with quantities of fresh and leached manures which would give exactly the same amount of nitrogen. The results, stated in percentage of gain over a plot receiving no manure, are given below.

Open Yard Feeding a Wasteful Practice.-Upon a majority of the farms in America, perhaps, the cattle are fed during the winter in open lots, the manure not being hauled away until the following summer or fall, if indeed it is removed at all. This method of feeding presents ideal conditions for excessive losses from leaching, and it is safe to say that more than half the fertilizing value of the manure is lost where this practice is pursued. In the corn belt of this country for instance, large numbers of cattle are fed during the winter, and it is not unusual to see a large feeding lot covered to a considerable depth with manure which is spread out and exposed to the weather in such a way that the maximum effects of leaching must take place. There is no doubt that considered from the fertility point of view alone these farms would be better off if the corn were sold from the farm, and the stover all plowed under.

Losses Due to Fermentation.-There is another source of loss in stored manure that may be quite as

wasteful as leaching, i, e., what is known as "hot fermentation." Manure is very easily decomposed, and there is no doubt that decomposition begins almost as soon as the excrement is voided by the animal. The first evidence of decomposition or fermentation is the odor of ammonia that is noticeable in the barn, especially in the morning, if the stable has been closed dur

ing the night. This is due to rapid decomposition of urea, a nitrogeneous substance found in the urine. Ammonia contains nitrogen, and when its odor is perceptible it is a sign that nitrogen is being given off into the air, and that the manure, therefore, is undergoing a loss of this valuable constituent. The early decomposition of the urea will not be so likely to occur if plenty of absorbing material is used.

The fermentation of manure is due to different forms of bacteria. Some of these germs can exist only in the presence of oxygen, and are called “ærobic" bacteria, while others do not require free oxygen, and are designated as "anærobic" bacteria. The aerobic organisms are responsible for the hot fermentation which is the cause of great loss of value in manure. It is well known that if manure is thrown loosely into a heap, especially if it contains large quantities of horse or sheep excrement, it soon becomes very hot and dry and oftentimes white or "fire-fanged" as it is popularly termed. During this process large losses of nitrogen are occurring. Experiments conducted to show the loss due to fermentation alone indicate that from thirty to eighty per cent of the nitrogen is removed, but that the phosphoric acid and potash are not affected. In the case of the fire-fanged material in one experiment it was found that all of the nitrogen was lost. As the value of manure depends for the most part on the nitrogen content, it follows that more than half its 'worth may be lost by hot fermentation.

If the manure heap is so compact that the air cannot penetrate it the ærobic bacteria are unable to live, and hence hot fermentation is not possible. The presence of a large quantity of water also checks this kind. of decomposition, and for that reason the excrement of cows and pigs is not so subject to hot fermentation as is that of horses and sheep. Where the manure is in a compact mass the fermentations that take place are due to the anaerobic organisms. These bacteria cause decompositions in the manure which convert the insoluble plant food in the excrement into soluble forms,

but do so with little loss of the fertilizing constituents provided that the heap is protected from leaching rains.

Always Some Loss in Stored Manures.-Even under the best of conditions it is impossible entirely to eliminate losses in stored manure, although if properly preserved the loss may be limited to about ten per cent of the nitrogen, and none of the other two constituents. This loss, however, is insignificant in comparison

Waste of manure in a market garden. The manure from the city stables was thrown into a loose pile and allowed to undergo hot fermentation and be leached by the rains. It should have been carefully piled and protected from the weather

with the losses which result from not saving the urine, from leaching due to rains, or from allowing the manure to undergo hot fermentations, all of which waste may be prevented to a great extent as will be explained in the next chapter.

CHAPTER XIV

PRESERVATION OF MANURE

Barn Floors Should be Perfectly Tight.-The great value of the manure produced on the farm, and the losses that may occur in it have been discussed at some length. The next point to be considered is the best method of caring for manure so as to prevent these losses as far as possible. Much that will be said under this heading has undoubtedly been already suggested to the reader by his perusal of the preceding pages, but the subject is of sufficient importance to justify devoting some space to it, even though repetition becomes

necessary.

Attention has been called to the fact that over onehalf of the value of the manure is in the liquid excrement, and it is desired to emphasize the statement, that the first consideration in caring for manure is to have that part of the barn floor upon which the excrement falls so tight that none of the liquid can drain away. The manure trough behind the cattle, especially, should be made absolutely tight by the use of pitch, cement or some other material that is impervious to water. In addition to this care should be used to supply litter in quantities large enough to absorb the urine so thoroughly that the manure may be removed without loss from dripping. If the farmer possesses a feed cutter he will be well repaid for cutting up all of the bedding materials. Straw cut in one inch lengths, for

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