LAUSR

The magnitude of bacterial transport through runoff into surface water or infiltration into groundwater is influenced by the adsorption processes in soil. The objective of this study was to evaluate fluorescent-labeled E. coli adsorption by soil under agroforestry buffer (AB), grass buffer (GB), and row crop (RC) management. Adsorption experiments were conducted by inoculating three masses (0.5, 1, and 10g) on each treatment (AB, GB and RC) with E. coli O157:H7-GFP several concentration ranges (105 - 108 cfu/mL). Adsorption data were evaluated using Langmuir, Freundlich and Temkin adsorption isotherm models. The Freundlich isotherm model was found to describe the observed data well for all treatments using the 10 g soil mass, with the coefficients of determination closer to unity in all treatments. Freundlich Kf parameter (cfu/mL), an indicator of adsorption capacity was higher for the AB treatment (9.93) compared to both GB and RC treatments (2.32 and 1.27). The multiple pairwise comparisons test (Tukey Test) of the Freundlich 1/nf parameter demonstrated a significant difference (p < 0.05) between the AB treatment and the other two treatments (RC and GB). Similarly, the Kf values were significantly (p = 0.05) higher for the 10 g mass under the same test conditions, but no significant differences were observed in both the 0.5 g and 1 g masses. This study demonstrated that the agroforestry buffer (AB) has higher E. coli adsorption capacity and the potential for mitigating the effects of E. coli O157:H7 transport to surface or groundwater through the soil ecosystem. This article is protected by copyright. All rights reserved.