Soil serves as one of the most vital natural resources in every country. Nowadays, soil erosion is found to be a hazard for human welfare and even his life among others. Gully erosion as a most common soil erosion can reduce soil fertility and land utilization, damaging roads, constructions and building substantially. Gully is a steep channel with abrupt erosional head created as a result of alternate surface stream flow action. The present research was aimed to investigate determinant factors affecting gully erosion in study sites of Jushghan and Kamu located at Kashan sity in Karkas Mountains from October 2012 to April 2013. The principle goal was determination of factors affecting on gullies regression. For this, the number of five gullies were selected and their profile was drawn. Soil samples were taken from head walls in three horizons. Soil properties of texture, EC, saturated moisture, PH, Ca and Mg, So 4 , organic matter, Na and soil component percent in every horizon, gravel percent, aggregates mean weight and sodium adsorption ratio were measured.in addition, relationship between gully length and its volume and its thresholds were calculated. Results showed that the largest number of gullie were recorded in Neogen era and Shemshak formation was related to Jurassic period so that all of them were located at three land uses of rangeland, agriculture and irrigation. Results did not showed significant significance among gullies in different land uses. Of course, gullies regression rate varied in various land uses so that the highest and lowest rate was in rangeland and irrigation land uses with 54 and 9.5 cm respectively. While studying gullies frequency in slope justify; MARGIN: 0cm 0cm 0pt" dir=ltr Keywords: Gully backward, Ca and Mg, Na, average slope, soil texture, gravel percent, rainfall, drainage
