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. 2016 Apr 15;153:92–105. doi: 10.1016/j.chemolab.2016.02.013

Table 5.

Calibration and validation (independent samples) sets' R2 and Q2 values. C refers to total soil carbon. No archetypes generated for 2nd derivatives spectra.

Subspace Preprocessing R2 for calibration set; n = 1329
Q2 for validation set; n = 575
pH m3.Al m3.Ca C Clay Sand pH m3.Al m3.Ca C Clay Sand
HQI First derivative 0.86 0.88 0.91 0.93 0.78 0.77 0.60 0.82 0.59 0.86 0.80 0.83
Second derivative 0.90 0.90 0.91 0.92 0.80 0.79 0.73 0.79 0.65 0.85 0.78 0.84
Msc 0.81 0.82 0.89 0.90 0.74 0.70 0.10 0.50 0.10 0.10 0.63 0.60
SNV 0.80 0.96 0.98 0.98 0.93 0.83 0.33 0.69 0.10 0.75 0.81 0.82
SNV_Detrend 0.80 0.82 0.89 0.92 0.74 0.72 0.35 0.73 0.10 0.77 0.78 0.81
Cosine First derivative 0.83 0.85 0.90 0.88 0.74 0.73 0.61 0.84 0.50 0.85 0.75 0.78
Second derivative 0.85 0.86 0.89 0.89 0.78 0.77 0.69 0.83 0.62 0.79 0.75 0.78
Msc 0.79 0.81 0.89 0.89 0.73 0.72 0.10 0.10 0.10 0.10 0.43 0.34
SNV 0.78 0.80 0.88 0.87 0.73 0.72 0.55 0.76 0.10 0.63 0.73 0.73
SNV_Detrend 0.79 0.82 0.88 0.91 0.74 0.72 0.44 0.72 0.22 0.78 0.73 0.74
SOM First derivative 0.85 0.88 0.91 0.92 0.79 0.78 0.59 0.78 0.41 0.86 0.79 0.80
Second derivative 0.89 0.90 0.91 0.92 0.80 0.80 0.71 0.81 0.54 0.84 0.79 0.82
Msc 0.80 0.81 0.90 0.91 0.74 0.72 0.10 0.06 0.10 0.40 0.46 0.61
SNV 0.81 0.81 0.89 0.92 0.74 0.71 0.53 0.77 0.55 0.81 0.76 0.76
SNV_Detrend 0.80 0.81 0.89 0.93 0.74 0.71 0.46 0.77 0.57 0.80 0.75 0.77
Archetype First derivative 0.87 0.89 0.91 0.93 0.79 0.78 0.60 0.79 0.41 0.87 0.79 0.80
Second derivative
Msc 0.80 0.82 0.89 0.91 0.75 0.72 0.10 0.06 0.10 0.40 0.47 0.61
SNV 0.81 0.83 0.89 0.90 0.74 0.71 0.53 0.79 0.55 0.79 0.76 0.76
SNV_Detrend 0.80 0.82 0.88 0.93 0.76 0.73 0.46 0.78 0.56 0.80 0.77 0.79
All First derivative 0.87 0.89 0.91 0.93 0.79 0.78 0.62 0.84 0.29 0.78 0.79 0.81
Second derivative 0.74 0.85 0.67 0.86 0.80 0.81 0.52 0.80 0.21 0.72 0.80 0.84
Msc 0.82 0.83 0.90 0.92 0.75 0.72 0.10 0.17 0.10 0.26 0.45 0.39
SNV 0.82 0.83 0.89 0.92 0.75 0.72 0.58 0.78 0.28 0.77 0.75 0.75
SNV_Detrend 0.81 0.84 0.89 0.93 0.75 0.73 0.49 0.78 0.29 0.80 0.76 0.76