Dear Derek,

I think, the proposal from Mohammad is dangerous. Because, when you change or
'play' with the genetic coeffients (the genetic coeffiients are constant and
independent from the special environment), your are adapting the model about
these coeffients to your special environment conditions. That means in
reality, the model doesn't work with the input parameters of your environment
(weather, soil, production techniques etc.).
Securely, you can have success with this model, in case you determine the
genenetic coeffients for each of yours production fields. But this - from
scientific view - does not satisfie and is a much of work - from practice
side - .
What is your target? To predict yields or to optimise fertilising ? May be, I
can help with the long term model N-Prog (s. www.n-prog.de).

Please tell me and all the best

Peter
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Schoop, Peter, Dr. sc. agr., Dipl. Ing.
Institut of Agri- and Environment Research
Sonnenweg 1, 21647 Moisburg
Germany
Phone: +49-4165-224 700
Fax:     +49-4165- 224 701
E-Mail: [log in to unmask]
Internet: www.n-prog.de
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