Table 2 Relationship between gibbsite equilibrium constant (Kgibb) and soil organic matter content.

From: High-resolution maps of critical loads for sulfur and nitrogen in China

Soil organic matter (%)

<1.5

1.5–3.5

3.5–5.0

5.0–15

15–30

>30

Kgibb (m6/eq2)

9500

3000

950

300

100

9.5