Water-Saving Innovations in Chinese Agriculture

Water scarcity, water pollution, and water-related waste threaten humanity globally, largely due to the limited supply of freshwater on the planet, the unbalanced distribution of water resources, and the excessive consumption of water from the growing population and its economic development. China is facing severe water shortages; the northern part of the country has an average freshwater availability of 760 cubic meter per capita per year, 25% below the internationally accepted threshold for water scarcity. Agriculture in northwest China relies on annual precipitation of 50-500 mm, 70% of which occurs from July to September, and annual evaporation from 1500 to 2600 mm. In the Hexi Corridor regions where annual precipitation is below 150 mm, farming largely depends on irrigation with water from Qilian Mountain snowmelt. However, permanent snow on the mountain has moved upwards at a rate of 0.2-1.0 m annually, and groundwater in the valley has declined at a rate of 0.5-1.8 m year(-1). Consequently, some natural oases, along the old Silk Road, have shrunk or disappeared and wells have dried up. At the meantime, some farms use irrigation water at a rate as high as 11,000 m(3) ha(-1), much greater than crop water requirements for high yield. In recent years, many innovative research projects have dealt with the water issue in arid and semiarid northwestern China. In this chapter, we summarize some key water-saving technologies developed from some of these recently completed research projects, and discuss integrated and innovative approaches for the development of water-saving agricultural systems. Our goal is to encourage the use of innovative water-saving technologies to reduce agricultural water use, increase crop water-use efficiency, and improve agricultural productivity.