The Effect Of High Temperature Ammonia Oxidizing Bacteria On The Transformation Of Nitrogen In Aerobic High Temperature Composting

Ammonia volatilization is the major pass of nitrogen losses from aerobic high-temperature composting,which as a serious problem,induces the poor quality of compost products.Aiming at this problem,high-temperature ammonia oxidizing bacteria were screened from 14 strains of ammonia oxidizing bacteria which were screened in the early stage by the research group.After exploring its ammonium transformation capacity,as a biological nitrogen retention agent,it was applied to aerobic high-temperature composting which used chicken manure as the main material and Chinese medicine residue as auxiliary material.The dynamic changes of nitrogen transformation,humus component,etc.were monitored in the compost to explore the nitrogen retention effects of screened ammonia oxidizing bacteria in aerobic high-temperature composting,and explore their effects on the fertility of compost,which will provide new technical methods for effectively controlling the ammonia volatilization in aerobic high-temperature composting and improve the quality of products.The main results of this study are as follows:(1)After 15 days of cultivation of ammonia oxidizing bacteria in inorganic salt specific medium,the L8 and L17 strains were screened out by virtue of excellent ammonia transformation ability.And they were preliminary identified as Bacillus and Saccharopolyspora sp.by sequencing,respectively.Further research results showed that 20 day was the optimized culture time for the ammonium nitrogen conversion rate of the two strains,and 0.5 g/L ammonium sulfate was the optimal culture substrate concentration for both strains.(2)The high-temperature ammonia oxidizing bacteria showed obviously nitrogen preservation effect in the aerobic high-temperature composting.They can significantly reduce the volatilization of ammonia in the mixture,and promote the transformation of ammonium nitrogen to nitrate nitrogen.And the total nitrogen,dissolvable total nitrogen,inorganic nitrogen and dissolvable organic nitrogen of the treatment applying bacteria were significantly higher than the control treatments.The above indicators all indicated that the effect of bacterial agent treatment L8 was the best,and the effect of L8+L17 mixed bacterial agent treatment was weaker than that of L8 and L17 single bacterial agent treatment,which revealed that the high temperature ammonia oxidizing bacteria L8 had a good nitrogen retention effect in aerobic high temperature composting and that there was a negative interaction effect between L17 and L8,so they should not be added at the same time.In addition,the temperature change trend of each treatment in the compost was basically the same.The high temperature period(>50 ℃)lasted for 5 days,reaching the harmlessness requirements of compost.At the end of composting,the water content,p H,and electrical conductivity(EC)of the compost mixture also reached the Y525-2012 organic fertilizer agricultural industry standard.(3)The addition of high temperature ammonia oxidizing bacteria also significantly improved the compost fertility and compost quality.Humic acid content rose in the compost,while the fulvic acid content was opposite.At the end of composting,the content of humic acid and HA/FA(the ratio of humic acid and fulvic acid)in the inoculated treatments were significantly higher than the sterilized water treatment and sterilized culture solution treatment,however,the content of fulvic acid was significantly lower than that of the two treatments.The differences of FA and HA between L8 and the two control treatments were the most significant.At the same time,the organic carbon and dissolvable organic carbon of the inoculated treatment were lower than the control treatment,and the treatment of L8+L17 had a significant effect.In addition,at the end of composting,the nitrogen,phosphorus and potassium nutrients and total nutrient content of the inoculated treatment were significantly higher than other treatments.The C/N ratio of each treatment was less than 20,the T value(product(C/N)/original(C/N))was less than 0.6,and the seed germination rate(GI)was more than 80%,reaching the compost standard.