Effects of Aggregate Diameter on Soil Splash under Laboratorial Conditions

Splash, as an important step in the erosion process of the soil, detaches and prepares soil particles to be transported by runoff. The amount of splash depends on various characteristics of erosive factor (rainfall) and erodible surface (soil). Aggregate characteristics, which have been considered in soil erosion researches, are among the main effective soil factors on splash and erosion. Therefore, the present study was conducted to assess the variation of soil splash in various aggregate diameters (1.75, 3.55 and 5.18 mm) for a sandy-clay-loam soil from the Kojour watershed. All the data was collected using splash cups with the slope gradient of 18 percent under the rainfall simulation with the intensity of 80 mm h-1 and duration of 18.28 min in three replications for each aggregate diameter treatment. Although the results indicate that the upslope, downslope, net and gross splash parameters decrease with increase of aggregate diameter, none of these changes were significant. The maximum and minimum decreasing ratios in the splash parameters belongs to the net (83.75 percent) and upslope splash (72.55 percent), respectively. The results also show that when the aggregate diameter increases 2 and 3 times, the amount of the net splash decreases 57 and 84 percent, respectively