The composition of soil microbes around a growing plant can meaningfully impact that plant’s fitness in a number of ways, including nutrient uptake, yield, and disease resistance. With the microbiome in mind, analyzing the impact of different soil treatments on a crop across regions can create valuable insights on which treatments have potential to improve crop health and yield.
This is exactly what Drs. Scott Klasek and Linda Kinkel aimed to do when analyzing soil treatments and cover cropping in potato fields in growing regions across the continental US. This research was done as part of the Potato Soil Health Project, in partnership with UMN-SWAC’s Drs. James Crants and Carl Rosen, along with Dr. Kenneth Frost of Oregon State and Dr. Brenda Schroeder at the University of Idaho.
With eight sites across the continental US (located in Oregon, Colorado, Wisconsin, Idaho, Wisconsin, Michigan, and Maine, with some states holding multiple sites), sites were arranged into plots with twelve soil and cover cropping treatments with 4-5 replicate plots. Soil treatments were divided into: amended with composted or aged manure, conventionally fumigated, or neither, with the added layer of whether a mustard green manure was tilled back in as a biofumigant at any point. The specific potato cultivars and cover crops were chosen based on geographic region and grower’s practice—growers included six universities, one private research group, and one grower’s field. This design totaled 96 discrete agricultural soil treatments in total. Full details on soil treatments, management scenarios, and their locations can be accessed by reading the paper in full.
This research characterized 1,824 potato soil microbiomes from 456 plots in the eight field sites across the continental USA. To quote the paper itself on the study’s methods of evaluation:
“We first evaluated the effects of soil management types (organic amendment, fumigation, or mustard incorporation) on tuber yields and on soil bacterial and eukaryotic microbiomes. Next, we identified amplicon sequence variants (ASVs) associated with tuber yields and specific treatments. Finally, we used analytical models to link soil treatments to ASV-associated changes in tuber yields.” These allowed them to identify cases where these soil treatments increased potato yields by stimulating particular members of soil microbiomes.
Potato yield improvement was linked to specific microbiome taxa in three of fourteen scenarios that applied compost, and in one of thirteen scenarios that used chemical fumigation as part of this research. Incorporation of mustard greens did not affect yield in any of its scenarios. Broadly speaking, results of DNA sequencing showed varied associations between tuber yield and soil bacteria and eukaryotes, reflecting the very extensive continental-scale variation in microbiome composition—further information is available in the the full paper.
This research provides a vital foundation for analyzing the connections between management practices, microbiome composition, and potato yields, and points the way to further research to develop specific soil and crop health targets by crop and region.
Read the paper in full:
“Compost amendments to potato soils enrich yield-associated members of soil microbiomes across the continental US.” Scott A. Klasek, James E. Crants, Kenneth E. Frost, Brenda K. Schroeder, Carl J. Rosen, Linda L. Kinkel. bioRxiv 2025.02.26.640387; doi: https://doi.org/10.1101/2025.02.26.640387