Phosphorus Adsorption and Desorption in Coarse-Textured Soils Bordering Recreational Lakes

Abstract

Sandpit lakes of Nebraska are residential developments frequently affected by excess phosphorus (P). The objectives of this study are to quantify P retention and release by sandpit lake soils and determine properties related to P retention and release. Soils were sampled at 0–15 and 15–30 cm deep from six developed and one undeveloped site. Adsorption was fit to the Langmuir isotherm and desorption was fit to the Elovich equation. Clay and organic matter contents identified some sites as amended with finer-textured soil. Iron, aluminum, and P fractions were low in all samples but greater in amended soil. Adsorption maximum was greater at 0–15 cm deep for all but the undeveloped site. Adsorption energy parameter was greater at 15–30 cm deep. Elovich slopes and intercepts were generally greater in the 0- to 15-cm samples. Slopes were positively related to soil P richness. Importing finer textured soil to lake sites increases P retention and should help preserve water quality.