212 



MODIFICATION OF THE SOIL POPULATION 



TABLE 50 



Change in Composition of Animal Manures during Decomposition 

 (from Waksman and Diehm) 



Chemical constituents 



Ether-soluble substances 

 Water-soluble substances 



Hemicelluloses 



Cellulose 



Lignin 



Crude protein 



Ash 



Percentage of Dry Material 



Sheep Manure '' 



Original 

 manure 



2.83 

 24.92 

 18.46 

 18.72 

 20.68 



17.21 



Manure 



decomposed 



for 192 



days 



2.58 

 17.89 



7.31 

 12.79 

 27.31 



19.23 



Horse Manure f 



Original 

 manure 



1.89 



5.58 



23.52 



27.46 



14.23 



6.81 



9.11 



Manure 



decomposed 



for 290 



davs 



0.95 

 5.71 

 12.67 

 5.97 

 28.43 

 16.38 

 19.32 



* Includes the mixed solid and liuqid excreta, 

 t Includes solid excreta only. 



the other hand, the synthesis of microbial cells is always associated 

 with these changes, whether the decomposition of the manure 

 takes place in composts or in the soil. 



In the decomposition processes, the liquid and solid excreta 

 should be considered separately, since the transformations asso- 

 ciated with the two materials are distinctly different. This 

 applies particularly to the nitrogenous constituents. Urea, which 

 makes up a large part of the organic material in the liquid manure, 

 is very rapidly transformed to ammonium carbonate. The soHd 

 excreta may contain about one per cent of nitrogen on the basis of 

 the dry material. On the other hand, the liquid manure contains 

 about 4.50 per cent of nitrogen on the dry basis. Not only do the 

 solid excreta contain a low percentage of nitrogen, but a consider- 

 able portion of the organic compounds containing this nitrogen are 

 only slowly decomposed. There is still another factor which 

 lowers the rate of liberation of ammonia from the solid manure. 

 The latter contains appreciable amounts of non-nitrogenous 



