Land draining; a handbook for farmers on the principles and practice of farm draining

Preface

A book on farm draining is evidently needed at the present time, to bring vnthin reach of practical farmers the established facts of science relating to the principles and advantages of thorough drainage, and the best and most economical method of making farm drains.

Under the present conditions of American farm practice, one of the most prominent defects in the prevailing system of management appears to be a lack of attention to thorough drainage as a means of diminishing the cost of production, and insuring uniformly remunerative returns in crop growing, by increasing the fertility of the soil, and avoiding the losses from unfavorable seasons. The manifest neglect of this important branch of rural economy by the majority of farmers is undoubtedly owing, to a great extent, at least, to the frequent failures observed in draining, from the practice of imperfect methods, and vague, or incorrect notions, in regard to the real advantages to be derived from draining.

This is not surprising, as attention has been turned in other directions, and the most valuable contributions to the principles of drainage, of late years, have been confined, in the main, to periodicals and reports not generally accessible to farmers, and there is no book on this special subject in which may be found a description of the best method of making tile drains, or an adequate discussion of the latest developments of science in their relations to the principles of drainage. Many of the

IV PREFACE.

maxims in draining^ of but a few years ago, have become obsolete, and more consistent methods have been adopted in the best modern practice, wliile the progress of science has extended our knowledge of correct principles, and made clear many details in regard to the most favorable conditions for growing crops, which are of great practical importance.

In this Handbook for Farmers, the aim has been to present the leading facts of practical significance, in connection with a popular discussion of the applications of science, and the results of experiments relating to draining have been summarized in tables in convenient form for reference, which furnish ready answers to many of the economic questions that will be suggested to the intelligent farmer.

An outline of the history of draining is given to illustrate the progress of discovery and invention in developing correct principles of practice, and the directions for laying tiles, which are the results of an extended experience in draining under widely different conditions, are confidently recommended as a decided improvement on former methods.

Lansing, Mich., 1892.

Chapter I. Geneeal Principles

The rapid growth of science, and the development of the mechanic arts which have made possible fche unprecedented activity in the industries during the past quarter of a century, have brought about economic changes in methods of production, which must be taken into consideration in attempts to improve the practice and increase the profits of agriculture.

From the intense competition in farm products of all kinds, arising from the extraordinary development of facilities for cheap transportation, the farmers of the United States are directly interested in every means of diminishing the cost of production, to enable them to hold a commanding position in the world's markets, and obtain remunerative returns for their labor, without impairing the value of their invested capital. The business methods that have been found necessary to insure success in other pursuits must be adopted, and attention must be given to every available means of increasing the productiveness of the soil and making the labor expended on it more effective, while the losses resulting from bad seasons must be reduced to a minimum by the intelligent direction and control of the forces of nature.

One of the first steps in the direction of improved methods of farm practice is to put the soil in a condition to yield the best net returns from the elements of plant food which it naturally contains, or that may be applied to it in the home supplies of manure. The questions that may arise in regard to artificial, or purchased fertility, are of secondary importance to the majority of American farmers, and the leading problem for them to solve is to obtain the best returns from the elements of production already within their control.

Among the available agencies for bringing about this desirable conservation and utilization of the elements of profitable crop-growing on a large proportion of the farms of this country, thorough drainage is the most important, as upon it will depend the successful application of other means of increasing productiveness, including thorough tillage and manures, which are relied upon to increase the net income that may be derived from the aggregate of farm operations.

In order to lay a foundation for the intelligent discussion of the advantages of thorough drainage it will be necessary to briefly review some of the conditions that are essential to the health and well-being of the crops grown on the farm. The results of scientific investigations are suggestive, and the knowledge that has been gained of the laws and processes of vegetable nutrition and growth must be recognized as of great practical value in farm economy, when their relations to details of practice are clearly understood.

The uniform certainty of results obtained in all operations in other industries can only be realized in agriculture Avhen the practice of the art is based on consistent principles, in harmony with those natural laws which it is the mission of science to discover and investigate. In dealing with the different forms of life with which the farmer is chiefly concerned, the best results can only be obtained by a strict conformity to physiological laws, the practical significance of which may readily be learned and appreciated, without any profound knowledge of the science of physiology.

