Effects of different fertilization systems on amount of soil microorganism and enzyme activity in red soil of Hunan

Amount of soil microorganism and enzyme activity of long-term fertilization experiment in red soil of Hunan were detected and analyzed. The results indicated that application of NPK fertilizers combined with organic manure could increase amount of useful soil microorganism in red soil. Similarily, the soil hydrogen peroxidase, urease and phosphatase activities were increased obviously. The application of wheat-soybean-sweet potato rotation also could improve soil fertility, increase amount of beneficial microorganism and activities of hydrogen peroxidase and phosphatase. The treatment of only organic manure, also had better result, but the treatment of N fertilizer was poorest.