Agricultural runoff from areas receiving livestock manure can potentially contaminate surface water with antimicrobials and antimicrobial resistance genes (ARGs). The objective of this study was to investigate the effectiveness of narrow grass hedges (NGHs) on reducing the transport of antimicrobials and ARGs in runoff after land application of swine manure slurry. Plot-scale rainfall simulation tests were conducted on 0.75 m by 4.0 m plots designed to test three treatment factors: manure amendment (control plots receiving no manure vs. amended plots receiving manure based on 3 times N requirement), NGH (plots with a NGH vs. plots without a NGH), and rainfall events (days 1-3). Runoff generated during three 30-min simulated rainfall events was sampled and analyzed for antimicrobials and ARGs. Manure amendment was responsible for the presence of antimicrobial tylosin (p < 0.0001) and tylosin resistance gene erm(B) (p < 0.0001) in runoff. Narrow grass hedges proved to be effective in reducing tylosin (p < 0.0001) and erm(B) (p < 0.0347) in runoff. Manure amendment was responsible for the introduction of tylosin (p < 0.0482) and erm(B) (p = 0.0128) into the soil; however, it had no significant impact on the abundance of the 16S rRNA gene in soil. Results from this study suggest that NGHs could be a best management practice to control the transport of antimicrobials and ARGs in agricultural runoff.
ASJC Scopus subject areas
- Environmental Engineering
- Water Science and Technology
- Waste Management and Disposal
- Management, Monitoring, Policy and Law