Investigating the Impact of Sequential Treatment of Herbicide Mixes on the Soil Microbiome
Faculty Mentor Information
Dr. Anirban Chakraborty, Idaho State University; and Eric Christen, Idaho State University
Presentation Date
7-15-2026
Abstract
Land management agencies in the United States frequently employ herbicides to control the spread of non-native invasive plants along roadways. While herbicides are highly effective in controlling weeds and invasive plants, they have been shown to have adverse effects on soil microbial communities and their multifaceted functions. Soil microbial communities drive nutrient cycling that impacts ecosystem health, stability, and functionality. Therefore, it is imperative that we understand the effects that herbicide application may have on these communities. To address this knowledge gap, we investigated the impact of sequential applications of herbicide mixtures on soil microbial communities. Three experimental sites situated at rest areas along the Interstate-15 highway, with each located within a distinct level IV EPA ecoregion, were treated with varying mixes of herbicides over a three-year period. 74 soil samples were collected across sample sites each summer annually to perform DNA-based microbial community surveillance and soil chemical property analyses. Beta diversity analysis of microbial communities revealed experimental sites to be the largest contributor to community dissimilarity with a statistically significant effect from herbicide application. Canonical correspondence analysis further showed pH, Iron, and Phosphate as major drivers shaping the microbial communities. Within the microbial community, 150 differentially abundant amplicon sequence variants (ASVs) were identified in herbicide-treated soils. These observations suggest that application of herbicides impact soil microbial ecosystems. Understanding microbiome responses to herbicide treatments can help inform management practices aimed at controlling invasive plants while maintaining soil ecosystem health.
Investigating the Impact of Sequential Treatment of Herbicide Mixes on the Soil Microbiome
Land management agencies in the United States frequently employ herbicides to control the spread of non-native invasive plants along roadways. While herbicides are highly effective in controlling weeds and invasive plants, they have been shown to have adverse effects on soil microbial communities and their multifaceted functions. Soil microbial communities drive nutrient cycling that impacts ecosystem health, stability, and functionality. Therefore, it is imperative that we understand the effects that herbicide application may have on these communities. To address this knowledge gap, we investigated the impact of sequential applications of herbicide mixtures on soil microbial communities. Three experimental sites situated at rest areas along the Interstate-15 highway, with each located within a distinct level IV EPA ecoregion, were treated with varying mixes of herbicides over a three-year period. 74 soil samples were collected across sample sites each summer annually to perform DNA-based microbial community surveillance and soil chemical property analyses. Beta diversity analysis of microbial communities revealed experimental sites to be the largest contributor to community dissimilarity with a statistically significant effect from herbicide application. Canonical correspondence analysis further showed pH, Iron, and Phosphate as major drivers shaping the microbial communities. Within the microbial community, 150 differentially abundant amplicon sequence variants (ASVs) were identified in herbicide-treated soils. These observations suggest that application of herbicides impact soil microbial ecosystems. Understanding microbiome responses to herbicide treatments can help inform management practices aimed at controlling invasive plants while maintaining soil ecosystem health.