| • Humus or other biogenic topsoil |
| • Natural soil: gravel, sand |
| • Natural soil: glacial till |
| • Natural soil: clay, silt |
| • Natural soil: peat |
| • Coarse-grained man-made soil material |
| • Man-made soil material with a varying grain-size distribution |
| • Fine-grained man-made soil material |
| • Mineral soil rich in organic matter |