Chapter 36

STABLE MANURE

Livestock Farming.--The fertility of the soil is most safely guarded in regions devoted to livestock farming. "Selling everything off the farm" is a practice associated in the public mind with soil poverty. It is a rule with few exceptions that the absence of livestock on the farm is an index of gradual reduction in the productive power of the land. Generally speaking, the farmers who feed the most of their crops on the farm are maintaining fertility, and those who do not feed their crops on the farm have been making drafts upon the soil's stores of available plant-food that are evidenced in a reduction of yields. These statements will have the assent of all careful observers. The inference has been that the maintenance of fertility requires the return to the land of all the manure that would result from feeding its crops on the farm. We know that by such feeding we can return to the fields at least four fifths of all the plant-food taken out by the crops, and we loosely reason that such a scheme is demanded by nature. The maintenance of fertility involves good arithmetic, and a plant must have certain weights of mineral elements at command before it can grow, but it is not true that the productive power of land is chiefly dependent upon the return to it in manure of all the fertility removed by its crops. If this were true, meat and other animal products would be the sole food supply of the world's markets.

The Place for Cattle.--There are general trends in human practice that cannot be changed by man. A change in human diet that makes the percentage of meat lower will not come through propaganda, but there are forces at work that will restrict the consumption of meat by the individual. The increase in population makes heavier demand for food. Armsby has shown that the fattening steer returns to man for food only 3 per cent of the energy value of the corn consumed by it, and in pork-production this percentage scarcely rises to 16. This is the reason meat-making animals give way before increase in population in congested countries. Their office becomes, more and more, the conversion of products inedible to man to edible products. In our country their number will increase, doubtless, for a long period of time, finding their places more surely on eastern farms rather than on western ranches. They must find the cheaper land, and that is no longer confined to the west. They must be where coarse materials, inedible to man, are found, and that is on eastern as well as on western farms. Their office will not be the conversion of crops into manure, but the conversion of coarse materials into human food in the form of meat or milk. This is the trend, and while the consummation may happily be far in the future, its consideration helps us to an appreciation of the facts regarding nature's provision for maintaining the productiveness of the soil.

Sales off the Farm.--The day is now here when the major portion of human food must be provided in grain and vegetables and fruit, and the demand for hay and grain for animals off the farm is very large. Fiber products likewise must be supplied. The draft upon the soil is heavy, but it must be good farm practice to supply bread and vegetables and fruit to the 70 per cent of our population that is not on farms. The great majority of farmers do not feed all their crops to livestock, and the amount of food-stuffs, for human beings and animals, that is now going off the farms is none too great.

Many farmers who incline to believe that they are safely guarding fertility by feeding the most of their crops are not returning to the fields one third of the plant-food that their crops remove. There is no virtue in feeding when the manure is permitted to waste away. The losses in stable and barnyard, the wastes from bad distribution by animals, and the sales from the farm of some crops, animals, and milk, lead to the estimate that one half of the farms on which livestock is kept do not give to the fields in the form of manure over 30 per cent of the fertility taken out of them by crops. This estimate, for which no accurate data is possible, probably is too high. The sales of food for man and animal are a necessity, and the scheme of farming involving such sales is right, provided the farmer makes use of other supplies of fertility. The area devoted to such sales will grow greater because human needs are imperative. Livestock will become more and more a means of working over the material that man cannot eat--the grass, hay, stalks, by-products in manufacture, and coarse grains. The demand for meat and milk will lead to careful conversion of material into this form of food, and the animals on eastern farms will increase in number for a time, while sales of grain and vegetables grow greater. The draft upon soil fertility through sales must increase because every pound of material sold from the farm carries plant-food in it.

