围封对伊犁河谷春秋草地土壤种子库的影响

Effects of enclosure on soil seed bank in springautumn pasture in Yili valley

以伊犁河谷昭苏马场春秋草地不同围封年限草地（围封6年、围封5年、围封1年和未围封）为对象,采用空间序列代替时间序列的方法,对围封条件下退化草地自然恢复过程中持久土壤种子库的变化进行了研究。结果表明：随着围封年限的增加,土壤种子库的密度和物种数逐渐增加,显著增加了禾本科草类和豆科草类土壤种子密度,杂类草所占比例逐渐下降。禾本科草类和莎草类种子只存在0~5cm土壤表层。土壤种子库与地上植被的物种相似性,随草地的恢复呈增大—减小—增大的变化趋势。

The persistent soil seed bank was analyzed by using the pasture enclosed for different years（enclosed for 6,5,1years and unclosed）in order to explore the effect of enclosure on spring-autumn pasture in Yili valley with the method of spatial sequence replacing time series.Species density of soil seed bank increased gradually with prolongation of enclosing,especially for the herbaceous grasses and legumes,but the proportion of forbs gradually declined.Seed of sedges and herbaceous grasses only existed in 0-5cm soil layer.Soil seed bank and aboveground vegetation showed the similarity of species composition,and the variation trend of similarity followed a pattern of‘increase-decrease-increase＇.