Clear and consistent notions of the philosophy of farm drainage can only be secured by an examination of the known facts relating to the nutritive activities of plants and their relations to the soil and its contained moisture, to ascertain what special conditions are likely to interfere with their normal processes of growth. The intelligent farmer will not be satisfied with the simple statement that the draining of retentive soils makes them more productive, but he will inquire how this result is brought about, and the knowledge he may acquire in tracing to their source the conditions that favor the vigorous growth of his crops, will be of value to him in suggesting many details of practice that may be profitably adopted in his general system of farm management.

We cannot, of course, in this connection, attempt a full discussion of the physiology of plants, and attention will only be directed to some of the leading facts in this department of science, that have a direct relation to the principles of farm drainage.

Physiologists tell us that a very large proportion of the dry substance of plants is derived from the atmosphere, but it is well understood that the atmospheric supplies of plant food are only made available when their roots are enabled to take from the soil, under favorable conditions, the comparatively limited amount of nutritive materials it is their function to furnish.

From a practical standpoint it is, therefore, a matter of the first importance to provide suitable soil conditions to promote the functional activities of the roots of plants, as they have direct relations with the part performed by the leaves in appropriating from the atmosphere materials that constitute the great bulk of the dry substance of the plant.

Dr. Gilbert makes the statement that in the Rothamsted experiments, ^^by the application of nitrogen to the soil, for mangels, there was, in ^lany cases, an increased assimilation of about one ton of carbon per

4 LAl!q"D DRAINING.

acre, from the atmospliere," and that one pound of nitrogen as manure for mangels gave an increase of over twenty-two pounds of sugar, derived almost exclusively from tlie atmosphere. With wheat and barley for twenty years there was an increase of from fourteen to twenty-two pounds of carbon in the crop for each one pound of nitrogen in the manure. The results here presented are in strict accordance with other known facts in vegetable physiology, which it is unnecessary to notice, and we cannot avoid the conclusion that soil conditions have a direct influence on all of the nutritive processes of plants, and that their chemical composition furnishes no index of their requirements in regard to the food constituents that may be profitably applied in the form of manures.

In the growing of crops, as well as in the care of his animals, the farmer is dealing with living organisms, and it is not sufficient to furnish the food elements required in building tissues, but he must also provide conditions that are in every way favorable for the exercise of their vital activities, on which the appropriation and assimilation of their food directly depends.

OoNDiTioiq-s OF Plaint G^rowth.

In common with other living organisms, our farm crops require certain conditions of environment for their active growth and perfect development, and among those which the farmer can, to a greater or less extent, control, may be enumerated as essential — a favorable temperature, a proper supply of moisture, and a supply of appropriate food. In the absence of, or any marked deficiency in, either of these conditions, the plants cannot thrive. These conditions must be studied in detail, as they have a direct relation to the subject of farm drainage.

Temperature. Plants do not grow in the spring, and seeds do not germinate until the soil is sufficiently warmed by the sun and the heat liberated in the processes of soil metabolism. Each crop is adapted, by its inherited habits, to a certain range of temperature peculiar to itself. There is a minimum temperature at which all growth ceases, a maximum beyond which the plant cannot live, and between these extremes there is an optimum temperature that is most favorable for rapid growth. Any agency, or condition of the soil that tends to lower the temperature from the optimum point must, therefore, retard the processes of growth and development, no matter how favorable other conditions may be.

