Table 1.
Overview of the obtained publications matching the search and eligibility criteria
| Criterion | SOC concentration | SOC stocks | C sequestration |
| Type of publications | |||
| Scientific journals | 70 publications | 26 publications | 18* publications |
| Dissertations/books chapters/proceedings | 4 publications | 3 publications | 2* publications |
| Type of comparisons | |||
| Plot scale | 26 publications | 23 publications | 19 publications |
| Farm scale | 48 publications | 16 publications | 1 publications |
| Coverage of land use types | Full coverage | Full coverage | Only arable and vegetables |
| Coverage of climatic zones | 6 of 8 (except boreal and arid) | 5 of 8 | 6 of 8 |
| Coverage of continents† | 5 of 6 (except Africa) | 5 of 6 (except Africa) | 5 of 6 (except Africa) |
| Sampling depth (top–bottom) (cm) | Mean: 2.4–18.4/median: 0–15.0 | Mean: 1.8–19.4/median: 0–15.0 | Mean: 0.8–22.5/median: 0–20.0 |
| For all SOC datasets | Mean: 1.8–19.0/median: 0–15 | ||
| Experimental duration (y) | Mean: 13.2/median: 8.0 | Mean: 16.1/median: 10.0 | Mean: 12.5/median: 11.0 |
| For all SOC datasets | Mean: 14.4/median: 10.0 | ||
SOC concentrations, stocks, and C sequestration rates are the three effect-sizes in this metaanalysis.
*Of 20 publications on SOC sequestration, 11 report measured bulk densities, for the other 9 bulk densities were estimated.
†Continents except Antarctica.