Journal of Environment and Earth Science www.iiste.org ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online) DOI: 10.7176/JEES Vol.9, No.5, 2019 14 Effects of Soil and Water Conservation on Selected Soil Physicochemical Properties and Its Implication on Soil Productivity in Ethiopia. A Review Leta Hailu Jimma Agricultural Research Center, PO box 192, Jimma, Ethiopia Abstract Soil erosion and land degradation have been a severe problem in the Ethiopian highlands due to dense population, high livestock density and intensive crop production in the area. Soil and water conservation practice is one the mechanism used to reduce soil and associated nutrient loss; thus, reduce the risk of production. Efforts were started through soil and water conservation strategy at a large scale on farmland since the mid-1970 and 1980’s. However, its effectiveness depends on specific site conditions. Therefore, reviewing the effects and implication of the soil and water conservation practices on selected soil physicochemical properties and soil productivity is essential. The study conducted in various part of the country showed that the implemented soil bund reduced annual runoff and soil loss at different rates. Soil and water conservation have improved the soil physicochemical properties on conserved cropland (BD, SMC, infiltration rate, clay content, pH, CEC, av. K, av. P, SOC and TN) than in the adjacent cropland without soil and water conservation measures. In contrast, the constructed soil and water conservation has shown no significant variations as compared to adjacent cropland in a study conducted at Dawuro zone, Southern Ethiopia. Soil and water conservation, reduce the removal of fertile topsoil and improves soil moisture, which favors crop growth as a result grain yield of the crops were increased at various rates based on agro ecology, crop type and local management practices. In general, the effect of constructed soil and water conservation had clearly showed positive impact on selected soil physicochemical properties and crop yields. Therefore, maintenance of the existing soil and water conservation structures is highly recommended to sustain its benefit, productivity and production; hence, improve the livelihood of the community. Keywords: land degradation, soil and water conservation, soil properties, soil productivity. DOI: 10.7176/JEES/9-5-02 Publication date:May 31 st 2019 1. Introduction Agriculture contributes substantial role in the Ethiopian economy (MoFED 2010). It creates employment opportunity for about 83-85 percent for the community and contributes 43-50 percent for growth and domestic products (GDP) and 90 percent of the total foreign exchange earnings. It also provides about 70 percent of the raw materials for different industries in the country to realize the agricultural-development-led industrialization strategy. Furthermore, the role of gender in agricultural system is critical, women contributes as much as 70 percent of on-farm labor (Awulachew et al. 2006, MoARD 2010). ` The majority of the population of the country is inhabited in a rural highland area where heavily depends on subsistence farming with no or low management of farmland that exacerbate soil erosion and land degradation. Small holder farmers are predominantly responsible for producing about 90 percent of the agricultural production (Awulachew et al. 2006 Gebreyesus & Kirubel 2009; MoARD 2010; Birhanu 2014). Nevertheless, much of the land is degraded in sub-Saharan Africa, particularly in Ethiopia, where poor farmers highly depend on land for their livelihood improvements (Nkonya et al. 2008). Soil erosion and land degradation have been increasing in Ethiopian highlands due to the existence of arable land (90 %), high human population (90%) and livestock density (60%) which resulted in natural resources degradation (Hurni et al. 2010; Darley 2015). This is a noticeable environmental concern that results in declining agricultural productivity, food insecurity and rural poverty (MoARD 2010; Gashaw et al. 2014; Kirui 2016). Moreover, the loss of soil has dramatically reduces land productivity and biodiversity; and also disturbs downstream water quality through sedimentation and eutrophication. Thus, it affects ecosystem health and service that many people depend on for their livelihood (Darley 2015). Soil erosion is predominant on arable land, in which the average annual soil loss is estimated to be 12 t/ha/year. It ranges up to 300 t/ha/year on steep slope fields and low vegetative cover area (Demeke 2003). This loss of soil from arable land is associated with the loss of nutrients and soil moisture that affects food production and worsens poverty. That contributes to the inability of investing in natural resource conservation and hinders sustainable development of the agricultural sector (Kirui 2016). Consequently, adoption of soil and water conservation is necessary to limit the soil loss to a tolerable level (11 tons ha -1 yr -1 ) (Morgan 2005; Tulu 2011). Soil and water conservation practice is a mechanism of reducing the soil loss and risk of production that has brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by International Institute for Science, Technology and Education (IISTE): E-Journals