Tool Soil Water Capacity (Grid Collections)
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.
References
- R-Script AWCPTF {GSIF} by J. Leenaars, M. Ruiperez Gonzalez and T. Hengl
- Hengl, T., Mendes de Jesus, J., Heuvelink, G.B.M., Ruiperez Gonzalez, M., Kilibarda, M., Blagotic, A., et al. (2017): SoilGrids250m: Global gridded soil information based on machine learning. PLoS ONE 12(2): e0169748. doi:10.1371/journal.pone.0169748.
- Hodnett, M.G., Tomasella, J. (2002): Marked differences between van Genuchten soil water-retention parameters for temperate and tropical soils: A new water-retention pedo-transfer functions developed for tropical soils. Geoderma 108(3):155-180. doi:10.1016/S0016-7061(02)00105-2.
- Toth, B., Weynants, M., Nemes, A., Mako, A., Bilas, G., Toth, G. (2015): New generation of hydraulic pedotransfer functions for Europe. European Journal of Soil Science, 66, 226–238. doi:10.1111/ejss.12192.
- Toth, B., Weynants, M., Pasztor, L, Hengl, T. (2017): 3D soil hydraulic database of Europe at 250 m resolution. Hydrological Processes, 31:2662–2666. doi:10.1002/hyp.11203.
- Woesten, J.H.M., Verzandvoort, S.J.E., Leenaars, J.G.B., Hoogland, T., Wesseling, J.G. (2013): Soil hydraulic information for river basin studies in semi-arid regions. Geoderma 195:79-86. doi:10.1016/j.geoderma.2012.11.021.
- Author: O.Conrad (c) 2020
- Menu: Grid|Analysis|Soil Analysis
Parameters
| Name | Type | Identifier | Description | Constraints | |
|---|---|---|---|---|---|
| Input | Sand | Grids, input | SAND | [%] | - |
| Silt | Grids, input | SILT | [%] | - | |
| Clay | Grids, input | CLAY | [%] | - | |
| Soil Organic Carbon | Grids, input | CORG | [permille] | - | |
| Bulk Density | Grids, input | BULK | [kg/m³] | - | |
| Cation Exchange Capacity | Grids, input | CEC | [cmol/kg] | - | |
| pH | Grids, input | PH | - | - | |
| Output | Field Capacity | Grids, output | FC | - | - |
| Permanent Wilting Point | Grids, output | PWP | - | - | |
| Water Capacity at Saturation (*) | Grids, output, optional | THETA_S | - | - | |
| Options | Grid System | Grid system | PARAMETERS_GRID_SYSTEM | - | - |
| 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 | |
| (*) optional | |||||
Command-line
Usage: saga_cmd grid_analysis 28 [-SAND <str>] [-SILT <str>] [-CLAY <str>] [-CORG <str>] [-BULK <str>] [-CEC <str>] [-PH <str>] [-FC <str>] [-PWP <str>] [-THETA_S <str>] [-UNIT <str>] [-FUNCTION <str>] [-PSI_FC <double>] [-PSI_PWP <double>] [-ADJUST <str>] [-USERDEF <str>] [-COEFFICIENTS <str>] -SAND:<str> Sand Grids, input -SILT:<str> Silt Grids, input -CLAY:<str> Clay Grids, input -CORG:<str> Soil Organic Carbon Grids, input -BULK:<str> Bulk Density Grids, input -CEC:<str> Cation Exchange Capacity Grids, input -PH:<str> pH Grids, input -FC:<str> Field Capacity Grids, output -PWP:<str> Permanent Wilting Point Grids, output -THETA_S:<str> Water Capacity at Saturation Grids, output, optional -UNIT:<str> Output Unit Choice Available Choices: [0] cubic-meter per cubic-meter [1] percentage of volume Default: 1 -FUNCTION:<str> Pedo-Transfer Function Choice Available Choices: [0] Hodnett & Tomasella 2002 [1] Toth et al. 2015 Default: 0 -PSI_FC:<double> Soil Moisture Potential Floating point Minimum: 0.000000 Default: 316.000000 -PSI_PWP:<double> Soil Moisture Potential Floating point Minimum: 0.000000 Default: 15850.000000 -ADJUST:<str> Adjustments Boolean Default: 1 -USERDEF:<str> User Defined Coefficients Boolean Default: 0 -COEFFICIENTS:<str> User Defined Coefficients Static table 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