Effect of broiler litter application method on metal runoff from pastures

Authors: LAMBA, JASMEET - Auburn University; SRIVASTAVA, PUNEET - Auburn University; Way, Thomas - Tom; MALHOTRA, KRITIKA - Auburn University

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/2019
Publication Date: 7/12/2019
Citation: Lamba, J., Srivastava, P., Way, T.R., Malhotra, K. 2019. Effect of broiler litter application method on metal runoff from pastures. Journal of Environmental Quality. 48:1856-1862. https://doi.org/10.2134/jeq2018.08.0318.
DOI: https://doi.org/10.2134/jeq2018.08.0318

Interpretive Summary: Loss of metals from agricultural fields to surface water bodies causes deterioration of surface water quality. Method of application of broiler litter can affect metals losses in surface runoff. Subsurface-banding of broiler litter can decrease loss of phosphorus and nitrogen 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. Research was conducted to quantify differences in metals losses in surface runoff from a tall fescue pasture as a function of method of application of broiler litter (i.e., surface vs. subsurface application). 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. 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.

Technical Abstract: Broiler chicken litter is a mixture of chicken manure and a bedding material and is commonly used as a fertilizer on pastures and cropland in broiler-producing areas. Poultry litter is typically land-applied by broadcasting the litter on the soil surface. A prototype implement for applying poultry litter in shallow trenches and covering the litter with soil has been developed at the USDA-ARS National Soil Dynamics Lab in Auburn, AL. This subsurface band application of litter performs well in reducing nutrients in runoff and in leachate. Rain falling on soil to which poultry litter has been applied, may carry phosphorus and nitrogen nutrients from the soil into streams, lakes, and other water bodies. Poultry litter contains some metals, including copper (Cu), potassium (K), magnesium (Mg), and zinc (Zn). Little research has been done to compare the conventional surface broadcast application of litter with shallow subsurface banding of litter, in terms of the loss of these metals from the applied litter, in surface runoff water. A field experiment was conducted in the Sand Mountain region in northeastern Alabama which is the major broiler production area in Alabama. Broiler litter was applied at the rate of 5.0 Mg/ha, using surface broadcast application on some plots, and shallow subsurface band application on other plots. Surface runoff was produced for one hour using simulated rainfall at a moderately high intensity rainfall rate of 70 mm/h. The concentration and loading of Cu, K, Mg, and Zn in surface runoff decreased when the litter was applied in subsurface bands, compared to surface broadcast application. Concentrations of Cu, K, Mg, and Zn in surface runoff were similar between the subsurface-banded 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 in soil can be substantial. These results show that application of broiler litter in subsurface bands can reduce losses 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.