黄土丘陵区撂荒地不同侵蚀带土壤种子库特征

采用野外调查取样和室内实验相结合的方法,研究了黄土丘陵区撂荒地不同侵蚀带土壤种子库的密度、物种组成、物种多样性以及相似性特征。结果表明:各侵蚀带土壤种子库中共发现26个物种,隶属于13科24属,不同侵蚀带物种组成有所差异,菊科与禾本科为主要组成物种;0—10cm土层内土壤种子库密度随着侵蚀带的变化而变化,有明显的先减少再增大而后再急剧减少的趋势;不同侵蚀带土壤种子库物种多样性指数、丰富度指数、均匀度指数和生态优势度存在着差异,但未达到显著相关水平;土壤种子库组成物种相似性系数变化范围为0.40～0.82,相邻侵蚀带之间的土壤种子库物种相似性较高,随着侵蚀带之间距离的增加,其相似性逐渐变小。这说明不同侵蚀带土壤种子库因受坡面径流引起的土壤侵蚀使种子流失、二次迁移和沉积以及植被的拦截而产生再分布。

Characteristics of Soil Seed Banks under Different Erosion Zones on Abandoned Land in the Hilly-gullied Loess Plateau

Field survey and laboratory experiment were conducted to study the characteristics of the soil seed bank in terms of species density,composition,diversity and similarity over different erosion zones on abandoned land in the hilly-gullied Loess Plateau region.In this study,26 species belonging to 13 families and 24 genera germinated in different erosion zones.Compositae and Granimeae are the main species in different erosion zones which have different species composition.In 0—10 cm soil layer,the density of soil seed bank changes with erosion zones,it reduces first,then increases and finally sharply decreases.Diversity index,richness index,evenness index and ecological dominance of the soil seed bank are different among different erosion zones,but there is no significant correlation.The species similarity index of soil seed bank composition ranged from 0.40 to 0.82.The similarity index reduced with the increase of the distance between erosion zones.It indicated that soil seed bank in different erosion zones was redistributed by slope runoff and sediment transportation.This process includes seed removal and deposition with flow on the slope.