Table 2 Soil organic carbon pools and different units reported by referred authors
Soil organic carbon pool* | Number of observations | Percentage proportion (%) |
|---|---|---|
1. Soil carbon concentration (g/kg) | 3 | 8.3% |
2. Soil carbon concentration (%) | 9 | 25% |
 Soil carbon concentration |  | 33.3% |
3. Soil carbon stock (Mg/ha) | 3 | 8.3% |
4. Soil carbon stock (kg m-2) | 1 | 2.8% |
5. Soil carbon stock (t/ha) | 1 | 2.8% |
 Soil carbon stock |  | 13.9% |
6. Soil carbon concentration (g/kg) and Soil carbon stock (Mg/ha) | 6 | 16.7% |
7. Soil carbon concentration (%) and Soil carbon stock (Mg/ha) | 8 | 22.2% |
8. Soil carbon concentration (%) and Soil carbon stock (t/ha) | 3 | 8.3% |
9. Soil carbon concentration (g/kg) and Soil carbon stock (g m-2) | 1 | 2.8% |
10. Soil carbon concentration (%) and Soil carbon stock (g m-2) | 1 | 2.8% |
 Soil carbon concentration and Carbon stock |  | 52.8% |
Total | 36 | 100 |