CHAPTER XXXII 



THE CONSERVATION OF MANURIAL 

 CONSTITUENTS 



VARIOUS chemicals have been tried as a means to 

 check the losses of nitrogen, and, to some extent, also, 

 of the organic matter in manure. 



CHEMICAL METHODS 



Gypsum was thus employed almost a half a century 

 ago, its probable usefulness having been indicated by 

 purely theoretical considerations. It was thought that 

 gypsum, which is a sulfate of lime, would react with the 

 volatile ammonium carbonate in the manure and give 

 rise to the more stable ammonium sulfate. Laboratory 

 experiments on a small scale seemed to bear out this 

 view, and gypsum, in a powdered state, was recom- 

 mended for strewing in the manure. 



Gypsum. Subsequent experiments by several in- 

 vestigators proved, however, that the efficiency of gyp- 

 sum as a conserver of nitrogen had been over-estimated. 

 To be sure, small amounts of ammonia are really held 

 back by the gypsum. It may also be said in its favor that 

 it stimulates the growth of the nitrifying bacteria and 

 leads, therefore, to a greater accumulation of nitrates 

 in the manure. For all that, it should be remembered 

 that the loss of nitrogen from manure is frequently 



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