عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Runoff causes soil loss and finally leads to sedimentation in water bodies. Water erosion as a selective process; generally removes the smaller components of soil particles with lower density. Organic amendments increase the soil infiltration rate and finally reduce the runoff and soil loss, but quantification of their effects on runoff parameters has less been attended. The present research was therefore conducted to study the effects of rice straw mulch as a conservation treatment on runoff threshold and coefficient for sandy-loam soils taken from the Alborz summer rangeland, north of Iran under laboratory conditions. Experiments were conducted by using straw mulch with an amount of 0.5 kg m-2 for simulated rainfall intensities of 30, 50, 70 and 90 mmh-1 and the slope of 30 %. Results showed that the straw mulch increased the runoff threshold and decreased the runoff coefficient significantly (p=0.01). The mulching treatment in the rainfall intensity of 90 mmh-1 with the amount of 110.10 % was the highest increase rate of runoff threshold compared with other intensities. The treatment of rainfall intensity of 30 mm h-1 had the lowest reduction rate of runoff coefficient with the amount of 19.36 %.