Exploiting Soil and Remote Sensing Data Archives for 3D Mapping of Multiple Soil Properties at the Swiss National Scale

Stumpf, Felix Michael; Behrens, Thorsten; Schmidt, Karsten; Keller, Armin (2024). Exploiting Soil and Remote Sensing Data Archives for 3D Mapping of Multiple Soil Properties at the Swiss National Scale Remote Sensing, 16(15), p. 2712. MDPI 10.3390/rs16152712

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Soils play a central role in ecosystem functioning, and thus, mapped soil property information is indispensable to supporting sustainable land management. Digital Soil Mapping (DSM) provides a framework to spatially estimate soil properties. However, broad-scale DSM remains challenging because of non-purposively sampled soil data, large data volumes for processing extensive soil covariates, and high model complexities due to spatially varying soil–landscape relationships. This study presents a three-dimensional DSM framework for Switzerland, targeting the soil properties of clay content (Clay), organic carbon content (SOC), pH value (pH), and potential cation exchange capacity (CECpot). The DSM approach is based on machine learning and a comprehensive exploitation of soil and remote sensing data archives. Quantile Regression Forest was applied to link the soil sample data from a national soil data base with covariates derived from a LiDAR-based elevation model, from climate raster data, and from multispectral raster time series based on satellite imagery. The covariate set comprises spatially multiscale terrain attributes, climate patterns and their temporal variation, temporarily multiscale land use features, and spectral bare soil signatures. Soil data and predictions were evaluated with respect to different landcovers and depth intervals. All reference soil data sets were found to be spatially clustered towards croplands, showing an increasing sample density from lower to upper depth intervals. According to the R2 value derived from independent data, the overall model accuracy amounts to 0.69 for Clay, 0.64 for SOC, 0.76 for pH, and 0.72 for CECpot. Reduced model accuracies were found to be accompanied by soil data sets showing limited sample sizes (e.g., CECpot), uneven statistical distributions (e.g., SOC), and low spatial sample densities (e.g., woodland subsoils). Multiscale terrain covariates were highly influential for all models; climate covariates were particularly important for the Clay model; multiscale land use covariates showed enhanced importance for modeling pH; and bare soil reflectance was a major driver in the SOC and CECpot models.

Item Type:	Journal Article (Original Article)
Division/Institute:	School of Agricultural, Forest and Food Sciences HAFL School of Agricultural, Forest and Food Sciences HAFL > Agriculture School of Agricultural, Forest and Food Sciences HAFL > Agriculture > Soils and Geoinformation
Name:	Stumpf, Felix Michael; Behrens, Thorsten; Schmidt, Karsten0000-0003-0337-3024 and Keller, Armin0000-0002-4977-4205
Subjects:	G Geography. Anthropology. Recreation > GE Environmental Sciences
ISSN:	2072-4292
Publisher:	MDPI
Language:	English
Submitter:	Fabrice Wullschleger
Date Deposited:	26 Aug 2024 15:06
Last Modified:	11 Sep 2024 08:36
Publisher DOI:	10.3390/rs16152712
Uncontrolled Keywords:	3D Digital Soil Mapping; multiscale spatial and temporal data; multispectral raster timeseries; Landsat; Sentinel; Switzerland
ARBOR DOI:	10.24451/arbor.22392
URI:	https://arbor.bfh.ch/id/eprint/22392