Comparative analysis of soil erodibility factor in Shazand Watershed

Soil erosion is related with different soil characteristics, measurements and its calculations. The soil erodibility factor (K) is one of the important factors in determining soil erosion. Different methods have been developed to determine of K using empirical models or field measurements. Currently, widely used equations that estimate K based on soil basic properties including soil texture, organic matter, structure, and permeability. Therefore, in this study, three commonly equations were used to estimate of K in Shazand watershed such as Wischmeier and Smith (1978), Romkens et al. (1986), Torri et al. (1997 and 2002) with K1, K2 and K3, respectively. In this regard, field sampling was done at 140 points of Shazand watershed with an area of 1740 km2. The Shazand watershed has limestone with low organic matter and medium texture. In the following, one-way ANOVA was used to analyze of K1, K2 and K3 results under the impact of different slope and elevation classes and different land uses, as well as Kriging's method for generation their spatial pattern. The results of one-way ANOVA showed that K1, K2 and K3 influenced by different slope and elevation classes with a significant difference (P< 0.05). But they had no significant difference (P ≤ 0.318) in different land use. Also, the average of K1, K2 and K3 was calculated to be 0.054, 0.039 and 0.035 t ha h ha-1 MJ-1 mm-1 respectively.