Effect of Soil Physical and Organic Matter on Soil Erodibility in Duhok Dam Sub Drainage Basin

Abstract

Soil erosion is a barrier to achieving sustainable land use especially in semi-arid regions with multiple soil types. This work evaluates the soil erodibility factor (K) at twelve sampling locations in Duhok Dam (Kurdistan Region, Iraq), it investigates impact of key physical and chemical soil properties including bulk density, permeability, organic matter, textural and structural properties of these soil samples. Organic matter content and soil texture were found to be the major drivers for controlling K-factor under different land uses, according the sensitivity analysis. The sensitivity to erosion decreased with increasing clay content of the soils, while sandy soils suffered from greater susceptibility to the erosion because of their lower permeability. The k-values had been predicted by a regression model, which accounted for 98.66% of the total variance (R2 = 98.6%). The increasing of bulk density and permeability have variable effects on erodibility. A Study of various soil properties shows significant correlations between bulk density, erodibility (K), permeability and OM content indicating useful information about the behavior and erosiveness property of the soil. The positive relationship between erodibility and bulk density implies that denser soils are more easily eroded, possibly because reduced porosity in such soils results in increased surface runoff. It is also interesting to note that as the erodibility increases, the permeability of soils tends to increase; thus, with greater water movement in susceptible soils, detachment and transport of particles could be quickened. On the other hand, the soil bulk density had a negative relationship with organic matter content, which is evidence of the importance of organic materials for maintaining good soil structure and reducing compaction. This emphasizes the interdependence between soil physical properties and their joint impact on land degradation, and draws attention for integrated soil management strategies aimed at mitigating the risk of erosion in vulnerable catchments.