Effect of fertilization systems on microbes in the paddy soil

The effects of different fertilization systems on the microbes were studied with an 18 year long-term fix position experiment.The soil samples were collected from three sites in Hunan province.The results showed that the organic matter content was not directly correlated to the numbers of bacteria and actinomycetes and could not be used as the indicator for the soil microbes.The quantities of fungi could be used as the indicator for soil fertility based on this study.The nitrogen concentration and nitrifying bacteria in the soils treated with 30% organic matter or traditional fertilization were higher than those in the other soils.Nitrifying bacteria was not related to the organic matter content.Denitrifying bacteria in the soil treated with 60% organic matter was higher than the others due to the lower oxygen concentration.The sulfur nutrient was significantly affected by fertilization system.The nitrogen fertilization could improve the quantities of ammonification bacteria in soil.Fertilization system significantly influenced the microbial activities in soil.The microbial activities in soil without fertilization were the lowest.The microbial activities increased with increasing of soil organic matter.Soil quality must be improved using multi-agricultural technologies instead of single technology.