Analyzing the Influences of Cropping Calendar on Wheat Water Requirement in Sistan and Baluchestan Province under Climate Change

Global warming is a one of the most important natural hazard in the current world which could affect crop yields through affecting plant physiology¡ soil water balance and crop water requirement via green and blue water. Under such circumstances¡ achieving water and food security through an optimal usage of water resources and maintaining crop yield level requires measures for adapting with this major environmental challenge in the future periods. Since wheat and its produces has a the most important share in peoples’ food diet¡ the climate change effect on wheat cropping calendar and its water requirement in Sistan and Baluchestan province was investigated in this research. Also¡ the influence of managing sowing date on diminishing the negative effects of this global event was assessed. After calibrating and validating LARS-WG¡ the climatic variables in six synoptic stations of Zabol¡ Zahedan¡ Iranshahr¡ Saravan¡ Khash and Chabahar were downscaled under three scenarios of A1B¡ A2 and B1 of HADCAM3 model up to 2100. Crop water requirement was calculated by determining suitable crop cultivation periods based on cardinal temperature and determining the length of initial¡ developing¡ mid-season and late-season stages based of growth degree day coefficient. Climate change decrease the length of different growth stages by 1-20 days due to significant temperature increase which led to 0.03-42.7 percentage decrease in wheat water requirement. Although delaying wheat cultivation will intensify the climate change effects and shorten the growing period by 12-25 days¡ water requirement will increase by 1.27-778 M3 ha-1. Based on the results¡ the management ofwheat cultivation calendar can be effective way to achieve sustainable agriculture under future climate condition of the Sistan and Baluchestan province.