Nitrifying bacteria was not related to organic matter content.Denitrifying bacteria in the soil treated with 60% organic matter was higher that the others due to the lower oxygen concentration.

• 长期施用大量有机肥（60%25）的土壤反硝化细菌数量高于其它施肥处理，这可能与长期使用大量有机肥后土壤氧化还原电位降低有关。