Study On Dynamic Monitoring Of Salinization In The Yellow River Delta By Multi-source Remote Sensing

Soil is the basic environment for human survival.With the increase of population,the rapid development of agriculture and industry,the soil has been damaged to a certain extent.There are land desertification,salinization,soil erosion and other types of land degradation.Soil salinization,as the main type of land degradation,is a serious global soil problem,mainly distributed in arid,semi-arid desert oasis and coastal alluvial plain.he use of remote sensing technology for dynamic monitoring of soil salinization,analysis of its spatial distribution and dynamic changes,is conducive to grasp the status of soil salinization,and has important significance for its protection,management,development and utilization.In this paper,the typical coastal salinization areas of the Yellow River Delta are studied ETM+/OLI and Sentinel-2A remote sensing images are data sources.The Landsat remote sensing data of long time series are obtained by spectral normalization of different sensor images.Combined with the data of field total soil salinity measured in 2006,the relationship between total salt content and spectral reflectance is established,and the best factor for simultaneous interpreting salt retrieval model based on remote sensing is screened.A variety of prediction models of soil salt content based on spectral reflectance and salinity index are constructed,and the accuracy of the total salt data simulated by the model is tested with the measured total salt data.The best salt inversion model is selected to invert the total salt of the soil in2006,2012,2017 and 2019 in the study area,and the inversion results are salinized according to the soil salinization level standard The area,land transfer matrix,area barycenter coordinates and offsets of different grades of saline soil are calculated to show the spatial distribution of different grades of saline soil.The results show that in the past ten years:(1)the degree of salinization in the study area is decreasing,the total area of cultivated land is decreasing by 30929.15 hectares,the areas of weak salinized soil,medium salinized soil,strong salinized soil and salinized soil are decreasing,each decreasing by 1522.29,6264.36,8862.41,14280.10 hectares,and the areas of non salinized soil are increasing by 26277.23hectares;(2)the transfer matrix shows that The transfer proportion of other land types to non saline soil is the largest,especially for weak saline soil and medium saline soil,which are more than 40%;(3)spatial distribution shows that non saline soil is mainly distributed in the middle of the study area,while weak saline soil and medium saline soil are mainly distributed in the middle and south of the study area,and strong saline soil is widely distributed,and saline soil is widely distributed in 2006,Then the distribution range decreased,mainly distributed in the East and north;(4)the area transfer track showed that the area center of non saline soil shifted to the southeast,the area center of weak saline soil shifted to the northeast,the area center of middle saline soil and strong saline soil shifted to the northwest,and the area center of saline soil shifted to the southwest;(5)the soil salt content was affected by precipitation and average temperature Under the influence of sunshine hours,the decrease of precipitation,the increase of temperature and the long sunshine time will lead to the increase of soil salt content and the salinization of soil.Comprehensive analysis shows that with the improvement of climate,the decrease of irrigation water consumption,the increase of effective irrigation area,the implementation of government policies,and the decrease of salinization degree in the study area,it is suggested that by taking reasonable control measures to the problem of soil salinization,improving the damaged ecological environment,improving and transforming the salinized soil into arable land,we can greatly improve our country The current situation of a large population and a small amount of cultivated land in China is to increase the reserves of cultivated land.