Table 4. Stepwise multiple linear regression equations.

Regression equations	n	R 2	P	RMSE
log[LREEpulp] = −1.214 + 0.296 log[LREEsoil] − 0.050 pH − 0.326 log[CEC] + 0.376 log[Feox]	114	0.59	<0.000	0.14	(12)
log[HREEpulp] = −1.499 + 0.346 log[HREEsoil] − 0.056 pH − 0.389 log[CEC] + 0.260 log[Feox]	114	0.53	<0.000	0.18	(13)
log [REEpulp] = −1.036 + 0.272 log[REEsoil] − 0.056 pH − 0.360 log[CEC] + 0.370 log[Feox]	114	0.60	<0.000	0.14	(14)