The Effects of Spectral Pretreatments on Chemometric Analyses of Soil Profiles Using Laboratory Imaging Spectroscopy

Table 4

Number of latent PLSR variables, coefficient of determination (𝑅²), adjusted 𝑅², and relative root mean square error (%RMSE) for the selected PLSR models of chemical constituents of the Podzol.

		Al	Fe	Mn	C	N
	𝑁	7	7	7	5	4
𝑅	𝑅^2	0.81	0.82	0.55	0.49	0.36
	adj. 𝑅^2	0.76	0.77	0.44	0.40	0.27
	%RMSE	34.3	32.1	28.8	58.9	75.3
	𝑁	5	5	5	4	4
SNV-DT	𝑅^2	0.79	0.83	0.55	0.51	0.36
	adj. 𝑅^2	0.76	0.81	0.47	0.45	0.28
	%RMSE	36.0	30.9	28.6	56.6	71.2
	𝑁	5	5	4	1	1
Diff	𝑅^2	0.78	0.79	0.51	0.41	0.31
	adj. 𝑅^2	0.74	0.75	0.45	0.40	0.28
	%RMSE	36.9	34.8	29.6	61.3	71.0
	𝑁	4	3	4	3	1
2nd Diff	𝑅^2	0.76	0.78	0.56	0.53	0.23
	adj. 𝑅^2	0.73	0.76	0.51	0.49	0.20
	%RMSE	38.8	35.3	28.0	55.3	75.2
	𝑁	3	6	5	1	1
CR	𝑅^2	0.84	0.78	0.49	0.56	0.28
	adj. 𝑅^2	0.82	0.73	0.40	0.54	0.26
	%RMSE	31.4	36.1	31.0	53.2	72.3
	𝑁	6	6	7	7	3
NCR	𝑅^2	0.78	0.77	0.61	0.71	0.28
	adj. 𝑅^2	0.73	0.72	0.51	0.64	0.21
	%RMSE	37.6	36.9	26.9	42.9	74.7
	𝑁	6	5	6	6	5
MSC	𝑅^2	0.81	0.82	0.53	0.52	0.43
	adj. 𝑅^2	0.77	0.79	0.44	0.42	0.33
	%RMSE	34.7	31.7	29.3	57.1	68.4
	𝑁	5	4	8	5	4
EMSC	𝑅^2	0.80	0.77	0.57	0.49	0.41
	adj. 𝑅^2	0.76	0.73	0.44	0.41	0.33
	%RMSE	35.4	36.8	28.1	58.1	66.2