Abstract
It is essential to assess the crop growth state because the agricultural water usage is dominant to total water consumption whole the world. One crop model which is written by empirical formula and another crop model which is described by the basis on physiology are successfully coupled with the land surface scheme, SiBUC to assess the climate change impact on irrigation water requirement by MRI-AGCM3.2S. Simulated irrigation water requirement is larger than the statistic water withdrawal so the change tendency of irrigation water requirement by climate change is analyzed. It is assumed that the empirical crop model could be representative of crop which has shorter growth period and the physiological one could describe longer term crop growth.
