A Quantifying Approach to Soil Salinity Based on a Radar Feature Space Model Using ALOS PALSAR-2 Data

Nuerbiye Muhetaer,Ilyas Nurmemet,Jing Zhao,Adilai Abulaiti,Sentian Xiao

doi:10.3390/rs14020363

Abstract

In arid and semi-arid areas, timely and effective monitoring and mapping of salt-affected areas is essential to prevent land degradation and to achieve sustainable soil management. The main objective of this study is to make full use of synthetic aperture radar (SAR) polarization technology to improve soil salinity mapping in the Keriya Oasis, Xinjiang, China. In this study, 25 polarization features are extracted from ALOS PALSAR-2 images, of which four features are selected. In addition, three soil salinity inversion models, named the RSDI1, RSDI2, and RSDI3, are proposed. The analysis and comparison results of inversion accuracy show that the overall correlation values of the RSDI1, RSDI2, and RSDI3 models are 0.63, 0.61, and 0.62, respectively. This result indicates that the radar feature space models have the potential to extract information on soil salinization in the Keriya Oasis.

Highlights

Quantifying Approach to Soil SalinitySoil salinization is one of the most serious factors having a negative effect on agricultural sustainability and environmental health [1], causing the low emergence rate of crops, dwarf plants, and significant losses in soil fertility and exacerbating the desertification process [2,3,4]
Freeman, Freeman Durden, Pauli, Sinclair, VanZyl, H/A/Alpha, and Yamaguchi polarization decomposition methods were applied to the PALSAR-2 images of the study area
In this study, based on the feature space theory combined with the radar remote sensing image analysis and field investigation, it was found that the soil salinization process is reflected in the middle of the feature constructed by the Freeman_vol_g, Sinclair_g, Freeman Durden vol_g, and VanZyl_vol_g

Summary

Introduction

Quantifying Approach to Soil SalinitySoil salinization is one of the most serious factors having a negative effect on agricultural sustainability and environmental health [1], causing the low emergence rate of crops, dwarf plants, and significant losses in soil fertility and exacerbating the desertification process [2,3,4]. It is estimated that by 2050, the salinity of global arable land will reach more than 50% [6,7,8]. The situation in China seems to be more critical [9]. 10% of the world’s salinized land [10,11]. Xinjiang has the largest distribution of saline land in China, and its saline land accounts for 36.8% of the country, primarily at the oasis–desert ecosystem of southern Xinjiang (close to 50%) [12]. Soil salinity is very sensitive to variations in precipitation, temperature, and groundwater levels [2] but can rapidly change after irrigation or precipitation. A drought may cause salinity rates to increase in a matter of weeks [10]

Objectives

Methods

Results

Discussion

Conclusion