Time variations of rainfall infiltration into the soil under the influence of soil initial moisture

Initial soil moisture has a major role in water infiltration during a rainfall event. The study was conducted to investigate water variations of infiltration as affected by initial moisture contents in different soil textures under the simulated rainfall. The study was performed in three soil textures (Loamy, Sandy loam and Sandy clay loam) with four initial soil moisture contents at three replications as a completely randomized design in a hillslope located. Twelve plots with a dimension of 60 cm × 80 cm were installed up to down in the hillslope. The plots were gravitationally saturated and soil moisture content was determined by weight method after 1, 4, 7 and 10 days. The plots were exposed to five simulated rainfalls with an intensity of 55 mm h-1 for 30 min and 10-day interval. Results indicated that soil moisture was affected by soil texture (Loamy, Sandy loam and Sandy clay loam) and the day after the saturated (1, 4, 7 and 10 days) of the plots (P<0.001). The average infiltration rate in the total rainfall period (30 min) was 30.5, 41.9 and 41.8 mm.h-1 in Loamy, Sandy loam and Sandy clay loam soil respectively. In turn, this was influenced by the soil moisture and also the coarse soil porosity.