TY - JOUR

T1 - Agricultural phosphorus and water quality

T2 - sources, transport and management

AU - Sharpley, A.

AU - Gburek, W.

AU - Heathwaite, A. Louise

N1 - Agricultural phosphorus and water quality: sources, transport and management 19 cites: http://scholar.google.com/scholar?num=100&hl=en&lr=&cites=18127540156840397455

PY - 1998

Y1 - 1998

N2 - Freshwater eutrophication is usually controlled by inputs of phosphorus (P). To identify critical sources of P export from agricultural catchments we investigated hydrological and chemical factors controlling P export from a mixed land use (30% wooded, 50% cultivated, 20% pasture) 39.5-ha catchment in east-central Pennsylvania, USA. Mehlich-3 extractable soil P, determined on a 30-m grid over the catchment, ranged from 7 to 788 mg kg-1. Generally, soils in wooded areas had low Mehlich-3 P (<30 mg kg-1), grazed pasture had Mehlich-3 P values between 100 and 200 mg kg-1, and cropped fields receiving manure and fertiliser applications were in most cases above 200 mg kg-1. Average P concentrations for ten storms during 1996 decreased 50% downstream from segment 4 to segment 1 (catchment outlet). Flow-weighted streamflow P concentrations were more closely related to the near-stream (within 60 m) than whole catchment distribution of high-P soils. This suggests that near-stream surface runoff and soil P are controlling P export from the catchment. Remedial measures should be targeted to these critical P source areas in a catchment. Measures include source (fertiliser and manure application) and transport management (reduce surface runoff and erosion).

AB - Freshwater eutrophication is usually controlled by inputs of phosphorus (P). To identify critical sources of P export from agricultural catchments we investigated hydrological and chemical factors controlling P export from a mixed land use (30% wooded, 50% cultivated, 20% pasture) 39.5-ha catchment in east-central Pennsylvania, USA. Mehlich-3 extractable soil P, determined on a 30-m grid over the catchment, ranged from 7 to 788 mg kg-1. Generally, soils in wooded areas had low Mehlich-3 P (<30 mg kg-1), grazed pasture had Mehlich-3 P values between 100 and 200 mg kg-1, and cropped fields receiving manure and fertiliser applications were in most cases above 200 mg kg-1. Average P concentrations for ten storms during 1996 decreased 50% downstream from segment 4 to segment 1 (catchment outlet). Flow-weighted streamflow P concentrations were more closely related to the near-stream (within 60 m) than whole catchment distribution of high-P soils. This suggests that near-stream surface runoff and soil P are controlling P export from the catchment. Remedial measures should be targeted to these critical P source areas in a catchment. Measures include source (fertiliser and manure application) and transport management (reduce surface runoff and erosion).

M3 - Journal article

VL - 7

SP - 297

EP - 314

JO - Agricultural and Food Science in Finland

JF - Agricultural and Food Science in Finland

SN - 1795-1895

IS - 2

ER -