The world's arid and semi-arid regions are severely affected by desertification. In China, wind erosion, water erosion, soil salinization and the freezing and melting processes have contributed to 2.64 million km2 of desertified land, covering 27.5% of the country's land surface (State Forestry Administration, Peoples' Republic of China 2005). Although climate change could be a reason for desertification, anthropogenic factors such as overgrazing and overcultivation also contribute to degradation in grassland areas (Millennium Ecosystem Assessment 2005; Zheng et al. 2006). The Chinese government has adopted afforestation as the main measure to control desertification. Major projects, including the ‘Three North Shelterbelt Programme’ (also known as the ‘Green Great Wall’) and the ‘Sandstorm Source Control Project around Beijing and Tianjin’, are necessary to shield northern and eastern agricultural ecosystems against sand and dust (Zhou 2002). However, these countermeasures require substantial effort and investment, and, in the semi-arid and arid regions of Inner Mongolia, newly planted trees have often died of drought, while tree planting could also be responsible for exhausting the precious groundwater resources of these regions (Jackson et al. 2005). Alternative and more practical ways of combating desertification by using multi-disciplinary approaches observing both social and ecological principles are required. The Hunshandake Sandy Land restoration demonstration project conducted by the Chinese Academy of Sciences was an attempt to restore desertified grassland mainly through natural processes, and requiring limited investment.
Spatiotemporal Variation Characteristics of Groundwater Quality in A Semi-Arid Steppe Area in Northwest China