Effects of green manure application combined with chemical fertilizers on microbial biomass C,N and nitrogen supplying characteristics of tobacco-planting soils

In field experiments,the effects of green manure application combined with chemical fertilizers on microbial biomass C,N and nitrogen supplying characteristics of tobacco-planting soils were studied to provide a theoretical basis to study low carbon agriculture and to build resource-saving,environment-friendly agriculture and to promote the sustainable development of tobacco agriculture and the production of tobacco leaves with specific characteristics.Green manure application combined with chemical fertilizers increased soil microbial biomass C,N and soil nitrogen supplying capacity.The effects of application ratio of green manure and chemical fertilizer were different at different growth stages.In comparison with the control at different growth stages,soil microbial biomass C,N and soil urease activity were increased 7.07%-123.32%,3.28%-157.69% and 3.13%-50.00%,respectively by green manure application.The contents of soil total nitrogen and alkalytic nitrogen increased by 22.21% and 15.42%.The dynamics of microbial biomass C and N were different at different growth stages.Microbial biomass C peaked at the rosette stage and the budding stage,while microbial biomass N peaked at the rosette stage and the topping stage.The contribution of green manure to soil microbial biomass C,N and enzyme activity was greater than that of chemical fertilizer.Green manure was a main resource of soil microbial biomass N and soil nitrogen.At the same time,green manure also played an important role in the preservation of soil nitrogen.The above results revealed green manure application could promote the activity of soil organisms,favouring the turnover of organic matter in the soil and the provision of nutrition to meet the needs of tobacco's normal growth.