Reaction parameters

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Joined: Mon Apr 08, 2019 8:00 am
Location: Sweden

Reaction parameters

Post by theoden » Mon Apr 29, 2019 9:45 am


I'm new to Hydrus and I have some questions regarding the reaction parameters that I don't find answers to in the tutorial or the technical manual. I'm trying to model spreading of nitrogen from irrigation water in one dimension, where I consider urea(1), ammonium(2) and nitrate(3).

Is it correct that hydrolysis of urea to ammonia is represented by " SinkWater1' "?
And then " SinkWater2' " represents nitrification, " SinkWater3' " represents denitrification?

Also, what input parameter represents production (mineralization org-N)?

Thanks in advance!

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Location: Riverside, CA

Re: Reaction parameters

Post by Jirka » Mon Apr 29, 2019 1:44 pm

I suggest that you look at multiple manuscripts (see below) when similar problem has been resolved. Note that nitrification rates that lead to daughter products (e.g., NH4 and NO3) needs be be given in the SinkWater1'. See Test3 and multiple other examples posted in the HYDRUS public library.

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.

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.

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.


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