Indicator

Type

x₁

x₂

Function

SOM (g∙kg⁻¹)

M (x)

6

20

$\text{M}(x)=\{\begin{array}{l}0.1x<x_1\\ 0.9\times \frac{x-x_1}{x_2-x_1}+0.1x_1<x<x_2\\ 1x>x_2\end{array}$

$\text{L}(x)=\{\begin{array}{l}1x<x_1\\ 1-0.9\times \frac{x-x_1}{x_2-x_1}{x}_1<x<x_2\\ 0.1x>x_2\end{array}$

$\text{R}(x)=\{\begin{array}{l}0.1x<x_1\\ 0.9\times \frac{x-x_1}{r_1-x_1}+0.1x_1<x<r_1\\ 1r_1<x<r_2\\ 1-0.9\times \frac{x-r_2}{x_2-r_2}{r}_2<x<x_2\\ 0.1x>x_2\end{array}$

TN (g∙kg⁻¹)

M (x)

0.3

1.2

AP (mg∙kg⁻¹)

M (x)

5

15

AK (mg∙kg⁻¹)

M (x)

40

200

EC (mS∙cm⁻¹)

L (x)

0.2

4

BD (g∙cm⁻³)

L (x)

1.25

1.55

Clay %

R (x)

5

40

pH

R (x)

5.5

9.5