Research On Soil-plant Communities Feature And Ecological Restoration Planning In Luanhe Estuary Saline-alkali

As a special habitat condition,soil salinization is widely distributed in China.Estuary delta was one of the areas with more distribution of coastal saline-alkali land.It has become one of the focal points of ecological restoration in territorial space,due to it is located in a special location,where rivers,oceans and land meet,and has a fragile ecological environment.Luanhe estuary delta,as an impingement sedimentary plain at the mouth of the Luanhe river,was also a typical representative of the relatively well-developed small and medium-sized estuarine delta in the northern region.It had some ecological problems,such as soil salinization,saline-alkali resistant vegetation construction and ecological restoration.With the development of saline-alkali land management technology,ecological restoration was considered to be one of the most effective ways for the sustainable development of saline-alkali land.In order to facilitate the ecological restoration of the Luanhe river estuary,a special saline area,the paper summarized the theoretical and practical research on ecological restoration in saline and alkaline areas,and visually interpreted remote sensing images and classified land use types.Through the research method of combining background investigation and data analysis,45 sample plots and 137 quadrats were randomly selected in the research area for soil-vegetation background investigation and soil sample collection in the soil layer of both 0～20cm and 20～40cm.The paper classified the plant communities by TWINSPAN and analyzed floristic element and diversity.Measured the content of water salt,nutrient and ion in the collected soil.The paper also analyzed the distribution characteristics of soil factors by statistical methods and Kriging.Spearman correlation coefficient was used to analyze the relationship between soil and vegetation communities.According to the results of data analysis and the problems of ecological restoration in the research area,the plan of ecological restoration in the Luanhe river saline area was put forward.The following research results are listed below:（1）In the horizontal spatial distribution,the water and salt content of soil increased as the ocean gets closer.The contents of SOM,TN and TP increased first and then decreased with the increase of distance from the ocean,showing a"parabolic"change trend.In vertical spatial distribution,with the increase of soil depth,soil salt content,nutrient content decreased,moisture content increased.（2）In the study,Cl^-,SO₄^2-,Ca²⁺and Mg²⁺were the main components of salinized soil.Among them,Cl^-and SO4^2-played a leading role in the composition of soil salt,forming salinized soil dominated by chloride and sulfate.The surface soil variability was strong and the change was active.The content of soil moisture and nutrient in luanhe river is higher than that in Luanhe river.（3）There were 67 species of seed plants from 31 families,52 genera,including compositae,gramineae and chenopodiaceae.Artemisia was the dominant family,and artemisia was the dominant genus.（4）The species of salt-tolerant trees and shrubs were less,and the species of herbaceous plants were relatively rich with high diversity.The herbaceous plants were divided into 8 plant communities with salt tolerance and water tolerance by TWINSPA.Herbaceous layer plant communities were distributed from coast to inland space as follows:Severe salt tolerance and Water tolerance to Mild salt tolerance and Not resistant to salt.Soil salinity was the main dynamic factor affecting vegetation succession.（5）Based on the present situation and the ecological restoration of vegetation,soil environment faced problems,put forward the issue of Luanhe river estuary saline-alkali land ecological restoration solution and planning idea,the study area is divided into five repair areas,put forward different repair methods for different area and plant configuration,build deltas saline-alkali land ecological landscape.