[Effect of Biodegradable Mulching Film on Soil Microbial Community in Cotton Field was Revealed Based on...

Biodegradable mulching films （BMPs） have been widely used as an alternative to conventional plastic mulching films （CMPs）. However， the long-term effects of BMPs on soil microbial community structure remain unclear. Therefore， in this study， we set up two treatments， CMPs and BMPs， and conducted a field experiment with 26 a of CMPs and 11 a of BMPs coverage. Using metagenomics technology， the effects of BMPs on soil microbial community structure in cotton fields in arid areas were investigated. The results showed that compared with those under the CMPs treatment， the BMPs treatment significantly reduced soil water content （SWC）， bulk density （BD）， and available phosphorus （AP） by 25.00%， 12.50%， and 12.09%， respectively， but significantly increased soil porosity （SP） by 10.07%. The BMPs treatment （124） significantly reduced the number of unique species compared with that in the CMPs treatment （182）. At the phylum level， the BMPs treatment significantly increased the relative abundance of Proteobacteria and significantly decreased the relative abundance of Actinobacteria. At the genus level， the BMPs treatment significantly increased the relative abundances of Nocardioides， Solirubrobacter， and Nitrospira and significantly decreased the relative abundance of Sphingomonas. Meanwhile， the proportion of positive correlations and the average degree between microbial communities in the BMPs treatment were increased significantly by 16.32% and 8.71% compared with those in the CMPs treatment， respectively， reducing the modularization degree of the microbial community by 1.89% and promoting the symbiotic relationship and stability of the microbial community. The BMPs treatment significantly increased the relative abundance of genes such as xylA， narG/nxrA， and nasA and significantly decreased the relative abundance of genes such as accA， frdA， nirB， nrtA， gcd， and phoR， promoting carbon degradation， denitrification， and assimilative nitrate reduction processes and inhibiting dissimilatory nitrate reduction and inorganic phosphorus solubilization processes. Soil SWC and AP were the key environmental factors affecting microbial community composition. Biodegradable mulching film increased the complexity and stability of soil microbial communities compared with traditional mulching film， and soil SWC and AP were the key environmental factors affecting the composition of microbial communities.