三江源风沙活动区沙漠化风险与风动沙含量关系
Relationship between the desertification risk index and blowing sand content of typical aeolian erosion areas in Sanjiangyuan

通过调查采样，分析了三江源多个典型风沙活动区的沙土颗粒成分，发现风动沙（最易蚀颗粒）含量与沙漠化程度间存在一定的关系。进而定义了用于表征区域发生沙漠化的风蚀风险指数，并应用到多种类型的土地的沙漠化风险评价中。分析结果表明：风蚀风险指数与风动沙百分含量直接相关，当区域内风动沙百分含量低于50%时，发生沙漠化的风险极低；当风动沙百分含量超过60%时，沙漠化风险随风动沙百分含量的增加而显著增长。因此，可通过判定区域样地中的风动沙百分含量，及时预警该区域在一定时期内发生沙漠化的风险，通过采取相关措施降低风动沙百分含量，抑制风动沙活动，结合合理有效的植被措施，可使活动沙丘逐步被固定下来。
Abstract：Field investigations and samplings in typical aeolian erosion areas in Sanjiangyuan were taken to study the features of sediment particles. The sediment composition distributions of active, semi-fixed, and fixed sand dunes were analyzed to identify the components of blowing sand when eroded by wind. The content of the blowing sand then influences the desertification. A desertification risk index which indicates the risk of desertification for an area was defined and applied to assess the desertification risk of the aeolian erosion areas. The desertification risk index of the sampled areas was correlated with the blowing sand percentage. Desertification is unlikely when the blowing sand percentage was less than 50%, with the desertification risk increasing exponentially as the blowing sand percentage increased for percentages over 60%. Therefore, the blowing sand percentage is recommended as an index for indicating the desertification risk of a region. Strategies to reduce the proportion of blowing sand and promoting vegetation coverage are recommended for preventing desertification in the Sanjiangyuan region.