Combining machine learning and environmental covariates for mapping of organic carbon in soils of Russia

Robust and detailed quantitative prediction of soil organic carbon (SOC) is of great significance to studying the carbon budget, soil management and decision-making. Spatial variations of SOC content were modelled using 863 soil profiles and a set of 22 environmental covariates representing relief,...

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Main Authors: Andrey Chinilin, Igor Yu. Savin
Format: Article
Language:English
Published: Elsevier 2023-12-01
Series:Egyptian Journal of Remote Sensing and Space Sciences
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S111098232300056X
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author Andrey Chinilin
Igor Yu. Savin
author_facet Andrey Chinilin
Igor Yu. Savin
author_sort Andrey Chinilin
collection DOAJ
description Robust and detailed quantitative prediction of soil organic carbon (SOC) is of great significance to studying the carbon budget, soil management and decision-making. Spatial variations of SOC content were modelled using 863 soil profiles and a set of 22 environmental covariates representing relief, bioclimate variables and remote sensing data. The article provided the results of 3D modeling of SOC content in several soil layers (0–5, 5–15, 15–30, 30–60 and 60–100 cm) for the territory of the Russian Federation with 500 m spatial resolution. Machine learning framework was used, with random forest and spatial cross-validation techniques (150 km blocks) to handle the spatial autocorrelation of the training points. Compared with randomized cross-validation (R2 0.66, Concordance Correlation Coefficient (CCC) 0.79, RMSE 0.99 g/kg), using spatial cross-validation to predict the SOC content yielded less accurate results — R2 0.45, CCC 0.63, RMSE 1.41 g/kg. Regarding the importance of the variables, soil depth and temperature seasonality were major contributors to the SOC content prediction, followed by the EVI, 7 (MIR) MODIS band, and the topographic wetness index. The model was next evaluated with procedure so-called „area of applicability“ (AOA) of prediction model — the areas for which we cannot estimate prediction quality. AOA spatial distribution showed that the feature space not represented by training data is located in the mountain provinces. The proposed framework can be used for SOC modeling with a limited soil profile number, and it is provides a reproducible approach for long-term SOC monitoring.
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spelling doaj.art-f61c2357c3f84166ace237180a3b8df82023-11-02T04:13:13ZengElsevierEgyptian Journal of Remote Sensing and Space Sciences1110-98232023-12-01263666675Combining machine learning and environmental covariates for mapping of organic carbon in soils of RussiaAndrey Chinilin0Igor Yu. Savin1V.V. Dokuchaev Soil Science Institute, Moscow, Russia; Corresponding author.V.V. Dokuchaev Soil Science Institute, Moscow, Russia; Institute of Environmental Engineering, Peoples Friendship University of Russia (RUDN University), Moscow, RussiaRobust and detailed quantitative prediction of soil organic carbon (SOC) is of great significance to studying the carbon budget, soil management and decision-making. Spatial variations of SOC content were modelled using 863 soil profiles and a set of 22 environmental covariates representing relief, bioclimate variables and remote sensing data. The article provided the results of 3D modeling of SOC content in several soil layers (0–5, 5–15, 15–30, 30–60 and 60–100 cm) for the territory of the Russian Federation with 500 m spatial resolution. Machine learning framework was used, with random forest and spatial cross-validation techniques (150 km blocks) to handle the spatial autocorrelation of the training points. Compared with randomized cross-validation (R2 0.66, Concordance Correlation Coefficient (CCC) 0.79, RMSE 0.99 g/kg), using spatial cross-validation to predict the SOC content yielded less accurate results — R2 0.45, CCC 0.63, RMSE 1.41 g/kg. Regarding the importance of the variables, soil depth and temperature seasonality were major contributors to the SOC content prediction, followed by the EVI, 7 (MIR) MODIS band, and the topographic wetness index. The model was next evaluated with procedure so-called „area of applicability“ (AOA) of prediction model — the areas for which we cannot estimate prediction quality. AOA spatial distribution showed that the feature space not represented by training data is located in the mountain provinces. The proposed framework can be used for SOC modeling with a limited soil profile number, and it is provides a reproducible approach for long-term SOC monitoring.http://www.sciencedirect.com/science/article/pii/S111098232300056XSoil carbonSpatial predictionRandom forestSpatial cross-validationRussiaArea of applicability
spellingShingle Andrey Chinilin
Igor Yu. Savin
Combining machine learning and environmental covariates for mapping of organic carbon in soils of Russia
Egyptian Journal of Remote Sensing and Space Sciences
Soil carbon
Spatial prediction
Random forest
Spatial cross-validation
Russia
Area of applicability
title Combining machine learning and environmental covariates for mapping of organic carbon in soils of Russia
title_full Combining machine learning and environmental covariates for mapping of organic carbon in soils of Russia
title_fullStr Combining machine learning and environmental covariates for mapping of organic carbon in soils of Russia
title_full_unstemmed Combining machine learning and environmental covariates for mapping of organic carbon in soils of Russia
title_short Combining machine learning and environmental covariates for mapping of organic carbon in soils of Russia
title_sort combining machine learning and environmental covariates for mapping of organic carbon in soils of russia
topic Soil carbon
Spatial prediction
Random forest
Spatial cross-validation
Russia
Area of applicability
url http://www.sciencedirect.com/science/article/pii/S111098232300056X
work_keys_str_mv AT andreychinilin combiningmachinelearningandenvironmentalcovariatesformappingoforganiccarboninsoilsofrussia
AT igoryusavin combiningmachinelearningandenvironmentalcovariatesformappingoforganiccarboninsoilsofrussia