Effect of grain crop-pasture rotations on bacterial and archaeal communities in a grain-pasture system in Uruguay

A better understanding of soil and plant-associated microbiomes in agroecosystems holds the potential to increase agricultural sustainability. We hypothesized that crop-pasture rotation improves grain production by maintaining soil health and fostering microbial diversity and plant-beneficial microorganisms. In a grain cropping system with no-tillage, continuous cropping (CC), short (SR) and long (LR) crop-pasture rotation (two and four years of pasture with cattle grazing, respectively) and an adjacent native grassland (NG, reference of a healthy soil) were compared in terms of soil health. We assessed soil health based on various physicochemical and biological properties. Soil aggregate distribution, soil bulk density and crop yields in SR/LR were improved compared to CC. In spring, the soil and rhizosphere microbial (Bacteria and Archaea) communities were shaped by the rotation. Resulting in an increase of the relative abundance of e.g. Bacillus and Xanthobacteraceae in SR/LR soils. In summary, our results suggest that crop-pasture rotations have the potential to maintain soil health and crop production better than CC when compared to NG.