The range of temperature within which plants can grow lies between the freezing point and about 122° F. The optimum temperature in any particular case can only be stated approximately, as the results may be modified by other conditions. According to the experiments of Sachs, Koppen and Alphonse de Candolle, wheat and barley do not sprout if the temperature is below 41°, and the most rapid growth was made at about 84° F. Maize required a temperature of at least 48° for germination, and the most rapid growth of the roots was made when the temperature was about 90° to 93°.*

Carbon, which constitutes about one-half of the dry substance of plants, is appropriated by chlorophyll (the green coloring substance of plants), in the presence of light, from the small percenta2:e of carbonic acid present in the atmosphere. The larger part of the carbon assimilated by plants from carbonic acid is obtained by the leaves, but the air permeating cultivated soils contains a larger percentage of carbonic acid than the normal atmosphere, and this is absorbed by soil water, and may therefore gain access to the plant through the roots. The presence of chlorophyll, however, appears to be necessary for the assimilation of the carbon from the

*Saclis' Text Book of Botany, p- 750.

G LAND DRAINING.

carbonic acid introduced through the roots, as well as by the leaves. The lowest temperature at which chlorophyll was formed in maize was observed, by Sachs, to be between 43° and 59°.* When the temperature is too low for the active formation of chlorophyll, as in cold, backward spring months, the pale appearance of the plants indicates a defective power of appropriating carbon from the atmosphere. The summer teaiperature in England is barely sufficient to mature wheat and barley, and Indian corn, which requires a higher temperature, cannot be grown as a farm crop.

Moisture. When growing, or in the green state, from about 68 to 88 per cent, of the weight of farm crops is water, and the remaining 12 to 32 per cent, is referred to as dry substance. The water contained in the crop, however, represents but a small part of that which is made use of in its processes of growth. The roots of a healthy and rapidly growing plant are constantly absorbing water from the soil, which is finally exhaled by the leaves, and disappears, in the form of vapor, in the atmosphere. A circulation of water through the tissues of the plant is thus maintained for the introduction and distribution of the inorganic nutritive materials derived from the soil. From this it will be seen that the amount of water required by farm crops is in fact very much larger than would be suspected by those who are not familiar with these well known processes in the nutrition of plants.

In a careful series of experiments made at Eothamsted, it was found that from 250 to 300 pounds of water was exhaled by field crops, for each pound of dry substance formed and stored up by the plants. "Hellriegel (at Dahme, Prussia) found that summer wheat and rye, oats, beans, peas, buckwheat, red clover, yellow lupines and summer colza, on the average, exhaled three hundred grams of water for one gram of dry matter produced, above ground, during the entire season of growth, when, stationed in a sandy soil."* It is probable that field crops, from their more vigorous growth and active powers of assimilation, may exhale a larger amount of water than plants under the artificial conditions required in exact experiments. Lawes and Gilbert estimate the average amount of dry substance produced on some of their experimental wheat plots at 5,600 pounds per acre, and this would involve the exhalati.on of over 800 tons of water. Estimated on the same basis, a crop of wheat of 25 bushels per acre would exhale, in its processes of growth, more than 500 tons of water, and a crop of one acre of Indian corn, of 60 bushels, would exhale about 960 tons of water, equivalent to more than 8.5 inches of rainfall.

The absolute amount of water in the soil that is most favorable for the growth of plants can only be approximately stated, as it will probably vary with the character of the soil, the kind of crop grown, and atmospheric conditions influencing evaporation.

^'Hellriegel experimented with wheat, rye, and oats, in a pure sand mixed with a sufficiency of plant food. The sand, when saturated with water, contained 25% of the liquid." The results are given in the following table, the weights being in grams.

TABLE 1.

Water in Soil, akd Yield of Chops.

WATER IN Soil.

Y'LD OF Wheat.

Yield of Rye.

Yield of Oats.

In per

cent, of soil.

Straw and cliaff.

Grain.

Straw and

Grain.

Straw and chaff.

Grain.

2^5 5-10 10-15 15-20

7.0 15.1 21.4 23.3

2.8 8.4 10.3 11.4

3.9 8.1 10.3 10.3

4.2 11.8 13.9 15.8

1.8

7.8

10.9

11.8

"In each case the proportion of water in the soil was preserved within the limits given in the first column

How Crops Grow, 1890 ed., p, 311.

