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.