Soil acidity under multiple land-uses: assessment of perceived causes and indicators, and nutrient dynamics in small-holders’ mixed-farming system of northwest Ethiopia

Abstract

Knowledge on farmers’ perspectives is of paramount importance in order to design appropriate agricultural research and development interventions attuned to local farming systems. A participatory rural appraisal was conducted in order to understand perceived causes and indicators of soil acidity under multiple land-uses in three Districts of northwest Ethiopia. Soil samples were also collected from five dominant land-uses. The samples were analysed for soil pH, exchangeable acidity and other physico-chemical properties. The result indicated that the pH(H2O) of most of the soils in the study sites were in a strongly acidic range (4.6–5.5). Gashena Akayita of the Banja District was the most acidic of all. Among the land-uses, eucalyptus fields were the most acidic followed by crop outfields and grazing lands in that order. At all the study sites, exchangeable Al was detected in soils having a pH of less than 5.0. Overall, the nutrient dynamics showed variation across land-uses and study sites. Farmers’ perceived causes of soil acidity included: soil erosion; contending use of fertility replenishing local resources; abandoning traditional fertility management practices and minimal use of external inputs. The farmers attributed the exclusive use of acid-forming inorganic fertilizers to exhaustion of the soil. Various land and soil characteristics, plant growth attributes, changes in genetic diversity were mentioned as indicators of soil acidity. Particularly, the farmers used prevalence of acidophilic weed species on crop fields and grazing lands as marker of strongly acidic soil. Farmers’ perceived causes and indicators were in agreement with scientific facts and can be utilized as input in designing sustainable acid soil management strategies. Decline in genetic diversity of the once widespread crop species and land races, and expansion of newly introduced soil acidity tolerant species, suggests the need to undertake rescue collections in these areas.

Keywords

• ethiopia
• farmers’ perception
• participatory rural appraisal
• soil acidity