Table 1 Different methods of soil carbon determination used in referred authors
| Methods* | Number of observations | Percentage proportion (%) |
|---|---|---|
| Ex-situ methods: | ||
|
1. Walkley and Black Method (Wet oxidation or combustion) | 21 | 58.2% |
| 2. Dry combustion method: CN analyser | 9 | 25% |
| 3. Dry combustion: weight-loss-on-ignition | 2 | 5.6% |
| In-situ methods (in combination with Ex-situ methods): | ||
| 4. Isotope ratio mass spectrometer | 1 | 2.8% |
|
5. Dry combustion coupled Infra-red spectroscopy Isotope mass spectrometer | 2 | 5.6% |
|
6. Walkley and Black Method coupled Reflectance spectrometer | 1 | 2.8% |
| Total | 36 | 100 |