天津蓟运河故道消落带土壤种子库特征与土壤理化性质分析

为确定蓟运河故道消落带土壤种子库特征与土壤理化性质之间的关系,开展土壤萌发试验并测定了土壤理化性质. 结果表明:①土壤物种呈3个聚类组,聚类组1分布在土壤含水率为50%~100%、w(全盐)为0.8~1.4 g/kg的区域,聚类组2分布在土壤含水率为40%~50%、w(全盐)为0.4~0.8 g/kg的区域,聚类组3分布在土壤含水率为25%~40%、w(全盐)为0.2~0.4 g/kg的区域；②土壤w(有机质)、w(全盐)和含水率对土壤种子库物种的分布影响较大,而w(速效K)、w(速效N)、w(速效P)和pH对其影响不大；③随着土壤w(全盐)、含水率的增加及w(有机质)的减少,土壤种子库物种中一年生植物所占比例呈增加趋势,二年生植物比例先减少后增加,多年生植物比例先增加后减少；④随着土壤w(全盐)、含水率的增加以及w(有机质)的减少,消落带土壤种子库的Shannon-Wiener指数和Margalef丰富度指数呈下降趋势,而生态优势度和Pielou均匀度指数随着水位的降低有增大的趋势. 研究得出天津蓟运河故道消落带土壤种子库特征与土壤理化性质有重要关系,适当地进行人为管理和调控对土壤环境的改善及土壤种子库多样性增加有积极作用. 

Characteristics of Soil Seed Banks and Soil Physical and Chemical Properties of Hydro-Fluctuation Belt in Jiyun Canal

The experiments of the seed germination and the soil physicochemical factors were conducted in the hydro-fluctuation belt of Jiyun Canal. The results showed that:1) Different species in the ordination axes of Canonical Correspondence analysis (CCA) presented with the water content (WC) and the salt content (SC) in three cluster groups (group1, WC 50%-100%, SC 0.8-1.4 g/kg; group2, WC 40%-50%, SC 0.4-0.8 g/kg; group3, WC 25%-40%, SC 0.2-0.4 g/kg). WC, SC and percentage of organic matter were the main factors that affected patterning results of the soil seed bank distribution along Jiyun Canal hydro-fluctuation belt. However, the available K, available N, available P and pH had little influence. 2) With the increasing SC, WC and the decreasing organic matter, the proportion of annual species in the soil seed bank increased gradually, and the ratio of biennial plant species decreased first and then increased again. However, perennial species showed an opposite trend. For instance, the percentage increased first and then decreased. 3) The Shannon-Wiener index and Margalef richness index of the soil seed bank showed a downward trend with the high SC, WC and the low organic matter. In addition, indices of the ecological dominance and the Pielou evenness increased to some extent. This suggested that characteristics of soil seed banks had a great relationship with soil physical and chemical properties of hydro-fluctuation belt of Jiyun Canal. Appropriate artificial land management and regulation was suggested as a useful method for improving the diversity of the soil seed bank.