Table 2: Performance of model fits using lab spectra of dried samples, evaluated with leave-one-out cross-validation.

pH

Total P (mg/100 g)

Total K (mg/100 g)

Total N (%)

Total N (%)

Total C (%)

Total C (%)

Moisture (%)

Method

PLSR

PLSR

PLSR

PLSR

SMLR

PLSR

SMLR

PLSR

No. of factors

5

2

2

8

2

2

9

2

0.50

0.38

0.79

0.73

0.80

0.79

0.95

0.42

RMSE CV

0.47

29.77

193.92

0.26

0.23

5.17

2.59

10.09

RPD CV

1.42

1.28

2.20

1.93

2.18

2.22

4.43

1.33

RMSE CV: root mean square error of cross-validation, RPD CV: ratio of performance to deviation of cross-validation, PLSR: partial least squares regression, SMLR: stepwise multiple linear regression.