Xiping Deng
Institute of Soil & Water Conservation, Northwest A&F University
Water shortage in China, particularly in the north and northwest of China, is very serious. The region accounts for half of the total area of China, but has less than 20% of total national available water resources. While the water shortage in this region is severe, irrigation water use efficiency is only about 40%, with a typical agricultural water use efficiency of about 0.46 kg m-3. It is widely believed that an increase in the agricultural water use efficiency is the key to mitigating water shortage and reducing environmental problems. The Loess Plateau is a typical semiarid area that covers 640,000 km² in the upper and middle of China's Yellow River and China proper. The Loess Plateau was highly fertile and easy to farm in ancient times, which contributed to the development of early Chinese civilization around the Loess Plateau. Centuries of deforestation and over-grazing, exacerbated by China's population increase, have resulted in degenerated ecosystems, desertification, and poor local economies. Recent years, many trees were planted and nature is now reclaiming a portion of the Loess Plateau. Results have reduced the massive silt loads to the Yellow River. For the food security, we believe that extending and adopting valuable techniques such as terracing, mulching, fertilization, .supplemental irrigation, drought-tolerant varieties and cash crops to dry land agricultural practices in the Loess Plateau, to improve crop productivity and poverty alleviation is possible. Great advances have been made in recent years in understanding the molecular basis of plant responses and plant tolerance to drought stress. Hundreds of drought responsive genes have been identified and the function of some of these has been resolved at the cellular level. However, there is a huge gap between the molecular level science and the interpretation and application of this knowledge at the whole plant/crop level in the field. Effective approaches to achieve better crop productivity under drought conditions as well as the research needed to move forward in this direction.
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