8 LAITD DRAINING.

of tlie table, tlirougliout the entire period of growth. It is seen that in this sandy soil 10-15 per cent, of water enabled the rye to yield a maximum crop of grain, and brought wheat and oats very closely to a maximum crop. Hellriegel noticed that the plants exhibited no visible deficiency of water, except through stunted growth, in any of these experiments. Wilting never took place except wheu the supply of water was less than 2^ per cent."*

As farm crops will not grow well in a wet soil, it must be evident that the soil must be well pulverized and porous, and readily permeable to moisture, so that healthy roots may be distributed throughout its entire mass, to enable them to gather the large amount of water they require from the moist particles that represent the normal conditions of a productive soil. The capillarity of soils or permeability to moisture, so that a moderate but continuous supply is furnished to the growing crop, must then be recognized as an essential condition of fertility.

Food Supply. The roots of farm crops obtain from the soil certain materials that are needed in their constructive processes, among which are : nitrogen, chiefly in the form of nitric acid, or, to a limited extent, perhaps as ammonia — free oxygen from the, air permeating the soil — and the mineral constituents that appear as ash when the plant is burned.

The larger rpots serve simply as supports to the plant, or, in some cases, as stores of nutritive materials; while the absorption of plant food is exclusively carried on by the slender, thin-walled fibrils, or fine branches, forming the ultimate subdivisions of the larger roots. In most cases the absorbing surface is materially increased by numerous still more delicate cells, called root-hairs, which are thickly distributed near the end of

*How Crops Feed, pp. 215-216.

GENERAL PIUNCIPLES. 9

the fibrils. As the root fibrils increase in length, feelino- their way, as it were, between the particles of soil, the older root-hairs disappear and new ones are formed a short distance behind the slender growing tip of the fibrils, and, in a vigorous, healthy plant, tlicse delicate absorbing organs are found to penetrate every available space between the particles of soil.

The extent of these absorbing fibrils and root-hairs would not be observed in a careless examination, as most of them, under average conditions, are left in the soil when the plants are pulled up, the larger roots, only, remaining attached to the stalk. Hellriegel estimated the aggregate length of the roots of a single barley plant at one hundred and twenty-eight feet, and of an oat plant at one hundred and fifty feet, and he found that but a small fraction of a cubic foot of soil sufficed for this extended root development.* Under suitable conditions, the roots of a growing plant may be observed under the microscope, and the slender fibrils and root-hairs can then be seen closely in contact with each particle of the soil. These facts furnish a ready and simple explanation of the injurious effects of drainage water when retained in soils. These delicate absorbing organs of the roots of plants are not fitted for an aquatic life, and they readily succumb under the encroachments of standing or drainage water in soils. Their function is to absorb free oxygen, as well as the mineral constituents of plant food, and air must be allowed to circulate between the soil particles, to furnish the needed supply. When the space between the particles of soils is filled with drainage water" the air is excluded, the supply of free oxygen cut off, and the active agents of absorption cannot live under these abnormal conditions.

We must, then, include among the essential conditions of vigorous growth in plants, a finely pulverized

10 LAI^D DRAINING.

soil free from drainage water, ' that will permit and encourage the free ramification of these delicate organs of absorption, in free contact with air, and the moist surface of the soil particles.

Soil Metabolism. Soils are not an inert mass of matter from which plants passively obtain their food supplies. All soils that are, or may be made, fertile, are constantly undergoing change, and the transformations taking place in the arrangement, or relations of their constituents, may be favorable, or otherwise, to the well being of the crops growing in them, according to the conditions present for thfe time being. The aggregate of chemical, physical and biological changes, or transformations that take place in soils, are conveniently expressed by the general term metabolism, without attempting to distinguish between them, which, in the present state of knowledge, would, in most cases, be impossible.

For a more detailed account of the purely chemical and physical changes taking place in soils, than, for lack of space, is here given, the reader is referred to readily accessible works, in which they are more or less fully discussed.*

Biological Factors. Eecent investigations, however, tend to show that biological activities are important, and, perhaps, in some cases, dominant factors in soil metabolism, and in their relations to our present subject of farm drainage they require notice in greater detail.

