Abstract: Potato is the dominant crop in Inner Mongolia, its growth and yield is mainly restricted to water conditions. Studying the distribution of precipitation in Inner Mongolia and water requirement rules during potato growth period can provide the basis for the rational distribution of potato producing in Inner Mongolia and rational utilization of water to achieve stable yield. Based on the daily meteorological data of 46 meteorological stations from 1961 to 2010, authors calculated the effective precipitation and its distribution in Inner Monglia, evapotranspiration(ET) during potato growth period and irrigation amount in different rainfall years. The results showed that the effective precipitation was 25-240mm during potato growth period and its spatial distribution was non uniform. ET was 300-700mm and 400mm ET contour started from northern Hulun Buir, across northern Xilin Gol league, east to Hinggan league. As for the irrigation amount,there was an increasing trend from east to west and the irrigation amount contours were distributed by longitude. Hulun Buir and northern Hinggan league, east to the 1500m3/ha irrigation amount contour, were suitable for planting potato, where effective precipitation could basically meet potato water requirement in normal years. On the other hand, it was not suitable for planting potato in western and northern Inner Mongolia, where effective precipitation was insufficient to support potato producing. Compared to normal years, dry years had less precipitation and more ET, and the potato irrigation amount increased by an average of 40.4%.

Key words: Inner Mongolia, Potato, Effective precipitation, Irrigation amount