Hi Bipin,

In my email to the DSSAT Listserver of last week (Jan 30), I wrote some
about the leaching and soil-N-dynamics option of DSSAT.

You wondered which variables indicate the leaching. Almost all variables in
the *.OUT files are explained in the DETAIL.CDE and DATA.CDE files in the
DSSAT root directory. Leaching can be found as NLCC in the NITROGEN.OUT
file, as NLCM in the SUMMARY.OUT file, or as 'Leached NO3' in the NBAL.OUT
file. Please keep in mind what I wrote in my last-week's email, as it
sometimes gives surprising results.

In you earlier email you wrote that "measured value=3.63 kg/ha for nitrate
and 18.2 kg/ha for Total nitrogen". Does this mean that the difference
between total-N leached and nitrate leached is ammonium? Seems rather
unlikely, as ammonium is sorbed onto the soil particles much stronger than
nitrate. DSSAT simulates only nitrate leaching, and has an option of reduced
nitrate leaching due to adsorption (which happens e.g. with some
highly-weathered soils); for this option, see Bowen,W.T., Jones,J.W.,
Carsky,R.J. & Quintana,J.O. (1993) Evaluation of the nitrogen submodel of
CERES-maize following legume green manure incorporation. Agron. Journal
85:153-159. I do not know whether this also is activated in the Rice model.


Hope this helps.

Arjan Gijsman


-----Original Message-----
From: Bipin Pathak [mailto:[log in to unmask]]
Sent: Thursday, January 31, 2002 9:07 PM
To: [log in to unmask]
Subject: Re: About nitrate leaching


Dear sir

Could you tell me who are export in N?. No  body answered me about nitrate
leaching.I checked both file(RIN and Nbal) thoroughly but unable to find
Nitrate leaching.
I am waiting your response.

Thanks for your prompt cooperation

Bipin



----- Original Message -----
From: Brian Baer <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, January 30, 2002 11:20 PM
Subject: Re: About nitrate leaching


> Bipin,
>
> I'm no expert on N.  I was just pointing out that there are two N output
> file.  The .RIN file that you have been looking at where N leached is in
> the NLCC column, and the NBal.out file where there is one line for the
> total N leached as well as other lines for different source and loses of
> N.  This second file might help you find out where your N is going that
you
> expect to be leached.
>
> You are running flooded rice which means there is the whole question of
> flood water chemistry.  That is a big can of worms that I have no
> experience with.  Hopefully there are others on this list that can be of
> more help in this area.
>
> Good luck.
>
> Brian
>
> >Thanks for kind cooperation
> >I read the N balance.out file. Here I have two question. First,  which
term
> >is nitrate leaching, and second why N leached (NLCC:1.1 Kg/ha)  is very
low
> >in comparison to measured value( 18.2 kg/ha).I need help to justify
it.Can I
> >send  to you my N balance .out file ? Please tell me how can I send this
> >file through DSSATserver.I tried many times but unable to send.I if you
need
> >other file , please write me.
>
>