Abstract: The effects of nitrogen transformation bacteria on micro-ecological environment of the rhizosphere soil of 2 years old tea plant were studied in Taian City of Shandong Province. The Bacillus subtilis (T1) and Azotobacter chroococcum (T2) were set up as inoculation treatments, and the noninoculation as the control in this research. The number of bacteria, fungi, actinomycetes, ammonifying bacteria, azotobacter, nitrifying bacteria and the modification of microbial diversity in rhizosphere soil in different periods were measured, using the methods of culture counting and T-RFLP. Meanwhile, the nutrient contents in the soil were also determined. The results showed that the bacterial number of T1 and T2 were significantly higher than CK, but there were no significant impact on fungi and actinomycetes. In the whole test process, the number of ammonifying bacteria and azotobacter were higher than that of CK, among which ammonifying bacteria of T1 was the most, azotobacter of T2 was the most; the nitrifying bacteria numbers of CK was significantly higher than T1 and T2. Based on T-RFLP mapping analysis and compared with the control group, microbial diversity, the richness and evenness were rise in the bacterium treatments. The ammonium nitrogen concentration of T1 and T2 were significantly higher than that of CK, but the nitrate concentration were lower than that of CK. The available P concentration of T1 and T2 significantly increased by 8% and 25% for CK. Meanwhile, the available K concentration of T1 and T2 significantly increased by 15% and 11% for CK. The inoculation of Bacillus subtilis and Azotobacter chroococcum showed the positive effects, which could improve micro-ecological environment and soil nutrients of tea rhizospheric soil.

Key words: nitrogen fixing bacteria, ammonifying bacteria, T-RFLP, microbial diversity, soil nutrient