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The enrichment of soil phosphorus in runoff sediments
- Sharpley, A.N.
- Journal of environmental quality 1980 v.9 no.3 pp. 521
- runoff, soil nutrients, phosphorus, sediments, water pollution, rainfall simulation, soil physical properties, soil chemical properties, slope, rain intensity, linear models, sandy loam soils, clay soils, kinetics, overland flow, prediction, soil erosion
- The effect of varying soil physical and chemical properties, soil slope, rainfall intensity, and source on the enrichment of soil P in runoff was evaluated under simulated rainfall conditions. The enrichment of P in runoff increased with increased P additions. The P enrichment ratio (ER) of Bernow soil increased from 2.43 to 6.29 at P additions of 0 and 100 kg P/ha, respectively. As rainfall intensity and soil slope were increased, ER decreased correspondingly. A significant linear relationship between in (ER) and in (sediment discharge) was obtained for all treatments studied. Similar slopes were obtained for soils ranging in texture from a fine sandy loam (-0.233, Bernow soil) to a clay (-0.264 and -0.252 for Houston and Pullman soils, respectively) under similar experimental conditions. In addition, the slopes were not affected by soil P status as slopes of -0.233 and -0.276 at 0 and 100 kg P/ha additions, respectively, were obtained for Bernow soil. With an increase in energy of runoff and kinetic energy of rainfall, a significant increase in slope of the relationship between In (ER) and in (sediment discharge) was obtained. In contrast, a decrease in energy of rain as in the case of overland flow and increased soil cover, resulted in a significant decrease in slope. The data indicated that runoff and rainfall energy and soil P status have a greater effect on ER than soil physical properties. A general relationship between ER and sediment discharge covering all treatments studied predicted ER values very similar to those measured in field studies and those predicted by a general relationship derived from field studies.