Evaluation of climate change effects and adaptation strategies on grain yield and water use efficiency of irrigated wheat (Triticum aestivum): A cae study in Khorasan Razavi province

Among the field crops in Iran, wheat is one of the most importance crops and it is anticipated that country demand to this crop will be increased in the future. On the other hand, to improve the resilience and efficiency of agricultural systems, it seems to be urgent to anticipate the effects of climate change (changes in CO2, temperature and rainfall) on crops particularly on wheat in arid and semi-arid regions. So, this study was conducted to simulate yield and water use efficiency of wheat in four locations in the future (2050)

In this research, future projection (2050) was conducted in four locations in Khorasan Razavi province (Ghoochan, Gonabad, Sabzevar and TorbateHeydariyeh), Iran by using long term climate data at baseline (2010-1980) under two emission scenarios (RCP4.5 and RCP8.5). Future climatic scenarios were produced using the delta scenario of the CMIP5 General Circulation Model (GCM) and the climate scenario generation tools in R as introduced in the Agricultural Model Intercomparison and Improvement Project (AgMIP). A Global Circulation Model (MPI-ESM-MR) was applied. APSIM-Wheat model was used to simulate growth, yield and water use efficiency of wheat. Regarding CO2 concentration, two scenarios were considered: CC scenario (climate change along with increasing CO2 concentration) and FC scenario (climate change without increasing CO2 concentration).

Simulated results showed that average of growth season temperature in study locations in future will be increased by 1.6 ºC and rainfall will be decreased by 5.85 percent, in comparison with baseline. In CC, the average of yield increased 4.91 percent under RCP4.5 and 4.77 percent under RCP8.5. However, in FC the average of yield decreased (except Gonabad) 4.98 and 7.56 percent under two RCPs, respectively. In addition, water use efficiency in CC increased by 12.21 and 15.35 percent for RCP4.5 and RCP8.5, respectively. However, under FC, WUE increased 0.33 percent for RCP4.5 and decreased 0.41 percent for RCP8.5. Also, the finding of this study suggested that changing sowing date as two weeks earlier in Gonabad and Sabzevar will increase yield and water use efficiency, and two weeks later in TorbateHeydariyeh will relief the decreased yield.

Results of the current study showed that if the climate change accompanied with increasing CO2 concentration, the negative effect of climate change on wheat growth and yield would be compensated Also, changing sowing date in future will have further positive impacts on wheat yield and water use efficiency.