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. CHAPTER XIII CARE OF STABLE MANURE