**Rainfall Erosivity Factor**

The erosivity factor *R* was calculated according to the equation given by Hurni [8], for Ethiopian conditions based on the easily available mean annual rainfall (*P*). *R* = −8.12 + 0.562\**P*; Where *P* is mean annual rainfall in mm. The correspondence R values of the four stations were calculated as follows in **Table 1**.

The above data with their location were used to generate a rainfall erosivity map using Arc GIS 10.3 Spatial Analyst, IDW Interpolation. The R-map was simply generated from the mean annual rainfall data.

#### **Figure 5.**

*Methodology flow chart of soil loss estimation using RUSLE. Variables like soil, rainfall, and slope, which have a great relationship with land degradation were analyzed at the same time to assess land degradation.*


**Table 1.** *RUSLE, R-factor.*
