Assessment of future climate change impact on rainfed wheat yield in the semi-arid Eastern High Plain of Algeria using a crop model

Abstract

Maintaining sustainability in rainfed wheat production under changing climate is a grave concern for food security in Algeria. This study aims to assess the impact of future climate change on rainfed wheat yield in the semiarid Eastern High Plains (Setif and Bordj Bou Arreridj (BBA)) in Algeria using AquaCrop model. For this purpose, the EURO-CORDEX climate projections by 2035–2064 and 2065–2094 were downscaled using ICHEC_KNMI model under two representative concentration pathway (RCP) scenarios RCP 4.5 and RCP 8.5. The crop model predicted wheat yield increase by 82–95% and 77–118% at Setif and by 8–16% and 133–135% at BBA under the RCP 4.5 (2035–64 and 2065–94) and RCP 8.5 (2035–64 and 2065–94) scenarios, respectively, compared to the yield of the baseline period of 1981–2010. Future yield improvement is due to the fertilizing effect of the elevated carbon dioxide (CO2) concentration in the atmosphere, which offsets the negative impacts of rising temperature, decreasing precipitations and the net solar radiation. The expected increase in yield is much higher under RCP 8.5 compared to RCP 4.5 because CO2 concentration is higher under RCP 8.5. The model predicted an increase in wheat water productivity because of the expected decrease in evapotranspiration losses. To adapt rainfed wheat to future climate change in the study area, early sowing in mid-October provides better yields because it allows the wheat crop to take more benefits from increased precipitation during the vegetative development stage and to avoid the spring warming temperature.