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Spatial Variation of Soil Phosphorus within a Drainage Ditch Network
Author(s) -
Vaughan Robert E.,
Needelman Brian A.,
Kleinman Peter J. A.,
Allen Arthur L.
Publication year - 2007
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2006.0095
Subject(s) - ditch , drainage , spatial variability , hydrology (agriculture) , environmental science , soil water , phosphorus , nonpoint source pollution , surface runoff , soil science , ecology , chemistry , geology , mathematics , biology , statistics , geotechnical engineering , organic chemistry
Agricultural drainage ditches serve as P transport pathways from fields to surface waters. Little is known about the spatial variation of P at the soil‐water interface within ditch networks. We quantified the spatial variation of surficial (0–5 cm) soil P within vegetated agricultural ditches on a farm in Princess Anne, MD with an approximately 30‐yr history of poultry litter application. Ditch soils from 10 ditches were sampled at 10‐m intervals and analyzed for acid ammonium oxalate‐extractable P, Fe, Al (P ox , Fe ox , Al ox ), and pH. These variables were spatially autocorrelated. Oxalate‐P (min = 135 mg kg −1 , max = 6919 mg kg −1 , mean = 700 mg kg −1 ) exhibited a high standard deviation across the study area (overall 580 mg kg −1 ) and within individual ditches (maximum 1383 mg kg −1 ). Several ditches contained distinct areas of high P ox , which were associated with either point‐ or nonpoint‐P sources. Phosphorus was correlated with Al ox or Fe ox within specific ditches. Across all ditches, Al ox ( r = 0.80; p < 0.001) was better correlated with P ox than was Fe ox ( r = 0.44; p < 0.001). The high level of spatial variation of soil P observed in this ditch network suggests that spatially distributed sampling may be necessary to target best management practices and to model P transport and fate in ditch networks.