Predicting soil erosion by water: RUSLE Application for Soil
Conservation planning in Central Rift Valley of Ethiopia
Abstract
In Ethiopia, research on soil erosion assessment has largely focused in
its cereal crop dominated subtropical and temperate highlands. This
study is almost unique since it has been carried in the semiarid and
arid lowland areas of pastoral economic belts of Ethiopia where little
research attention has been given. The RUSLE model is employed to
estimate soil erosion rates in the pastoral and agro-pastoral semiarid
lowland of the Afar region, Ethiopia. The RUSLE parameters were acquired
from meteorological, soil and satellite image data, group discussions
and field observation. The result showed that mean annual soil loss
rates varied from 0.5 on flatter slopes to slightly over 20 t ha-1 yr-1
on poorly vegetated areas. The study area was classified into very high
(>20 t ha-1 yr-1), high (10- 20 t ha-1 yr-1), medium (1
–10 t ha-1 yr-1), low (0.5 – 1 t ha-1 yr-1) and very low (0-0.5)
erosion risk categories. Areas with high (10 to 20 t ha-1 yr-1) and very
high (>20 t ha-1 yr-1) erosion risk parts of the study site
need to be prioritized for land management interventions. Areas which
require immediate land management account about 22.06% (473.9m km2) of
the study area. The severity of soil erosion was largely linked to high
soil erodibility, poor vegetation cover and lack of effective
conservation practices. Therefore, improving soil erodibility,
vegetation cover and implementing locally suitable soil and water
conservation technologies are recommended.