Map of Somodo watershed, Jimma zone, southwestern Ethiopia.

Agroecology and soil: Somodo Watershed is characterized by the Agroecological zone of Tepid sub-humid and mid-highland (SH3). The altitude of the study area ranges from 1900 to 2075 m.a.s.l. The long-term means annual rainfall of the watershed is 1954.3 mm with the mean temperature of 19.3°C ranging from 15.0 T min to 23.5 T max (Fig 2). Nitisols and Orthic Acrisols are the most dominant soil types of the area and Nitisols accounting for 64% of slightly acidic soil [17]. The textural class of the soil is sandy clay loam, while the pH is found to be strongly acidic [18].