Table 4.

Summary of soil properties for both calibration and independent validation set for self-organizing maps spectral subspaces.

			Calibration						Validation
Subspace	Variable	Units	n	Min	Max	Mean	s.d	%CV	n	Min	Max	Mean	s.d	%CV
SOM1
	Clay	%	202	0.32	55.71	19.7	11.2	56.9	172	3.3	69.47	15.5	10.5	67.7
	m3.Al	ppm	202	106	1660	470.6	219.1	46.6	172	60.9	1490	332.1	167.5	50.4
	m3.Ca	ppm	202	29.26	3696	402.4	387.1	96.2	172	0	1700	392.6	276	70.3
	pH	–	202	4.32	8.78	5.9	0.7	11.9	172	4.72	9.86	6.1	0.8	13.1
	Sand	%	202	15.58	99.68	62.7	19.7	31.4	172	8.93	93.89	74.5	14.8	19.9
	Totalcarbon	%	202	0.11	1.58	0.5	0.3	60.0	172	0.09	1.64	0.3	0.2	66.7
SOM2
	Clay	%	458	1.55	87.61	36.8	17.8	48.4	218	12.13	100	36.9	16.5	44.7
	m3.Al	ppm	458	224	1903	827.8	329.6	39.8	218	271	2120	796.2	378.9	47.6
	m3.Ca	ppm	458	63	5862	763.5	672.1	88.0	218	9	3220	489.2	529.5	108.2
	pH	–	458	3.94	8.76	6	0.9	15.0	218	4.01	9.43	5.7	0.9	15.8
	Sand	%	458	1.59	97.83	46.4	22.1	47.6	218	0.82	78.57	43.2	18.3	42.4
	Totalcarbon	%	458	0.14	6.66	0.9	0.7	77.8	218	0.08	3.16	0.7	0.5	71.4
SOM3
	Clay	%	439	3.83	99.27	55.9	22.4	40.1	134	9.68	100	70.3	16.4	23.3
	m3.Al	ppm	439	345.8	3041	1224	487.2	39.8	134	430	2240	1064.6	346.4	32.5
	m3.Ca	ppm	439	83.9	8550	1330.4	1208.9	90.9	134	20.8	5290	1368.4	1325.5	96.9
	pH	–	439	4	8.79	6	0.8	13.3	134	4.19	9.72	5.9	0.9	15.3
	Sand	%	439	0.12	93.63	24.4	20.1	82.4	134	0.12	67.55	13.8	12.6	91.3
	Totalcarbon	%	439	0.11	7.4	1.9	1.5	78.9	134	0.21	9.4	1.6	1.3	81.3
SOM4
	Clay	%	230	4.23	97.3	59.2	19	32.1	51	24.77	100	53.9	17	31.5
	m3.Al	ppm	230	1.67	1640	573.5	321.7	56.1	51	14.3	1940	930.3	550.4	59.2
	m3.Ca	ppm	230	593	35,200	8512.1	6174.1	72.5	51	73.4	11,000	3415.9	2821.3	82.6
	pH	–	230	3.61	9.27	7.9	0.9	11.4	51	4.08	8.89	7	1.3	18.6
	Sand	%	230	1.38	93.29	22.2	17.2	77.5	51	0.97	100	25.9	18.4	71.0
	Totalcarbon	%	230	0.19	11.29	2.1	2	95.2	51	0.49	6.98	2.4	1.9	79.2