Abstract: In the early stage of artificial shrub-herb community,the growth of shrub seedlings was inhibited by herb and it is difficult that shrub grew in the artificial shrub-herb community. However,it is not clear that the competition between herb and shrub seedlings and the influence of herbaceous density on the growth of shrub seedlings. Therefore,the effect of herbaceous density to biomass,morphological characteristics and interspecific competition between herb and shrub seedlings were studied to provide experimental evidence for the construction of artificial shrub-herb community. In this study,pot experiment was carried out and soil condition were simulated according to highway slope restoration. Three species of shrubs (Caragana korshinskii Kom.,Vitex negundo Var. Heterophylla,Amorpha fruticosa) were selected,and biomass,height,specific leaf area (SLA) and root surface area (RSA) of three shrubs among different herb density were compared. The competitive ability between herb and shrub seedlings was compared by calculating the relative yield,relative competition intensity and competitive attack coefficient. The results showed that the growth of three shrubs was inhibited by herb in shrub-herb mixed sowing treatment,and the height of three shrubs decreased by 71%-87%,and the biomass of three shrubs decreased more than 96% under shrub-herb mixed sowing treatment compared to that under shrub monoculture treatment. The seedlings growth of the three shrubs was affected by herbaceous density. And herbs were of more strong competitiveness than shrub seedlings,and herbaceous density has significant impact on the relative competition strength of the three shrub seedlings. At the same time,Caragana korshinskii Kom. seedlings died in high herbaceous density,so herbaceous density need be control when construct artificial shrub-herb community. Herbaceous density should be less than 200 plants·m^-2 in Caragana korshinskii Kom shrub-herb community,and herbaceous density should be less than 500 plants·m^-2 in Vitex negundo var. heterophylla and Amorpha fruticose-herb community.

Key words: Artificial shrub-herb community, Density dependence, Biomass, Specific leaf area

摘要： 在人工灌-草群落建植初期，灌木幼苗生长经常受到草本植物的抑制。为了明确草本植物及其种植密度对灌木幼苗生长特征的影响，为人工灌-草群落构建提供理论依据。本研究以柠条锦鸡儿(Caragana korshinskii Kom.)、荆条(Vitex negundo Var. Heterophylla)、紫穗槐(Amorpha fruticosa)为研究对象，设置4个草本种植密度，分别比较3种灌木幼苗生长特征在4个草本种植密度处理之间的差异。结果表明：3种灌木幼苗都受到了草本的抑制和草本种植密度的影响，株高与灌木单一种植相比降低幅度达71%~87%；生物量降低达96%以上。此外，3种灌木幼苗在灌-草群落中竞争能力较弱，且在高密度草本植物种植处理中，出现灌木幼苗死亡现象。在构建人工灌-草群落时，以柠条为灌木物种的灌-草群落，草本植物种植密度建议小于200株·m^-2；荆条和紫穗槐草本植物种植密度建议小于500株·m^-2。

关键词: 人工灌-草群落, 密度制约, 生物量, 比叶面积