[ 523 



836. Farm-yard manure. The most easily available 

 manure . which is used for bringing N directly and indirectly 

 into the soil is farm-yard manure. It consists of solid and 

 liquid excrements and litter. It varies very much in composi- 

 tion. The conditions that determine the variation of composi- 

 tion are: Ji) age; (2) condition of the animal, whether lean 

 or fat ; (3) the species; (4) food; (5) temperature ; (6) accom- 

 modation generally ; (7) quantity and kind of litter used, and 

 (8) management during accumulation and its after treatment. 



837. During the passage of food through the alimentary 

 canal of an animal, a large portion of the C and some of the 

 H are lost by the processes of respiratien and evaporation, as 

 CO 2 and H 2 0. Nearly the whole of the N and the mineral 

 matter are got back either in the solid or the liquid excre- 

 ments. This is the case chiefly with adult and fattening 

 animals. In the case of young animals and milking cows, the 

 N excreted is much less. A little more than half the quantity 

 of N taken in as food is given off in urine, which shows what 

 a valuable nitrogenous manure urine is. The remaining half 

 (or less) is partly voided with the solid excrement and partly 

 stored up in the body of the animal. The N in urine occurs 

 in the forms of Urea, Uric acid, Hippuric acid and Guanin. 



838. The following table compiled from Johnston and 

 Cameron's Elements of Agricultural Chemistry and Geology 

 gives an idea of the composition of dung and urine of the 

 various classes of farm animals in 1,000 parts ; 



