| Clue | Source | Date |
|---|---|---|
| Clay-based fertilisers | The Telegraph Cross Atlantic | 13 Jun 2024 |
| Clayey soils | Wall Street Journal | 15 Jun 2019 |
| Clayey soils | ||
| Crumbly, friable soils | Universal | 22 Jun 2017 |
| Crumbly, friable soils | ||
| Crumbly earth deposits | Universal | 24 Jun 2016 |
| Crumbly earth deposits | ||
| Earthy deposits | ||
| Friable soils | ||
| Loose clays | ||
| Clay mixtures | ||
| Earthy deposits | ||
| Fertilizes with loam | ||
| Crumbly earth deposits | ||
| Friable soils | ||
| Fertilizes | ||
| Fertilizers. | ||
| Crumbly soils. | ||
| Clayey deposits. | ||
| Earthy deposits. | ||
| Clay soils. | ||
| Soils of clay and sand. | ||
| Valuable fertilizers. |