|Freshwater Resources in Arid Lands (UNU, 1997, 94 p.)|
|4: Water resources and agricultural environment in arid regions of China|
In arid regions, water is one of the most challenging current and future natural-resources issues. For a sustainable agriculture and, hence, a healthy economy, water is the key to success. The importance of water in arid regions is self-evident indeed.
The arid regions occupy a vast area in north-western China that mainly includes the Alxa Plateau in the western part of Inner Mongolia, the northern part of Ningxia Hui Autonomous Region, most of Qinhai and Gansu provinces and the Xinjiang Uygur Autonomous Region - about 2.5 million km² or one-quarter of the Chinese territory. In these regions, mean annual rainfall is less than 250 mm, and even less in the western plains (50-150 mm) and the Taklimakan Desert (less than 25 mm). The annual evaporation is more than 1,400 mm in general, and about 2,000-3,000 mm in desert areas. Because of the arid climate, about 70 per cent of the total arid regions are unusable areas such as sandy deserts, gravel deserts, and other wildernesses. Although there are enough wasteland, light, and heat resources, the local economy depends only on irrigated agriculture and animal husbandry because of the limited water supply.
Water is not only the most precious natural resource in arid regions but also the most important environmental factor of the ecosystem. Human impact on the water supply will certainly cause a chain reaction within the ecosystem. Since ancient times, water utilization has always had a decisive impact on local socioeconomic development. But the increased intensity of human activities and overuse or misuse of water resources caused, and quickly spread, agroenvironmental degradation, including salinization, vegetation degeneration, and sandy desertification. Water resources are already under great pressure to support agricultural production in the arid regions and will face a much more difficult situation in the future. Therefore, understanding the relationships between water and environment, and water and development, and recognizing how to practice sound water management, are crucial subjects to study for sustainable agriculture and a stable environment in the arid regions.