Use of FT-NIRS for determination of chemical components and nutritional value of natural pasture

Figures & data

Table 1. Descriptive statistics of samples’ composition.

	DM	CP	Ash	EE	CF	ADF	NDF	ADL	UFL	UFV
No.	105	105	103	105	98	103	101	100	98	100
Mean^a	27.06	13.89	10.01	1.91	27.58	34.49	51.99	5.72	0.87	0.76
SD^a	11.52	5.83	1.50	0.63	6.19	8.09	10.06	2.39	0.17	0.20
CV%	48.78	42.00	14.99	33.27	22.43	23.46	19.35	41.90	26.83	25.56
Min^a	11.14	4.19	6.55	0.51	17.58	12.51	30.82	1.72	0.51	0.38
Max^a	59.92	25.84	14.41	2.84	41.48	50.06	71.66	10.83	1.31	1.28

No.: number of samples; SD: standard deviation; CV: coefficient of variation.

^a Data are expressed as per cent on dry matter.

Table 2. Summary statistics for the PLS calibration and prediction models.

		Calibration (CAm)			Prediction (CPm)
Parameter	FPLS	R^2c	RMSE	RPD	R^2p	RMSEP	RPD
DM	8	0.997	0.937	11.8	0.993	0.973	9.4
CP	8	0.995	0.585	10.3	0.992	0.592	8.6
Ash	8	0.978	0.301	5.1	0.965	0.333	3.7
EE	8	0.989	0.091	7.0	0.982	0.137	4.6
CF	5	0.979	1.200	5.2	0.960	1.470	3.9
ADF	7	0.991	1.120	7.4	0.988	1.140	6.8
NDF	6	0.994	1.150	9.1	0.990	1.330	7.0
ADL	8	0.991	0.271	8.5	0.983	0.500	5.3
UFL	6	0.823	0.106	1.6	0.825	0.101	1.7
UFV	7	0.823	0.119	1.5	0.812	0.112	1.6

CAm: calibration models; CPm: external validation (prediction models); FPLS: number of PLS factors; R²c: coefficient of determination in calibration; R²p: coefficient of determination of prediction (external validation); RMSE: root-mean-square error of calibration; RMSEP: root-mean-square error of prediction (external validation); RPD: residual prediction deviation.

Table 3. Summary statistics of cross-validation of the PLS calibration model (CVm).

Parameter	FPLS	R^2CV	RMSECV
DM	8	0.957	0.980
CP	8	0.977	1.210
Ash	8	0.753	0.858
EE	8	0.924	0.245
CF	5	0.939	1.960
ADF	7	0.948	2.490
NDF	6	0.958	2.930
ADL	8	0.926	0.913
UFL	6	0.768	0.120
UFV	7	0.778	0.126

CVm: cross-validation models; FPLS: number of PLS factors; R²CV: coefficient of determination in cross-validation; RMSECV: root-mean-square error of cross-validation.