Relationship between the microbial community and catabolic diversity in response to conservation tillage

Abstract

The present study investigates the microbial (bacterial and fungal) community diversity and carbon substrates utilization in rhizosphere and bulk soil under three tillage practices (chisel plow, zero, and plow tillage) by using high-throughput sequencing technology and community-level physiological profiles. Conservation tillage practices increased the DOC, SOC, and invertase activity in bulk soil compared with conventional tillage. Tillage disturbances changed the soil microbial phylogenetic composition and utilization abilities of carbon substrates, and there was a significant positive correlation between soil microbial alpha diversity and catabolic diversity under different tillage practices. The soil microbial phylogenetic composition was significantly different with different soil types (rhizosphere and bulk) under three tillage practices, which had great influence on carbon substrate utilization. The soil physicochemical parameters were significantly correlated with microbial taxonomy composition. Structural equation model (SEM) analysis suggested that the relative abundances of Proteobacteria (Alpha- and Betaproteobacteria), Bacteroidetes, Capnodiales, and Pleosporales in the rhizosphere helped in the utilization of amino acids, carbohydrates, and carboxylic acid under different tillage practices. Our results suggested that conservation tillage practices and crop root activities modified soil physicochemical parameters and enrich soil nutrient conditions, which contributes to differences of soil microbial phylogenetic and taxonomic compositions, thereby increasing copiotrophic microbial populations in the rhizosphere and enhances metabolic capacities. Thus, these results can improve our understanding of the roles of conservation tillage in changing soil microbial community and catabolic diversity, as well as can help to establish a profitable agroecosystem to enhance soil nutrient conditions and modify soil microbial ecology, in turn improving plant production sustainability.