ARS | Publication request: Changes in Soil Carbon and Phosphorus Associated with Conversion of Beef Cattle Pasture to Wetland

Submitted to: Florida Cattleman
Publication Type: Trade Journal
Publication Acceptance Date: February 27, 2009
Publication Date: March 16, 2009
Citation: Sigua, G.C., Coleman, S.W. 2009. Changes in soil carbon and phosphorus associated with conversion of beef cattle pasture to wetland. The Florida Cattleman and Livestock Journal.73(6):42-45.

Technical Abstract: Basic information on the ecological understanding of the responses of systems to water regime change is essential in both the environmental integrity and productivity of the ecosystem. Progress in this area may facilitate some reversal of wetlands losses in the future. Flooding of formerly drained areas (e.g., beef cattle pastures) has become common practice in wetland restoration. Such variation could profoundly affect the processes underlying nutrient transformations in these systems. To better understand the dynamics of soil total organic carbon and phosphorus during wetland conversion to beef cattle pastures and beyond, soil core samples were collected from the converted beef cattle pastures and from the natural wetland at Plant City, FL in summer of 2002, 2003, 2005, 2006 and 2007. The concentration of total organic carbon was reduced by 96% over the periods of land use conversion. It appeared that conversion of wetland was proceeding toward a soil condition/composition like that of mineral soils. Soils taken from natural wetland (180 g/kg) had the greatest amount of total organic carbon while the altered pasture sites (5.4 g/kg) had the lowest concentration of total organic carbon. Concentrations of soil total phosphorus (parts per million, ppm) were significantly lower in dried soils than in wet soils (natural wetlands: 763 ppm > grazed pastures: 444 ppm > altered pastures: 340 ppm). These results are valuable information in determining phosphorus exchange potential. Concentrations of all forms of phosphorus (water-soluble P, KCl-bound P, FeMn-bound P, Al-bound P, CaMg-bound P, and organic-bound P) differed significantly with land use.