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Questions about root water uptake modeling

Posted: Sat Aug 11, 2018 4:26 pm
by ahmed_almayahi
Dear Hydrus users
I am currently trying to simulate root water uptake (sweet corn) in a box of silt loam soil of dimensions length=40 cm, width=40 cm and height=28 (see figure 1). This is a 3D modeling in hydrus (2D/3D) version 2.05.0200.
I am using Feddes model. However, i encountered many challenges and i looked into the user and technical manuals plus couple of papers but i could not find an answer for my challenges.
The challenges are as follow:
1. Can i set the origin of the plants at an exact x,y,and z coordinates? how? (see figure 1)
2. Can i place 2 plants in the soil at an exact coordinate?
3. When i select the crop type from the database in the root water uptake parameters, i dont see any changes? why? how to make choice of plants functioning? how to know whether it is functioning or not? (see figure 2)
4. I am not able to get graphs for actual and potential transpiration with time. how to view them? is there any option to select before running the simulation?
5. not able to get graphs for potential water uptake with time. how to do it?
6. do i have to specify a value for RWU in the domain property? what is the logic behind the selection?

I appreciate your continuous helps

Re: Questions about root water uptake modeling

Posted: Sun Aug 12, 2018 9:36 am
by Jirka
1. No. In Version 2, the origin of the root system at the origin of the coordinate system. Only version 3 allows you to vary the x coordinate of the center of the plant (the origin for the z coordinate is the soil surface). For details about the new “root growth and distribution” model in version 3 see:
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.
2. Yes, in version 3, you can place multiple plants at different x coordinates.
3. See the original references from which this database is drawn. You should certainly see differences between different crops.
4. I do not answer questions like this.
5. Ditto
6. See the manuals.


Re: Questions about root water uptake modeling

Posted: Sun Aug 12, 2018 12:59 pm
by ahmed_almayahi
Dear prof. Simunek,
Thank you very much for the help
I will install the new version