Corn rhizosphere microbial community in different long term soil management systems

Abstract

Soil management systems are a set of farming techniques and practices used to avoid degradation, erosion, and depletion of the soil. This study proposes an evaluation of two of the several management techniques: no-tillage and fallow system. No-tillage is a tropical management system which improves soil quality by adding organic matter in the form of straw covering, which also maintains the soil's friability and structure due to reducing mechanization. On the other hand, a fallow system is the resting state of soil for several vegetative cycles, which allows the soil to recover and store organic matter while retaining moisture and disrupting the life cycles of pathogens through natural soil microbiota. In both techniques, the soil microbiota is an important parameter that is affected by the management system. The rhizosphere microbiota, in particular, is highly affected. Thus, this study aimed to characterize the corn rhizosphere microbial community of soils under the no-tillage (NT) and fallow soil (FS) management systems, correlating the data with soil chemicals and productivity parameters. Bacterial networks were also checked to get the main taxa in each soil management system. As a result, the diversity of the rhizosphere community in FS was significantly higher than in the NT system, with Proteobacteria, Actinobacteria and Acidobacteria being the more abundant phyla in both systems. The estimated productivity showed a weak correlation to the bacterial community. In addition, the Verrumicrobia and Cyanobacteria phyla were exclusive to FS, while the Actinobacteria, Firmicutes and Chlamydiae phyla were exclusive to NT. The main bacterial genera that were able to distinguish soil management were DA101 (Verrucomicrobia) in FS, and Geodermatophilus in NT. These results show that different soil management systems lead to significant shifts in the microbiota of the rhizosphere.