SWCharEst
SWCharEst is an implementation of an algorithm that estimates soil hydrological parameters from soil texture and organic matter content using the method of Saxton and Rawls (2006).
The implementations are in four programming languages: C++, Fortran90, Python3, and R.
All implementations are in object-oriented form as a class, or for Fortran90, as a module. Each has an accompanying test program that demonstrates the class use. The name of each class is SWCharEst.
Source code for the classes are in the src directory.
Source code for the test programs are in the tests directory.
At the top of each file is an explanation with usage examples.
| Language | Class File | Test File |
|---|---|---|
| C++ | SWCharEst.cpp/h | Test_SWCharEst.cpp |
| Fortran90 | SWCharEst.f90 | Test_SWCharEst.f90 |
| Python3 | SWCharEst.py | Test_SWCharEst.py |
| R | SWCharEst.R | Test_SWCharEst.R |
Calculating the soil hydrologic parameters
Input:
| value | units |
|---|---|
| sand weight fraction | fraction in range 0-1 |
| clay weight fraction | fraction in range 0-1 |
| soil organic matter | weight percent (70% maximum) |
Results:
| variable | description | units |
|---|---|---|
| WP | wilting point | volume fraction |
| FC | field capacity | volume fraction |
| thetaS | saturated water content | volume fraction |
| Ks | saturated hydraulic conductivity | cm/sec |
Each class implementation has two public methods. Usage displays the use of the class. Get returns a vector (or array or list) containing the results of the calculations: WP, FC, thetaS, Ks, in that order.
Units
The units of the calculated variables in the Saxton and Rawls paper are volumn percent for WP, FC and thetaS, and mm/hour for Ks. Conversions are:
- volume % = volume fraction * 100
- mm/hour = cm/sec * 36000
The R script tests/SaxtonRawls_Table3.R calculates the estimates
for each soil texture in Saxton and Rawls (2006), table 3 using
SWCharEst.R. The differences between table 3 and the new
estimates are displayed. All differences are zero.
Citation
K. E. Saxton and W. J. Rawls, 2006. Soil Water Characteristic Estimates by Texture and Organic Matter for Hydrologic Solutions. Soil Sci. Soc. Am. J. 70:1569–1578.
Copyright and License
Package SWCharEst: Copyright 2020 Thomas E. Hilinski. All rights reserved.
Copyright 2020 Thomas E. Hilinski. All rights reserved. This software including source code and documentation, is licensed under the Apache License version 2.0. See the file “LICENSE.md” for more information.