Abstract: To understand the effects of pruning on herbaceous plants of bush community,this paper takes Caragana microphylla Lam community in Inner Mongolia steppe in semi-arid region as the research object. We designed three kind of treatments,i.e. control,pruning once a year and pruning twice a year. The community characteristics and vegetation stoichiometric characteristics before and after pruning were analyzed. The results showed that the density of gramineous plants increased significantly after pruning,the biomass of gramineous plants in the second year of pruning was significantly higher than that of control. The diversity index of grassland community increased with the increase of the times of pruning,and Margalef richness index in the second year of pruning was significantly higher than that of non-pruning treatment. The total biomass of herbaceous community decreased firstly and then increased,there existed no significant difference of C、N content and C/N ratios of vegetation after pruning,but the N/P ratios of vegetation increased significantly. It can be seen that pruning treatment changed the structure of C. microphylla community,improved species diversity and the density of gramineous plants,which contributes to the vegetation restoration of typical grasslands.

Key words: Prune treatment, Caragana microphyllaLam, Biomass, Species diversity, Vegetation stoichiometry

摘要： 为了了解平茬对灌丛群落草本植物的影响，本文以内蒙古典型草原小叶锦鸡儿（Caragana microphylla Lam）群落为研究对象，设置了不平茬、一年平茬1次和一年平茬2次共3种处理，分析了平茬前后群落特征与植被化学计量特征的变化。结果表明：与未平茬相比，两种平茬处理下群落内禾本科植物密度均显著增加，平茬第二年禾本科生物量显著高于未平茬处理；平茬后两年内草地群落物种多样性指数随平茬次数增加均有增加趋势，且一年平茬2次处理时，Margalef丰富度指数显著高于未平茬处理；草本群落总生物量随平茬次数增加呈现先下降后增加的变化趋势；平茬后植被C、N含量、C/N比无显著变化，但植被N/P比显著增加。可见，平茬处理改变了小叶锦鸡儿群落的结构特征，提高了群落物种多样性及禾本科植物的密度，有助于典型草原的植被恢复。

关键词: 平茬, 小叶锦鸡儿, 生物量, 物种多样性, 植被化学计量特征