Shifting-sand control in central Tibet

The middle reaches of the Yarlung Zangbo, the Lhasa, and the Nianchu rivers form the center of politics, economy, and culture in the Tibetan Autonomou s Region. Due to the fragility of the natural environment and overexploitat ion of land by the local people, desertification is becoming a serious prob lem in the valleys. Shifting sands cover an area of 578 km(2) and have caus ed problems such as damage to farmland and grassland, traffic blockage and burying of water projects. This paper discusses strategies and techniques f or combating shifting sands, including reformation of the agricultural stru cture, exploitation of new sources of energy, and combinations of mechanica l and biotic measures. Using mechanical measures, straw barriers, and grave l layer covers, artificial vegetation can be established on the mobile sand dune by sowing and planting introduced species.