title: Runoff phosphorus losses as related to phosphorus source, application method, and application rate on a Piedmont soil.
abstract: Land application of animal manures and fertilizers has resulted in an increased potential for excessive P losses in runoff to nutrient-sensitive surface waters. The purpose of this research was to measure P losses in runoff from a bare Piedmont soil in the southeastern United States receiving broiler litter or inorganic P fertilizer either incorporated or surface-applied at varying P application rates (inorganic P, 0-110 kg P ha(-1); broiler litter, 0-82 kg P ha(-1)). Rainfall simulation was applied at a rate of 76 mm h(-1). Runoff samples were collected at 5-min intervals for 30 min and analyzed for reactive phosphorus (RP), algal-available phosphorus (AAP), and total phosphorus (TP). Incorporation of both P sources resulted in P losses not significantly different than the unfertilized control at all application rates. Incorporation of broiler litter decreased flow-weighted concentration of RP in runoff by 97% and mass loss of TP in runoff by 88% compared with surface application. Surface application of broiler litter resulted in runoff containing between 2.3 and 21.8 mg RP L(-1) for application rates of 8 to 82 kg P ha(-1), respectively. Mass loss of TP in runoff from surface-applied broiler litter ranged from 1.3 to 8.5 kg P ha(-1) over the same application rates. Flow-weighted concentrations of RP and mass losses of TP in runoff were not related to application rate when inorganic P fertilizer was applied to the soil surface. Results for this study can be used by P loss assessment tools to fine-tune P source, application rate, and application method site factors, and to estimate extreme-case P loss from cropland receiving broiler litter and inorganic P fertilizers.
authors.affiliation: Department of Agronomy and Horticulture, University of Nebraska-Lincoln, West Central Research and Extension Center, 461 West University Drive, North Platte, NE 69101, USA. dtarkalson2@unl.edu
authors.forename: David D
authors.initials: DD
authors.lastname: Tarkalson
authors.forename: Robert L
authors.initials: RL
authors.lastname: Mikkelsen
mesh_terms: D000383:Agriculture; D000818:Animals; D001682:Biological Availability; D002645:Chickens; D056890:Eukaryota / Q000502:physiology; D005308:Fertilizers; D008372:Manure; D010758:Phosphorus / Q000032:analysis*; D011891:Rain; D012037:Refuse Disposal; D012989:Soil Pollutants / Q000032:analysis*; D014872:Water Movements; D014873:Water Pollutants / Q000032:analysis*
chemical_list: D005308:Fertilizers; D008372:Manure; D012989:Soil Pollutants; D014873:Water Pollutants; D010758:Phosphorus