Model

R²

RMSE

F

Sig.

1

Clay CEC = 19.86 − 6.46 × 10⁻⁸ Sand³ + 1.32 × 10⁻⁵ Sand² + 0.01Sand

0.102

5.33

3.08

0.032

2

Clay CEC = 5.09 + 5.14 × 10⁻⁷ Silt³ + 0.14Silt

0.180

5.09

5.92

0.001

3

Clay CEC = 11.47 − 0.01 ${\text{CEC}}_{\text{soil}}^{\text{3}}$ + 0.17 ${\text{CEC}}_{\text{soil}}^{\text{2}}$ − 0.47CEC_soil

0.473

4.08

24.20

0.000

4

Clay CEC = −12.66 − 0.04 ${\text{CEC}}_{\text{clay-c}}^{\text{2}}$ + 2.11CEC_clay−c

0.437

4.22

20.92

0.000

5

Clay CEC = −3.40 + 0.01Sand + 0.02Silt + 1.05CEC_soil

0.589

3.61

38.64

0.000

6

Clay CEC = 10.32 − 0.14pH − 0.05OM − 0.11Fe₂O₃ + 0.01Silt − 0.01Clay + 1.17CEC_soil

0.705

3.11

31.07

0.000