摘要:Field experiments were conducted at Sanganeh Research Station at North-east of Iran to determining runoff production, soil accumulated moisture and develop semiempirical model to determine the best plant row spacing for reclamation and optimum production of degraded rangelands under natural precipitation. Runoff production and soil accumulated moisture were determined in 80 experimental plot on different combination of soil type , vegetation cover and slop gradient, during autumn, winter and spring precipitations during 1996-2005. Results from 90 precipitation events with various magnitude and intensity indicated that, soil accumulated moisture was not considerable in September to November period and the amount of evapotranspiration was more than precipitation up to 6 fold. The average of soil accumulated moisture, evapotranspiration and surface runoff in winter were calculated around 64, 33 and 3% of precipitation, respectively. In spring, the average of evapotranspiration, infiltration and runoff were 62, 36 and 2% of the rainfalls, respectively. The resulted values for moisture accumulation in the soil and surface runoff on the experimental plots make it possible to estimate the potential deficit of moisture and assess the water supply of the plant. Experimental data was used to develop a semiempirical model for determining the best plant row spacing for optimum production and water requirement of pastures. Generally we concluded that there is a strong possibility for reclamation of eroded rangelands using surface runoff in arid and semi arid regions.