Nitrogen and Sulphur Transformations in Composts Containing Chicken Feathers

Abstract

Chicken feathers composted with pine bark and rye straw are subject to intensive mineralisation and biotransformation with efflux of water-soluble components: N-NH4, N-NO3 and S-SO4. The content of N-NH4, N-NO3 and S-SO4 in water extracts of the studied composts was positively correlated with the time of composting. The release of those components reached a maximum after 15 weeks of composting feather wastes. The highest amounts of soluble forms of nitrogen and sulphur were recorded in composts enriched with straw, especially those with C/N=25, and the lowest in composts without straw, with C/N=25. It was also demonstrated that changes in the concentration of N-NH4 were correlated with increase in the concentration of N-NO3 and S-SO4 in water extracts of the composts. Increase in the content of N-NO3 and S-SO4 in extracts from the compost mass, with simultaneous decrease in the level of soluble N-NH4, may be used as a reliable indicator in the estimation of the maturity of composts containing waste feathers.