Effects Of Different Green Manure And Maize Rotations On Soil Physicochemical Properties And Microbial Characteristics

Declining soil quality has become a widespread problem worldwide,which not only affects crop yield and food security in the short term,but also hinders the sustainable development of agriculture in the long term.In this study,we collected field soils after 1 and 5 months of treatment in 2021 and 2022,respectively,to determine the mass of soil aggregates and organic matter content at each grain level.The effects of green manure on soil structure(especially on the stability of aggregates)and microbial communities were investigated and the results of the study were as follows:(1)Vicia villosa Roth significantly increased the content of large aggregates at the0.25-2 mm level,while the return of Orychophragmus violaceus significantly increased the content of large aggregates at >2 mm level.In terms of indicators,the MWD and GMD of Orychophragmus violaceus treated soil were significantly higher than those of the control group,while the Vicia villosa Roth soil exceeded the former after 5 months,with the highest MWD and GMD.Further analysis revealed that soil aggregates distribution and its organic matter content were correlated,and the strongest correlation was found at the >2 mm size level.(2)Analysis of several characteristics of the soil microbial community such as species composition,Alpha diversity,Beta diversity and metabolic channels after the green manure return treatment showed that both green manures could increase the richness and diversity of microbial populations in the soil to some extent.Based on the above findings and the results of RDA analysis,it can be implied that there was a promotion effect on the formation of macroaggregates and the organic matter content.(3)Returning green mature to maize field can improve soil aggregate stability and erosion resistance,and has a good potential on the improvement of soil structure and microbial community structure.