By Zablon Adane and Tinebeb Yohannes
Soil loss and degradation in Ethiopia threaten livelihood security and economic growth. These challenges are gaining long overdue attention particularly as global fertilizer prices rise and farmers’ access to agricultural inputs diminishes, partly because of the Russia-Ukraine conflict.
Experts estimate that more than 85 percent of land in Ethiopia is moderately or severely degraded. Degradation and associated soil loss are particularly pronounced in the highlands across the country. The scope of the challenge has tremendous implications for water and food security, as well as the country’s ability to adapt to a changing climate. The annual cost of land degradation attributed to land use and cover change in Ethiopia is estimated to be about $4.3 billion USD, roughly equivalent to the total Ethiopian exports in 2021.
When soil is healthy, it offers a variety of benefits to communities and ecosystems including agricultural productivity, availing nutrients and habitat to support biodiversity, water availability, and sequestering carbon. For example, the Earth’s soils contain about 2,500 gigatons of carbon, which is a greater amount than the carbon contained in the atmosphere and all biomass combined. Soils also remove about 25 percent of global fossil fuel emissions each year, helping to mitigate climate change.
Soil deterioration in Ethiopia is mainly driven by the pressure of a growing population combined with poor land conservation practices. Lack of proper land conservation is manifested through widespread deforestation, overgrazing, cultivation on steep slopes, and unsuitable farming practices that erode soil. Aridification and rainfall intensity related to climate change also stand to exacerbate soil losses with great consequences to livelihoods and socioeconomic development.
While soil benefits for food production related to nutrient availability are more recognized, contributions towards water quality, availability, and flow regulation are often overlooked. Scientists estimate that soils on earth hold nearly 8 times more water than rivers flowing around the world. Because soils act as a sponge, rainfall is stored in near-surface soils and within the deeper soil profile, protected from the direct impact of atmospheric demand and evaporation. The moisture within the soil profile can be accessed by plant roots and is particularly critical in drier periods. This has significant implications in overcoming drought shocks and periodic water shortages.
Healthy soil also supports greater availability of shallow and deep groundwater. Groundwater provides more than 90% of domestic water supply in Ethiopia and has become increasingly threatened. Unavailability of shallow groundwater is especially concerning to rural households. Depending on suitability, soils support greater rainfall infiltration and percolation, which result in higher groundwater recharge rates and faster aquifer recovery for water-stressed regions. In many parts of the country, soil and land degradation has greatly contributed to severe groundwater depletion. Dire Dawa City is a prime example of this phenomenon where in less than three decades, its groundwater well fields have declined from 100 meters to 600 meters in depth.
Through their capacity to slow, store, and infiltrate water, soils are extremely effective in regulating the flow of water and reducing floods during heavy rainfall events. With significant parts of Ethiopia naturally exposed to flooding risks, soil and landscape degradation upstream puts downstream communities at risk of increased flooding. Dechatu River, in eastern Ethiopia, is an example of a naturally flood prone area where the risk of flashfloods has intensified due to severe soil and landscape degradation upstream.
Because hydropower generates over 90% of energy in Ethiopia, soil erosion has significant consequences on power production. Degraded catchments result in increased siltation and sedimentation of hydropower reservoirs. A recent study by the World Resources Institute estimated that siltation from the Gojeb Watershed has the potential to reduce the lifetime energy revenue from the Gilgel Gibe III Hydropower Plant by $698 million USD. Moreover, irrigation schemes like the Koga Reservoir in the Upper Blue Nile Basin near Lake Tana, which provides water for over 6,000 smallholder households, are already facing premature and severe sedimentation challenges.
Municipal reservoirs in Ethiopia are also not immune to the impact of soil erosion. Siltation and sedimentation of reservoirs has intensified water shortages; increasing water treatment and maintenance costs, and reducing urban water resilience and adaptation capacity. In the case of the Gefersa Reservoir, which provides 25% of Addis Ababa’s water supply, the Addis Ababa Water and Sewage Authority estimates a significant decrease in storage capacity owing to severe soil erosion from settlement and cultivation in the upstream catchment.
Soil deterioration is not limited to soil loss – it contributes to desertification, landslide and flood, increase in pollution and can cause reduction in soil quality. Healthy soils consist of minerals, organic matter, water, and air. Soil parent material is attributed to be the main source of soil acidity in Ethiopia, but the widespread use of acidic agricultural inputs, combined with the decomposition of organic matter has contributed to the high level of soil acidity. As a result, 43 percent of the land cultivated in Ethiopia is affected by soil acidity with significantly lower capacity to support agricultural productivity.
Salinity is also affecting soil quality particularly in arid parts of Ethiopia with low rainfall and high evapotranspiration rates. Accumulation of water-soluble salts like sodium (Na+) and chloride (Cl−) on surface soils has caused soil salinity in over 11 million ha of land. By inhibiting the absorption of water, salinity causes reduced productivity, limited nutrient availability, and even toxicity to several crops.
Deteriorating water quality reduces the availability of clean drinking water. Agricultural input like fertilizers and pesticides as well as contaminants related to waste have affected water quality across Ethiopia. The different layers of the soil profile and pore sizes act as water filters, providing much needed protection from contaminants and bacteria originating from the surface. In the absence of this protection, water borne illnesses like cholera and diarrhea, which are the leading causes of deaths in Ethiopian children under five years old, stand to get worse.
Short term solutions to address soil quality degradation include leaching to drain salts and other pollutants, application of agricultural input to improve soil fertility, liming to reduce acidity, and chemical treatment for biological contaminants. However, proper and informed soil, land, and water resources management is the better approach for a more sustainable ecosystem and viability of the environment and its services. At the local level, supporting sustainable land management practices such as terracing, crop residue management, and agroforestry can provide significant benefits in maintaining soil stability, soil quality, and land fertility. This requires greater investment to create awareness of the relationship between resources management, land degradation, soil loss, and livelihoods among resources managers and the community.
At the national and regional level, developing effective land use policies, boosting restoration activities, and enforcing buffer zones and land enclosures to protect land degradation can have lasting benefits to soil and water conservation, agricultural productivity, and food and energy security in Ethiopia.
Soils are essential for sustainable livelihoods and vitality of the environment. Promoting effective soil, water, and land resources management is a critical step to ensure food security in Ethiopia. As we observe the World Soil Day on December 5, sincere commitment by the Government of Ethiopia, private sector, development partners, and communities to protect our soil, water, and land resources will help reduce risks to food security, livelihoods of all Ethiopians, and sustainable development of the country.
Zablon Adane is Associate, World Resources Institute. Tinebeb Yohannes is Associate, World Resources Institute.