Ken: Thank you for the information. I have a correlation for GDD for
soybean from Canada, but only for maturity groups 00, 0 and 1, so I was
wondering if such a thing existed for the maturity groups grown in the
US. We are in the process of trying to switch our crop models to the
DSSAT ones, so I know there is going to be a "leap" in the complexity as
we make the transition. I appreciate the help!
Angela
-----Original Message-----
From: DSSAT - Crop Models and Applications
[mailto:[log in to unmask]] On Behalf Of Ken Boote
Sent: Thursday, April 06, 2006 3:58 PM
To: [log in to unmask]
Subject: Re: Growing Degree Day (GDD) Correlations for soybean
Angela,
I forgot to tell you places to look for the phenological scales. If
you have the DSSAT CD-ROM, look in DSSAT4\Documentation for the Volumes
1 to 4, and also in DSSAT4\Documentation\DSSATv3.5 for other volumes 1
to 4. I think phenological stages are in one of the v3.5 documents.
The stages for soybean correspond to the Fehr and Caviness, Crop Science
11:929 (1971), except that we predict first occurrences for R3, R4, R5,
and R6 rather than occurrence at the top 4 expanded nodes. The R stages
for peanut are from Boote. 1982. Peanut Science. I don't know where
to send you for the cereals.
Ken Boote
Ken Boote wrote:
> Angela,
>
> The phenology in the DSSAT model for soybean does not translate into
> GDD for two reasons: 1) our temperature function is more complex,
> having a flat topped Topt, and a temperature (Topt2) above which the
> rate of development slows down. So you can not translate into GDD;
> 2) the reproductive stages are also mostly daylength sensitive, plus
> having the complex temperature function, so even more reason you can
> not translate to GDD. So what you want, does not exist. You will
> need to use it the DSSAT soybean model the way we use it. V stages
> predict very well, and there is no need to adjust anything. If you
> have a soybean cultivar for which the R stages are not predicted
> accurately, you need to adjust to the correct maturity group type (or
> changing the CSDL) in the cultivar file.
>
> Good luck with it.
> Ken Boote
>
>
>
> Angela Gessleman wrote:
>
>> Hello. I am a new user of the DSSAT program. Does anyone know of a
>> reference which corresponds GDD with the Vegetative (V) and
>> Reproductive
>> (R) stages in soybean? Additionally, is there an area in the DSSAT
>> software that lists the phenological scales that are used for barley,
>> chickpea, potato, soybean and wheat. If anyone knows of someone doing
>> work in DSSAT for canola, that would be appreciated as well.
>>
>>
>>
>> Regards...
>>
>> Angela Gessleman
>>
>>
>
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