Long‐Term Runoff Water Quality as Affected by Broiler‐Litter Application to a Udult in the Ozark Highlands

Abstract

Repeated annual land application of organic soil amendments, such as broiler litter (BL), to managed grasslands for increased forage yields has increased concerns about potential surface water contamination from runoff. Furthermore, water quality concerns are exacerbated in areas of underlying karst, such as the Ozark Highlands, where runoff can rapidly enter the groundwater system. Therefore, the objective of this study was to determine 8‐yr (May 2003–April 2011) linear trends in annual runoff water quality from a silt loam soil in the Ozark Highlands region of northwest Arkansas under natural precipitation and typical forage management amended annually with BL at three application rates (0 [control], 5.6 [low], and 11.2 [high] Mg BL ha−1) with a history of BL amendments and high soil‐test P. Average annual runoff, flow‐weighted mean (FWM) runoff concentrations of Ca, Cd, Cu, Na, and Se, and all nutrient and metal losses increased with time (P < 0.05) but were unaffected (P > 0.05) by BL application rate. Average annual FWM concentrations of As decreased with time (P < 0.05) and were unaffected by BL (P > 0.05). Eight‐year cumulative runoff losses of Se exceeded 200% of that applied in BL. Results indicated that pasturelands with a history of BL application and high soil‐test P may continue to release BL‐derived As and Se at concentrations potentially harmful to human and environmental health regardless of current management practice long after litter application has ceased.