Fig 5. Independent validation results: Predicted vs. measured topsoil organic carbon concentrations using the Cubist model with different predictor datasets:

(a) Prediction results from Model A (UW). The RSAE data and one estimated spectrum (1930 nm) were used for model calibration; the model was built on the combined upland & wetland dataset (validation: 82 samples). (b) Prediction results from Model B (UW). Only RSAE data were used for model calibration, and the model was based on the same soil dataset as model A (UW). (c) Prediction results from Model C (U). The RSAE data and one estimated spectrum (1930 nm) were used for model calibration; the model was built on only the upland soil dataset (validation: 61 samples).