Remote Sensing Monitoring of Soil Salinization Based on SI-Brightness Feature Space and Drivers Analysis: A Case Study of Surface Mining Areas in Semi-Arid Steppe

Zhenhua Wu,Xia Hua,Qingwu Yan,Shaogang Lei,Shutao Zhang,Qingqing Lu

doi:10.1109/access.2021.3101873

Abstract

The real-time monitoring and driving force research of soil salinization in semi-arid grassland are of great significance for regional and local ecological environment protection, management, and sustainable development. We selected a typical “mine-town-agriculture-pastureland-industry” interlaced ecologically fragile area as the study area. Based on the method of SI (Salinization Index)-Brightness feature space, we constructed a new spectral index named Semi-Arid Steppe Salinization Index (SASSI), which is more suitable for soil salinization remote sensing monitoring in semi-arid steppe. The geodetector method was used to analyze the driving forces of the temporal-spatial changes of soil salinization. The results indicated that: (1) SASSI presented a high correlation with soil surface salt content (R 2 = 0.7698), and made full use of multi-dimensional remote sensing information. SASSI can reflect the salinization status of surface soil. The indicator calculation was simple and easy to obtain, which was conducive to the quantitative analysis and monitoring of salinization. (2) The driving factors affecting the spatial distribution and change of soil salinization were water, surface mines, town, agriculture, industry, road network, and elevation. The salinized areas were mainly distributed around the wetlands of the Xilin River Basin, mining landscapes, and town landscapes. (3) The total area of salinized soil in the study area increased from 32.03 km 2 in 2002 to 150.46 km 2 in 2017. The area of salinized soil increased rapidly from 2005 to 2014, but the growth rate slowed down after 2014. The salinized soil was mainly located in the salt marsh wetland in 2002, however had spread to the whole study area in 2017. This study provides references for remote sensing monitoring of soil salinization and the impact of land use, topography and other natural factors on soil salinization in the semi-arid steppe.

Highlights

Soil salinization is a phenomenon of land degradation caused by the interaction of many factors, such as the unreasonable development and utilization of natural resources, the fragile ecological environment, and the aggravation of climate change
From the perspective of the spatial distribution of soil salinization, the salinized soil in 2002 was mainly located in the salt marsh wetland, and in 2017, the salinized soil has spread to the whole study area
Based on the theory of feature space, using Landsat image and field survey data, studying spectral characteristics and many spectral indices of Landsat image in depth, constructing SIBrightness feature space by selecting SI and cap transform Brightness index, this paper proposed a new spectral index, Semi-Arid Steppe Salinization Index (SASSI), which is simple, accurate and more suitable for semi-arid steppe

Summary

Introduction

Soil salinization is a phenomenon of land degradation caused by the interaction of many factors, such as the unreasonable development and utilization of natural resources, the fragile ecological environment, and the aggravation of climate change. It is an increasingly serious global problem. About 30% of the land in arid and semi-arid regions is affected by soil salinization. Due to the seriousness of the problem, countries all over the world have incorporated soil salinization into their future development plans, which has become an important part of the global climate change research framework [5]

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