Bacteria in Manures. 209 



changes that the plant tissue does in the soil. As has 

 been previously stated, it is of the greatest advantage to 

 the farmer to return to the soil as large a part of the ma- 

 terial removed in the crop as possible. This is true not 

 only for the mineral ingredients of the soil, as potassium 

 and phosphorus, but also for the organic matter. The 

 problem of the farmer is to handle all manures made on 

 the farm in such a way that the least loss may occur. 



Decomposition of manure. Manure when placed in 

 piles rapidly decomposes under the action of micro-or- 

 ganisms, continuing as it were, the changes inaugurated 

 in the intestinal tract. The bacteria voided with the ex^ 

 creta serve to inoculate the bedding or litter used. The 

 bacteria decompose the organic matter with the result 

 that in a well-rotted manure, but little trace of the ma- 

 terial used as bedding can be found. 



Nitrogenous compounds. Stable manure contains 

 various nitrogen-containing compounds that are found in 

 the plant. These undergo a process of ammonification, 

 due to the action of the same kinds of bacteria that are 

 responsible for similar changes in the soil. A part of the 

 nitrogen that is used in the cell processes of the animal 

 is eliminated in the urine in the form of urea, uric acid, 

 and hippuric acid. These substances are converted into 

 ammonia salts. In the summer the odor of ammonia is 

 often noticeable in horse manure, due to the decomposi- 

 tion of the nitrogenous compounds in the urine. The am- 

 monification of the nitrogen in the solid manure and in 

 the litter is less rapid. As ammonia is readily soluble 

 and is also volatile, it follows that where fermentation is 

 rapid much of this valuable fertilizing ingredient is lost 

 in the leachings from the pile or passes off into the air. 



