Comparison of sediment content in runoff and drainage water under two different slopes and cultivation types

Land cover type and slope are two dominant parameters in soil and water erosion intensity. Although many studies have been conducted to explore the effects of slope or vegetation cover on soil erosion, but the there wasn’t any report regarding comparison of their effects in sediment generation in run off or derange. The objective of this study was to comparison of sediment in surface runoff and drainage water under influence of cultivation type (Alfalfa and Wheat) and slope (5% and 20%) in a sandy loam soil. The laboratory experiments were conducted using a soil box with dimensions of 100 cm long, 30 cm wide, and 25 cm deep, with one soil drainage outlet and one surface flow outlet, packed with soil in Agricultural Faculty of Bu-Ali Sina University. The result showed that intensive vegetation cover (alfalfa than wheat) can considerably reduce the loss of soil erosion. As under alfalfa cultivation less sediment was observed than wheat cultivation in both runoff and drainage. The current results showed that sediment generation in runoff and drainage vary with slope; as under both alfalfa and wheat cultivations larger sediment was observed in 20% slope in runoff, whereas in drainage the higher amount was observed in 5% slope. The observation of slighter sediment after 60 minute of rainfall in runoff could attribute to the generation of a surface crust that encouraged runoff and reduced soil erosion. Although there were no significantly effects of land cover and slope on mean weight diameter, it was larger under alfalfa as a result of erosion-reducing effectiveness of plant covers.