Mean annual temp. (˚C) | >25 | 22 - 25 | 20 - 22 | 18 - 20 | <18 |
Relative humidity (%) | >75 | 70 - 75 | 60 - 70 | - | <60 |
Topography (t) |
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Slope (%) | 0 - 8 | 8 -16 | 16 - 30 | 30 - 50 | >50 |
Wetness (w) |
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Drainage class | Moderate to Imperfect | Well and somewhat excessive | Poor (aeric) (easily drained) | Poor (typic) (difficult to drain) | Very poor |
Flooding | Not flooded | Not flooded | Minor | Moderate | Severe |
Soil physical properties (s) |
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Texture/structure | CL, SCL, L | SCL | SCL - LFS | Any | C, CS |
Coarse fragments (Vol %) 0 - 10 cm | <5 | 5 - 15 | 15 - 35 | 35 - 45 | >45 |
Depth (cm) | >100 | 75 - 100 | 50 - 75 | 25 - 50 | <25 |
Soil fertility conditions (f) |
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CEC (meq/100g) | ≥16 | <16 | - | - | - |
pH topsoil | 5.0 - 5.8 | 4.5 - 5.0; 6.0 - 7.0 | 4.0 - 4.5 | <4.0, >7.0 | <4.0, >7.0 |
Base saturation (%) | >35 | 20 - 35 | <20 | - | - |
Organic carbon (%) 0 - 15 cm | ≥1.5 | <1.5 | - | - | - |
Mg: K ratio | >3.5 | 2 - 3.5 | 1 - 2 | - | - |
K (mole fraction) | >1.75 | 1.5 - 1.75 | 1.2 - 1.5 | <1.2 | <1.2 |
Salinity and alkalinity (n) |
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EC (dS/m) (50 cm) | <1.0 | 1.0 - 2.0 | 2.0 - 3.0 | 3.0 - 4.0 | >4.0 |