New York Agricultural Experiment Station. 77 



It will be readily seen that of two foods costing the same price 

 and having equal feeding value, it is economy for the farmer to use 

 that one which contains the largest amount of fertilizing materials. 



Amount of Fertilizing Materials of Food Recovered in Manure. 

 —7 Generally speaking, manure produced from working or fattening 

 animals contains from 90 to 95 per cent, of the fertilizing constitu- 

 ents contained in the food. Manure made from cows in milk and 

 young, growing animals contains from 50 to 75 per cent, of the 

 fertilizing constituents contained in the food. In the case of 

 animals which are neither increasing in weiglit nor giving milk, the 

 amount of fertilizing materials in the manure will be exactly equal 

 to that contained in the food eaten. The foregoing statements pre- 

 suppose that all the dung and urine are saved, a supposition which 

 is not often true, considering the manner in which stable-manure is 

 commonly treated. 



The Digestibility of Food and Its Manurial Value. — The solid 

 excrement of animals consist largely of the undigested portions of 

 food ; these undigested portions are mostly insoluble and, therefore, 

 not readily available as plant-food. The urine contains those por- 

 tions of food which have been digested ; its constituents are all in a 

 soluble form and readily available as plant-food, and, therefore, 

 more valuable than the insoluble fertilizing materials contained in 

 the solid excrement. It therefore follows that the more digestible 

 a food is, the larger is the proportion of its fertihzing constituents 

 that will appear in the urine, and the greater will be the value of 

 the plant-food in the manure produced. 



The Use of Litter. — Litter is used in stables primarily to furnish 

 a clean and comfortable bed for animals. In connection with the 

 manure, it is used to absorb the liquid portion of the manure, thus 

 preventing loss by drainage. The presence of litter mixed with 

 manure makes the manure easier to handle, tends to check and 

 control its decomposition, and in some cases influences both the 

 physical and chemical action of the manure. The materials com- 

 monly used for litter are usually not rich in fertilizing materials. 

 The use of too much litter diminishes the relative value of the 

 manure and adds to the cost of handling. Enough should be used 

 not onl}^ to absorb and retain the urine, but also to absorb any 

 ammonia formed in the process of decomposition. 



Fermentation of Manure. — Causes. It is a familiar experience 

 of every farmer that fresh stable-manure, when left in a heap, com- 



