Soil Salinity Inversion And Soil Quality Evaluation In Tianjin Binhai New Area

As the economic center of the Bohai Bay region,Tianjin has the problem of soil salinization,which is outstanding and become one of the important factors restricting the sustainable development of social economy,so It is of great significance to carry out research on soil salinization in Binhai New Area.The paper took Binhai New Area as the research object and by the way of field investigation and indoor analysis.Using classical statistics,geostatistics methods and GIS techniques to analysis spatial variability of soil salinity in study area.Building soil salinity inversion model based on Landsat8 OLI remote sensing image and spectral index to analysis the spatial distribution characteristics of soils with different salinization degrees.soil quality evaluation for different salinization degrees was carried out by the method of fuzz mathematical evaluation method.The paper aims to provide a theoretical basis for the protection and treatment of saline soil,the sustainable development and utilization of land resources,the optimization of planting structure,the improvement of soil productivity and the healthy development of agriculture.conclusions as below:(1)Soil salinity in each layer has strong variability in the horizontal direction.It appears that the degree of variation gradually decreases with the increase of soil depth.As the depth of the soil increases,the spatial autocorrelation increases.It shows that the random factors are gradually weakened and the influence of structural factors are continuously strengthened.(2)A comprehensive model of soil salinity based on multiple spectral indices is significant and it's R2=0.766.The predictive effect of the model is better.Soil salinity is mainly affected by DVI,NDVI and MNDWI.Soil salinity increases as distance from the coastline increases.The salinized soil area:coastal salinized soil>severe salinized soil>non-salinized soil>lightly salinized soil>moderately salinized soil>.The soil of study area is mainly coastal salinized soil and the degree of salinization is heavier.(3)Most of the soil in the study area is of medium quality.The overall level of soil quality is medium low level and it has an apparent strip distribution.Soil quality increases as distance from the coastline increases.With the deepening of salinization,the proportion of low-quality soil is on the rise and the high-quality soil is go down.In other words,As soil salinization increases,soil quality declines.(4)In the study area,the application of organic fertilizer,nitrogen fertilizer and phosphate fertilizer should be increased and Biological nitrogen fixation should be carried out to improve soil nutrient levels and soil quality.The results show that the degree of soil salinization is negatively correlated with soil quality.Therefore,soil quality can be improved by reducing soil salinity.