Abstract: By combining field survey sampling and laboratory experiments,we sampled for two consecutive years on different slope directions and slope positions of artificial shrub grass ecosystem on the Loess Plateau,in order to provide a preliminary understanding of the species composition,density characteristics and species diversity of the soil seed bank in the area. The results showed that there were 9 families and 15 species in the soil seed bank of the artificial shrub grass ecosystem in the study area,and their composition varied with the slope direction,position,and year;The slope direction and position significantly affected the species diversity index and richness index and density of the soil seed bank. The density of the soil seed bank is ranged from 3 218 to 5 492 seeds·m^-2,and the shady slope is significantly higher than the sun slope (P<0.05),and the downslope position is significantly higher than the upslope position (P<0.05);However,no significant effect on species homogeneity coefficient was observed by the slope direction or position;The year had no significant effect on the soil seed bank. This study can provide a reference for the sustainable use and restoration of artificial shrub grass ecosystem on the Loess Plateau.

Key words: Soil seed bank, Site conditions, Species composition, Species diversity

摘要： 本研究通过野外调查取样与室内试验相结合，连续两年对黄土高原人工灌草系统不同坡向、坡位进行取样，以期对该区土壤种子库的物种组成、密度特征及其物种多样性进行初步了解。研究结果表明：该人工灌草生态系统土壤种子库共有9科，15种，其组成因坡位、坡向以及年份而异；坡向、坡位均显著影响土壤种子库物种多样性指数、丰富度指数与土壤种子库密度（P<0.05），土壤种子库密度为3 218～5 492粒·m^-2，总体呈现为阴坡显著高于阳坡（P<0.05），下坡位显著高于上坡位（P<0.05）；坡位和坡向均对物种均匀性系数无显著影响；年份对土壤种子库无显著影响。上述研究可为黄土高原人工灌草系统的可持续利用与恢复提供参考依据。

关键词: 土壤种子库, 立地条件, 物种组成, 物种多样性