Date of Graduation

Fall 2006


Master of Science in Geospatial Sciences


Geography, Geology, and Planning

Committee Chair

Robert Pavlowsky


phosphorus, soil, water quality, lawns, land use

Subject Categories

Hydrology | Soil Science


Eutrophication of surface waters due to high phosphorus (P) concentrations is an important water quality concern in Greene County, Missouri. Phosphorus enrichment has been linked to a variety of non-point sources including runoff from both agricultural and urban land uses. Soil P has been shown to be a source of P in runoff. The differences in soil P among different land uses may provide insight into which land use contributes more P in runoff. This study examines the soil composition, geochemistry and total P concentration of surface soil (0-5cm) in four land uses in Greene County, Missouri. The land uses sampled were residential lawns, city parks, agricultural pastures, and undisturbed forest. The amount of P extracted by de-ionized (DI) water from each land use was also examined. Total P concentrations for all land uses ranged from 250 to 1200 ppm P. Mean P concentrations did not differ significantly (α=0.05) among land uses. Total P was highly correlated with organic matter (OM) for all land uses, indicating that OM is both a significant source of P and a primary sink for P. Organic Matter was used as the primary variable for regression models predicting TP. A mean of 4.05% of the total P in lawns was extractable by de-ionized water. This is significantly higher (α=0.05) than the mean DI water extractable P in the other land uses. This suggests that lawns may contribute more P per unit area to storm runoff than the other land uses examined. The relationship of TP to the % of DI water extractable P was curvilinear for lawns, parks and forested sites indicating a maximum limit of P sorption by runoff water. However, the same relationship was linear for agricultural sites. 75% of sampled lawns had a TP concentration between 300 and 700 ppm. Within this range lawns can contribute a significantly greater percentage of P to runoff water.


© Timothy R. Davis

Open Access