Phosphorus fate in treatment wetlands - a tale of sources, sinks, and soils

Session: Beyond the Edge of the Field: Mitigating the Impacts of Nutrient Pollution on HABs (2)

Jacob Berkowitz, US Army Corps of Engineers, [email protected]
Christine VanZomeren, US Army Corps of Engineers, [email protected]
Derek Schlea, LimnoTech, [email protected]
Tony Friona, US Army Corps of Engineers, [email protected]

Abstract

Increasing interest focuses on utilizing wetlands to reduce nutrient loading to surface waters, including excess P linked with Great Lakes HABs. In response, two studies evaluated P retention capacity at different spatial scales. The first study examined soil P sorption capacity in three treatment wetlands receiving inputs from an agricultural tile drainage system. Results demonstrate that wetland soils sequestered P; however, the magnitude of P retention varied significantly across treatment systems related to differences in soil properties. Soil P sorption capacity increased in the direction of treatment water flow, but differed across treatment wetlands with soils ranging from P sinks (5.8 ± 1.5 mg P kg^-1) to potential P sources (-17.2 ± 2.0 mg P kg^-1).  Findings suggest wetlands receiving P loadings from tile drainage waters accumulate soil P over time, but maintaining P removal efficiency may require periodic management to decrease soil P concentrations via nutrient removal and/or soil amendments. The second study highlights the need to couple landscape model outputs with site specific soils analysis when evaluating potential treatment wetland locations. Preliminary findings demonstrate that linking remote sensing and soil test approaches accounted for historic landuse effects (e.g., legacy soil P), improving efforts to optimize wetland P retention in areas impacted by HABs.

Twitter handle of presenter
@wetlandsoils