Soil Nutrients and Veterinary Pharmaceutical Compound Concentration Change in Abandoned Beef Cattle Backgrounding Feedlot Site with Hay Harvesting.

Animal congregation around feeders and water sources is common in beef production operations including backgrounding. Intense manure and urine deposited around feeder areas can cause nutrients and manure derived veterinary pharmaceutical compound accumulation in soil. Elevated soil nutrient levels can deteriorate soil/water quality and antibiotics in soils may raise antibiotic resistance related public health concerns. We tested 6 years of hay harvesting after animal exclusion as a management practice to lower P, Fe, Cu, Zn, and Monensin concentrations in feeder and nearby areas of small beef cattle backgrounding site. After six years, soil P, Fe, Cu, and Zn concentrations in feeder areas were dropped by 13.7 (1645 to 1418 mg kg^-1), 28.2% (677 to 486 mg kg^-1), 14.2 (3.5 to 3.0 mg kg^-1), and 33.6 (50 to 33 mg kg^-1), respectively. In near grazing areas soil P, Fe, Cu, and Zn concentrations were lowered by 24% (390 to 296 mg kg^-1), 40% (349 to 209 mg kg^-1), 14.2 (3.5 to 3.0 mg kg^-1), and 41% (24 to 14 mg kg^-1). Monensin concentrations in feeder and nearby areas were degraded by 88% (37.1 to 4.4 ng g-1) and 37.5% (0.8 to 0.5 ng g^-1), respectively. This result suggest that long-term hay cropping on isolated highly animal impacted areas of small beef backgrounding sites can mitigate associated environmental risks potential.