University of Tehran Press Iranian Journal of Soil and Water Research 2008-479X 51 6 2020 08 22 Study of Morphometric Characteristics of Gullies and Factors Affecting Gully Development in Dryland Farming Area in South of East-Azarbaijan Province Study of Morphometric Characteristics of Gullies and Factors Affecting Gully Development in Dryland Farming Area in South of East-Azarbaijan Province 1373 1384 75387 10.22059/ijswr.2020.277316.668141 FA Ali Reza Vaezi Associate Professor of Soil Science- Soil erosion and Conservation Ouldouz Bakhshi Rad Soil Science Department, Faculty of Agriculture University of Zanjan Journal Article 2019 03 18 Gully erosion is one of the most important types of water erosion, due to sediment production and severe soil degradation. There is a few information on development of gully erosion in agricultural rainfed areas. This study was carried out to investigate the relationship among gully morphometric characteristics and to find out the effect of land factors (gully length, slope, surface drainage area, land use and plough direction) on gully formation. Also, some conservation strategies for reducing soil losses were studied in a 900 km² agricultural area in south of Eastern Azarbijan province. For this purpose, 223 gullies were identified in the study area and some characteristics including length, width, depth, elevation difference between the two sides of gully, cross section area and volume, along with land factors consist of slope gradient of land and upland, slope length, surface drainage area, and management factors (land use and plough direction) were determined. Based on the results, gullies have developed in the areas with a drainage surface ranged from 1.5 to 45.1 ha and their length varies from 52 to 2088 m and the volume is between 150 and 35088 m³. Significant correlations are found between gully volume and length, width, depth, shape factor and cross section area. The length is the most important morphometric characteristics to explain gully volume in the lands. Gully development is directly affected by land’s factors including the elevation difference between the two sides of gully (r= 0.51), surface drainage area (r= 0.71), and length (r= 0.78), while it inversely affected by land and upland slope. The gully length is the major factor controlling gully erosion in the area. So that in long slopes, the longitudinal development of the gully and consequently the volumetric expansion of the gully is more. In such areas it is necessary to carry out soil conservation practices. Gully erosion is one of the most important types of water erosion, due to sediment production and severe soil degradation. There is a few information on development of gully erosion in agricultural rainfed areas. This study was carried out to investigate the relationship among gully morphometric characteristics and to find out the effect of land factors (gully length, slope, surface drainage area, land use and plough direction) on gully formation. Also, some conservation strategies for reducing soil losses were studied in a 900 km² agricultural area in south of Eastern Azarbijan province. For this purpose, 223 gullies were identified in the study area and some characteristics including length, width, depth, elevation difference between the two sides of gully, cross section area and volume, along with land factors consist of slope gradient of land and upland, slope length, surface drainage area, and management factors (land use and plough direction) were determined. Based on the results, gullies have developed in the areas with a drainage surface ranged from 1.5 to 45.1 ha and their length varies from 52 to 2088 m and the volume is between 150 and 35088 m³. Significant correlations are found between gully volume and length, width, depth, shape factor and cross section area. The length is the most important morphometric characteristics to explain gully volume in the lands. Gully development is directly affected by land’s factors including the elevation difference between the two sides of gully (r= 0.51), surface drainage area (r= 0.71), and length (r= 0.78), while it inversely affected by land and upland slope. The gully length is the major factor controlling gully erosion in the area. So that in long slopes, the longitudinal development of the gully and consequently the volumetric expansion of the gully is more. In such areas it is necessary to carry out soil conservation practices. https://ijswr.ut.ac.ir/article_75387_f6499ae3a40cc5a1bd3a4bbb1f46b2cd.pdf