Effect Of Biochar On Nutrient Content And Humus In Chicken Manure Aerobic Compost

With the rapid development of urbanization,the large-scale intensive livestock and poultry farming model has gradually replaced the traditional small-scale farmer's free-range model,and also produced and discharged a large amount of livestock and poultry manure,which has brought serious environmental pollution problems.The nutrient content of N and P in livestock manure is high and has good agricultural value.If it is not treated in time,it will cause serious environmental pollution problems.Aerobic composting is one of the effective measures for the harmless and resource treatment of livestock manure.However,the traditional aerobic compost has the disadvantages of slow heating,large nitrogen loss,long maturity cycle and poor quality of compost products.In this study,the biochar produced by pyrolysis of rice straw at 400 °C,600 °C and 800 °C was used as compost additive.The chicken manure of large-scale farm was used as composting material,and aerobic composting experiment was carried out to study the organism.The effects of charcoal on the physical and chemical properties,nutrient content and humification degree of chicken manure composting were combined with elemental analysis and Fourier transform infrared spectroscopy to analyze the structural changes of humic acid before and after composting.The main findings are as follows:1)There are differences in the properties of biochar obtained by pyrolysis at a final temperature of 400 ° C,600 ° C,and 800 ° C.As the pyrolysis temperature increases,the biochar yield decreases,the ash content increases,and the pH increases.The content first increased and then decreased,the O content decreased first and then increased,the H and N contents decreased,the H/C ratio decreased,the aromaticity increased,and the BC600 had the lowest O/C and the weakest polarity.2)The pore structure of rice straw biochar is mainly mesoporous.With the increase of pyrolysis temperature,the pore size of biochar decreases,the pore volume increases,and the specific surface area increases.3)Biochar can shorten the warming period of compost and prolong the time of high temperature.Compared with the control,the addition of biochar can shorten the warming period of compost for 4 days,extend the high temperature period for 1-3 days,shorten the composting period by 1-3 days,which is helpful to achieve Rapid humification of compost.Biochar can also increase the loss of compost water dispersion.The moisture content of biochar treatment compost is 2.65%~5.53% lower than that of the control,and the higher the pyrolysis temperature,the better the biochar can promote the dehydration of the heap.4)The addition of biochar can increase the pH of the compost product,and the effect of biochar on the conductivity at different temperatures is different.The addition of biochar organic matter decreased rapidly,and the degradation rate of organic matter was improved.The degradation rate of organic matter treated by BC600 was the highest,which was 25.41%.5)Compared with the control,the total nitrogen content of biochar treatment increased by 5.77%~6.35%,and the nitrogen loss decreased by 5.66%~9.36%,indicating that biochar can reduce the nitrogen loss of compost and has a certain nitrogen retention effect.BC600 has the best effect on nitrogen retention in compost.Biochar can also increase the concentration of total phosphorus and total potassium in compost products,increase the nutrient content of compost products,and promote the activation of phosphorus during composting,which is beneficial to increase the content of available phosphorus in compost products.6)The total humic acid content of compost in each treatment was slightly reduced,and the total humic acid content in the biochar-treated compost product was higher than that in the control.With the composting,the content of fulvic acid in humus decreased,the content of humic acid increased,and the degree of humification of compost increased.After the end of composting,the ratio of H/F added to biochar was significantly higher than that of the control.Improve the degree of humification of compost products,and the difference between different temperatures of biochar treatment is small.7)The structure of humic acid changed greatly before and after composting.After composting,the contents of C,H and N of humic acid decreased,the content of O increased,the ratio of H/C decreased,and the degree of aromatization increased.Compared with the composting raw materials,the degree of polymerization and aromatization of the humic acid in the compost product is enhanced,and the compost humus is more stable;the addition of biochar has no significant effect on the humic acid structure.