暗管改碱技术试验区不同生境盐生植物资源及其群落特征

盐生植物群落的空间格局因受土壤盐碱化的影响而呈现一定的地域性差异,其群落特征及分布对土壤盐碱化程度具有良好的指示作用。研究盐碱地区盐生植物群落特征及其分布规律,对补充和完善土壤盐碱化程度的检测和评估方法及当地盐碱地的改良和生态环境治理均具有一定的指导意义。本文以河北沧州黄骅市暗管改碱技术试验区为例,采用五点取样法分别对地下埋设暗管的荒地、夏季休耕地和未埋设暗管的荒地、夏季休耕地4种生境的植被进行调查,并采用聚类分析方法和Shannon-Wiener指数、Pielou均匀度指数、Simpson指数等分析4种生境下盐生植物资源及其群落特征。结果表明,被调查的20个样方内共有植物8科17属19种,均为草本植物,划分为5种植物群落类型。地下埋设暗管后,抗盐能力相对较低的假盐生植物和非盐生植物逐渐替代真盐生植物,成为荒地和夏季休耕地植物群落的优势种。并且地下埋设暗管的荒地和夏季休耕地物种多样性指数和均匀度指数均高于未埋设暗管的荒地和夏季休耕地。由此可见,暗管改碱技术的实施能在一定程度上降低土壤盐渍化程度,有利于保护和提高植物物种多样性,对盐碱地生态环境质量的改善具有重要意义,建议对其进行进一步研究及推广应用。

Halophyte resources and community characteristics in different habitats with subsurface pipe drainage system

Soil salinity is a major environmental problem in China. In recent years, several related organizations and researchers sought to reduce soil salinity/alkalinity. For example, the subsurface pipe drainage system is a physical method used to reduce soil salinity and alkalinity in the coastal saline regions of Hebei Province. It was then critical to determine the degree to which soil salinity/alkalinity was reduced under this physical method. The distribution and diversity of halophyte communities in coastal saline regions have been impacted by soil salinity. As halophyte communities presented regional differences, they constituted a possible useful indicator for determining the degree of soil salinity. Thus this research on halophyte resources, community types, characteristics and distribution not only supplemented and improved evaluation methods of soil salinity reduction techniques, but also provided a guiding sense to soil salinity/alkalinity as a way of improving local land/ecological environmental management. This paper used the subsurface pipe drainage system region in Huanghua City, Hebei Province, where there had existed chronic soil salinity. In August 2012, a 5-point sampling method was used to investigate halophytic vegetations under 4 different habitats in the study area. The habitats included wasteland with subsurface drainage system, summer fallow land with subsurface drainage system, wasteland without subsurface drainage system and summer fallow land without subsurface drainage system. Then a hierarchical cluster analysis based on key values of the plant population and several diversity indices (e.g., Shannon-Wiener index, Pielou index, and Simpson index) were used to analyze vegetation community type and composition in the area. The study also analyzed the differences in vegetation community characteristics and distributions among the 4 different habitats. The results of the study were that in the 20 sampling plots, a total of 19 species existed. The 19 species belonged to 8 families and 17 genera, and the vegetation was classified into 5 communities. Through analysis of the differences in vegetation community characteristics and distributions among the 4 different habitats, it was concluded that community composition of both wasteland and fallow land changed from usual euhalophyte to pseudohalophyte and then to non-halophyte vegetation after application of subsurface pipe drainage system. The Shannon-Wiener index and Pielou index of wasteland and summer fallow-land vegetation with subsurface pipe drainage system were higher than those without subsurface pipe drainage system. The study therefore showed that habitats with subsurface pipe drainage system had higher species diversity index and community evenness than those without subsurface pipe drainage system. The results indicated that the use of subsurface pipe drainage system was an effective method in reducing soil salinity and improving biological diversity. It was recommended to continue research and application of subsurface pipe drainage system to improve the fertility of saline/alkaline lands.