Long-term broiler litter amendments can alter the soil's capacity to sorb monensin.

Environ Sci Pollut Res Int. 2017 May;24(15):13466-13473. doi: 10.1007/s11356-017-8727-9. Epub 2017 Apr 7. Doydora SA1, Sun P2, Cabrera M1, Mantripragada N1, Rema J1, Pavlostathis SG2, Huang CH2, Thompson A3. Author information 1 Department of Crop and Soil Sciences, University of Georgia, 3111 Miller Plant Sciences Building, 120 Carlton Street, Athens, GA, 30602-7272, USA. 2 School of Civil and Environmental Engineering, Georgia Institute of Technology, 790 Atlantic Dr NW, Atlanta, GA, 30332-0355, USA. 3 Department of Crop and Soil Sciences, University of Georgia, 3111 Miller Plant Sciences Building, 120 Carlton Street, Athens, GA, 30602-7272, USA. AaronT@uga.edu. Abstract Monensin is a common antiparasitic drug given to poultry that contaminates poultry manure and bedding material (broiler litter). As broiler litter is commonly applied to agricultural fields as fertilizer, monensin could be released beyond the farm if it is not retained or degraded in the soil. This study aimed to assess the impact of long-term surface application of broiler litter (i.e., 17 years) on the capacity of pasture soil to sorb monensin. The soils were exposed to a range of monensin concentrations (0.18 to 1.81 μmol L-1), solution pH (pH 4-9), and temperatures (15, 25, and 35 °C) and monensin was measured as loss from solution (i.e., sorption). Soils receiving long-term litter applications were hypothesized to retain more monensin than unamended soils because they have higher organic matter concentrations. However, soils from broiler litter-amended fields sorbed 46% less monensin than soils from unamended fields, likely because broiler litter also increased soil pH. The sorption of monensin to soil was strongly influenced by pH, with an order of magnitude greater sorption at pH 4 than at pH 9. Both soils had similar capacity to sorb monensin under similar solution pH, despite differences in organic carbon content (with the broiler litter-amended having 25% greater relative to the unamended soil). Temperature did not significantly impact monensin sorption for either soil. Our findings suggest increasing soil pH, for instance through liming, could enhance mobility of monensin. KEYWORDS: Broiler litter; Dissolved organic matter; Monensin; Pasture soil; Sorption; Temperature; pH