**4.2 Soil Erodibility factor (K)**

K factor is the quantitative depiction of soil erodibility analyzed for a particular soil type. It basically is measure of soil particles susceptibility towards the impact of rainfall and runoff. The erodibility factor is mainly influenced by the texture of soil, soil structure, soil permeability and organic matter. For an individual soil type, K factor is particularly defined as the rate of soil erosion per unit erosion index measured by average unit plot of 22.13 m long. It chiefly determines the rate at which soil loss takes place per rainfall erosivity index (**Figures 5** and **6**).

## **4.3 Slope length and slope steepness factor (LS)**

Slope length or Steepness factor, The LS factor is the output of 2 individual factors combined together i.e. Slope length factor (L) and a Slope steepness factor (S), both of these factors were delineated using the ALOS PALSAR DEM. The LS factor proves to be an important parameter in the modeling of soil erosion risk in eastern Hindukush region.

L factor depicts the abrupt impact of slope on soil erosion. The soil loss increases per unit area as the slope length increase. Whereas, the S factor represents the impact *Spatial Quantification of Soil Erosion Using Rusle Approach: A Study of Eastern Hindu… DOI: http://dx.doi.org/10.5772/intechopen.112346*

#### **Figure 5.** *Soil content.*

of slope steepness on erosion. The rate of soil loss intensifies with increasing steepness of slope more than it does with length of slope. LS factor depicts erodibility because of slope steepness and length. It signifies the influence of topography, specifically slope features, on soil erosion. Hence, proving it to be directly proportional to the soil erosion for example, an increase in slope steepness and length marks an immense increase in the LS factor.

Slope length and steepness for the study area was calculated by utilizing an elevation model. The DEM was filled to fill all the depressions to get accuracy in the imminent analysis. When all the depressions or sinks formed because of erroneous data are filled, by assigning them the values of neighboring cells (**Figure 7**) [23].
