Effect of Broiler Litter Application Method on Metal Runoff from Pastures

Loss of metals from agricultural fields to surface water bodies causes deterioration of surface water quality. Method of application of broiler litter can affect loss of metals in surface runoff. Subsurface banding of broiler litter can decrease loss of P and N in surface runoff relative to surface application of broiler litter. However, limited research has been done to evaluate the impact of litter application method on loss of metals in surface runoff. Therefore, the objective of this research was to quantify differences in loss of metals in surface runoff from a tall fescue pasture as a function of method of application of broiler litter (i.e., surface vs. subsurface application). A rainfall simulation study was conducted in the Sand Mountain region of north Alabama. Results indicate that concentration and loadings of Cu, K, Mg, and Zn decreased in surface runoff as a result of application of broiler litter in subsurface bands and were similar between the subsurface-banded broiler litter and control (no litter applied) treatments. Greater than 90% of the applied rainfall infiltrated, indicating that losses of metals via lateral and subsurface flows can be substantial. Overall, results of this study show that application of broiler litter in subsurface bands can reduce loss of metals in surface runoff. Future research studies should investigate the impact of method of application of broiler litter on the metal losses in leachate and subsurface flows.