Using plant-soil feedback to optimize crop rotations

Plant-soil feedback (PSF) is a major driver of plant performance and positive PSF effects can enhance plant growth via enhanced nutrient availability, disease suppression, and interactions between plants and microbes. Such positive PSF effects can therefore be used to optimize crop rotations for sustainable agricultural production. However, how to optimize crop rotations based on PSF is still poorly understood. Here, we studied PSF for twelve crop species commonly grown in Chinese agricultural systems. We trained soil by growing each of the twelve crops in a ‘conditioning phase’ and then reciprocally planted the twelve crops in the conditioned soils in a ‘feedback phase’ under controlled greenhouse conditions. PSF for each crop was calculated by comparing the aboveground biomass of each crop grown in soil conditioned by the other eleven crops against aboveground biomass in self-conditioned soil. Overall, most crops experienced positive PSF in broad bean-conditioned soils, potentially explained by broad bean being a nitrogen fixer. In addition, graminoid species (oat, maize and wheat) generally benefitted from soils conditioned by other plant families, which may be due to their nutrient acquisitive strategy. For all conditioned soils, we use analyses of the microbial community, nutrient cycling and disease suppressiveness, and plant traits to explain the PSF 114 effects. With our results, we will build a framework to determine the most productive rotation sequence.