Land degradation and blown-sand disaster in China

Abstract

China is a country with severe land degradation and blown sand disasters. The arid and semi-arid regions, in which land desiccation, vegetation degeneration, wind erosion, sandification, Gobi-pebblization and salinization occur, take up one third of China's total land area. Vegetation degradation is most serious in lower flood plains of the inland rivers and the semi-arid Agro-pastoral Ecotone due to excessive use of water resources, grassland reclamation, overgrazing and collection of firewood and herbal medicines. Wind erosion features are common around terminal dry lakes, in inland-river fluvial plains, and the semi-arid dry grasslands. Studies by the methods of aeolian sand transport, soil texture analysis, Cs-137 tracing and archaeology confirmed that the rate of wind erosion is normally between 1000 to 2000 ton km(-1) a(-1). The gravel Gobi on Mongolian Plateau has been formed to a large degree by wind erosion. The severity of sandification has been manifested by the twelve sandy deserts and lands occupying 710, 000 km(2), and the enlargement of sandy land at increasing spreading rates in the past three decades. Salinization has not received enough public attention yet, but soil salinization in Ningxia and Hetao Plains and dry take basins is unfavorable for crop growth and natural vegetation. Salinization of surface water and ground water in the lower reaches of most inland rivers restricts utilization of insufficient water resources. The exacerbation of sand and dust storms disasters is the ultimate outcome of desertification in China.