Effect of biochar plus fertilizer on the rhizospheric functional bacteria related to the nitrogen transformation in soybean

Biochar made by maize straw at 450 ℃ insulated from oxygen was set as materials.Five experimental treatments were as follows: Control with no fertilizer and biochar application, fertilizer treatment(N 100 mg· kg-1, P 100 mg· kg-1, K 150 mg· kg-1with no biochar application), fertilizer with few biochar(N 100 mg· kg-1, P 100 mg· kg-1, K 150 mg· kg-1with 1% biochar), fertilizer with moderate biochar(N 100 mg· kg-1, P 100 mg· kg-1, K 150 mg· kg-1with 5% biochar) and fertilizer with mass biochar(N 100mg· kg-1, P 100 mg· kg-1, K 150 mg· kg-1with 10% biochar). The present study was proceeded to analyze the amounts of the functional bacteria, pH and available nitrogen related to nitrogen transformation of rhizosphere in soybean. The results showed that pH of rhizosphere increased significantly, and dosage effect was observed in amount of azotobacteria, ammonification bacteria and nitrobacteria when fertilizer plus biochar was applied. Moreover, 5% biochar application was favorable to increase the amount of bacteria related to nitrogen transformation in soybean rhizosphere. The results above can offer the evidence to reveal the microbial mechanism of biochar effect on the nutritive substance in soybean rhizosphere.