Effects of different returning method combined with decomposer on decomposition of organic components of straw and soil fertility

In view of the problems of low straw decomposition rates and reduced soil fertility in southern Liaoning, China. Using nylon mesh bags method, the decomposition rules of cellulose, hemicellulose and lignin in straw and straws and the dynamic changes of soil organic carbon (SOC), soil microbial biomass carbon (MBC) and soil dissolved organic carbon (DOC) contents were analyzed after 15, 35, 55, 75, 95, 145 and 365 days of returning. At 365 days after return to the field, rotating tillage + straw decomposing agent(refer to decomposer)(RT+S) was the most favorable for straw decomposition and its components, straw decomposition proportion reached 73.25%, and the decomposition proportion of lignin, cellulose and hemicellulose were the highest, being 35.49%, 84.23% and 85.50%, respectively. DOC content in RT+S treatment was higher than in other treatments at each stage, SOC content reached 18.02 g· kg-1 at 145d, which was higher than other treatments. The improvement effect of deep turning + deep rotary tillage + straw decomposing agent (PT+S) treatment on microbial biomass carbon (MBC) was the best, followed by RT+S treatment. Our results suggest that the straw and its organic components decomposition proportion could be increased by adding straw decomposing agent, the straw decomposition proportion and the SOC content of various forms were significantly increased with the RT+S treatment.