All processes of fermentation and putrefaction are now known to be caused by living organisms, each of

* Master's Plant Life on the Farm, and Warington's Chemistry of the Farm, are admirable popular elementary works that may be profitably consulted by the general reader. For the advanced student Johnson's Hotv Crojps Feed, and HoiO Croi^s Grow, new ed., 1890, and Storer's Agriculture, 2 vols., will be more satisfactory, from the more detailed illustration of the principles under discussion.

GEKERAL PRINCIPLES. 11

which performs a specific role in tearing down and disintegrating organic substances in their processes of nutrition. Yeast, a minute plant, of which there are several species, is the type of the true alcoholic ferments. The lactic, butyric, acetic, and. other ferments, belong to the group of minute organisms popularly known as bacteria, or microbes. To the same group belong the yarious ferments concerned in the complex processes of putrefaction.

The rotting of manures and the disintegration of organic matters in the soil are brought about by a series of micro-organisms that succeed each other with the change of conditions presented in the course of the putrefactive process. One species, beginning the work of putrefaction, after taking the supplies of food fitted for its nourishment, leaves a residual mass that is better suited to the requirements of some other species which succeeds it, and this, in turn, for the same reasons, is succeeded by anotlier form better fitted for the new conditions, and these changes in the active agents of decay are repeated, whollj^, or in part, until the entire mass is reduced to its elements, or simple binary compounds. Each species requires, for the exercise of its vital activities, certain conditions of environment, and as these are constantly changing as the putrefactive process proceeds, the microbes that, Jfcr the time being are best adapted to the prevailing conditions, become the dominant species. This is, in fact, but a phase of the *' struggle for existence," and '^survival of the fittest," that is now recognized as an important factor in the evolution of organic beings.

Agricultural plants cannot make use of organic substances as food, but in the processes of disintegration, to which they are subjected in the soil, plant food is liberated in an available form ; but in case no growing plant is present to appropriate it, the next series of changes, brought about by the accession of other species

12 LA:tTD DRAINING.

of microbes, may transform what is valuable plant food to a condition unfitted for the nutrition of plants. Soil exhaustion cannot, therefore, be measured by the amount of the chemical elements of fertility removed in crops. In the absence of growing plants a loss of fertility may not only take place through the agency of microbes, but it may be washed out of the soil by rains, or locked up in more stable compounds with other soil constituents. Summer fallows were supposed to increase the available elements of fertility in the soil, but the soluble materials formed in the metabolism of fallow soils are liable to be washed out by rains, in the absence of . growing plants to make use of them.

Schloesing and Muntz made the notable discovery, in 1877, that nitrification is caused by microbes, and this led to further investigations, by numerous observers, in regard to the agency of these organisms in preparing plant food, which have proved to be of great practical interest. Nitric acid, in combination with bases, forming nitrates, seems to be the favorite form of nitrogenous food for farm crops, and this is provided by nitrifying microbes, under suitable conditions for the exercise of their processes of nutrition, from the nitrogen of the organic substances, and ammonia of the soil and manures, and from the atmo^heric nitrogen permeating the soil.

Nitrification is carried on very slowly at temperatures but little above the freezing point, and then rapidly increases as the temperature is raised to an optimum of 90° to 99°, when the organisms are most active. At higher temperatures nitrification diminishes, and ceases entirely at 125° to 131°. At Rothamsted thirty-seven days were required for the nitrification of the substances under experiment at 52°, while it was completed in eight days at a temperature of 86°. Schloesing and Muntz state ^^that at 99° nitrification is ten times more rapid than at 57°."

We have already noticed the relations of temperature to the vigorous growth of the plants themselves, and it now appears that the supplies of plant food are likewise influenced by the temperature of the soil, through its effects on the living organisms that prepare it. The atmosphere is composed, of a mixture of gases consisting, by volume, of 20.96 per cent, of oxygen, 79.00 per cent, of nitrogen and 0.04 per cent, of carbon dioxide (carbonic acid), to which should be added a variable amount of the vapor of water and minute quantities of combined nitrogen, in the form of nitric acid, ammonia, and organic matters, which are washed out by rains and thus carried to the soil. The nitrogen annually added to the soil from this source, at Eothamsted, is estimated not to exceed four or five pounds per acre.

