The Pedological Context Modulates the Response of Soil Microbial Communities to Agroecological Management

Conservation agriculture is based on harnessing and optimizing natural ecological
processes such as thosemediated by the soilmicrobiota and represents a very promising
approach to overcome the limitations of current conventional practices. Agronomic
conservation strategies such as increasing plant diversity at field scale and minimizing
soil disturbances such as tillage aim at fostering the presence of beneficial microbial
communities to support intrinsic agroecosystem functions and reduce the reliance on
agrochemicals andmechanical soilmanagement. However, it remains poorly understood
how these positive contributions are modulated by the pedological context. Moreover,
only few studies have assessed the management-dependent responses of microbial
communities in real-life farming systems. Here, in close association with the farmers
and under realistic field conditions, we explored the response of bacterial and fungal
community structure to conventional and conservation (using agroecological principles)
management regimes across two pedological sites (loamy sand and sandy loam) in
Belgium. Microbial diversity was assessed using a DNA metabarcoding approach of
ribosomal markers with the Illumina MiSeq sequencing technology. Our results show
that different management approaches select for distinct soil microbial communities and
that these management-related effects were modulated by the pedological context.
Therefore, designing new agricultural systems to foster the presence of beneficial
organisms and reduce the level of pathogenic organisms should account for variability in
the underlying pedological context.