• Laser & Optoelectronics Progress
  • Vol. 57, Issue 19, 192801 (2020)
Guolin Ma1、2、3, Jianli Ding1、2、3、*, and Zipeng Zhang1、2、3
Author Affiliations
  • 1College of Resources & Environmental Science, Xinjiang University, Urumqi, Xinjiang 830046, China;
  • 2Key Laboratory of Oasis Ecology, Ministry of Education, Xinjiang University, Urumqi, Xinjiang 830046, China
  • 3Key Laboratory of Smart City and Environment Modelling of Higher Education Institute, Xinjiang University, Urumqi, Xinjiang 830046, China
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    DOI: 10.3788/LOP57.192801 Cite this Article Set citation alerts
    Guolin Ma, Jianli Ding, Zipeng Zhang. Soil Organic Matter Content Estimation Based on Soil Covariate and VIS-NIR Spectroscopy[J]. Laser & Optoelectronics Progress, 2020, 57(19): 192801 Copy Citation Text show less
    Distribution of the study area and sampling points
    Fig. 1. Distribution of the study area and sampling points
    PCA-Mahalanobis distance distribution
    Fig. 2. PCA-Mahalanobis distance distribution
    Original spectra and the pretreated soil spectral reflectance curves. (a) Original spectral reflectance; (b) spectral reflectance after SG smoothing; (c) spectral reflectance corrected for multiple scattering; (d) spectral reflectance treated with first order differentiation
    Fig. 3. Original spectra and the pretreated soil spectral reflectance curves. (a) Original spectral reflectance; (b) spectral reflectance after SG smoothing; (c) spectral reflectance corrected for multiple scattering; (d) spectral reflectance treated with first order differentiation
    Contribution diagram of the first 10 variables. (a) Original spectral reflectance; (b) spectral reflectance after SG-MSC treatments; (c) spectral reflectance after SG-MSC-FD treatments
    Fig. 4. Contribution diagram of the first 10 variables. (a) Original spectral reflectance; (b) spectral reflectance after SG-MSC treatments; (c) spectral reflectance after SG-MSC-FD treatments
    Comparison of soil organic matter prediction variables
    Fig. 5. Comparison of soil organic matter prediction variables
    Correlation between different soil parameters (n=101), in which the curves are fitting curves
    Fig. 6. Correlation between different soil parameters (n=101), in which the curves are fitting curves
    Correlation between SOM, EC, Fe and pH and original spectral reflectance (n=101)
    Fig. 7. Correlation between SOM, EC, Fe and pH and original spectral reflectance (n=101)
    Correlation between soil organic matter and the first five principal components for original spectrum and preprocessed spectra under two spectral treatments of SG-MSC and SG-MSC-FD
    Fig. 8. Correlation between soil organic matter and the first five principal components for original spectrum and preprocessed spectra under two spectral treatments of SG-MSC and SG-MSC-FD
    Fitting scatter diagrams of PLSR model under three strategies. (a) Model 1; (b) model 2; (c) model 3; (d) model 4; (e) model 5; (f) model 6; (g) model 7
    Fig. 9. Fitting scatter diagrams of PLSR model under three strategies. (a) Model 1; (b) model 2; (c) model 3; (d) model 4; (e) model 5; (f) model 6; (g) model 7
    VIP values of prediction variables in different PLSR models. (a) Model 3; (b) model 4; (c) model 5
    Fig. 10. VIP values of prediction variables in different PLSR models. (a) Model 3; (b) model 4; (c) model 5
    PropertyDataset(CV/%)nMinMeanMaxStd
    Content ofSOM /(g·kg-1)Whole(57.91)1010.608.9423.005.18
    Calibration(57.33)680.608.9023.005.10
    Validation(59.92)331.39.0221.725.41
    EC /(dS·cm-1)Whole(86.52)1010.056.5428.405.66
    Content of Fe /(g·kg-1)Whole(56.93)1010.1013.1825.917.67
    pHWhole(4.12)1018.228.879.930.37
    Table 1. Statistical characteristics of soil properties
    StrategyVariableCalibration setValidation set
    Model numberR2RMSER2RMSERPD
    StrategyIOriginal spectrum10.693.420.663.121.73
    SG-MSC20.693.350.673.101.76
    SG-MSC-FD30.842.140.822.512.15
    StrategyIISoil auxiliary covariates40.444.190.404.461.21
    StrategyIIIOriginal spectrum combined withsoil auxiliary covariates50.753.090.673.101.74
    SG-MSC combined with soil auxiliary covariates60.861.910.832.542.13
    SG-MSC-FD combined with soil auxiliary covariates70.911.540.881.202.70
    Table 2. PLSR modeling results under three strategies
    Guolin Ma, Jianli Ding, Zipeng Zhang. Soil Organic Matter Content Estimation Based on Soil Covariate and VIS-NIR Spectroscopy[J]. Laser & Optoelectronics Progress, 2020, 57(19): 192801
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