黔中石漠化地区不同土地利用方式土壤种子库研究

Different applied type soil seed banks in Karst rocky desertification zone, middle Guizhou province of China

在贵州省普定县喀斯特石漠化地区进行种子萌发试验，对3种不同利用方式土壤（Ⅰ．封山育林、Ⅱ．退耕还林2a、Ⅲ．农耕）的土壤种子库进行了分析。结果表明：土壤种子库组成以草本植物为主，菊科、禾本科居优势，各类型土壤中种子数量和物种数差异显著。平均种子密度Ⅰ类型为1664粒／m^2，Ⅱ类型为8060粒／m^2，Ⅲ类型为6239粒／m^2；土壤中的种子集中分布在表层0～5cm范围内，种子数量随土层深度逐渐降低，物种数亦呈减少的趋势。不同土地利用方式土壤种子库物种相似指数虽然较低，但仍表现出了一定的相关性，物种数、多样性指数、均匀度及生态优势度指数均以Ⅱ类型最大，Ⅲ类型高于Ⅰ。从种子生活型分析，Ⅰ、Ⅱ属于进展演替，其中，Ⅰ处于较高演替阶段，Ⅲ仍处于破坏之中，属于逆行演替。

The seeds bourgeoning experiments were carried out in Karst rock desertification zone, Puding city of Guizhou province of China. Three applied soil seed banks were analyzed. The results showed that the difference of soil species and quantity was prominence. Herbages were the most abundance. Asteraceae and Poaceac species were predominant. The average seed density was 1 664 seeds per m^2 at regeneration area （ Ⅰ ）. T ey were 8 060 seeds per m^2 and 6 239 seeds per m^2 at forest land （ Ⅱ ） and farmland （ Ⅲ）,respectively. Seeds mainly distributed in the layer of 0-5 cm. The seeds quantity and species decreased with soil depth increased. Though the similarities indices of seed banks of at different soils were lower, similarities indices represented some orderliness. Species, diversity indices, evenness indices and dominant indices of type Ⅱ were the maximum. The indices of type Ⅲ was higher than those of type Ⅰ . From the analysis of seeds life forms, it was found that type Ⅰ ＆ Ⅱ belonged to progressive succession, and type Ⅲ belonged to retrogressive succession.