Temporal variation of interrill erosion under different rainfall intensities in semi-arid soils

Interrill erosion can change during rainfall due to change of soil conditions. This research was carried out to investigate the temporal variation of interrill erosion in different soils under different rainfall intensities. For this purpose, laboratory experiments were carried out in three soil textures consists under three simulated rainfalls under slope of 10 percent in three replications. In total, twenty seven experiments were stetted up according to completely randomized design in in soil erosion lab. The interrill erosion was measured using measurement of soil loss mass at 1 min intervals from beginning of surface runoff production. The results showed that there are significant differences between the rainfall intensities in the time threshold of surface runoff and interrill erosion and their rate (P< 0.001). Significant relationship was found between interrill erosion and rainfall intensity (R2= 0.93, P<0.01). Interrill erosion increased during rainfall with the same trend with surface runoff production from beginning runoff, but after reaching to the maximum value (at 45th minute. As a consequence this study revealed that temporal trend of interrill erosion in most times of rainfall from beginning runoff can controlled by surface runoff rate and in final times it value is limited by the existence of erodible particles.