1 66 



SOILS AND FERTILIZERS 



(In each experiment the amount of liquid excrement was 4 pounds.) 



The amount and composition of the solid excre- 

 ments vary with the amount and kind of food con- 

 sumed. If the food is indigestible, the solid excrements 

 contain a larger part of the nitrogen as indigestible 

 protein. When an animal is supplied with the proper 

 food for all purposes, normal conditions exist, and the 

 amount of nitrogen voided in the liquid and solid 

 excrements is equal to that supplied in the food con- 

 sumed, except in the case of growing and milk-pro- 

 ducing animals. 



Experiments at the Rothamsted Station show that 

 from 57 to 79 per cent of the total nitrogen in the 

 food of farm animals is voided in the liquid excrements, 

 and from 16 to 22 per cent is voided in the solids. 

 Nearly all of the mineral elements of the food are 

 voided in the excrements, less than 4 per cent being 



