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Effect of tillage and static abiotic soil properties on microbial diversity

Legrand, Fabienne, Picot, Adeline, Cobo-Díaz, José Francisco, Carof, Matthieu, Chen, Wen, Le Floch, Gaétan
Applied soil ecology 2018 v.132 pp. 135-145
Acidobacteria, DNA barcoding, Hydrogenophaga, Mycoplana, Sphingomonas, agricultural soils, animal manures, bacteria, bacterial communities, climatic factors, conventional tillage, corn, crop rotation, denitrification, fertilizer application, functional diversity, fungi, manure spreading, mineral fertilizers, minimum tillage, nitrogen cycle, physicochemical properties, soil chemical properties, soil ecology, soil microorganisms, soil physical properties, species richness, wheat, France
Agricultural soil microbial communities are largely impacted by agronomic practices, soil physicochemical properties and climatic conditions. To understand how these factors induce changes in fungal and bacterial communities in soil, we used a metabarcoding approach to profile the microbial communities of 31 agricultural wheat fields with maize as previous crop, representative of usual crop rotation in Brittany, France. Our results clearly highlighted the importance of tillage for both bacteria and fungi, with species richness and evenness significantly higher in fields under minimum tillage practices than in fields under conventional tillage, despite that the core microbiota was similar between fields under these two practices. The functional diversity of the bacterial communities, predicted using FAPROTAX, was also significantly higher in fields under minimum tillage notably that involved in nitrogen cycling (denitrification, respiration). We also observed that animal manure increased bacterial richness and evenness compared to chemical fertilization only. Interestingly, fungal diversity was less sensitive to disturbance than bacterial communities. We also identified taxa groups as potential bioindicators of a specific agronomic practice, such as the strong association between animal manure application and Hydrogenophaga, Mycoplana and Sphingopyxis, as well as the enrichment of oligotrophic Acidobacteria under conventional tillage.