Objective To acheive the innocuous treatment and resource utilization of silkworm excrement.

Method Fresh silkworm excrement pile was mixed with 5.21% hydrated lime, 0.20% EM agent, or 10% mulberry sawdust in mass fraction. The silkworm excrement pile without any addition served as the control. These four different aerobic composting systems were used for investigating the dynamic changes of physicochemical indexes and population of microbial flora during the composting process.

Result The treatment with 5.21% hydrated lime facilitated the reproduction of fungi and actinomycetes, decreased the organic matter content and the moisture content of the pile, increased the total nitrogen content of the pile, delayed 5 d before the temperature of the pile heating up to 50 ℃, resulted in 1.05 higher pH compared to the organic fertilizer standard, and decreased the number of bacterial colonies. The treatment with EM improved the total phosphorus content by 28%, which increased the number of bacterial colonies, but negatively affected the reproduction of fungi in the middle and later periods and the reproduction of actinomycetes throughout the composting process. No significant differences of other indicators were observed between the treatment with 0.20% EM and the control. The treatment with 10% mulberry sawdust reduced the moisture content by 40%, led to higher temperature which was disadvantageous for the reproduction of fungi and actinomycetes, and caused a significantly lower C/N ratio and 0.66 higher pH of the pile compared to other treatments. Germination indexes of four piles were above 100%, and all pile temperatures kept above 50 ℃ for more than 7 d.

Conclusion All four piles of silkworm excrement can meet the demand of resource utilization after composting.