PS 31-119 - Soil microbial community response to prairie strips in rowcrop agroecosystems

Background/Question/Methods

Prairie strips are zones of prairie wildflowers and grasses planted within agricultural fields. Converting 10% of a rowcrop field to prairie strips has been shown to reduce soil erosion, inhibit runoff of agrochemicals to adjacent habitat, and increase soil organic carbon. Soil microbes are integral to these processes; however, it is unclear how soil bacterial and fungal communities respond to prairie strip establishment. The conversion of annual cropland to perennial prairie generates rapid shifts in soil microbial community composition over the span of months to years. It is likely that the establishment of prairie strips causes similar changes to soil microbial communities at the subfield scale. Shifts in microbial community structure have the potential to alter soil functions relevant to agricultural production and conservation. In this study, we investigated soil microbial community composition during the first two years of prairie strip establishment at the Kellogg Biological Station Long Term Ecological Research site. We assess soil microbial community structure as a function of prairie strip age, distance from prairie strip, agricultural management regime, and soil biochemical properties.

Results/Conclusions

Prairie strip soil bacterial communities diverge from rowcrop communities after one year of establishment (distance*year, p=0.02), such that prairie strip and rowcrop soil share fewer bacterial taxa one year after prairie strip planting. Regardless of prairie strip age, the rate of root colonization by a fungal mutualist microbe, arbuscular mycorrhizal fungi, did not change with distance from the prairie strip (p=0.58), suggesting that either belowground fungal dispersal is limited by rowcrop soil disturbance, or that prairie plants and rowcrop plants are associating with fungal mutualists at a similar rate. Prairie strip establishment also affected soil biochemical properties. Compared to surrounding rowcrop areas, prairie strips soils accrued greater microbial biomass C than surrounding row crop soils (p=0.04). Forthcoming results to be included on the final poster include 1) analyses of ITS1F-ITS2 amplicon sequencing data describing fungal community response to prairie strip establishment and 2) analyses describing which specific bacterial and fungal taxa exhibited significant changes in abundance following prairie strip establishment.