This tool derives the soil water capacity for the given soil moisture potentials (psi) based on pedo-transfer functions.
Suggested psi values for field capacity estimation range between 60 hPa (pF=1.8) and 316 hPa (pF=2.5). For permanent wilting point estimation take a psi value of about 15850 hPa (pF=4.2). This tool re-implements the R-script AWCPTF by Hengl as well as the regression approach by Toth et al. (2015). See Hengl et al. (2017), Woesten & Verzandvoort (2013) and Toth et al. (2015) for more details.
| Name | Type | Identifier | Description | Constraints |
Input | Sand (*) | Grid, input, optional | SAND | [%] | - |
Silt (*) | Grid, input, optional | SILT | [%] | - |
Clay (*) | Grid, input, optional | CLAY | [%] | - |
Soil Organic Carbon (*) | Grid, input, optional | CORG | [permille] | - |
Bulk Density (*) | Grid, input, optional | BULK | [kg/m^3] | - |
Cation Exchange Capacity (*) | Grid, input, optional | CEC | [cmol/kg] | - |
pH (*) | Grid, input, optional | PH | - | - |
Output | Field Capacity | Grid, output | FC | - | - |
Permanent Wilting Point | Grid, output | PWP | - | - |
Water Capacity at Saturation (*) | Grid, output, optional | THETA_S | - | - |
Options | Grid System | Grid system | PARAMETERS_GRID_SYSTEM | - | - |
Default | Floating point | SAND_DEFAULT | default value if no grid has been selected | Minimum: 0.000000 Maximum: 100.000000 Default: 15.000000 |
Default | Floating point | SILT_DEFAULT | default value if no grid has been selected | Minimum: 0.000000 Maximum: 100.000000 Default: 37.000000 |
Default | Floating point | CLAY_DEFAULT | default value if no grid has been selected | Minimum: 0.000000 Maximum: 100.000000 Default: 48.000000 |
Default | Floating point | CORG_DEFAULT | default value if no grid has been selected | Minimum: 0.000000 Maximum: 1000.000000 Default: 15.000000 |
Default | Floating point | BULK_DEFAULT | default value if no grid has been selected | Minimum: 100.000000 Maximum: 2650.000000 Default: 1350.000000 |
Default | Floating point | CEC_DEFAULT | default value if no grid has been selected | Minimum: 0.000000 Default: 45.000000 |
Default | Floating point | PH_DEFAULT | default value if no grid has been selected | Minimum: 0.000000 Maximum: 14.000000 Default: 6.400000 |
Output Unit | Choice | UNIT | - | Available Choices: [0] cubic-meter per cubic-meter [1] percentage of volume Default: 1 |
Pedo-Transfer Function | Choice | FUNCTION | - | Available Choices: [0] Hodnett & Tomasella 2002 [1] Toth et al. 2015 Default: 0 |
Soil Moisture Potential | Floating point | PSI_FC | [hPa] | Minimum: 0.000000 Default: 316.000000 |
Soil Moisture Potential | Floating point | PSI_PWP | [hPa] | Minimum: 0.000000 Default: 15850.000000 |
Adjustments | Boolean | ADJUST | Specifies whether to correct values of textures and bulk density to avoid creating nonsensical values. | Default: 1 |
User Defined Coefficients | Boolean | USERDEF | - | Default: 0 |
User Defined Coefficients | Static table | COEFFICIENTS | - | 4 Fields: - 1. [8 byte floating point number] ln(alpha) - 2. [8 byte floating point number] ln(n) - 3. [8 byte floating point number] theta s - 4. [8 byte floating point number] theta r
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(*) optional |