Table 3: Performance of model fits using spectra of samples under field conditions, evaluated with leave-one-out cross validation.

pHTotal P (mg/100 g)Total K (mg/100 g)Total N (%)Total N (%)Total C (%)Total C (%)Moisture (%)

MethodPLSRPLSRPLSRPLSRSMLRPLSRSMLRPLSR

No. of factors42224481
0.450.160.440.340.430.450.740.11
RMSE CV0.4834.93314.730.400.398.386.0312.7
RPD CV1.351.091.351.241.281.371.901.05

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.