Fig 1.
Location of study area and sampling sizes.
Fig 2.
The flowchart of this research.
Table 1.
Statistical characteristics of soil organic matter content.
Fig 3.
Soil mean spectral curves and continuum removal of different SOM content.
Fig 4.
Correlation coefficient distribution between soil spectral data and SOM content.
Fig 5.
Relationship between SOM and deviation of arch related wavelengths.
Fig 6.
A contour map of the correlations between SOM content and spectral index (n = 178).
Table 2.
The optimal spectral indexes selected by correlation for each spectral transformation.
Table 3.
The correlation between SOM and bands composing of optimal spectral indexes.
Fig 7.
Key variables selected by CARS of raw spectra.
Fig 8.
Plot of screened bands based on CARS for different spectral transformations.
Table 4.
SOM modeling results using optimal spectral index datasets.
Fig 9.
Scatter plots of measured and predicted SOM (n = 45).
Table 5.
SOM modeling results using full spectral bands.
Fig 10.
Scatter plots of measured and predicted SOM of CARS-based models (n = 45).
Table 6.
SOM modeling results using characteristic bands.