Effects Of Bio-carbon On Physical And Chemical Properties Of Biogas Residue Composting

Biogas residue as anaerobic digestion residue,with nutrient-rich features,is a high-quality organic fertilizer raw materials.In this paper,biogas residue was taken as the main fermentation raw material,pig manure and corn stalks were added to adjust the carbon to nitrogen ratio of the material to 25-30:1 and the moisture content to 65%-70%.The effects of adding different proportions of biochar on the physicochemical properties and microbial population during the biogas composting of biogas residue were studied,and the optimal biochar addition ratio was screened out.On the basis of clarifying the optimum biochar addition ratio,different ratios of EMs(Effective Microorganisms,mainly photosynthetic bacteria,lactic acid bacteria,yeasts and actinomycetes)were added to screen out the best proportion of EM additions,to further improve the quality of carbon-based biogas residue organic fertilizer;selection of better quality biochar biogas residue organic fertilizer,EM bacteria agent-biocarbon biogas residue organic fertilizer and traditional organic fertilizer,the blank test for comparison of fertilizer efficiency test,detection of the actual application of different organic fertilizer effect.This research not only makes up the research on the impact of biochar on biogas residue compost,but also provides technical support for biogas residue fertilizing,and solves the problem of resource utilization of biogas residue and reduces environmental pollution.The results shown that the addition of biochar can prolong the high temperature period,improve physical and chemical properties,promote the maturity,increase the total nutrient content.Compared with the control,the contents of organic matter with different treatments(2%,5%,10%of biochar addition,respectively)were reduced by 12.96%,9.26%and 7.41%respectively,and the total organic matter content was higher than 45%,and the total nutrient content increased by 6.5%,4.3%,2.2%,seed germination index were also higher than 85%.The addition of biochar could increase the number of microbes,but the effects on bacteria,fungi and actinomycetes were different.At the same time,with the increase of the proportion of biochar,the number of bacteria decreased but negatively;the curve of biochar on actinomycetes was concave,and the addition of 5%biochar had the most inhibitory effect on actinomycetes;There was a positive correlation between the amount added and the amount of fungi,and the addition of biochar is good for fungal growth.The addition of EM microbial agents compost helped to increase the rate of heating,prolonged the high temperature period,reduced the water content and promote the maturity.At the same time,the addition of EMs helped the formation of humus and improved the humus content.Compared with the control,the content of humus with different treatments(2‰,3‰,4‰ of EM microbial agents,respectively)increased by 21.43%,33.49%and 12.81%,and the total nutrient contents increased by 10.69%,8.06%and-3.61%,respectively.Germination index of 95%or more,no toxic effects.The addition of EMs could increase the number of microorganisms,but it had no effect on bacteria.And it could increase the number of fungi in the early stage of composting.Compared with CK treatment,the number of fungi increased by 71.57%、93.97%、91.69%,69.94%、98.41%、114.60%respectively in the first and second days.The number of actinomycetes was significantly increased(P<0.05),which was helpful for composting.Compared with no application of organic manure,B1(traditional pig manure organic fertilizer),F1(adding 2%biochar biogas residue organic fertilizer)and T2(adding 3 ‰bacteria +2%biochar biogas residueorganic fertilizer)was significantly improved the yield of rape,increased by 25.22%,35.10%and 54.56%respectively.The addition of organic manure could significantly increase the soil fertility and soil microbial biomass,and the number of soil microbes increaseed with the growth of rape.The effects of different organic fertilizers on soil bacteria,actinomycetes and fungi were different.T3 had the best effect on soil bacteria and actinomycetes,which increased by 2.94 and 1.49 times,respectively.The effect of F1 on fungi was the best,increased by 3.52 times.Comprehensive rape yield,soil fertility,microbial biomass and other indicators,T2 treatment of soil fertilizer the best.