Table 1.
Characteristic clay minerals of typical soil types formed under different climate conditions.
| Climate [41] | Soil types [40] | Characteristic clay phases [44] | pH [40] | |
|---|---|---|---|---|
| Tropical to subtropical | Humid | Ferralsols; Lixisols; Acrisols | Kaolinite (or halloysite), Fe-, Al-oxyhydroxides | 3–5 |
| Contrasted wet-dry | Lixisols; Acrisols; Luvisols, Retisols; Vertisol | Kaolinite, smectite, illite, vermiculite, Fe-, Al-oxyhydroxides | 4–6 | |
| Semi-arid to arid | Vertisol; Gypsisols; Calcisols | Illite, vermiculite, mixed-layers, chlorite | 6–8 | |
| Temperate rainfall (variable temperature); monsoon climate | Andosols | Halloysite, kaolinite/smectite, Fe-hydroxy-oxides | 4–5 | |
| Temperate | Warm, or humid | Podzols; Umbrisols, Luvisols | Illite, vermiculite, I/S minerals, Fe-oxides | 3–4 |
| Cool, dry | Solonetz; Vertisols; Phaeozems; Fluvisols | Illite, illitic I/S minerals | 6–7 | |
| Cool | Phaeozems; Umbrisols; Fluvisols | Vermiculite and hydroxy-interlayered (HI) minerals | 6–9 | |
| Arid to semiarid | Solonchaks; Gypsisols; Calcisols | Sepiolite, palygorskite, I/S, carbonates (smectite, illite, chlorite, kaolinite) | 7–9 | |
| Dry continental zone | Phaeozems, Chernozems, Kastanozems | Illite, smectite, vermiculite, chlorite | 6–7 | |
| Very cold | Glacial and peri-glacial climate | Cryosols, Leptosols | Illite, chlorite | 5–7 |