Changes in microbial and physicochemical properties under cover crop inclusion in a degraded common bean monoculture system

The expansion of the common bean monoculture system along with intensive agricultural practices focused on productivity has generated a misuse of natural resources, accompanied by a significant decline of the soil ecosystem services. The aim of this study was to analyze the short-term effect (3 years) of the inclusion of different cover crops (legumes, non-legumes and mixtures) on the physicochemical, biological properties and crop yield in a degraded common bean monoculture system in the north region of Argentina. The inclusion of legumes (vetch and melilotus) and non-legumes (oat and wheat) as sole cover crops over three consecutive years significantly increased the abundance of the main microbial groups, microbial biomass C and N (MBC and MBN) and the activity of the common bean rhizosphere microbial community, which resulted into a fast improvement of soil quality and rhizosphere microbiota compared with bean monoculture. However, mixed cover crops (oat + vetch) had a positive but lower impact on rhizosphere microbial community abundance compared to legume or non-legume cover crops when used as sole cover crops. The information generated in this study will contribute to the evaluation of the inclusion of specific cover crops as a conservation strategy to recover soil health and minimize soil degradation, while maintaining crop yields.

Automated summary

The inclusion of different cover crops, especially legumes, in the common bean monoculture system significantly improved soil quality and rhizosphere microbial community, highlighting the positive impact of legume cover crops on microbial abundance.