Abstract
We developed a crop yield model in order to estimate the present and future rice yield, evapotranspiration, and irrigation requirements of a paddy field in Matsuyama city, Ehime prefecture at regional scale, and to also assess the climate change impact on its rice yield and water balance. The results show that 1) irrigation water requirements increased by 30% due to the precipitation decreased in the future summer, 2) the yield increased by 34% due to CO2 fertilization effect (ex, promoting photosynthesis), while the transpiration rate from the rice plants decreased by 15% due to the water stress for stomatal closure, 3) if bring the transplanting date forward from the present to about one month, it may be possible to effectively use the water resources while maintaining the paddy yield.
