Effects of Straw Returning on Soil Urease Activity and Soil Microbial Biomass Nitrogen

[Objective] The effects of straw returning on soil urease activity and microbial biomass nitrogen were studied to provide a basis for exploring the development of low carbon agriculture,building a resource-conserving and environment friendly agriculture,and realizing the sustainable development of grain production.[Method] Located trails were carried out for a few years and the office analysis methods were used.[Result]The wheat and maize straw returning could obviously increase the total nitrogen content,the urease activity and the microbial biomass nitrogen of the soil.During che growth periods from wheat seeding time to maize harvest time,compared with CK,the soil urease activities of the treatment(wheat and maize straw returning but no fertilizing) were separately increased from 21.93% to 12.89%.Wheat and maize straw returning with fertilization could obviously increase the activity of soil urease.Meanwhile,the soil microbial biomass nitrogen of the treatment(wheat and maize straw returning with no fertilization) was more than 19.32% compared with the one of fertilizing.[Conclusion]The straw returning was the key factor of the increase of the soil urease activity and microbial biomass nitrogen.