Effect of straw returning method on physicochemical properties and microbial community of paddy soil in Northeast China

Abstract:

[Objective] To investigate the effect of straw returning method on physical and chemical properties and microbial community of black soil in Northeast China. [Methods] The experiment was carried out from December 2019 to October 2021. Two ways of straw returning were adopted:direct straw returning+microbial agent WJ (hereinafter referred to as MD) and straw composting before returning+microbial agent WJ (hereinafter referred to as MC). Soil fertility, enzyme activities, and microbial community were analyzed. [Results] The content of soil organic matter, humus and fulvic acid carbon was 2.28 g/kg, 7.82 g/kg and 5.26 g/kg, respectively, higher in MD than in MC. Content of soil ammonium nitrogen and available phosphorus in MD was slightly higher than that in MC, which peaked in June. Content of humic acid carbon decreased. In addition, the activities of urease, sucrase, cellulase and alkaline phosphatase in soil were 8.55%, 15.46%, 4.35% and 6.19% higher in MD than in MC, respectively. High-throughput sequencing results showed that the diversity of bacteria and fungi in MD was higher than that in MC. The dominant bacterial genera were Anaerolinea, Bacteroidetes and Pseudomonas, while Tausonia, Mrakia and Mrakiella dominated the fungi. [Conclusion] MD was conducive to the increase of soil organic matter, humus, enzyme activities and microbial diversity as compared with MC, suggesting that addition of WJ into straw can reduce the loss of organic nutrients and maintain the fertility of the soil in the field.

Key words:direct straw returning;straw composting before returning;microbial agent;soil fertility;microbial diversity