Hi Derek

Though I have not experimented with CERES-Wheat model
but I have some experience on changing initial LAI in
another Wheat Model WTGROWS which is also a production
level 3 model (Simulate Pot Prod, Water and N stress)
and very similar to CERES-WHEAT. In that model when
simulating potential production or only water
stress,the change in Initial LAI caused model growth
curve go up and down only. But when water and N stress
was simulated besides growth curve going up and down,
their was change in magnitude. I could infer that the
change in magnitude happened due to complex feedback
mechanism of N stress affecting crop phenology.Hope
this experience may help you in your research with
CERES-Wheat.

Dr V.K. Sehgal
Crop Inventory & Modelling Division
Space Applications Centre
Indian Space Research Organisation
Ambawadi Vistar P.O.
Ahmedabad - 380015 INDIA

Ph. +91-79-6774107, 6774001
Fax +91-79-6748813

--- Derek McNamara <[log in to unmask]> wrote:
> Hello,
> If one was to change the initial value of LAI used
> in CERES-Wheat (.4cm2)
> to whatever, would this result in a new growth curve
> with a different
> magnitude, or would the magnitude be the same but
> the growth curve would be
> shifted up or down depending on the change of the
> initial value of LAI.  It
> seems to me that it would just result in the growth
> curve being shifted up
> or down.  Is this correct, if not why is the
> magnitude of the growth curve
> affected by the initial value of LAI?  Thank you in
> advance for any help.
>
> Derek McNamara



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