EFFECT OF SOIL SLOPE AND RAINFALL CHARACTERISTICS ON PHOSPHORUS IN RUNOFF

Effects of soil slope length, degree of slope, soil cover, and storm size on soluble P released to runoff were investigated under controlled conditions. These effects were related to a simplified kinetic model, presented earlier. An increase in slope length from 33 to 100 cm increased the average P released per unit area of soil. An increase in percent soil slope also increased the P release, directly proportional to slope between 4 and 16%. Soil covers, simulated by different-mesh screens, decreased the P release. The effects of soil covers on P release increased with an increase in soil slope. The storm-average P concentration of runoff decreased logarithmically with an increase in storm size.