CHANGE OF SPLASH EROSION RATE IN RAINFALL DIFFERENT DURATION AND INTENSITY ON MARL SOILS

Splash erosion is recognized as the first stage in the process of erosion that results in bombardment of the soil's surface with rain drops. Two basic processes in soil erosion are the dispersement of soil particles by rain drops and the changes caused to the soil's structure, which are then moved by runoff. In this research, the effect of various rainfall intensity (60, 90 and 120 mm/hr) on the amount of splash erosion at three rain durations (10, 20 and 30 minute) by the use of laboratory generated rain (FEL3) were analyzed. Experiments were undertaken with marl soil. After calibrating the rainfall simulator, soil samples were weighed and were studied three rain intensity and durations. Initially samples were oven-dried for 24 hours, at 105ºC. Next, samples were reweighed to determine the amount of soil lost. According to the results, there was significant difference between rain intensity and durations and increased splash erosion. However the interaction effect of rain intensity and duration, were not statistically significant. The statistical analyzes showed when rain duration increased from 10 to 30 minute, the splash erosion enlarged in various rainfall intensity due to destruction of soil aggregates. The most of splash erosion was observed in rain intensity 120 mm/hr and rain duration 30 minute. Also, in rain duration 20 minute with each three rain intensities, due to existence of surface water layer, Although splash erosion increased but that was not statistically significant.