News Release

Mapping the world's salted soils: a leap forward in combatting land degradation

Peer-Reviewed Publication

Journal of Remote Sensing

Spatial distribution of the global climate class and the ground soil salinity observations.


Notes: the subfigure shows an example of acidic soil areas defined by the World Reference Base for Soil Resources; the scatterplot shows the salt content of soil samples in five climate regions.

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Credit: Journal of Remote Sensing

A team of researchers has developed an innovative approach that maps the soil salt contentaround the world with an exceptional detail of 10 meters. This breakthrough tackles the pressing need for accurate assessments of soil salinity, a formidable challenge that jeopardizes agricultural productivity and soil vitality on a global scale.

Soil salinity, a form of land degradation, affects over 1 billion hectares globally, compromising agricultural productivity and environmental health. Previous attempts at mapping soil salinity were hindered by the coarse spatial resolution of existing datasets and limitations in capturing the continuity of soil salinity content. Recognizing these challenges, the research team embarked on developing a model that integrates Sentinel-1/2 images, climate data, terrain information, and advanced machine learning algorithms to estimate soil salt content across five climate regions. These findings were detailed in a study (DOI: 10.34133/remotesensing.0130) published on March 28, 2024, in Journal of Remote Sensing. This research introduces a device that skillfully integrates slanted spiral channels with periodic contraction-expansion arrays.

At the heart of this groundbreaking endeavor is the fusion of data from an array of remote sensing technologies, notably the advanced Sentinel-1/2 satellites, and the strategic application of machine learning algorithms. This innovative approach has birthed a sophisticated model capable of delineating soil salinity with unprecedented precision—a 10-meter resolution across varying climates. This methodological breakthrough propels us far beyond the limitations of past attempts, which were shackled by their coarser resolution and a narrower scope in salinity analysis. The dedicated research team has assembled an extensive dataset, capturing global climate patterns, precise ground-level soil salinity readings, and a comprehensive set of geospatial variables. Employing the Random Forest algorithm, the model not only excels in predicting soil salinity with remarkable accuracy but also sheds light on the pivotal roles that climate, groundwater levels, and salinity indices play in the formation of soil salinity landscapes. This innovation marks a monumental stride in our ability to monitor and manage soil health on a global scale.

Professor Zhou Shi, the lead researcher, stated, "This study marks a significant leap in our ability to assess and manage soil salinity at a global scale. By combining satellite imagery with machine learning, we can now identify saline soils with unprecedented accuracy and detail, offering valuable insights for sustainable land and agricultural practices."

The high-resolution global soil salinity map generated from this research provides an essential tool for scientists, policymakers, and farmers to address soil salinity issues effectively. It enables targeted interventions for soil health restoration, supports sustainable agricultural practices, and aids in resource management planning. The methodology also sets a new standard for environmental monitoring, potentially applicable to other land degradation assessments.





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Funding information

This study was supported by the National Key Research and Development Program (grant numbers 2018YFE0107000 and 2023YFD1900102), the National Science Foundation of China (grant numbers 42261016 and 41061031), the Bingtuan Science and Technology Program (grant number 2020CB032), the Tarim University President’s Fund (grant number TDZKCX202205), the China Scholarship Council (CSC), the Academic Rising Star Program for Doctoral Students of Zhejiang University, and the Outstanding Ph.D. Dissertation Funding of Zhejiang University.

About Journal of Remote Sensing

The Journal of Remote Sensing, an online-only Open Access journal published in association with AIR-CAS, promotes the theory, science, and technology of remote sensing, as well as interdisciplinary research within earth and information science.

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