Prediction of soil organic matter using different soil classification hierarchical level stratification strategies and spectral characteristic parameters

Whether a finer soil classification hierarchical stratification strategy and the spectral characteristic parameters (SCPs) that describe the shape of the spectral curve can be used to improve the prediction accuracy of soil organic matter should be clarified. We measured the visible, near-infrared a...

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Main Authors: Xiangtian Meng, Yilin Bao, Xinle Zhang, Xiang Wang, Huanjun Liu
Format: Article
Language:English
Published: Elsevier 2022-04-01
Series:Geoderma
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S0016706122000039
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author Xiangtian Meng
Yilin Bao
Xinle Zhang
Xiang Wang
Huanjun Liu
author_facet Xiangtian Meng
Yilin Bao
Xinle Zhang
Xiang Wang
Huanjun Liu
author_sort Xiangtian Meng
collection DOAJ
description Whether a finer soil classification hierarchical stratification strategy and the spectral characteristic parameters (SCPs) that describe the shape of the spectral curve can be used to improve the prediction accuracy of soil organic matter should be clarified. We measured the visible, near-infrared and shortwave infrared (VIS-NIR-SWIR, 400 – 2500 nm) spectral reflectance of 322 topsoil samples. The spectral reflectance was converted to continuum removal curves, and then, SCPs were extracted based on the curves. According to the results of the Second National Soil Survey of China, the samples were divided into 4 great groups or 8 genus, and a variety of stratification strategies were constructed based on great group (GR-S), genus (GE-S), spectral similarity (SS-S) and decision tree model (DT-S). A local random forest model was established to evaluate the performance of different stratification strategies and input variables. Our results are described as follows: (1) In different stratification strategies, the SOM prediction model based on DT-S exhibits the highest accuracy, followed by the SOM prediction models based on GE-S and SS-S; the SOM prediction model based on GR-S exhibits the lowest accuracy; (2) among the different input variables, the root mean squared error (RMSE) and coefficient of determination (R2) of the best SOM model predicted by SCPs are 5.18 g kg−1 and 0.89, respectively. Compared with the original reflectance based on the nonstratified strategy, the RMSE decreases by 4.88 g kg−1 and R2 increases by 0.32. The study results highlight the advantages of refining the soil hierarchy, which is helpful for identifying the differences in soils at the regional scale and analysing the relationship between stratification results and the characteristics of the soil environment to obtain a highly accurate prediction model.
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spelling doaj.art-c5241c75eb78456a99ec20e91b89e3a62023-07-31T04:08:59ZengElsevierGeoderma1872-62592022-04-01411115696Prediction of soil organic matter using different soil classification hierarchical level stratification strategies and spectral characteristic parametersXiangtian Meng0Yilin Bao1Xinle Zhang2Xiang Wang3Huanjun Liu4Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, Jilin, ChinaCollege of Earth and Planetary Sciences, University of Chinese Academy of Sciences, 100049 Beijing, ChinaCollege of Information Technology, Jilin Agricultural University, Changchun 130118, ChinaNortheast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, Jilin, ChinaNortheast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, Jilin, China; Corresponding author.Whether a finer soil classification hierarchical stratification strategy and the spectral characteristic parameters (SCPs) that describe the shape of the spectral curve can be used to improve the prediction accuracy of soil organic matter should be clarified. We measured the visible, near-infrared and shortwave infrared (VIS-NIR-SWIR, 400 – 2500 nm) spectral reflectance of 322 topsoil samples. The spectral reflectance was converted to continuum removal curves, and then, SCPs were extracted based on the curves. According to the results of the Second National Soil Survey of China, the samples were divided into 4 great groups or 8 genus, and a variety of stratification strategies were constructed based on great group (GR-S), genus (GE-S), spectral similarity (SS-S) and decision tree model (DT-S). A local random forest model was established to evaluate the performance of different stratification strategies and input variables. Our results are described as follows: (1) In different stratification strategies, the SOM prediction model based on DT-S exhibits the highest accuracy, followed by the SOM prediction models based on GE-S and SS-S; the SOM prediction model based on GR-S exhibits the lowest accuracy; (2) among the different input variables, the root mean squared error (RMSE) and coefficient of determination (R2) of the best SOM model predicted by SCPs are 5.18 g kg−1 and 0.89, respectively. Compared with the original reflectance based on the nonstratified strategy, the RMSE decreases by 4.88 g kg−1 and R2 increases by 0.32. The study results highlight the advantages of refining the soil hierarchy, which is helpful for identifying the differences in soils at the regional scale and analysing the relationship between stratification results and the characteristics of the soil environment to obtain a highly accurate prediction model.http://www.sciencedirect.com/science/article/pii/S0016706122000039Soil organic matterStratification strategySoil hierarchicalDecision treeDensity peak clusteringSpectral characteristic parameters
spellingShingle Xiangtian Meng
Yilin Bao
Xinle Zhang
Xiang Wang
Huanjun Liu
Prediction of soil organic matter using different soil classification hierarchical level stratification strategies and spectral characteristic parameters
Geoderma
Soil organic matter
Stratification strategy
Soil hierarchical
Decision tree
Density peak clustering
Spectral characteristic parameters
title Prediction of soil organic matter using different soil classification hierarchical level stratification strategies and spectral characteristic parameters
title_full Prediction of soil organic matter using different soil classification hierarchical level stratification strategies and spectral characteristic parameters
title_fullStr Prediction of soil organic matter using different soil classification hierarchical level stratification strategies and spectral characteristic parameters
title_full_unstemmed Prediction of soil organic matter using different soil classification hierarchical level stratification strategies and spectral characteristic parameters
title_short Prediction of soil organic matter using different soil classification hierarchical level stratification strategies and spectral characteristic parameters
title_sort prediction of soil organic matter using different soil classification hierarchical level stratification strategies and spectral characteristic parameters
topic Soil organic matter
Stratification strategy
Soil hierarchical
Decision tree
Density peak clustering
Spectral characteristic parameters
url http://www.sciencedirect.com/science/article/pii/S0016706122000039
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AT xinlezhang predictionofsoilorganicmatterusingdifferentsoilclassificationhierarchicallevelstratificationstrategiesandspectralcharacteristicparameters
AT xiangwang predictionofsoilorganicmatterusingdifferentsoilclassificationhierarchicallevelstratificationstrategiesandspectralcharacteristicparameters
AT huanjunliu predictionofsoilorganicmatterusingdifferentsoilclassificationhierarchicallevelstratificationstrategiesandspectralcharacteristicparameters