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