Plant-soil feedback (PSF) can be a major driver of plant performance in communities, and this concept can be used in selecting crop rotation sequences to maximize agricultural yields. Potential benefits of using PSF in this context include nutrient use optimization, pathogen reduction and enhancement of mutualisms between crops and microbes. Yet, the contributions of these combined mechanisms are poorly understood. Here we investigated the relative contributions of these mechanisms using five major crops commonly cultivated in rotation (alfalfa, canola, maize, soybean and wheat) under controlled conditions. We trained soil by growing each of the five crops in a ‘training phase’, and then reciprocally planted the five crops in the trained soils in a ‘feedback phase’. To tease out soil biota from nutrient effects, we established three treatments: ‘control’ (trained unsterilized soil used in the feedback phases), ‘biota’ (sterilized soil in the feedback phase inoculated with soil biota from the ‘control’ treatment after the training phase), and ‘nutrient’ (sterilized soils in both phases). Plant-soil feedback for each crop was calculated by comparing the total biomass of each crop grown in soils trained by each of the four other crops (i.e., in rotation) against total biomass in self-trained soil (i.e., monocropping). We found that PSF values varied among crop combinations in all the treatments, but such variation was the greatest in the ‘nutrient’ treatment. Overall, soil ‘biota’ feedback tended to be lower whereas ‘nutrient’ feedback tended to be greater compared to the unsterilized ‘control’ soil, suggesting that effects of antagonistic biota outweighed those of beneficial microbes in the ‘biota’ treatment, and that plants optimized nutrient uptake when the soil microbiome was absent in the ‘nutrient’ treatment. Furthermore, soils in the ‘nutrient’ treatment trained by the legume crops (alfalfa and soybean) tended to provide the greatest positive feedback, emphasizing the important legacy of N₂-fixers in crop rotation. Taken together, our data demonstrate how nutrients and soil biota can be integral to PSFs among crops, and that assessing PSFs under controlled conditions can serve as a basis to determine the most productive crop rotation sequences prior to field testing.

The data set was collected during a greenhouse study at Ontario Forest Research Institute (OFRI) in Sault Ste. Marie, Ontario, Canada. Plant biomass data were used to calculate feedback values via bootstrapping. Fix-effect ANOVAs were used to test treatment effects. The data set resulted in a manuscript accepted in Ecological Applications

The README file contains an explanation of each of the variables in the dataset and its measurement units, n/a =  values not available. Information on how the measurements were done can be found in the associated manuscript referenced above.