Class

Extremely high

High

Moderate to high

Low to moderate

Low

Extremely low

Organic matter

>40

30 - 40

20 - 30

10 - 20

6 - 10

<6

Total nitrogen

>2

1.5 - 2

1 - 1.5

0.75 - 1

0.5 - 0.75

<0.5