采用样方调查和室内检测相结合法对内蒙古浑善达克沙地迎风坡、坡顶、背风坡和丘间地不同土层（0～10、10～20和20～40 cm）的土壤物理性质（包括含水量、田间持水量、容重、总孔隙度和毛管孔隙度）及草本群落的生产力（包括盖度和地上部生物量）和物种多样性（包括Margalef丰富度指数、Simpson多样性指数、Shannon-Wiener多样性指数和Pielou均匀度指数）进行比较分析；在此基础上，采用Pearson相关性分析法对不同微地形的土壤物理性质与草本群落各指标间以及草本群落生产力与物种多样性各指标间的相关性进行分析。结果表明：4种微地形的土壤物理性质总体上差异显著，但不同土层的土壤物理性质总体上无明显差异；从丘间地、背风坡、坡顶到迎风坡，土壤的含水量、田间持水量、总孔隙度和毛管孔隙度依次递减，而土壤容重则依次递增，说明迎风坡的土壤结构较差且水分散失较多，而丘间地的土壤结构和水分状况均相对较好。不同微地形间草本群落生产力和物种多样性总体上也存在明显差异，从背风坡、丘间地、坡顶到迎风坡，草本群落的生产力和物种多样性依次递减，仅Margalef丰富度指数表现为在丘间地最高、在迎风坡最低，说明迎风坡的草本群落物种多样性较低，群落稳定性差，而背风坡和丘间地的草本群落物种多样性和生产力水平均较高，群落稳定性较好。相关性分析结果表明：该区域的草本群落生产力和物种多样性与土壤容重呈负相关，与土壤的其他物理性状呈正相关，但仅部分指标间有显著或极显著相关性；草本群落生产力与物种多样性各指标间呈正相关，但多数指标间的相关性并不显著。研究结果显示：微地形能够显著影响浑善达克沙地的土壤物理性质和草本群落的分布特征，气候和人为干扰使该沙地的土壤物理性质受到严重破坏，导致草本群落生产力降低并处于不稳定状态。

Soil physical properties （including water content， field capacity， bulk density， total porosity and capillary porosity） in different soil layers （0-10， 10-20 and 20-40 cm）， herbaceous community productivity （including coverage and biomass of above-ground part） and species diversity （including Margalef richness index， Simpson diversity index， Shannon-Wiener diversity index and Pielou evenness index） of windward slope， slope top， leeward slope and interdune in Otindag Sandy Land of Inner Mongolia were compared and analyzed by a combination method of field sampling and laboratory testing. On this basis， correlations of soil physical properties with herbaceous community indexes and herbaceous community productivity with species diversity indexes of different microtopographies were analyzed by Pearson’s correlation analysis method. The results show that in general， there are significant differences in soil physical properties of four microtopographies， while there is no significant difference in that of different soil layers. Soil water content， field capacity， total porosity and capillary porosity decrease successively in the sequence from interdune， leeward slope， slope top to windward slope， while soil bulk density increases successively， indicating that windward slope has a poor soil structure and loses much water, but soil structure and water situation in interdune are relatively good. In addition， there are also significant differences in herbaceous community productivity and species diversity of different microtopographies， which decrease successively in the sequence from leeward slope， interdune， slope top to windward slope, only Margalef richness index is the highest in interdune and the lowest in windward slope， indicating that herbaceous community species diversity is low and community stability is poor in windward slope, but herbaceous community species diversity and productivity level are high and community stability is relatively good in leeward slope and interdune. Correlation analysis results show that herbaceous community productivity and species diversity are negatively correlated with soil bulk density in this region， and are positively correlated with other soil physical properties， but significant or extremely significant correlation is only between some of these indexes. Moreover， there is a positive correlation between productivity and species diversity indexes of herbaceous community， but there is no significant correlation between most of these indexes. It is suggested that microtopographies could significantly affect soil physical properties and herbaceous community distribution pattern of Otindag Sandy Land， climate and artificial interference seriously damage its soil physical properties， which results in reduced productivity and instability of herbaceous community.