Review Article

Soil and Water Conservation Nexus Agricultural Productivity in Ethiopia

Table 5

Impacts of SWC measures on soil moisture, soil loss reduction, and soil fertility improvement (Kirubel M and Ghebreyesus Brhane, 2011).

Land useSoil conservedMoisture conservationSoil fertilityErosion reduction

CultivatedTerraces filled by soil ranging from 0.2 to 0.90Yield increased by 25% while rainfall is similar to that beforeYield increment of 25% with some fertilizer inputFormation of rills and inter-rills decreased by 60%
Natural forestSoil deposition increased by 0.3–0.9 m after implementation of SWC measuresGreenness increased from time to time by 50% compared to before SWC implementationRegeneration rate of plant species increased by 5–58% depending on soil conditionsExpansion of gullies decreased by 95% compared to before SWC implementation
ReforestationErosion decreased but soil deposition increased by 0.3–0.9 m depthSurvival rate of seedling increased by 55%High survival rate of seedlings (increase of more than 55%)Rainfall droplets dissipated by soil cover increased
GrazingExtent of soil erosion decreased by soil deposit of 0.2–0.6 mGrowth and species diversity of grass increased by >30%Biomass of grass species increased by 65%Infiltration increased due to water stored in SWC measures
Area closureExtent of soil erosion decreased as evidenced by 0.3–1.2 m soil depth depositionGrass, trees, and brush biomass and diversity increased by 18–87% depending on slopeGrass, trees, and brush biomass and diversity increase by 18–87%No further new erosion channels were created or expanded
Marginal landTerraces were poorly maintained but contributed to soil accumulation of 0.1 to 0.4 m in depthPlant diversity and regeneration increased by 10%Plant diversity increased by 10% compared to before the programLow runoff amount decreased the number of erosion channels
GullyChecked dam accumulated soil with depth range of 0.4–1.5 mPlants spread for most of gully by 5–90%Plant growth rate was fast with highly diversified speciesLittle gully expansion and development were observed