Abstract:

This study aims to investigate the effect of different C/N ratios on composting process of chicken manure and bagasse in tropical area, find the optimum C/N ratio, and optimize the composting parameters. The aerobic composting was used in this study, the effect of different C/N ratios on physical-chemical indexes, e.g. temperature, NH₃ volatilization, content of total nutrients and maturity were studied, and the composting effect of chicken manure and bagasse under different C/N ratios was explored. Results showed that the duration time of high composting temperature (>50℃) of different C/N ratios, which was 20 (T1), 30 (T2) and 40 (T3) respectively, was 38, 32 and 20 d. The cumulative volatilization of NH₃ in T1 treatment was significantly higher than those of the other two treatments. The volatilization rate of NH₃ in T2 treatment was the fastest in the first week, indicated that the degradation rate of organic matter was the fastest. The content of OM was increased followed the increase of C/N ratio. Contrarily, total nutrient content of NPK were decreased. The OM, pH, NPK total nutrient, GI and NH₄⁺content of C/N ratio in T2 and T3 treatment reached the composting standards, while the content of OM and NH₄⁺ from C/N ratio in T1 treatment did not meet the standards at the end of composting. Taken together, the treatment of 30 C/N ratio is the best for aerobic composting in the study.

Key words: C/N ratio, tropics, chicken manure, bagasse, composting, putrescibility