秸秆还田配施腐解菌剂对稻田土壤生态系统多功能性的影响OA

Crop straw is an important resource for improving soil fertility.However,its decomposition rate under natural conditions is slow due to the presence of recalcitrant components such as cellulose and lignin.The combined application of decomposing microbial agents can accelerate straw decomposition and enhance nutrient release efficiency,providing a potential approach for improving the soil environment and ecological functions.To clarify the effects of straw returning combined with decomposing microbial agents on the microbial communities and ecosystem multifunctionality(EMF)in paddy soils,a pool experiment was conducted with three treatments:straw removal(CK),straw returning(SR),and straw returning with decomposing microbial agents(SR1).Soil nutrient indicators and extracellular enzyme activities related to carbon and nitrogen cycling were measured to calculate the EMF index.Meanwhile,high-throughput sequencing was used to analyze bacterial and fungal community compositions,and a random forest model was employed to identify the key microbial drivers of EMF.The results showed that,compared with the CK treatment,the SR1 treatment significantly increased soil nutrient levels in paddy soils,with significant increases in soil organic matter,total nitrogen,alkali-hydrolyzable nitrogen,available phosphorus and available potassium contents.In particular,the soil organic matter content under the SR1 treatment increased by 103.92%and 16.85%compared with that under the CK and SR treatments,respectively.Compared with the CK treatment,both the SR and SR1 treatments significantly enhanced the soil EMF index(0.58 and 0.65,respectively),with the greatest enhancement effect under the SR1 treatment.Microbial community analysis indicated that the SR1 treatment significantly altered the composition and structure of soil bacterial and fungal communities and markedly enriched functional taxa such as Firmicutes and Ascomycota.Compared with the SR treatment,the relative abundances of Firmicutes and Ascomycota under the SR1 treatment increased by 2.73%and 34.15%,respectively.Differential indicator species analysis identified Firmicutes,Clostridia,Dothideomycetes,and Cladosporium endophyticum as characteristic indicator taxa for the SR1 treatment.The random forest model revealed that bacterial β-diversity,fungal α-diversity,fungal β-diversity,and the relative abundances of Firmicutes,Clostridia,Acidobacteria,Planctomycetes,Rozellomycota,and Dothideomycetes were the main driving factors influencing soil EMF(P＜0.05).In conclusion,straw returning combined with decomposing microbial agents significantly enhances the multifunctionality of paddy soil ecosystems by improving the soil nutrient status and enriching specific functional microbial communities.This study provides a theoretical basis for the efficient utilization of straw resources and the sustainable management of paddy fields.