When the discovery was made of the composition of the atmosphere it was at once supposed that the vast envelop of free atmospheric nitrogen was the main, or sole, source of the nitrogen of plants. Experiments by Boussingault, in France, and by Lawes and Gilbert, at Rothamsted, in England, however, showed that free atmospheric nitrogen was not appropriated by plants, and that their supplies of nitrogen were obtained from the soil. Notwithstanding this conclusive evidence to the contrary, it is a popular notion, indorsed even by some chemists, that leguminous crops (clover, beans, peas, etc.) obtain their nitrogen directly from the atmosphere. The practical inferences from this erroneous theory are misleading, as they ignore the importance of soil conditions on the supplies of nitrogenous plant food.

It was likewise shown in the Eothamsted experiments that, while leguminous plants removed from the soil much larger amounts of nitrogen than the cereals, they were not benefited by nitrogenous manures, which had a marked influence in increasing the growth of the cereals. It was also found that on land where cereal crops failed to grow from a deficiency of soil nitrogen, large leguminous crops were grown containing much more nitrogen than a heavy crop of cereals. It was, in fact, evident that leguminous crops obtained nitrogen in some way, or from some source, that was not available for the cereals.

An explanation of these anomalous results has been furnished by recent experiments, and it is now known that the tubercles, or nodules, that have been frequently observed on the roots of leguminous and some other plants, are caused by microbes, and that, through their agency, the free nitrogen of the atmosphere permeating the soil is appropriated and made ayailable, as combined nitrogen, in the nutrition of the plants with which they are associated.

Some of the experiments leading to these conclusions will be of interest here, as they have a direct bearing on the subject of farm drainage in its relations to soil metabolism. Hellriegel, in experiments with agricultural plants, in pots filled with washed quartz sand, to which nutritive solutions containing no nitrogen were added, found that in some of the pots the plants grew luxuriantly, while in others the growth seemed to be limited and determined by the amount of nitrogen contained in the seed. He observed numerous nodules on the roots of the plants that made a good growth, while there were none on the roots of the plants of limited growth. A probable relation of the root-nodules to the supply of nitrogen obtained by the plants was suggested and made the subject of inyestigation.

Experiments were planned *^to determine whether, by the supply of the organisms, the formation of the root-nodules and luxuriant growth could be induced, and whether, by their exclusion, the result could be prevented. To this end he added to some of a series of experimental pots 25 c.c. (0.88 ounces), or, sometimes.

GENERAL PRINCirLES. 15

50 c.c. (1.76 ooncGD) of a turbid extract of a fertile soil, made by shaking a given quantity of it with five times its weight of distilled water. In some cases, however, the extract was sterilized (by the application of heat, to destroy all living organisms). In those in which it was not sterilized there was almost uniformly luxuriant growth and abundant formation of root-nodules ; but w^ith sterilization there were no such results. Consistent results were obtained with peas, vetches and some other Papilionaceae ; but the application of the same soil-extract had no effect in the case of lupines, seradella and some other plants of the family which are known to grow more favorably on sandy, than on loamy, or rich humus soils. Accordingly he made a similar extract from a diluvial sandy soil where lupines were growing well, in which it might be supposed that the organisms peculiar in such a soil would be present ; and on the application of this to nitrogen-free soil, lupines grew in it luxuriantly and nodules were abundantly developed on their roots."

At Kothamsted* experiments were made on the same lines, in 1888, with peas, blue lupines and yellow lupines; and in .1889, with changes suggested by the experiments of the preceding year, they were repeated with '^peas, red clover, vetches, blue lupines, yellow lupines and lucern," under the following conditions : For the lupines and lucern special glazed earthenware pots were made, fifteen inches deep and six inches in diameter, and for the other plants the pots were seven inches deep and about six inches in diameter. "There were four pots of each description of plant." Three of these were filled with clean-washed quartz sand, to which was added 0.1 per cent, of the ash of the plant to