Soil layer (cm)

C₀

C

C₀ +C

a(m)

R²

RSS

F

Model

0 - 20

1.21

20.49

21.7

0.0558

30.13

0.906

0.89

**

Gaussian

20 - 40

0.21

21.45

21.66

0.0097

25.28

0.829

1.73

*

Gaussian

40 - 60

0.06

9.57

9.63

0.0062

25.66

0.841

1.11

*

Gaussian

60 - 80

0.05

14.85

14.9

0.0034

25.46

0.837

1.05

*

Gaussian