Current and future cropland suitability for cereal production across the rainfed agricultural landscapes of Ethiopia

Abstract

• Cropland suitability for major cereal crops in Ethiopia was modelled and mapped. • Changes in suitability are accompanied by altitudinal shifts and areal contraction. • Teff and wheat croplands are highly affected by climate change in lowland areas. • Cropland suitability is rainfall-sensitive in hyper-humid and semi-arid areas. • Suitability is temperature-sensitive especially at the lowest and highest altitudes. One of the major challenges posed by climate change in agriculture is the alteration in cropland suitability. This alteration has serious consequences for food security and economic stability at global, regional, and local scales, especially in smallholder and rainfed agricultural systems like in Ethiopia. A comprehensive understanding of the current state of croplands and future changes under warming temperatures and increasing rainfall uncertainty is critical for national climate adaptation planning. Here, we evaluated cropland suitability (CLS) for four major cereal crops (teff, maize, sorghum, and wheat), under both current and future climates across the rainfed agriculture (RFA) landscapes of Ethiopia. We utilized a novel suitability modelling approach that establishes functional relationships between crop yield, and climatic factors (rainfall, temperature, and solar radiation) and soil factors (texture, pH, and organic carbon). Furthermore, we analyzed the relative influences of the growing season rainfall and temperature on the changes in CLS. The results show that 54 % of the RFA area has a suitability index of 0.6 or higher (moderately to highly suitable) for teff and that 51 %, 63 %, and 29 % of the grid cells are suitable for maize, sorghum, and wheat crops, respectively. The suitable agroecologies of the four crops will likely undergo altitudinal shifts and areal contraction, with magnitudes of the changes depending on the emission scenarios. Under the SSP2–4.5, the suitable areas are projected to decrease by 25 % for teff, 7 % for maize, 10 % for sorghum, and 16 % for wheat in the 2080s. In semi-arid and hyper-humid climates, CLS is sensitive to changes in the growing season rainfall, whereas in low and high elevation regions, it is temperature-sensitive. In light of our results, we argue that adaptation actions tailored to agroecological conditions and topographic locations are vitally necessary to mitigate the long-term impacts of climate change on Ethiopia's rainfed agriculture.

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