Résumé
The production of cereals in West Africa is constraint by several yield limiting factors such as poor soil fertility and erratic rainfall distributions and is largely dominated by smallholder farmers. Projected changes in climate thus poses a threat since crop production is mainly rainfed. In this study, two crop models; Decision Support System for Agro-technological Transfer (DSSAT) and Agricultural Production Systems sIMulator (APSIM) were calibrated, evaluated and used to quantify climate change impact on the yield of maize, sorghum and millet under future production systems in Nioro, Senegal and Navrongo, Ghana. Data on management practices (sowing dates, time and amount of fertilizer) obtained from household surveys, soil data, weather data (historical; 1980-2009 and 5 Global Circulation Models (GCMs); Mid Century time slice 2040 – 2069 for two representative concentration Pathway (RCP); 4.5 and 8.5) were used for the impact assessment. Temperatures were projected to increase in both study areas with higher temperatures for Nioro. Change in total rainfall amounts varied in Nioro with rains in Navrongo to remain same or increase slightly. Ensembled maize yield changes under RAP 4 were between -22 to -1% in Nioro, and -19 to 0 in Navrongo for DSSAT and APSIM respectively. The impact of climate change on sorghum and millet were lower than those of maize. Yield reductions under RAP 5 were generally higher than under RAP 4. The extent of yield loss varied among households due to differences in management practices and soils. There is need to explore potential adaptations to reduce yield loses.