不同年限退耕地植被与风沙流之间的关系研究

下垫面性质决定了近地面风沙流输沙量，而植被状况是下垫面中影响风沙流的重要因素之一。在不同年限退耕地上安装0～100 cm的积沙仪，测定植被不同生长阶段的风沙流输沙率及植被特征，分析不同生长阶段植被对输沙率的影响以及输沙率随高度变化的特征。结果表明:1）退耕地物种丰富度、植被盖度、年输沙率随退耕时间呈规律性变化，物种数量、物种丰富度与退耕年限呈显著负相关，年输沙量与退耕时间呈显著正相关，与植被总盖度呈负相关；2）在不同退耕年代退耕地上，输沙率随高度的增加逐渐降低，风沙流主要集中在近地面0～30 cm，越到上层，输沙率变化幅度越小；3）在同一风速条件下植被不同生长阶段，输沙率在植被生长高峰期明显低于生长初期，同时与植被盖度、草本植物数量显著相关；4）输沙率在不同高度范围内因植被增加而呈减少趋势，随着高度的增加输沙率增加百分比逐渐降低；5）干旱荒漠区退耕地灌木种类稀少，草本植物对群落的影响主要集中在雨季，进而影响了退耕地风沙流输沙率。研究结果为退耕地采取植物治理措施提供了科学依据。

Relationship between Vegetation and Wind-sand Flow in Different Abandoned Lands

Wind-sand flow is determined by the properties of underlying surface,but one of the factors of influencing wind-sand flow is vegetation condition.Multistep sand collecting instrument 100 cm high was installed in different ages of abandoned lands.The characteristics of vegetations in different growth stages and wind-sand flow were measured.The affection vegetation of different growth stages and sand transport rate of wind-sand flow were analyzed.The results showed 1) the vegetation coverage,quantity,species richness and annual sand transport rate exhibited a regular change with the ages of abandoned lands,species quantity,species richness exhibited a significant positive correlation with abandoned age.2) The sand transport rate gradually reduced with the increase of the height,the wind-sand flow was mainly concentrated in the surface within 0-20 cm,the nearer to the top,the smaller varied range was.3) Under the condition of vegetation different growth stages in the same wind speed,the sediment transport rate in vegetation growth peak period was significantly less than the beginning of the growth,at the same time,which was significantly associated with vegetation coverage and the number of herbaceous plants.4) The sand transport rate showed decreasing trend with vegetation increased at different heights,the sand transport rate percentage gradually decreased with the increase of height.5) The shrub species was rare in arid desert area farmland.The impact of herbage on community mainly concentrated in the rainy season,then influenced the sand transport rate of the farmland.The study results would provide scientific basis for plant management measures of the farmland.