Effect of covering composting piles with mature compost on ammonia emission and microbial community structure of composting process
Received for publication February 14, 2008. To control ammonia (NH3) volatilization from the dairy cattle (Bos taurus) manure composting process, a compost pile was covered with mature compost and the gas emissions evaluated using the dynamic chamber system. The peak of NH3 volatilization observed immediately after piling up of the compost was reduced from 196 to 62 mg/m3 by covering the compost pile with mature compost. The accumulation of NH4–N to the covered mature compost was also observed. Covering and mixing the compost with mature compost had no effect on the microbial community structure. However, over time the microbial community structure changed because of a decrease in easily degradable organic compounds in the compost piles. The availability of volatile fatty acids (VFA) was considered to be important for microbial community structure in the compost. After the VFA had disappeared, the NO3–N concentration increased and the cellulose degrading bacteria such as Cytophaga increased in number.