The Value of Manure.--It is not possible to put a commercial valuation upon farm manures that may be a sure guide to any farmer. The value depends upon what the individual can get out of it in crops and improved soil conditions. It is rather idle to say that the annual product of a horse in the form of manure is $30, or more or less, even when an analysis shows that the nitrogen, phosphoric acid, and potash contained in it are worth that sum when valued at the market prices of those plant constituents. If the total amount of fertility found in the voidings of all the animals of the farm were provided in a pile of commercial fertilizer containing the same amount of each plant constituent, its worth to the farmer would depend upon his ability to convert all that fertility into crops at a profit. There are farmers so situated in respect to soils, crops, and markets that they can make a good profit from an investment of $30 in the total liquid and solid voidings of a horse for a year. On the other hand, there are many who would fail. The values usually given are relative and suggestive. They are aids in forming judgment. Actual value on the farm depends much on the man.

The Content of Manure.--When the crops of a farm are fed, the manure contains nearly all the plant-food that went originally into the crops. In the case of idle work-horses on a maintenance ration, the manure contains practically all the plant-food. Cows giving milk remove some fertility, and a growing calf or colt may take out 30 per cent. There is some waste beyond control, but when manure is made on tight floors with good bedding, and is drawn to the field fast as made, on the average it carries back to the soil fully four fifths of the plant-food that existed in the feed. Disregarding all cash valuations for the moment, here is an index of value that should be sufficient in itself to encourage the feeding of crops on the farm and the careful saving of the manure. When one can market his crops to animals on the farm at their cash value, and at the same time retain for his fields four fifths of all the fertility, he is like a manufacturer who can use much of his raw material over and over again. The value is in the manure, and full appreciation is lacking only because a majority of farms do not provide for careful saving of its valuable constituents.

Relative Values.--The plant-food content of manure is determined chiefly by the feed. The animals add nothing: they subtract. The kind of animals consuming the feed does not affect materially the value of the manure made from it, if the animals are mature and not giving milk. The manures from the various kinds of animals differ in value per ton because the feeds differ in character and the manure varies in percentage of water. On an average, however, the total annual product of manure from farm animals, per 1000 pounds of live weight, does not vary widely in value. The rich protein feeds given the cow, and the heavy feeding, more than make amends for the fertility that goes into the milk, and her annual product, per 1000 pounds of live weight, may exceed in value that of the horse by 25 per cent. This is likewise true of the pig, figured on the 1000-pound basis, while in the case of the sheep the value, per 1000 pounds of live weight, is near that of the horse.

These variations are not wide enough to have great importance to the livestock farmer. The manure represents to him four fifths of all the fertility that was contained by the feed he gave the various animals. They added no plant-food, and they took away only a fraction that was not large. They converted the crops into a form of plant-food that either is available or can become so quickly enough, and in addition to the nitrogen, phosphoric acid, and potash that would have a high valuation in a commercial fertilizer, there is a body of organic matter that affects the physical condition of the soil favorably. The manure also promotes the multiplication of friendly soil bacteria. Its possibilities are so great that the inference of many farmers that no successful agriculture can be maintained without it is very natural.

Amount of Manure.--Vivian states that the amount of manure that may be made from feed can be determined by multiplying the total weight of dry matter in the feed by 3. This assumes that bedding will be used in sufficient amount to absorb the urine, and that will require material containing one fourth as much dry matter as there is in the feed. When the amount of hay and grain is known, and the dry matter in all succulent feed is estimated, the total product of manure in tons can be arrived at with fair accuracy.

Analysis of Manure.--As has been stated, the content of the manure must depend chiefly upon the character of the feed. We are accustomed to combine feeding stuffs in differing proportions for horses, cows, pigs, and sheep. Van Slyke names the following approximate percentages of plant-food constituents in fresh excrements of farm animals, the solid and liquid being mixed:

+----------+----------+------------+----------+ | Animal | Per Cent | Per Cent | Per Cent | | | Nitrogen | Phosphoric | Potash | | | | Acid | | +----------+----------+------------+----------+ | Horse | 0.70 | 0.25 | 0.55 | | Cow | 0.60 | 0.15 | 0.45 | | Pig | 0.50 | 0.35 | 0.40 | | Sheep | 0.95 | 0.35 | 1.00 | | Hen | 1.00 | 0.80 | 0.40 | +----------+----------+------------+----------+

He estimates that one ton of average mixed stable manure, inclusive of absorbents, contains approximately 10 pounds of nitrogen, 5 pounds of phosphoric acid, and 10 pounds of potash.