四合木灌丛衰退对沙堆养分及沉积特征的影响OA北大核心CSTPCD

[Objective]The effects of Tetraena mongolica shrub decline on the nutrient and sedimentary characteristics of nebkhas in the West Ordos National Nature Reserve were determined,in order to provide a theoretical basis for the study of shrub decline and the nutrient accumulation effect of nebkhas in arid desert areas.[Methods]Taking Tetraena mongolica shrubland as a study area,soil samples from Tetraena mongolica shrubland areas with different degrees of shrub decline were collected,and the effects of shrub decline on sand piles were determined by analyzing the grain size of surface sediments and nutrient characteristics of sand piles.[Results]① The surface sediments of the sand piles of the Tetraena mongolica shrub in the Ordos National Nature Reserve were mainly fine sand.The fine sand content of the surface sediments of the Tetraena mongolica shrub in each decline degree exceeding 60％.With decreasing shrub decline,the content of fine sand and coarse sand in shrub surface sediments increased.The grain size of the surface sediment of the sand pile of the Tetraena mongolica shrub was approximately a single peak,and the peak particle size was between 15.07 and 447.95 μm.The bare sandy land showed obvious double peaks at 12.35-494.94 μm and at 546.86-1482.94 μm.② There were significant differences(p＜0.05)in soil nutrient content between the sand dunes and the interdune space(areas with Tetraena mongolica shrub decline greater than 60％had higher nutrient content).③ The nutrient content of sand piles in Tetraena mongolica shrubland was significantly higher than that in interdune open space,which had a positive effect on nutrient accumulation,and there was a"fertilizer island"effect.The enrichment ability of AN was the strongest,and the enrichment ability of SOM was the weakest.Except for Tetraena mongolica shrublands with decline degrees between 30％and 60％,the recession degree of other Tetraena mongolica shrublands on the sand nutrient enrichment effect difference was not obvious.[Conclusion]On the whole,the greater the decay degree of the sand pile in the study area,the smaller the content of fine sand and coarse sand in the surface sediment,and the higher the nutrient content under it.