Root Growth Examples

HYDRUS Projects – Root Growth

The previous Version 2 of HYDRUS(2D/3D) includes a relatively comprehensive macroscopic root water and solute uptake model (Šimůnek and Hopmans, 2009) to account for the effects of both water and salinity stresses on root water uptake, while additionally accounting for possible active and passive root contaminant or nutrient uptake. Root water and solute uptake both can furthermore be treated as being either non-compensated or compensated, while users can select the degree of compensation (Šimůnek and Hopmans, 2009).

To extend the capabilities of the standard module of HYDRUS (2D/3D), a simple root growth model with similar capabilities as those in HYDRUS-1D was implemented into Version 3. The rooting depth, LR, can now be either constant (the standard approach) or variable during the simulations. For annual vegetation, a growth model is required to simulate changes in rooting depth with time. Time-variable rooting depth values can be provided either using a table on input, or calculated with the program assuming that the actual rooting depth is the product of the maximum rooting depth, Lm [L], and a root growth coefficient, fr(t) [-], which is calculated using the classical Verhulst-Pearl logistic growth function.

When a variable rooting depth is considered, the spatial distribution of roots must be described using either the Vrugt (Vrugt et al., 2001, 2002) or the Hoffman and van Genuchten (Hoffman and van Genuchten, 1983) functions.

• Project Group: Root Growth
• Description: Examples demonstrating the new root distribution and root growth options (Šimůnek et al., 2018).
• Availability: Download HYDRUS 2D (7.4 MB) and 3D (50 MB) projects now
• Note: These projects were created with version 3, and users using higher Hydrus versions need to convert them to their particular version.

References

• Šimůnek, J. and J. W. Hopmans, Modeling compensated root water and nutrient uptake, Ecological Modeling, doi:10.1016/j.ecolmodel.2008.11.004, 220(4), 505-521, 2009.

• Šimůnek, J., M. Šejna, and M. Th. van Genuchten, New Features of the Version 3 of the HYDRUS (2D/3D) Computer Software Package, Journal of Hydrology and Hydromechanics, 66(2), 133-142, doi: 10.1515/johh-2017-0050, 2018.

• Vrugt, J.A., M. T. van Wijk, J. W. Hopmans, and J. Šimůnek, One-, two-, and three-dimensional root water uptake functions for transient modeling, Water Resour. Res., 37(10), 2457-2470, 2001.

• Vrugt, J. A., J. W. Hopmans, and J. Šimůnek, Calibration of a two-dimensional root water uptake model, Soil Sci. Soc. Am. J., 65(4), 1027-1037, 2001.