Abstract:
Abstract: Belonging to typical oasis wetlands in China, the wetland of Yinchuan not only is the barrier of biodiversity, but also plays a crucial role in environmental regulation and productive improvement. Unfortunately, it is prone to salt accumulation in the wetland. Therefore, it will be of great significance for having a good knowledge on the impact of the process of water and salt migration on wetland ecosystem to find out the spatial accumulation characteristics of soil salinity in the meadow wetlands in Yinchuan Plain. This paper uses the field survey and laboratory analysis methods to research the distribution of vegetation, the classification of soil salinization and the situation of salt accumulation in the meadow wetlands in Yinchuan Plain. In this study, we set up 57 experimental plots with 123 points, and the plant communities in the study area are divided into 3 vegetation types, 8 vegetation subtype s and 27 formations according to the traditional classification. A total of 44 species of plants are investigated, which is a relatively small number; according to the investigation results on the plant communities in ditch wetland in the Yinchuan Plain by Cheng Zhi, the investigated plants reached a total of 87 species, belonging to 31 families and 71 genera, and the plants along ditch slope were divided into hygrophyte, mesophyte and halophyte with plants in ditch base. On the basis of the soil surface salinity (0-20 cm), the soil in the study area is divided into 5 grades:Ⅰ, Ⅱ, Ⅲ, Ⅳ and Ⅴ, and the corresponding salt contents are ≥10, 4~10), 2~4), 1~2)和<1 g/kg, respectively. The results show that soil salt content increases from south to north in the meadow wetlands in Yinchuan Plain. Salinity of different kinds of vegetation meadows is in a descending order as follows: salty vegetation, typical meadow and wet meadow. And Salinity in different topographical meadows is dry lake beach > floodplain > lake beach outside river levee > wet lake beach > sand beach. Buried depth of groundwater and salt-water cycle process are the decisive factors of salt distribution characteristics. Behind the large-scale wetland restoration in Yinchuan Plain, there is a hidden risk of land salinization in the lakeside zone, and if there is no good artificial recharge of irrigation and drainage vent of salt leaching, the natural restoration vegetation in lakeside meadow will be salt meadow or salt shrub. The vegetations artificially planted also have the problems of the accumulation and degradation of soil salinity. The study on the spatial accumulation characteristics of soil salinity in the meadow wetlands of Yinchuan Plain were found out is helpful to understand the biogeochemical cycle, source and sink effect in wetland ecosystem, reveal the salt accumulation effect and its distribution characteristics in the process of wetland development in Yinchuan Plain, and further understand the effect of water and salt migration process of wetland ecosystem in Yinchuan Plain. The results provide the scientific guidance to the lakeside and bank afforestation and ecological construction and to wetland comprehensive utilization, especially wetland grassland construction.