Soil Acidity and Its Management Options in Western Ethiopia: Review

Abstract

Soil acidity has become a serious threat to crop production in most highlands of Ethiopia in general and in the western part of the country in particular. An earlier study estimated that about 41% of arable lands of Ethiopia are affected by soil acidity/Al 3+ toxicity. But recently the status of most soil in western Ethiopia were became acidic though the degree varied from location to location; severely limiting crop production. In western Ethiopia acidification occurs simultaneously with other conditions including eroded topsoil and depleted organic matter, depleted nutrients, and alternating drought stress and high rainfall which is high enough to leach appreciable amounts of exchangeable basic cations. In moisture-stressed areas, acidification can also be caused by continuous application of acid-forming chemical fertilizers. As low pH affects the availability of nutrients particularly that of phosphorus and other macronutrients, correction of the low pH through liming, and/or application of organic materials is critical for sustainable management of these soils. Agricultural liming is proved a good way of correcting soil pH along with supplying calcium to the soil. Another potential organic amendment sources in coffee producing areas of western Ethiopia were coffee pulp and husk, by products from wet and dry coffee processing respectively. These coffee by-products are utilized in other coffee producing countries as soil amendments especially in highly weathered soils. While in Western Ethiopia enormous quantities are either dumped into streams or burnt in big piles, with contributions to environmental hazards. Therefore, farmers should be encouraged to increase productivity of the acidic soils by using lime and organic amendments which is easily available such as composted coffee wastes (coffee husk and pulp).

Soil pH mapping as a function of land use, elevation, and rainfall in the lake tana basin, northwestern of ethiopia

“…Sandy soils are often more acidic than silt and clay soils due to their strong infiltration and fast rate of penetration. In addition, due to their low content of clay and organic matter, sandy soils also have a limited supply of basic elements (Takala, 2019). It may take several years for the formation of new parent material to become acidic in places with high precipitation since the influence of precipitation on acidic soil growth is very sluggish on soils with different textures (Slessarev et al., 2016).…”

Effect of oil palm compost and sandy soil on the growth of cacao (Theobroma cacao L.) seedlings

“…Also, the high Al concentration in excessive doses of compost may restrict plant growth, photosynthesis, and nutrition (Arévalo-Hernández et al, 2022;Siecińska & Nosalewicz, 2016). The low effect on plant growth despite Al may be related to the higher concentration of Ca with increasing doses of compost and this element is known to reduce the stress generated by aluminum, reducing its activity in soils (Takala, 2019). Also, the higher concentration of OM reduces the acidity's activity by complexing Al (Lazicki et al, 2022).…”

Coupled Impacts of Soil Acidification and Climate Change on Future Crop Suitability in Ethiopia

“…As the impacts of climate change become more apparent, certain regions in Ethiopia, previously unsuitable for certain crops, are now becoming more suitable, while other regions that were once ideal for those same crops are now becoming less favorable [29]. Several studies have assessed suitability changes at the watershed [30][31][32] and country [29] scales, while other studies have investigated the dynamics of soil acidity in Ethiopia, considering the causes, the extent of the problem, effects on crop production and potential methods for amelioration [21,[33][34][35]. These studies stress the significance of climate factors and of soil quality in determining crop yields and production potential in Ethiopia.…”