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Field‐Scale Evaluation of Phosphorus Leaching in Acid Sandy Soils Receiving Swine Waste
Author(s) -
Nelson Nathan O.,
Parsons John E.,
Mikkelsen Robert L.
Publication year - 2005
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/jeq2004.0445
Subject(s) - soil water , leaching (pedology) , loam , environmental science , phosphorus , sorption , soil science , agronomy , environmental chemistry , hydrology (agriculture) , chemistry , geology , adsorption , geotechnical engineering , organic chemistry , biology
Accurate descriptions of P leaching are important because excess P applied to soils can enter surface water via leaching and subsurface transport, thereby negatively impacting water quality. The objectives of this study were to monitor P leaching in soils with a long‐term history of waste application, relate soil solution P concentrations to soil P status, and quantify P leaching losses. Soil solution was monitored for 20 mo with samplers installed at 45‐, 90‐, and 135‐cm depths in two pits (1 × 3 × 1.5 m) in Autryville (loamy, siliceous, thermic Arenic Paleudults) and Blanton (loamy, siliceous, semiactive, thermic Grossarenic Paleudults) soils located in a grazed pasture in Sampson County, NC, which had received swine waste for >20 yr. Maximum soil solution P concentrations at 45 cm exceeded 18 mg L −1 in both soils. Soil solution P concentrations at 90 cm in the Blanton soil were similar to that at 45 cm indicating low P sorption. Soil solution P concentrations at 90 cm in the Autryville soil averaged 0.05 mg L −1 compared to 10 mg L −1 at 45 cm. A split‐line model related soil solution P concentration to the degree of phosphorus saturation (DPS), identifying a change point at 45% DPS. Phosphorus movement past 45 cm equaled or exceeded surplus P additions for both soils. Long‐term waste applications resulted in DPS > 90%, high soil solution P concentrations, and substantial vertical P movement. Phosphorus leaching should be considered when assessing long‐term risk of P loss from waste‐amended soils.