Suwardi, L.T. Indriyati and
Nitrogen (N) concentration in chicken manure differs with the composting and handling processes. To improve N recycling in chicken manure, N loss from the manure must be reduced. Ten sample of chicken manure were collected from Japanese compost companies for analysis of their total N and organic carbon (C). Using the manure of the highest N concentration, chicken manure equivalent to 0,5 g N in combination with citric acid addition, rapid composting ("bokashi" treatment) and pelletizing, was mixed thoroughly with the air-dried soil equivalent to 1 kg oven-dried soil, then wetted to 60% of its water-holding capacity for a 10 week incubation. The total N concentration varied from 23,1 to 63,5 g N kg-1 based on dry weight basis; higher after short-term composting and drying. Addition of zeolite and pelletizing of chicken manure decreased the N mineralization. Addition of citric acid to chicken manure before pellezeting did not reduce the N mineralization, but addition of zeolite together with citric acic did. "Bokashi" treatment did not reduce the N mineralization, but reduce the offensive odor of chicken manure during composting.