| Selected 8 plots with different vegetation types in the nature Reserve for Vatica mangachpoi forest in Shimei Bay, rhizosphere and non-rhizosphere soil samples of 0~10 cm and 10~20 cm in these plots was taken at April, July, October, and December.Then the most probable number (MPN) method was used to investigate the quantitative distribution, isolated and preliminary selected strains which had stronger Nitrogen-fixing ability with Ashby medium in this area. Results showed that: the quantitative distribution of the soil azotobacter in this area is heterogeneity both time and space, and the space distribution was effected obviously by time. Judging from the time, the number of soil azotobacter was least in July, then its number increase slowly, the number was most until April. In space distribution, it had different results in each time, and is effected by vegetation, sampling depth, plant root system and terrain of each plot,these factors were all effect the quantitative distribution of soil Azotobacter by change the Nitrogen supply, water, thermal, and air of soil.In this research, 15 strains of azotobacter were isolated and 4 strains which had stronger Nitrogen-fixing ability was selected, it was the prepare that to use PGPR in the research that construct coastal protection forest and protect Vatica mangachpoi forest. |
