Studies On Maturity Indices And Factors Affecting Maturity Of Swine Manure Composting

Composting is an effective approach to treat animal manure for its recycling, reduction and harmless. Maturity of compost is one of the most important factors concerning organic fertilizer factory designing, operating, controlling and organic fertilizer quality. In this research, co-composting of swine manure and rice bran experiments were carried out to study the changes of pH, electric conductivity(EC), solid phase C/N, water soluble NH₄⁺ - N, water soluble NO₃-N , T-value(ratio of finial C/N to initial C/N ) ,seed germination index (GI) and the evaluation index of maturity during composting. Effects of initial C/N ratio, initial moisture content, aeration type on substance change and maturity of pig manure composting were also studied. The results obtained were as following:(1) After 56days' composting, C/N ratio,T-value,NH₄⁺—N / NO₃-N ratio were reduced to some degree .GI was raised apparently. Correlation analysis showed that T-value as well as NH₄⁺ — N / NO₃-N ratio was negative significantly to GI. GI, NH₄⁺—N / NO₃-N ratio, T-value could be used as biological and chemical indices of compost maturity. The result of pot experiment using different maturity compost to cultivate sweet pepper(Capsicum frutescens L.) showed that the biomasses of pepper adding 30day or 55day fermentation compost were higher significantly than those of 0day,7day,14day treatments. There was no significant difference between the biomass of pepper adding 30day fermentation compost and that of adding 50day fermentation compost. In order to insure compost maturity, 35d fermentation compost's maturity parameters were chosen as compost maturity indices. The result were T≤0.65, NH₄⁺- N/NO₃-N ratio≤0.60 and GI of radish≥45%.(2) The effects of initial C/N ratios on pig manure compost maturity were studied. The results showed that the compost at initial C/N ratio of 28 had higher temperature and longer high temperature maintenance time than that of initial C/N ratio of 18,35,40. For lack of available nitrogen or available carbon in the...