Land use change overrides the effect of management type on soil microorganisms

Despite the key role of soil microorganisms for regulating ecosystem functions, the relationships among: (i) soil microorganisms, (ii) agricultural management practices (iii) vegetation and (iv) soil quality, remain poorly understood. In this study, we used DNA extraction and sequencing to assess soil fungi and bacteria communities in twelve pastures and twelve coffee fields in Zona da Mata, Minas Gerais, Brazil. The pastures and coffee fields belong to three different farm types and represent a gradient of management intensity from conventional to agroecological. In addition, we recorded 41 quantitative variables related to vegetation, soil quality and management practices in each field. Our main objectives are (i) to understand the effects of management type and land use change on soil microbial communities and (ii) to identify specific drivers of change in soil microbiota. We found that changes in land use between coffee and pastures overrides the effect of management type on soil microorganisms. The main specific soil factor driving microbial communities was bare soil, which was negatively correlated with many groups of microorganisms. No specific management practice had significant correlations with microbial abundance. The only specific vegetation variable correlated with the abundance of microorganisms was variance in height, which was positively correlated with several microbial OTU‘s. Our findings suggest that land use change can drastically modify soil microbiota, and therefore, the associated ecosystem functions performed by microorganisms. Furthermore, our results suggest that soil cover and structural diversity are important drivers of soil microbiota and therefore, should be considered for the design of more sustainable agroecosystems.