Fjölrit RALA - 05.12.1999, Blaðsíða 79

Tamirie Hawando
77
already significantly degraded. Of this area 14 million ha are badly eroded and if the
present trend of soil degradation continues, per capita in come in the highlands will
fall by 30% in 20 years time (FAO 1984). Fifty four percent of the remaining high-
lands are highly susceptible to erosion.
FAO (1984) reported that on two million ha of cultivated land, the soil depth is so
reduced that the land is no longer able to support any vegetative cover. The Hararghae
highlands in Eastem Ethiopia, Tigrai, Wollo, and Semen Shoa highlands in the North
and the Gamo-Gofa highlands and the Bila-te River basin, which starts in Eastem
slopes of Gurage highlands and stretches through Eastem Hadiya and Kembatta high-
lands, are some of the seriously eroded land surfaces in Ethiopia. The highland areas
in Ethiopia are defined and delineated to represent the land areas above 1500 m a.s.l.
and the lowlands are defined as areas below 1500 m a.s.l. in altimde.
More than 90% of Ethiopia’s population live in the highlands including about 93%
of the cultivated land, around 75% of the country’s livestock and accounts for over
90% of the country’s economic activity. Land degradation is seriously threatening the
economic and social development of the country as a whole. Due to degradation, in-
creasing number of Ethiopians have become vulnerable to the effects of drought. The
severity of the devastating droughts and the resulting famines in 1972/73 and 1984/85
can be attributed to an accelerating process of degradation combined with widespread
general poverty of the population.
Measurements of land degradation usually focuses on the severity of soil erosion
mainly caused by high-intensity rain storms on mgged geomorphic features, steep
slopes, and barren land surfaces highly susceptible to soil erosion. The wide spread
practices of buming dung, buming crop residues for fuel and for seed bed preparation
under state farm conditions, buming of forests and range lands, deforestation for culti-
vation, fuel wood and construction materials, as well as poor farming practices par-
ticularly in the areas practicing cereal mono-culture farming system and cultivation of
steep slopes, increase the susceptibility of the land resources to erosion in dry sub-
humid and semi-arid areas.
SOIL EROSION
Current rates of soil erosion documented in Ethiopia range from 16-300 tons/ha/year
(Humi 1988, Hawando 1989, 1995). The Ethiopian Highlands Reclamation Study
(FAO 1984) suggested the average annual soil movement of 100 tons/ha/year for the
Ethiopian highlands. The amount of annual soil movement (loss) by erosion is esti-
mated to range from 1,248-23,400 million tons per year from 78 million ha of pasture
and range lands and cultivated fields throughout Ethiopia (Table 2). When the average
value of 100 tons/ha/year of soil erosion rate suggested by FAO (1984) is used, the
average annual local movement of soil is estimated to be 7,800 million tons per year
from the cultivated and grazing lands of Ethiopia.