The contemporary plant-soil feedback in legume-cereal intercropping systems: a review of carbon, nutrient, and microbial dynamics

Background: Crop diversification practices, such as legume-cereal intercropping, are receiving increasing attention for the large-scale implementation because of crop yield advantages while simultaneously preserving various soil functions. To date, a comprehensive understanding of the soil nutrient and carbon (C) cycling and microbial dynamics underlying the crop yield advantage remains elusive. Scope: This review employs legume-cereal intercropping systems as a model to examine the current knowledge on the modulation of soil nitrogen (N), phosphorus (P), potassium (K), and C biogeochemistry resulting from the co-cultivation of these crops. This analysis emphasizes the functional potential of the soil microbiome and the plant-induced assemblage of microbial communities, highlighting key knowledge gaps. Drawing from this examination, we suggest expanding the traditional Plant-Soil Feedback (PSF) definition to encompass hetero- and conspecific effects occurring within a single growing season. We define this concept as Contemporary Plant-Soil Feedback (CPSF). Conclusions: Our analysis revealed consistent plant-induced changes in the performance and nutrient acquisition of neighboring plants, an effect that would be inadequately classified without this new framework. The examination of the CPSF in legume-cereal intercropping systems demonstrated that yield advantages are supported by more efficient N and C cycling, enhanced P and K availability, and improved maintenance of microbial functionality. This approach offers a novel perspective for investigating plant-soil dynamics in agricultural systems.