Prediction of Soil Organic Carbon for Ethiopian Highlands Using Soil Spectroscopy

Table 3

Summary of model results.

	Model	Number of samples	𝑅^2	RMSE (%)	RPD
Anjeni	Calibration	145	90	0.46	3.1
	Validation	96	88	0.44	3.1
Bale	Calibration	59	93	0.42	3.7
	Validation	59	86	0.52	2.7
Basketo	Calibration	81	93	0.46	3.9
	Validation	81	89	0.57	3.0
Benishangul	Calibration	64	97	0.18	6.0
	Validation	64	91	0.30	3.4
Kersa	Calibration	135	90	0.35	3.2
	Validation	135	82	0.44	2.4
Kolatembien	Calibration	51	88	0.33	2.3
	Validation	51	75	0.44	1.9
Maybar	Calibration	115	87	0.53	2.8
	Validation	115	84	0.57	2.5
Megech	Calibration	118	94	0.11	4.0
	Validation	118	85	0.15	2.6
Wondogenet	Calibration	57	90	0.46	3.2
	Validation	57	86	0.52	2.7

𝑅²: the coefficient of determination, RMSE: root mean square error, RPD: ratio of performance deviation.