A review of soil salinity assessment methods

There is a large area of saline-alkali soil in China, because of its poor soil structure and low nutrient content, which seriously affects agricultural production and ecological health, and needs to be improved. Accurate measurement of soil salinity is an important step in amending the soil salinization, which is of great significance to improve agricultural productivity and the balance of arable land. This paper firstly sorted out the methods of soil salt measurement at points and then divided them into the mass method by directly measuring soil salt and the electrical conductivity method by indirectly characterizing soil salt. The mass method can be subdivided into extraction filtration and centrifugal method according to different ways of extraction solution acquisition. According to different principles, the conductivity methods can be subdivided into soil solution conductivity, soil leaching solution conductivity and soil saturated solution conductivity. Secondly, the surface soil salt measurement methods based on remote sensing technology are sorted out, which are divided into three different ways: satellite remote sensing monitoring, aerial remote sensing monitoring and ground remote sensing monitoring. Finally, the advantages and disadvantages of the above methods and their application scenarios were explained. Combined with the current research hotspots, we outlook the development trend of cloud platforms such as data fusion, soil hydrodynamic model and GEE applied in the soil salt measurement , which could provide references for selecting suitable soil salt measurement methods in scientifically improving saline-alkali land.