conditions are most favorable for their culture, yet, because of their location, it is unprofitable to grow them for the manufacture of sugar. In the first place, the soils are so situated as to make it impossible, or at least impracticable, to provide the means necessary for converting the sugar-producing crop into actual sugar, and, in the second place, even if it were possible to do so, the great distance from shipping stations to markets so increases the cost of transportation as to make it unprofitable to compete in the market with the crops grown upon lands possessing true fertility in a lower degree.

Practical fertility is usable potential fertility.

Practical fertility, therefore, is dependent upon many conditions, and fortunately our own country possesses it in a marked degree ; that is, the utility of the potential fertility, as represented by the total mineral content of our soil, is such as to make us one of the greatest agricultural nations in the world, both in the quantity and variety of products grown. Our soils possess the essential elements in lavish amounts, and our climatic and seasonal conditions are such as to permit of their ready conversion into a wide series of valuable products, and our location and facilities for handling and distributing our staple crops are such as to enable us to compete in any market of similar commodities.

Notwithstanding the truth of this general statement, it is also true that in certain sections of our country profitable crops cannot be grown without the addition of commercial fertilizers, because the soils are either naturally poor, or they have become partially exhausted of their plant-food elements. That is, the amounts that become available to the plant through the growing season are not sufficient to enable the plant to reach a maximum development, though other conditions are perfect.

Our future progress depends, therefore, upon how well we understand and apply the principles which are involved, both in the conservation and use of the fertility stored up in our soils, and in the use of purchased fertility ; and in this connection it is important to consider the sources of loss of the essential fertility elements, or those which in the beginning measured our capabilities in crop production.

WHAT BECOMES OF OUR FERTILITY?

Since fertility is dependent upon so many conditions, or, in other words, since the essential elements of fertility are dependent upon their utility, and since, in this sense, fertility is largely determined by natural conditions, it is pertinent to inquire, first, whether under our present systems of management, or mismanagement, of the land, it is suffering any natural loss of fertility. As already pointed out, the most important function of fertility is to furnish nitrogen, phosphoric acid and potash, and since the content of these in our soil, together with the knowledge we have as to their use, measures, in a sense, our prosperity as an agricultural people, the possibilities of losing them from the soil is a matter of national concern, and is of vital interest to individual farmers, who, in the aggregate, make up that part of the nation directly affected by the results of such loss.

It would, perhaps, be possible, by a careful chemical survey of our soils, to determine both the actual and potential fertility of our entire country, and this knowledge, together with an accurate measure of the intelligence exercised in its use, would enable a prediction as to our future development, if present methods were continued. That is, whether our land would become barren and worthless, as has been the case in many older countries which at one time were quite as productive, or whether it would constantly increase in productiveness, even with continuous and profitable cropping, — although, as already pointed out, the present barrenness or sterility of a country formerly fertile may not be due entirely either to the natural or to the artificial loss of these constituents.

SOURCES OF NATURAL LOSS OF NITROGEN

Of the essential constituent elements, nitrogen is, in one sense, of the greatest importance ; first, because it is the one that is more liable to escape than the others, and secondly, because it is more expensive to supply artificially than are the minerals. It is the most elusive of all the elements: to-day it may be applied to the soil, to-morrow it may be carried in streams to the ocean. It is also unstable — which is not the least valuable of its characteristics if properly understood : to-day it is an element of the atmosphere, to-morrow it is a constituent part of a growing plant, the next day the same element may exist as an animal product, and the day following it may be returned to the soil to feed the plant. It is more liable to escape than any of the others, because it is available as plant-food largely in proportion as it changes to a nitrate, and after it assumes that form it is seldom absorbed or fixed in the soil. Nitrogen in this form remains freely movable, and the probability of loss by leaching is increased in direct proportion to the lack of preventive measures used, or the presence of those conditions which favor leaching. The latter may be classified as follows : First, the amount and time of the rainfall ; secondly, the absorptive and retentive power of the soil and subsoil, due to their mineral and physical character ; and thirdly, the amount of vegetable matter (humus) acquired by the soil, which retards the passage of water. While the amount and time of rainfall cannot be controlled, its effect upon our soils in this direction can be largely governed if proper attention is given to correcting the other conditions, and these may be largely modified, if not entirely controlled. In the matter of the absorptive and retentive power of soils, it has been shown that if they are well supplied with vegetable matter and carefully cultivated, they retain and hold the plant-food constituents in a much greater degree than if devoid of humus and improperly managed, and also that the drainage water from soils upon which crops are growing seldom contains more than the merest trace of nitrates. The loss of nitrogen through the operation of the forces of nature may, therefore, be reduced by the careful management of the soil.

Importance of careful culture.

The presence of suitable amounts of vegetable matter, and good cultivation, are conditions that are within the power of all farmers to provide, though it is sometimes impracticable to keep the land continuously covered with a crop ; and sometimes it is thought that the loss incurred through leaching because of the absence of a growing crop is more than balanced by the gain in other directions. For example, though losses of nitrates may occur, the gain in availability of the mineral constituents, phosphoric acid and potash, with the accompanying improvement in texture, due to the exposure of the soil to atmospheric influence, more than balances these losses, particularly during the winter, with its wide changes of temperature.

Loss of nitrogen by drainage.

It has been shown by carefully conducted experiments, both in this and other countries, that in a season of average rainfall the drainage waters carry away from one acre, from uncropped soils only fairly rich in plant-food, as much as 37 pounds of nitrogen a year, while when continually cropped the drainage waters from the same soils contain practically no nitrogen. This difference in the loss of nitrogen under the two conditions may not seem a great matter at the first glance, but a careful study of the bearing of this loss in its relation to crop production shows that it is really a serious matter. In the first place, the amount of possible loss annually is practically equivalent in nitrogen to the amount contained in two tons of timothy hay, or in one ton of either wheat, rye, oats, corn or buckwheat, quantities nearly double the average yield to an acre of these crops throughout our whole country ; and in the second place, that the nitrogen which is carried away by the drainage water is in the very best form for feeding the plant, or it would not have been lost, and thus its loss leaves the soil not only poorer in this constituent element, but poorer in the sense that the remainder of it in the soil is in a less useful form. Furthermore, if this nitrogen is to be returned to the soil in the same form, which is the cheapest, it would cost at present prices $6.85.