Evaluation of the Effects of Climate Change on Wheat Growing Period and Evapotranspiration Using the CERES-Wheat Model (Case Study: Mashhad)

Study of the climate change impacts on agricultural products and agro-climatic variables can improve the management strategies regarding to the agricultural demands in future decades. The objective of this study is to evaluate the effects of climate change on growing period and evapotranspiration of wheat inMashhad. In this study the LARS-WG model was used to simulate the weather data of Mashhad station under A1B, A2 and B1 scenarios in the time periods of 2011-2030 and 2046-2065. The effects of climate change on growing period and evapotranspiration of wheat was simulated by the CERES-Wheat model. The obtained results in this study show that the temperature will be increase however, rainfall is going to be decreased. The temperature and rainfall variations will be sever in the A2 scenario compared with the other scenarios. Also, the results show that the time interval from planting to full maturity of all wheat varieties will decrease in the future. Evapotranspiration will be increased in the period of 2011-2030 while it will be decreased in the period of 2046-2065 compared to the base period. The increase of evapotranspiration in the period of 2011-2030 in A1B, A2 and B1 scenarios will be 3.51, 1.75 and 3.8 percent, respectively and the decrease of evapotranspiration in the period of 2046-2065 in A1B, A2 and B1 scenarioswill be 4.09, 4.68 and 4.39 percent, respectively. In general, in effect of climate change, the growing period and then the total water requirement of the crop will decrease in the future. So the cultivars of crop with a shorter lifetime and having the higher yield must be used.