In Press (Summer)
Back to the articles list |
Back to browse issues page
Jafar Karimi Shiasi 
, Farzaneh Fotouhi Firoozabad * , Ali Fathzadeh , Mehdi Hayatzadeh , Mostafa Shirmardi
, Farzaneh Fotouhi Firoozabad * , Ali Fathzadeh , Mehdi Hayatzadeh , Mostafa Shirmardi
Faculty of Agriculture & Natural Resources, Ardakan University, Ardakan, Iran , f.fotouhi@ardakan.ac.ir
Abstract: (4 Views)
The variability of the soil erodibility factor, or the soil’s resistance to particle movement, is one of the key components of the Universal Soil Loss Equation (USLE). This study aimed to investigate the spatial variability of the soil erodibility factor in part of the Dourahan watershed, located in Borujen County, Chaharmahal and Bakhtiari Province, Iran. To prepare the required maps, soil sampling was carried out on a systematic grid at 58 points from the 0–30 cm surface layer. Soil structure, organic matter content, permeability, percentage of coarse sand, very fine sand, and silt were measured. Spatial variability of the soil erodibility factor was analyzed using variograms and the nugget-to-sill variance ratio, and interpolation maps of the erodibility factor were produced using various methods (simple kriging, ordinary kriging, and inverse distance weighting). The accuracy of the maps was assessed using statistical error indices. Results showed that the soil erodibility index across the watershed ranged from 0.0148 to 0.0661 t·h·MJ⁻¹·mm⁻¹. The watershed’s erodibility index variability was classified as moderate. The best-fitted model for ordinary kriging was Gaussian, and for simple kriging it was spherical. Based on statistical error indices, ordinary kriging with the Gaussian model provided the most accurate estimation and was the most suitable method among those tested (RMSE = 0.01020). The erodibility factor zoning map indicated that the eastern part of the watershed is more susceptible to erosion, whereas the western part—due to mountainous landforms—had the lowest erodibility values. This pattern is primarily attributed to reduced soil permeability, increased silt content, lower clay content, and the presence of erosion-prone geological formations. However, the impact of external factors such as overgrazing in rangelands and degradation of vegetation cover should not be overlooked.
Keywords: Dourahan watershed, Soil erosion, Kriging, Inverse distance weighting (IDW), Universal Soil Loss Equation (USLE).
Received: 2025/08/24
Send email to the article author
| Rights and permissions | |
 |
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. |
