Simulating the impact of climate change on production of Chickpea in rainfed and irrigated condition of Kermanshah

Climate change as a result of increase in atmospheric CO2 concentration and other greenhouse gases may have major effects on productivity of crops in future. The objective of this study was to evaluate the effect of climate change on growth, yield and water consumption of chickpea under rainfed and irrigated conditions of Kermanshah. The studied scenarios were (1) doubling CO2 concentration (i.e., 700 ppm), (2) 4°C increase in temperature, (3) 2% reduction in the amount of precipitation, and (4) a combination of 700 ppm CO2, 4°C increase in temperature and 2% reduction in precipitation. Simulations were done using SSM-Chickpea model for the mentioned scenarios. Simulation results showed that climate change will cause 89% increase in grain yield under rainfed condition and a 33% decrease under irrigated condition. Although increasing concentration of atmospheric CO2 had directly positive effects on yield of chickpea, but it was found that increased temperature was more important. Water use efficiency enhanced by 81% under rainfed condition, but decreased by 25% under irrigated conditions. In addition, crop life cycle is shortened due to increase in temperature. According to the simulation results, the amount of required water for irrigated chickpea is reduced in the future. It was concluded that due to limitation of agriculture water, irrigated chickpea will be less profitable in the future; although area under irrigated chickpea is very low now.