Characteristics of grain size variation of dunes surface sediments before and after wandering dune control in Zoige Basin,China
In recent years,various counties in the Zoige Basin have taken measures such as setting checker-board sand barriers and planting shrubs to control desertification,and many wandering dunes have been fixed.To explore the changes of grain size characteristics of sand dune surface sediments under the influence of sand-fix-ing vegetation,surface samples were collected before and after sand dune control on the left bank of the Yellow River in Maqu County,Zoige Basin,and the relevant data were compared and analyzed.The results show:(1)After vegetation fixation,the proportion of silt and clay components increased from 1.3％to 9.9％,and the mean particle size decreased from 181.9 pm to 162.0 pm.The grain size components of surface sediments be-came finer,the sorting of dunes became worse,the skewness changed from near symmetry to very positive skewness,and the kurtosis changed from medium to very narrow.(2)The frequency distribution curve has a sec-ondary peak,and the probability accumulation curve has a sub-component in the suspension section.The overall change from two-stage to three-stage,the particle size of the suspension component becomes finer,and the pro-portion of the saltation component content decreases from 99％to 87％-88％.(3)Under the combined action of wheat straw grid and sand-fixing vegetation,the effect of desertification control is remarkable,but the local envi-ronment of desertification land will also affect the effect of sand control.Therefore,it is necessary to carry out sand control work according to local conditions,pay attention to the dynamic changes of the control area,and timely take measures to adjust.
combating desertificationgrain size characteristicsZoige Basinthe source region of Yellow RiverTibetan Plateau
NETL
NSTL
万方数据
