过度放牧是科尔沁地区土地沙化的主要原因之一，围栏封育可以有效的抑制牲畜对植被的破坏，促进沙地植被恢复，从而改善区域的生态环境.本研究以科尔沁沙地主要固沙植被——小叶锦鸡儿群落为对象，采用空间序列代替时间序列的方法，分析不同封育年限和自然放牧条件下小叶锦鸡儿群落的土壤种子库和地上植被特征、土壤理化性质和土壤水分动态，较系统地探讨了封育措施对沙地植被和土壤特性的影响.结果表明：①封育措施促使固沙植被区土壤种子库密度显著增加(P<0.05)，封育2 a、6 a和12 a的土壤种子库密度分别提高了15.7%、482.5%和728.1%；土壤种子库的物种多样性和均匀度随着封育年限的增加而降低.②封育措施对沙地植被恢复具有显著的促进作用(P<0.05)，封育6 a和12 a后植被密度分别提高了108.0%和239.3%，植物盖度分别提高了261.6%和271.6%；适度的封育年限(<6 a)可以提高群落的物种多样性，过长的封育年限(11 a)反而使物种多样性下降.③封育措施促使土壤表层(0-10 cm)的养分(有机质、全氮、碱解氮、全磷、速效磷、速效钾)含量有所提高，土壤含水量无显著变化(P>0.05).%Overgrazing generally results in vegetation degradation of grassland, and is one of the main causes leading to desertification development in Horqin Sandy Land in Northeast China. Fenc enclosure is a simple and effective measures for the restoration of degraded vegetation and the improvement of ecological environment and is widely used for this purpose in the sandy land. Caragana microphylla community is the indigenous and dominant vegetation type in the Horqin Sandy Land. The purpose of this study is to determine the effect of the fenc enclosure on vegetation and soil characteristics under the C. microphylla community. Soil seed bank, soil physical and chemical properties, and coverage and composition of vegetation in an age sequence (2-, 6-, and 12-yr) of enclosed C. mirophylla lands were compared with freely grazing land. The results showed that: ①the fence enclosure significantly increase soil seed bank density. The soil seed bank density of 2-, 6-, and 12-yr plots increased by 15.7%, 482.5%and 728.1%, respectively, compared with the free grazing plot,. However, the Shannon-Weiner index, Simpson index and Pielou evenness of soil seed bank decreased with the age; ②the fence enclosure facilitated vegetation restoration. Specifically, the density of vegetation increased by 108.0%and 239.3%, and the coverage of vegetation increased by 261.6%and 271.6%in the 6-and 12-yr plots respectively, compared with the grazing plot time (<6 a) could increase species diversity, while long fencing time (11a) could decrease species diversity. ③the fence enclosure increased nutrient contents (organic matter, total N and P, and available P and K) of topsoil (0-10 cm), while no significant differencs of soil moisture were found among the plots.
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