For CERES maize maturity is determined with P5
(c:\dssat35\genotype\MZCER9?0.cul file) this represent the cultivar specific
heat units (thermal units) to reach maturity from silking. The base
temperature is 8oC. The colder the temperature the longer it will take to
reach maturity. If their is severe stress the model will simulate maturity.
You can play around with the P5 value to obtain better results, if the
simulation of silking date is in reasonable limits.

On the potato simulations I have no idea.

Hope this help

Regards
Andre

-----Original Message-----
From: Jean-Philippe Brassard [mailto:[log in to unmask]]
Sent: Monday, July 22, 2002 4:16 PM
To: [log in to unmask]
Subject: ceres and substor


Dear listers,

I'm using CERES and SUBSTOR to simulate maize and potato yields in Quebec,
Canada. I'm having some difficulties with these models.

With CERES, in some sites and years, I have 'slowed grain filling', which
result in very late (almost ridiculously so) maturity and harvest dates
(harvest is done at maturity). I'm not sure what is causing this, and what I
can do to obtain better dates. Can somebody help me with that?

My problem with substor is the following: when I do a simulation, I get to
the screem titled 'SIMULATED CROP AND SOIL STATUS AT MAIN DEVELOPMENT
STAGES' (the 3rd, I think), and, just after the data line for 'Start Sim', I
receive the following error message:

'run-time error M6101:MATH
- Floating-point error:invalid'

I don't know what it means, and I don't know how to fix it. Any help would
be greatly appreciated.

Thank you for your time and counsel,
sincerely,

Jean-Philippe Brassard
Étudiant gradué
Laboratoire de climatologie
Département de géographie
Université de Montréal
tel: (514) 343-8039
email: [log in to unmask]


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