1) Changes of ammonifying, nitrosobacteria, denitrobacteria and anaerobic nitrogen fixing bacteria quantity at different soil dep ths with different tillage patterns .

2) Abundance of heterotrophic bacteria, ammonifying bacteria and nitrite bacteria, and heterotrophic bacterial population dynamics in the coastal waters of Zhejiang were investigated.

3) Main conclusions educed from this experiment were as follows:1. The effect of different fertilizing treatments on soil ammonifying bacteria, nitrobacteria, denitrobacteria was significant.

4) The dissolved oxygen had greater effects on heterotrophic bacteria, ammonifying bacteria and nitrifying bacteria.

5) If the sewage concentration was too high, it would stimulate fungi, ammonifying and denitro-bacteria to propagate.