Shielding effect of oasis-protection systems composed of various forms of wind break on sand fixation in an arid region: A case study in the Hexi Corridor, northwest China

Sandstorms are catastrophic weather phenomena that occur frequently in arid and semi-arid areas, with enormous effects on the ecological environment and human health. Particularly around oases, desertification is the major obstacle to sustainable development of oases in arid regions of northwest China. At present, the problem of how to build an optimal oasis-protection system must be resolved by local farmers and scientists. This paper used data on the sand transportation rate, wind speed, and the width and water requirement of vegetative barriers to evaluate the shielding effect of an oasis-protection system. The results showed that integrating straw checkerboards, a sand-fixing plant belt, and a farmland shelterbelt provided an effective oasis-protection system in the transitional zone between an oasis and shifting dunes. The system can reduce wind speed by 70% and the sand transportation rate by 96% when wind reached the farmland after passing through the oasis-protection system. For the transitional zone between the oasis and a Gobi desert, a desert vegetation preservation belt, a windbreak belt, a mixed belt that combines production forest and forage grass, and a farmland shelterbelt also provided significant shelter, and reduced wind speed and the sand transportation rate by 70 and 80%, respectively. For an optimal oasis-protection system, the width and water requirements of the vegetation barriers were also crucial factors because water resources are an important limiting factor for maintaining vegetation barriers in the long-term.