Impact of Global Warming on Water Requirement of Main Crops in Oasis Irrigated Area in Yanqi Basin

After simulating climate scenarios using incremental scenarios, the impact of future climate change on water requirement of winter wheat, summer corn and cotton in Yanqi basin was analyzed. The results showed that, (1) There was linearly proportional relationship between the crop water demand and increased temperature; when the future temperature rose 1-4 °C, the relative and absolute increase of water requirement of summer corn and winter wheat were more than that of cotton; the absolute and relative growth of water requirement of cotton was smaller. (2) In the different region, the relative increase of water requirement in Yanqi County was more than that of any other county; the relative growth of Hejing County is smaller 0.5%-47.21% than that of Yanqi County. The absolute increase of water requirement in Hejing County was the largest; the absolute increase in Heshuo County was the minimum, smaller 0.413-2.955mm than that of Hejing county. (3) Climate warming impacted on irrigation water demand of summer corn and cotton seriously, with the minimum impact on that of winter wheat. When the temperature rose 1-4°C, total irrigation water requirement in Yanqi basin increased by 6.02, 13.99, 20.87 and 28.17 ×108 m3. It can be seen that, it is appropriate to reduce summer corn planting area in the Yanqi basin, especially in Hejing county in the dry years.