Soil and solute specific parameters

A discussion forum for users of the new HYDRUS 2D/3D. HYDRUS is a software package for simulating water, heat and solute movement in two- and three-dimensional variably saturated media. Happy Posting!
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goitomta
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Soil and solute specific parameters

Post by goitomta » Tue Mar 07, 2017 12:21 pm

I am using Hydrus-2D/3D model to simulate nitrate, ammonia and ortho-phosphate leaching trends from a sewage sludge buried below a soil surface. The soil textural types where this sludge are buried include loam, sandy clay, sandy clay loam, silty clay, and clay loam. I need to input soil specific (DispL, DispT, Fract ThImob), solute specific parameters (Diff W and Diff G), and reaction parameters (Kd, Nu, Beta, Henry, SinkL1, etc...) in the dialog boxes found in the model. I am wondering where to get or source these values (like the default water flow parameters)?

Thanks

Goitom

Jirka
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Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Soil and solute specific parameters

Post by Jirka » Tue Mar 07, 2017 4:13 pm

You can check the parameters and their discussion that we have in:

Hanson, B. R., J. Šimůnek, and J. W. Hopmans, Numerical modeling of urea-ammonium-nitrate fertigation with drip irrigation using numerical modeling, Agricultural Water Management, 86, 102-113, 2006.

or in:

Li, Y., J. Šimůnek, Z. Zhang, L. Jing, and L. Ni, Evaluation of nitrogen balance in a direct-seeded-rice field experiment using Hydrus-1D, Agricultural Water Management, 148, 213-222, doi:10.1016/j.agwat.2014.10.010, 2015.

J.

goitomta
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Joined: Tue Jun 12, 2012 7:47 am
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Re: Soil and solute specific parameters

Post by goitomta » Wed Mar 08, 2017 3:06 pm

Thanks Jirka!

Jirka
Posts: 4712
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Soil and solute specific parameters

Post by Jirka » Wed Mar 08, 2017 6:13 pm

This may also be a good reference:

Ramos, T. B., J. Šimůnek, M. C. Gonçalves, J. C. Martins, A. Prazeres, and L. S. Pereira, Two-dimensional modeling of water and nitrogen fate from sweet sorghum irrigated with fresh and blended saline waters, Agricultural Water Management, 111, 87-104, doi:10.1016/j.agwat.2012.05.007, 2012.

Note that we post simulations carried out for this paper at: https://www.pc-progress.com/en/Default. ... b-Portugal

J.

goitomta
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Joined: Tue Jun 12, 2012 7:47 am
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Re: Soil and solute specific parameters

Post by goitomta » Wed Mar 15, 2017 2:48 pm

A sewage sludge was buried below a soil surface with the configuration consists of 30 cm depth top soil layer covering a 25 cm deep sludge which in turn overlying 65 cm deep soil all siting in a pan lysimeter (1m by 1m) filled with gravel layer that allow the drainage water to pass through and collected in a drainage sump. I have initial concentrations of Total P, Total N and Ammonium-N for each of the above layers (top 30 cm, 25 cm sludge, 65 cm soil and gravel in the pan). I have then measured ammonium-N, Nitrate-N and Phosphate-P from the drainage water. The main concept here is after exposing the whole profile setting described above to rainfall (atmospheric), the sludge will mineralize and the different nutrient species will be in the drainage water or absorbed in the soil or taken up by plants, which I monitored. Other processes like volatilization and denitrification were not measured in this particular study. I am using Hydrus 2D/3D for simulating the measured variables 1) the drainage water, and 2) the concentrations of ammonium-N, Nitrate-N and Phosphate-P. I have specified the initial conditions of Total N, Total P and Ammonium-N mainly for the sludge layer in terms of total concentration (Mass_solute/Volume_soil) with the understanding that sludge is applied once-off and monitored what is drained to the drainage sump, remained in the soil (residual), and plant uptake for 1-3 years. How does Hydrus distinguish between the Total N and Total P when setting them as initial conditions and the three solute concentrations of interest I measured (ammonium-N, Nitrate-N and Phosphate-P)?

Thanks In advance!

Jirka
Posts: 4712
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Soil and solute specific parameters

Post by Jirka » Wed Mar 15, 2017 5:05 pm

It is up to the users to specify initial and boundary concentrations for each solute they want to consider. Hydrus will, for example, not distribute "Total N" between different N species (e.g., NH4, NO2, NO3, etc). However, if you specify a total mass of a particular species, Hydrus will distribute that mass between different phases (e.g., Hydrus can distribute the total ammonium between the liquid, sorbed and volatile components). J.

goitomta
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Joined: Tue Jun 12, 2012 7:47 am
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Re: Soil and solute specific parameters

Post by goitomta » Mon Mar 20, 2017 1:11 pm

Thanks Jirka

In studying water and solute transport from sludge burial sites with a setting described by soil-sludge-soil-gravel layers (top to bottom sequencing) all sitting on 1m by 1m pan having 0.1 m high with the drain hole of 5cm diameter located at the center of the pan. The drain hole was connected to L-shape pipe which in turn connected to a pipe on the side to collect drainage water. Here, the drainage depth was calculated by dividing the volume of water collected in the drainage sump (L^3) by the surface are of the pan (L^2). Before jumping to simulate nitrogen and phosphorus transport from this particular setup, I tried to calibrate the model using measured drainage values. In doing so, at least the units of both parameters should be the same, i.e. calculated drainage depth was 4.34 cm (1-Dimensional) while the simulated seepage was 468 cm^2 (two-Dimensional). Are these values comparable or how does someone make conversions between these two values?

Regards

Goitom

Jirka
Posts: 4712
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Soil and solute specific parameters

Post by Jirka » Mon Mar 20, 2017 3:40 pm

The units for all outputs are described in the technical manual. All cumulative fluxes (for 2D simulations) are given in units of [L^2]. All fluxes are given in units of [L^2/T], except for atmospheric (and transpiration) fluxes, which are in units of [L/T]. Obviously, to get the same units as for other fluxes (i.e., [L^2/T]), you need to multiply atmospheric flux by the length of the atmospheric boundary. J.

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