Field-scale evaluation of phosphorus leaching in acid sandy soils receiving swine waste

• Published in: Journal of environmental quality Vol. 34; no. 6; pp. 2024 - 2035
• Main Authors: Nelson, N.O, Parsons, J.E, Mikkelsen, R.L
• Format: Journal Article
• Language: English
• Published: Madison American Society of Agronomy, Crop Science Society of America, Soil Science Society 01-11-2005; Crop Science Society of America; American Society of Agronomy
• Subjects: acid soils; Agronomy. Soil science and plant productions; Animal Husbandry - methods; Animals; Applied sciences; Biological and medical sciences; drainage; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; equations; evapotranspiration; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; irrigation; Leaching; losses from soil; Manure; Manures; mathematical models; Pasture; Phosphorus; Phosphorus - metabolism; pig manure; Pollution; Pollution, environment geology; Samplers; Sandy soils; Soil; Soil amendment; Soil conservation; soil nutrient dynamics; Soil Pollutants - metabolism; Soil solution; Surface water; Swine; Swine houses; water pollution; Water quality; North Carolina; USA, North Carolina, Sampson Cty; Waste utilization; Vertical motion; Spatial scale; Sandy soil; Modeling; Surplus; Transport process; Swine; Ground surface; Motion study; Chemical concentration; Soil solution; Ungulata; Acid soil; Underground leaching; Evaluation scale; Saturation; Phosphorus; Grazing; Leaching; Long term; Sorption; Vertebrata; Mammalia; Surveillance; Pasture; Surface water; Sampler; Water quality; Acid leaching; Artiodactyla; Wastes; Transport; Field study
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2004.0445

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 x 3 x 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.