Effects Of Microbial Enzyme Preparation On Composting Process Of Cow Manure Under Different C/N Ratios

In this study,cow manure and wheat straw were used as composting materials,and different C / N treatment groups were set up.The effects of exogenous bacteria and enzymes on the composting process of cow manure were studied.The experiment was divided into 9 composting treatment groups(3 replicates in each group)with C / N ratio of 25 / 1: C1 group(cattle manure 87% + wheat straw 13%),C2 group(cattle manure87% + wheat straw 13% + 3% compound microbial agent),C3 group(cattle manure 87%+ wheat straw 13% + 3% compound bacteria and 1% compound enzyme);C / N 30 / 1:C4 group(80% cow dung + 20% wheat straw),C5 group(80% cow dung + 20% wheat straw + 3% compound microbial agent),C6 group(80% cow dung + 20% wheat straw +3% compound bacteria and 1% compound enzyme);The treatments with C / N ratio of 35/ 1 were as follows: Group C7(75% cow dung + 25% wheat straw),group C8(75% cow dung + 25% wheat straw + 3% compound microbial agent),group C9(75% cow dung +25% wheat straw + 3% compound bacteria and 1% compound enzyme).The purpose of this study was to explore the effects of compound microbial agents and enzymes on fertilizer efficiency index,routine index,toxicity index,copper(Cu)and zinc(Zn)forms,bacterial and fungal diversity in the process of cow manure fermentation under different C / N conditions,so as to determine the best combination and provide effective data support for cow manure treatment.The results show that:Effects of microbial enzyme preparation on the composting process of cow manure under different C / N conditions: in the composting process,adding different microbial enzyme can accelerate the temperature rise and increase the duration of high temperature period;It has no obvious effect on the change of water and p H;The nitrogen content of the reactor is obviously increased;It effectively promoted the degradation of organic matter and increased the relative content of total phosphorus and total potassium.By analyzing the changes of composting indexes,the results showed that the composting effect of C8 group(Bacillus subtilis + Aspergillus niger + Streptomyces flavus)with C /N of 35 / 1 was the best.Effects of microbial enzyme preparation on the morphological changes of Cu and Zn in cattle manure composting process under different C / N conditions: the effects of a series of microbial complex microbial agents including Bacillus subtilis,Aspergillus niger and Streptomyces flavus,cellulase and protease on the morphological changes of heavy metals in cattle manure aerobic composting were investigated.The results showed that in the aspect of reducing the availability of heavy metals,the effect of adding microbial enzyme treatment group was better than that of the non adding group,and the C8 group was the best.Effects of microbial enzyme preparation on morphological changes of bacteria and fungi in cow manure composting process under different C / N ratios: Shannon diversity index of bacteria and fungi community had the same change trend in the composting process,showing an increasing trend,but the richness and diversity of bacteria community were significantly higher than that of fungi community.With the composting process,the community structure of bacteria and fungi changed significantly.At the level of phylum classification,Actinobacteria,Proteobacteria,Firmicutes and bacteroidota were dominant in the initial stage of composting.Ascomycota of fungi is dominant in the whole composting process.Except for a small amount of Basidiomycota,almost no other fungi are detected.