|Saporito, Louis - Lou|
|MCGRATH, JOSH - University Of Maryland|
|REITER, MARK - Virginia Polytechnic Institution & State University|
|ALLEN, ARTHUR - University Of Maryland Eastern Shore (UMES)|
|TINGLE, SHAWN - University Of Delaware|
|BINFORD, GREG - Wilbur-Ellis Company|
|HAN, KUN - Collaborator|
|JOERN, BRAD - Purdue University|
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/4/2014
Publication Date: 1/28/2015
Citation: Kleinman, P.J., Church, C., Saporito, L.S., Mcgrath, J.M., Reiter, M.S., Allen, A.L., Tingle, S., Binford, G.D., Han, K., Joern, B.C. 2015. Phosphorus leaching from agricultural soils of the Delmarva Peninsula, USA. Journal of Environmental Quality. DOI: 10.2134/jeq2014.07.0301.
Interpretive Summary: One of the most vexing environmental problems facing agricultural nutrient management today is the loss of phosphorus through the subsoil, rather than over the soil, in runoff water. This pathway of phosphorus loss, once considered a novelty, is now implicated in some of the great nutrient pollution cases of our time, from the Great Lakes to the Chesapeake Bay. A multi-institutional team, led by USDA-ARS and including major land grant universities, evaluated phosphorus leaching through dominant agricultural soils of the Delmarva Peninsula, a largely agricultural spit of land that borders the Chesapeake Bay. Results, intended to support nutrient management planning in Chesapeake Bay states, show that a number of measures of soil phosphorus can be used to predict phosphorus leaching potential, except following manure application, when other soil factors such as texture are important.
Technical Abstract: Leaching of phosphorus (P) mobilizes edaphic and applied sources of P and is a primary pathway of concern in agricultural soils of the Delmarva Peninsula, which defines the eastern boundary of the eutrophic Chesapeake Bay. We evaluated P leaching before and after poultry litter application from intact soil columns (30-cm diameter x 50-cm depth) obtained from low and high P members of four dominant Delmarva Peninsula soils. Soil textures ranged from fine sand to clay loam, and Mehlich-3 soil P ranged from 64 to 628 mg kg**-1. Irrigation of soil columns prior to litter application suggested a controlling role of surface soil P on dissolved P in leachate, but strong relationships between soil P and leachate P concentration were also observed in the subsoil (45-50 cm). Following poultry litter application (4.5 Mg ha**-1), leachate P concentrations increased significantly in fine textured soils, with litter derived P augmenting P derived from surface soil. Significantly higher P loads were observed in leachate from the finest textured soils, consistent with prior observations that well structured soils have the greatest propensity to transmit applied P. Results point to soil P, including P sorption saturation, as a sound metric of P loss potential in leachate when manure is not an acute source of P, but highlight the need to factor in macropore transport potential to predict leaching losses from applied P sources.