围封沙化草地土壤种子库动态研究

The Study on the Dynamic of Soil Seed Banks in Enclosing Sandy Grassland

以未围封沙化草地作对照,研究了围封1年、4年和9年的沙化草地土壤种子库特征的变化,获得如下结论:(1)对沙化草地实施围栏封育,可显著提高土壤种子库的植物种数。(2)围封过程中的沙化草地,土壤种子库群落组成中,1、2年生植物所占比例逐渐减小,多年生植物所占比例均逐渐增加。(3)围封过程中的沙化草地,土壤种子库群落组成的相似性,相临阶段较高,随围封年限差异的增加,相似性逐渐减小,表明土壤种子库的变化是一个连续的过程。(4)围封不同年限的沙化草地之间,土壤种子库密度存在极显著性差异,随围封年限的增加而增加,且与地上植被密度具有较高的相关性,其间可用二次曲线进行描述。

The dynamic characteristics of the soil seed banks are researched in the sandy grassland which have been enclosed for 1 year, 4 years and 9 years by contrasting with the unclosed sandy grassland. Following conclusion can be obtained： （1） Enclosure can increase significantly the species of the soil seed banks of sandy grassland. （2） The proportion of annual plant and biennial plant decrease gradually and the proportion of perennial plant increases gradually in the course of enclosure. （3） There is a high similarity in soil seed banks composition of sandy grassland between the samples which have a close enclosing time. And the similarity becomes smaller and smaller with the increasing of differences of the enclosing time. Results show that the variation of soil seed banks is a continuous process. （4） The difference of soil seed banks density among the 4 samples is very remarkable, and soil seed banks density increase gradually with the enclosing time increasing. There has a high correlation between the soil seed banks and the standing vegetation density, which can be described by secondary curves.