Ernesto,

I did some work with the bahiagrass model a few years back and haven't
used the model much since I graduated, but I'll try and help you.  If
Dr. Boote or Cheryl are reading this - please jump in with corrections.

The error message is that it either cannot find the Pest file
CACA0101.G0T or the file is not formatted correctly - from your
comments, it sounds like you did not create the file.

The Bahiagrass (G0) and Brachiaria (BR) models use the pest module to
simulate a harvest.  If you copied one of the experiment files that came
with DSSAT4, then the Disease option (same thing as the Pest module) is
enabled (in XBuild, you will see that Disease has a "Yes").  You cannot
use the regular Harvest date in the experiment file to simulate a forage
harvest as it terminates the simulation - so we "pretend" that a big
"Pest" damages/removes leaf mass, stem mass, and resets the VStage.

Look at one of the GOT files for the experiments included in DSSAT4 to
see how the file should be set up.  The HARV "pest" removes whatever
proportion of the leaf and stem mass that you specify (in the
ALTH5601.GOT file, they removed 80% of the leaf and stem mass at each
harvest).  Both leaf and stem mass are reduced by the proportion that
you specify - see the G0GRO040.PST file for details).  You also need to
reset the VStage to "restart" the plant at a younger VStage with
corresponding growth parameters.  To do this you use the HARVS "pest".
In the ALTH5601.G0T file, they reduced the VStage by the same proportion
that they reduced the leaf and stem mass.

The HARV and probably the HARVS pests can persist - that is, once you
create a HARV event, the "pest" will continue to remove whatever amount
of leaf and stem mass that you specify until the model encounters the
next HARV or HARVS event.  The ALTH5601 experiment was harvested for hay
- so HARV and HARVS are set to 0.0 on the days before and after the
harvest date so that the model only harvests on the one day that the hay
was cut.  If you are simulating grazing, you probably want to use a HARV
that is much lower than 80% but use a longer interval (equal to the
length of the grazing period) between HARV events.  Use the same
strategy for HARVS.

You should run the simulation for a year prior to the start of your
experiment to establish proper root mass and plant weight.  You can
create an existing sod in the experiment file by using the Transplant
seeding method then go to the transplant section and enter the initial
plant mass.  Also set a relatively mature plant age (90 days) so that
the model starts out with a mature plant and not a seedling.

The model probably works best for a single growing season (after the
"establishment season) but you can use it for multiple, consecutive
seasons.  The challenge in running the models for multiple, consecutive
growing seasons revolve around 2 issues; frost damage and dormancy.

In DSSAT, a killing frost will kill the entire plant and stop the
simulation - so we set the killing temperature to -50C so that it
wouldn't happen.  There is no way to have a frost "kill" the top of the
plant and then restart growing in the spring other than to create the
damage in the Pest file (create a new harvest).  Also, there is no good
way to simulate winter dormancy in the DSSAT model - I forget what we
did to slow the grass down in the winter, but initial runs had
bahiagrass growing continuously throughout the winter and depleting the
soil of moisture by springtime.  I can't remember how we "fixed" that
but it wasn't biologically accurate though it worked.

We did create a "perennial" version of the model but I never quite
finished it and never published any articles on it.  Dr. Boote did have
another person working on it after I graduated but I don't know what the
status of the model is.

Hope this helps,

Stu

Stuart Rymph, PhD, CCA, PAS
Manager Technical Services and Dairy Nutrition
Land O'Lakes Purina Feed LLC
6063 Beckman Rd.
Mazomanie, WI 53560
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On 1/27/2011 8:30 AM, Ernesto Viscarra wrote:
> Dear friends using the DSSAT series of models:
>
> First hve my kind greeting, I've been succesfully using the DSSAT software for the analysis of the impacts of climate change to agriculture (rice, maize, and soybean) and lately beggining to use it with bahia grass and brachiaria, but when I create my file x I try to run the model and ther is the following error message:
>
>
>
> *RUN-TIME ERRORS OUTPUT FILE
>
>
>
>   File not found. Please check file name or create file.
>
> File: CACA0101.G0T   Line:     0   Error key: IPPROG
>
>
> It seems that the file was not created but there is in the directory. Can anyone help me with this issue? or which other software would you recommend for analyzing pastures?
>
> That's all for now thank you very much in advance.
>
> Kin regards,
>
>
>
>
> Federico Ernesto Viscarra Riveros
> Environmental Economist
> Programa Piloto Departemental de Adaptacion al Cambio Climatico
> REDD - Camerun
> PhD (Candidate) Science and Management of Climate Change
> Agriculture and Water Management
> Universita Ca Foscari di Venezia
> Phone: +39 3934912205
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> [log in to unmask]
>
>