Submitted to: Journal of Environmental Quality
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/1/2003
Publication Date: 3/1/2004
Citation: Franzluebbers, A.J., Wilkinson, S.R., Stuedemann, J.A. 2004. Bermudagrass management in the southern piedmont USA. IX. Trace elements in soil with broiler litter fertilization. Journal of Environmental Quality. 33:778-784. Interpretive Summary: Floor waste from chicken houses is a mixture of manure, wood-chip bedding, and spoiled food. Its disposal onto nearby agricultural land is a common practice, and can benefit farmers by supplying an organic form of fertilizer at a relatively low cost. However, because of the wide diversity of nutrients present in poultry litter, there is concern that trace elements may be accumulating in soil and possibly leading to toxicity levels in plants, animals, and human food supplies. Trace elements are required by plants and animals in relatively low quantities. Researchers at the USDA-Agricultural Research Service in Watkinsville GA determined the concentration of 12 trace elements in soil following poultry litter application during 5 years to bermuda grass pasture in comparison with commercial fertilizer. Soil did accumulate higher levels of copper, manganese, and zinc with poultry litter fertilization, but at levels not considered toxic. Grazed pastures accumulated greater concentrations of trace elements than hayed fields, because feces from cattle returned elements to the soil. Farmers and environmental organizations can benefit from this information to guide safe utilization of this vast manure resource in the southeastern USA.
Technical Abstract: We evaluated changes in copper (Cu), manganese (Mn), zinc (Zn), and nine other trace elements during the first 5 years of bermudagrass management varying in fertilization and harvest strategies. Chicken broiler litter was a significant source of trace elements that led to 3.4 times higher Cu, 1.9 times higher Mn, and 2.1 times higher Zn in the surface 3 cm of soil than when forage was fertilized inorganically at the end of 5 years. Concentrations of all trace elements in soil at the end of 5 years were below toxic levels. At the end of 5 years, soil at a depth of 0-3 cm under grazed paddocks had 34% greater cadmium (Cd), 13% greater chromium (Cr), 62% greater Cu, and 23% greater Zn compared with unharvested and hayed management. Trace elements in soil were unaffected whether forage was unharvested or removed as hay. These results suggest that broiler litter is a significant source of several trace elements and that ruminant processing of forage and subsequent deposition of excreta on the paddock allow these trace elements to accumulate more at the soil surface where they might interact with the high concentration of organic matter.