Characteristics | Class I | Class II | Class III | Class IV | Class V | Class VI | Class VII | Class VIII |
Topography (t) | ||||||||
Slope (%) | 0 - 1 | 1 - 3 | 3 - 8 | 8 - 15 | up to 3 | 15 - 35 | 35 - 50 | >50 |
Erosion | nil | slight | moderate | severe | nil | severe | very severe |
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Wetness (w) | ||||||||
Flooding | nil (F0) | nil (F0) (F0/F1) | nil to slight (F1/F2) |
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Drainage (l) | well | mod. well | imperfect | poor | v. poor | excessive | excessive | excessive |
Permeability | moderate | mod. rapid | rapid, slow | v. rapid, v. slow | - | - | - | - |
Infiltration rate (cm∙hr−1) | 2 - 3.5 | 1 - 2 3 - 5 | 0.5 - 1.0 5 - 10 | <0.5 >10 | 2.0 |
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Soil conditions (s) | ||||||||
Surface texture | l | sil & cl | sl & c | scl | s, c(m) | ls, cl | ls, s, c | ls, s, c (m) |
Surface coarse fragments (vol %) | 1 - 3 | 3 - 15 | 15 - 40 | 40 - 75 | 15 - 75 | 75+ |
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Surface stoniness (%) | <1 | 1 - 3 | 3 - 5 | 5 - 8 | 8 - 15 | 15 - 40 | 40 - 75 | >75 |
Subsurface coarse fragments (%) | <15 | <15 | 15 - 35 | 35 - 50 | 50 - 75 | 50 - 75 | 50 - 75 | >75 |
Soil depth (cm) | >150 | 150 - 100 | 100 - 50 | 50 - 25 | - | 25 - 10 | 25 - 10 | <10 |
Profile development | Cambic/ Argillic hor. A - (B) - C | A - B - C | Stratified A - C; A - B - C | Salic(Z)/Calcic (Z) hor. A - Bz - C/ ABk - C | Az - C, A - Bz - C | Gypsic (y) hor. A - Cy | A – C (Stony) | A - C (bouldery) |
Fertility (f) | ||||||||
CEC (cmol (p+)/kg | 40 - 16 | 16 - 12 | 16 - 12 | - | - | - | - | - |
Base saturation (%) | 80+ | 80+ | 80 - 50 | 50 - 35 | 50 - 35 | 35 - 15 | <15 | - |
Organic carbon (0 - 15 cm) (g∙kg−1) | >10 | 7.5 - 10 | 5 - 7.5 | <5 | <5 | - | - | - |
Salinity EC (dS∙m−1) | <1.0 | 1 - 2 | 2 - 4 | 4 - 8 | 8 - 15 | 15 - 35 | 35 - 50 | >50 |
Gypsum | 0.3 - 2.0 | 2 - 5 | 5 - 10 | 10 - 15 | 15 - 25 | >25 | - | - |