Effects of Different Stockpile Methods on Dynamic Changes of Partial Physical and Chemical Indexes of Silkworm Excrement

Changes of partial physical and chemical indexes, including moisture percentage, temperature, pH, organic carbon, nitrogen, phosphorus, potassium, humus acid, germination index of silkworm excrement composted in open stockpile and close stockpile during different periods, were studied. The results showed that when the fermentation temperature was low, fermentaion rate was slow, but physical and chemical index were stable in close stockpile while there were two heating up periods in open stockpile, the first high temperature was 50 ℃ for 9 d, the second with low temperature, which created great effects on physical and chemical indexes. It basically reached the technical standards of organic fertilizer after 20 d open compost. The content of organic carbon in silkworm paeces dropping ran up to 352.41 g/kg,w(C)/w(N) being 11.01, the total nutrient content (N + P₂O₅ + K₂O) being 81.2 g/kg, pH being 7.14, germination index surpassing 50%.