Ammonia Losses 323 



Loss of ammonium carbonate.— It is evident, there- 

 fore, that, as the liquid manure is concentrated by evap- 

 oration, the proportion of ammonium carbonate in the 

 liquid is increased and is more readily volatilized. For 

 this reason, the application of fresh manure to the soil 

 without immediate plowing under may lead to very 

 considerable losses of valuable ammonia nitrogen by 

 the rapid drying of the manure. In rainy weather, the 

 danger of such loss is slight, for the soluble ammonium 

 carbonate is then washed into the soil. 



The ready volatility of ammonium carbonate also 

 accounts for the diminished losses of nitrogen from 

 manure piles that are kept moist. It is a common practice 

 in France to keep the manure in compact heaps and to 

 moisten it from time to time with the liquid manure 

 which drains away from it into cemented pits. In dry 

 weather, when the evaporation is intense, liquid manure 

 may become too concentrated and insufficient in amount 

 to keep the solid excreta and litter in proper moisture 

 condition. Water is then added to the manure. 



Urease. — A number of the uro-bacteria have been 

 found to produce an enzyme, urease, by means of which 

 the transformation of the urea into ammonium car- 

 bonate is accomplished. This may be readily demon- 

 strated by subjecting cultures of uro-bacteria to chloro- 

 form vapor, when the organisms themselves are destroyed, 

 but not the enzyme. It will be found that the cultures 

 thus treated still retain the power of changing urea into 

 ammonium carbonate. As in the case of other species, 

 the urea- or uro-bacteria differ in their ability to pro- 

 duce the enzyme. Varieties of the same species that 



