Gully erosion is one of the important features of soil degradation which causes huge lose of soil and sediment yield in different climates. It often occurs in agriculture lands in Iran and therefore degrades much amounts of the fertile agricultural land and fill up the dams and reservoir by sediment as well. Owing to the important of gully erosion in Poldokhtar city located in Lorestan province, Iran . this research has been Conducted. The relationship between the volume of sediment and soil properties, climate factors, land use, slope and drainage was investigated. To achieve the study purpose, the area induced by gully erosion was designated and 15 axial, digitated and frontal gullies were recognized. The dimensions surveyed after six rains stormy occurred during the study period. These soil samples were also taken from the top, middle and subsoil in the gully bank, and soil properties such as Texture, Ec, Na, Ca, mg. SAR, CaCO3, CaSO4, Organic matter were Surveyed. The relation ship between land use and volume of sediment was studied using. Regression analyses and this analyses method were applied to find out the most effective factors on gully erosion. The results have shown the no significant effect of land use on gully sediment yield. The relationship between gully frequency and slope stages shown that digitated, frontal and axial gullies were located on 0-5%,5-10%and more 10% slopes. And the more than 10% slopes gullies have more sediment product and sediment yield of gullies have significant effect the axial gullies located on pabdeh formation and the others located on quaternary .and have more sedimentation. The sedimentation of texture in difference layers was silty loam, loam, silty clay and clay that texture in top, middle and sub soil have significant effect on sediment yield. The study of soil properties shown that a top soil properties such as clay% , SAR, sand%. And gravel have significant effect but the middle and subsoil properties not. The gully drainage area with a good regression coefficient was most important factor in sediment yield and among climate factors that affects on gully sedimentation is precipitation quantity with the regression coefficient 94%, the minimum amount of precipitation to provide the run off was 17mm.
