| Name | Description | units/level |
| d | Water decay rate (physical rate at which water leaves a grid cell) | l.(day.cell)-1 |
| I | Water input (amount of water entering a grid cell) | l.(day.cell)-1 |
Soil hydraulics will be the central physical component of RooMoHR_, just like light processes are modeled with detail in most DVM. Incorporating the water movements within the system is cornerstone to produce a mechanistic model of dryland vegetation that relies on the ecophysiological and biophysical mechanisms governing plant growth and interactions (Kirkham, 2014). Hydrologists have been developing accurate models of water movements in plants and soil for long (Milburn, 1979), and such modeling approaches can be incorporated into RooMoHR_ to bring this knowledge from the details to the large-scale vegetation dynamics and structure. The hydraulics module will keep track of two fundamental model variables, the water input (I) and decay rate (d) of each grid cell. Initially, these two values can be kept constant in order to develop and test the dynamic allocation and energy budget modules. However, the soil hydraulics module will be then developed with the help of an hydrologist hired as a postdoc, to include more realistic resource physical dynamics. The main features that will be incorporated into the model are that: (i) The resource will enter the system as precipitation, and surface water will be able to move over the surface due to runoff. (ii) Superficial water will infiltrate into the soil surface grid cells, and infiltration rates can be heterogeneous across the modeled land based on soil compaction or microtopology. (iii) Infiltrated water will move across the three-dimensional soil space due to percolation in the vertical dimension, diffusion across horizontal cells, and will be taken up by the plants’ fine roots. (iv) Finally, seasonality of rainfall will be implemented as a variable into de model.
- Kirkham, M.B. (2014) Principles of soil and plant water relations, (2nd edn) Elsevier.
- Milburn, J.A. (1979) Water flow in plants, Longman Inc.
Ciro Cabal 