title: Phosphorus leaching from agricultural soils of the delmarva peninsula, USA.
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 × 50 cm depth) obtained from low- and high-P members of four dominant Delmarva Peninsula soils. Surface soil textures ranged from fine sand to silt loam, and Mehlich-3 soil P ranged from 64 to 628 mg kg. Irrigation of soil columns before litter application pointed to surface soil P controls on dissolved P in leachate (with soil P sorption saturation providing a stronger relationship than Mehlich-3 P); however, strong relationships between P in the subsoil (45-50 cm) and leachate P concentrations were also observed ( = 0.61-0.73). After poultry litter application (4.5 Mg ha), leachate P concentrations and loads increased significantly for the finest-textured soils, consistent with observations that well-structured soils have the greatest propensity to transmit applied P. Phosphorus derived from poultry litter appeared to contribute 41 and 76% of total P loss in leachate from the two soils with the finest textures. 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.
authors.forename: Peter J A
authors.initials: PJ
authors.lastname: Kleinman
authors.forename: Clinton
authors.initials: C
authors.lastname: Church
authors.forename: Lou S
authors.initials: LS
authors.lastname: Saporito
authors.forename: Josh M
authors.initials: JM
authors.lastname: McGrath
authors.forename: Mark S
authors.initials: MS
authors.lastname: Reiter
authors.forename: Arthur L
authors.initials: AL
authors.lastname: Allen
authors.forename: Shawn
authors.initials: S
authors.lastname: Tingle
authors.forename: Greg D
authors.initials: GD
authors.lastname: Binford
authors.forename: Kun
authors.initials: K
authors.lastname: Han
authors.forename: Brad C
authors.initials: BC
authors.lastname: Joern