Effects of inoculating azotobacter on soil enzyme activities and bacterial community functional diversity in the rhizosphere of maize (Zea mays L.)

In order to explore the response of soil micro-ecological characteristics associated with the rhizosphere of maize (Zea mays L.) to azotobacters inoculation, the responses of soil enzyme activities and bacterial community functional diversity in the rhizosphere soils of maize seedlings inoculated with azotobacter isolates including Azotobacter chroococcum YCYS, Phyllobacterium brasssicacearum QL54 and Paenibacillus sabinae MX31 were examined in pot culture conditions. The results show that the inoculation of azotobacter can change the soil enzyme activities and regulate the soil bacterial functional community associated with the rhizosphere of maize, and different strains have different inoculation effects. Compared with the control, the urease activities of A. chroococcum YCYS and P. sabinae MX31 treatments are increased by20.55% and 9.58%, respectively. However, there are not significant differences between the inoculation and control treatments in the phosphatase activity (P0.05). The BIOLOG results show that the azotobacter inoculation can increase the total bacterial metabolic activity, the activity of inoculating A. chroococcum YCYS is 1.8 times higher than that of the control. Meanwhile, the species richness (R) is significant higher that that of the control (P0.01). The results of six carbon sources reveal that there are different carbon metabolic communities among the treatments. Principle components analysis (PCA) suggests that the azotobacter inoculation can regulate the bacterial community associated with the rhizosphere soils.