5 years ago

Die Wirksamkeit von Boden

Die Wirksamkeit von Boden

Literature review 2.2

Literature review 2.2 Bio-physical conditions and economy of Ethiopia Ethiopia has a diverse geographical setup, and as a result it has a wide range of biophysical conditions such as geology, water resources, soils, climate and biodiversity (Tefera et al. 1996; Hurni 1998; Awulachew et al. 2007; Coltorti et al. 2007). For example, the country has geological formations of three categories namely sedimentary, volcanic and metamorphic rocks (Tefera et al. 1996). The topography ranges from depressions below sea level at Danakil to high mountains like Ras-Dashen and other landforms such as plateaus, plains and valleys (FAO 1984; Tefera et al. 1996; Coltorti et al. 2007). As a result, the climate ranges from extreme arid to humid (NMSA 1996; Hurni 1998). Based on agricultural and ecological characteristics, the country can be classified into five agro-ecological zones, i.e., Berha (arid), Kolla (warm), Weyna-Dega (mild), Dega (cool) and Wurch (cold) (Hurni 1998). The climatic, geological and topographic variability has led to diversified soil types. According to the FAO system of soil classification, more than 18 major soils types have been reported (FAO 1984). The climatic differences have favored a wide bio-diversity (Asefa et al. 2003; Oba et al. 2006; USAID 2008). Thus, Ethiopia is endowed by more than 6000 plant, 280 mammal, 861 bird and 201 reptile species (USAID 2008). It also has a wide range of crop types and a large livestock population of different species. However, only 14% of the land is arable (World Bank 2011). Due to the climatic and geomorphologic conditions, the country has ample ground- and surface-water potential. As a result, Ethiopia is regarded as the water tower of Africa (Awulachew et al. 2007). The potential surface and groundwater and irrigable land is estimated at about 122 billion m 3 and 2.6 to 6.5 billion m 3 , and 3.9 million ha, respectively (Awulachew et al. 2007). Despite the bio-physical resource potential, Ethiopia has been facing a challenge due to land degradation. The land degradation has mainly resulted from improper resource management and traditional agricultural practices (El-Swaify 1997; Lemenih et al. 2005; Nyssen et al. 2009). Deforestation and vegetation clearance were very high to fill the demand for additional cultivable and grazing lands (Puhr and Donoghue 2000; Dubale 2001; Feoli et al. 2002). Replacement of forest and grasslands on marginal lands with cultivation is followed by severe erosion and soil quality deterioration (Richter et al. 1999; Fu et al. 2003; Fu et al. 2008; Kalinina et al. 2009). A large part of the farmlands in the highlands substantially lost its productive potential and 8

Literature review a considerable amount (4%) of land reached a point of no-economic-return (FAO 1986). Consequently, agricultural production declined at a high rate (Sonneveld and Keyzer 2003). Annual agricultural production growth is estimated to be about 1.4%, which is much below the population growth rate (2.6%). This indicates that an over twofold gap exists between food demand and agricultural production (Sonneveld and Keyzer 2003; Bingxin et al. 2010; Spielman et al. 2011). Thus, agricultural production rate has to grow from the current level to 3.6% (Sonneveld and Keyzer 2003). 2.3 Agriculture and its challenges in Ethiopia Ethiopia is an agrarian country on which the economy mainly depends. Agriculture provides 47% of the gross domestic product (GDP), 80% of the employment and 60% of the export commodity (World Bank 2011). Agriculture is mainly in the highlands and is predominantly based on mixed-crop-livestock farming (Haileslassie et al. 2005). The crop and livestock production provides food and export commodities. Of the agricultural product, coffee is the first, and hides and skins are the second main export commodities. Crop and livestock productions support each other, i.e., livestock provide draft power while crop residues are used for livestock feed (Belay and Abebaw 2004; Haileslassie et al. 2005). This is very important for the livelihood and economy of the country (Belay and Abebaw 2004). Generally, the Ethiopian agriculture is characterized by low productivity (Spielman et al. 2011). Crop yields under farmer cultivation are over 50% less than those obtained under improved conditions (Belay and Abebaw 2004). Although chemical fertilizer import increased from 250,000 metric tons (MT) in 1995 to 400,000 MT in 2008, the national average use is only 29 kg ha -1 which is mainly used for cereals. The total grain production grew from 5.5 million MT in 1992 to 17 million MT in 2008, but the grain yields increased only by 0.3 MT ha -1 during this period, i.e., from 1.1 MT ha -1 to 1.4 Mt ha -1 (Spielman et al. 2011). This indicates a low input rate and crop production. Similarly, the livestock sector is also characterized by low productivity (Belay and Abebaw 2004). Low crop and livestock productivity has been attributed to different constraints. Crop production is constrained not only by low input utilization and low technology level but also by land fragmentation and soil erosion (Bingxin et al. 2010; Spielman et al. 2011). In spite of soil nutrient depletion due to soil erosion and crop 9

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