Pressure of water shortage on agriculture in arid region of China

The arid areas in China are mainly located in North China and Northwest China. The North China is the main region for food production. There is 31.19% of the total farmland and 26.01% of the total population, but only 6.14% of the available water resources of China. Groundwater is over pumped (6.53×109m3 every year) in the regions of Beijing, Tianjin, and Hebei Province, so water supply could not meet the water demand there. The distribution of water in Northwest China is uneven, some inland rivers and lakes are dried up, and desertification has expanded since river water in the upper and middle reaches is diverted for irrigation. Up to 2050, population will be up to 1.6×109 in China, and industry will be developed fast, therefore 50% of the water supply will be used by industry and resident, and water for agriculture will be decreased year by year. In the coming 50 years, water demand for agriculture will be increased by 5.6×109m3 in the Huanghe (Yellow) River valley, and by 1.7× 109m3 in the Northwest China. It will be impossible for the Huanghe River to meet the water demand, because it always dried up in the cold half year since 1984. To avoid water shortage of agriculture in the arid regions, it is necessary to divert water from the Changjiang (Yangtze) River in the south of China, and to use water efficiently. It is the best way to use drip irrigation in agriculture, recycle water in industry and resident use, and control water pollution. Otherwise water shortage in the arid regions will restrict the development of agriculture in China.