[Response of Nitrification Potential and Ammonia Oxidation Microbial Community in Purple Soils to the Application of Biochar Combined with Chemical Fertilizer and Manure].

The effects of manure and chemical fertilizer combined with biochar on nitrification potential and ammonia oxidation microbial change characteristics of purple soils were studied to explore the effects of fertilization measures and soil environmental factors on nitrification potential and ammonia oxidation microbial change characteristics. In this study, purple soil was taken as the research object, and five treatments were set up:no fertilizer(CK), chemical fertilizer(F), manure(P), chemical fertilizer plus biochar(FP), and manure plus biochar(PP). PCR and T-RFLP methods were used to study the characteristics of soil AOA and AOB communities, and soil nitrification potential and environmental factors were measured at the same time to determine the effect of manure combined with biochar on the nitrification potential of purple soil. The results showed that:① compared with that in the CK treatment, the FP and PP treatments significantly increased soil nitrification potential(P<0.05). ② Compared with that in the CK treatment, the F, P, FP, and PP treatments significantly increased the number of copies of the AOA amoA gene in the soil by 78.17%-162.22%(P<0.05), and the F, FP, and PP treatments significantly increased the number of copies of the AOB amoA gene by 21.56%-78.32%(P<0.05). ③ Compared with that in the CK treatment, the PP treatment significantly improved the Shannon, richness, and evenness indices of the soil AOA community(P<0.05), and the combination of biochar(FP and PP treatments) could change the community structure of the soil AOB. ④ The chemical fertilizer and manure affected the AOA and AOB community structure by changing soil properties such as pH, TP, AP, C/N, SOM, NO3--N, and NH4+-N. ⑤ Stepwise regression analysis further showed that AOB amoA gene abundance was the main factor affecting soil nitrification potential. Therefore, under the condition that chemical fertilizer and manure were applied together with biochar, the AOB community was the main driver of the ammonia oxidation process in acidic purple soil, and fertilization affected the ammonia oxidation process by regulating C/N and NO3--N.