144 SOILS AND FERTILIZERS 



with hen manure because the ammonia is so readily 

 liberated by alkaline compounds. The value of hen 

 manure is due to its being a quick-acting fertilizer 

 rather than to its containing such a large amount of 

 fertility. A hen produces about a bushel of manure 

 per year. 56 



COMPOSITION OF HEN MANURE. 



Per cent. 



Water 57.50 



Nitrogen. 1.27 



Phosphoric acid 0.82 



Potash. 0.28 



1 80. Mixing of Solid and Liquid Excrements. 



The solid and liquid excrements, when properly mixed, 

 make a well-balanced manure. The urine alone is 

 not a complete manure, as it is deficient in phosphoric 

 acid and other mineral matter. The solid excrements 

 with the urine, when mixed with soil, readily undergo 

 nitrification. The nitrogen in the solid excrements 

 is in the form of indigestible protein, and is rendered 

 available as plant food more slowly. Land heavily 

 dressed with leached manure has received an unbal- 

 anced fertilizer deficient in nitrogen but fairly well 

 supplied with mineral matter. A soil thus manured 

 may fail to respond because of the unbalanced char- 

 acter of the manure. 



181. Volatile Products from Manure. Fermen- 

 tation of manure in stables results in the production 

 of a large number of volatile compounds and in loss 

 of manurial value. Urea, when it ferments, produces 

 ammonia, which combines with the carbon dioxide 

 always present in stables in liberal amounts as a pro- 



