A Study On The Conversion And Utilization Of Dairy Cow Manure Feces By The Hermetia Illucens Larvae

Hermitia illucens(Black soldier fly,BSF)is a saprophagous insect originally from South American savanna.Its larvae feed on decaying organic matter and animal manure in nature,and can reduce environmental pollution.The results showed that the protein content of the dry matter was 45%-55%,and the fat content was 15%-30%,which could be used as animal protein feed;the feces of larvae could be used as organic fertilizer.In this study,the density of BSF larvae to convert fresh cow dung was studied.Each 20.0 kg of cow manure was treated by 3 500,8 750 and 17 500 4-day-old BSF larvae,respectively.The daily feeding of fresh cow dung for each density was 1.0 kg under the same condition.Then the differences of 100 larvae weight,crude protein,crude fat,water content and conversion rate of cow dung were analyzed.We analyzed how to select a feeding density and environment factors to convert fresh cow dung effectively.The results showed the 100 larvae weight and crude fat were negatively correlated with the density of the experimental group at the level of 0.01 and the highest conversion rate was found in the medium density group.The transformation products of fresh cow dung were applied to field returning experiment.The commercial organic fertilizer were replaced by transformation products of BSF at 30% of nitrogen base.The utilization potential of transformation products of BSF was evaluated by comparing the yield,nutrient content of lettuce and soil nutrient content(available N,P,K and p H)among three groups of experiments.The results showed that the yield of lettuce for the two treatments(30% of chemical fertilizer was replaced by equal amount of nitrogen)was reduced by 2.47%(commercial organic fertilizer)and 6.09%(water fly organic fertilizer)compared with the conventional treatment.There was no significant difference in the nutritional data of lettuce among the three treatments,and there was no significant difference in soil nutrient content among the three treatments.Above findings suggested that: the substitution of commercial organic fertilizer and BSF transformation products could improve the soil with good fertilizer effect and reduce the degree of soil acidification.