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perennial crop modelling
Posted: Thu Apr 17, 1997 12:23 pm
by Mary Milne
Dear colleagues,
I am working on a dynamic simulation model for cocoa production in PNG. Has
any-one come across a perennial crop supply model using a systems dynamics
framework rather than the standard econometric approach?
Regards,
Mary Milne
_________________________________________________________________________
Mary Milne
Department of Agricultural and Resource Economics
University of New England
Armidale
NSW 2350
AUSTRALIA
Fax: (067) 733281
e-mail:
mmilne@metz.une.edu.au
perennial crop modelling
Posted: Sun Apr 20, 1997 9:49 am
by "William Steinhurst"
Does the term "perennial" in your question simply relate to the fact
that being a tree, cocoa is biologically a perennial, or do you have
in mind a model for sustainable yield, or is there something else
intended?
Bill Steinhurst
From: "William Steinhurst" <
wsteinhu@psd.state.vt.us>
perennial crop modelling
Posted: Mon Apr 21, 1997 2:19 pm
by Jennifer Cover
I tried this link:
>Try contacting Wouter Gerritsma at:
>
Wouter.Gerritsma@USERS.AGRO.WAU.NL
>and on the web:
http://www.spg.wau.nl/agro
esearch/pps05abs.htm
and got an error message (wrong server). Here is the address I found:
http://www.agro.wau.nl/agro
esearch/Pps05abs.htm
Jen Cover
Modeling Consultant
__________________________
Address: Powersim AS, P.O. Box 206, N-5100 Isdalst=F8, Norway
Internet:
jenco@powersim.no
Web page:
http://www.powersim.no
Phones: +47 56 34 24 46 (Work); +47 56 34 24 00 (Secretary);
Faximile: +47 56 34 24 01 (Work)
perennial crop modelling
Posted: Tue Apr 22, 1997 8:38 am
by Mary Milne
William,
I was referring to cocoa as a perennial crop in the biological sense.
However, I am interested in modelling sutainable yields, given the climatic
and soil data that we have available and incorporating it into production
functions for smallholders and estates in Papua New Guinea.
Mary Milne
_________________________________________________________________________
Mary Milne
Department of Agricultural and Resource Economics
University of New England
Armidale
NSW 2350
AUSTRALIA
Fax: (067) 733281
e-mail:
mmilne@metz.une.edu.au
perennial crop modelling
Posted: Sun Oct 19, 1997 6:06 pm
by John Sterman
Besides Dennis Meadows classic "dynamics of commodity production cycles",
see Helmut Weymars "Dynamics of the World Cocoa Market" (19668, MIT
Press). Weymar did his phd thesis in economics but worked with the MIT SD
group; his model is basically a system dynamics model of the supply side of
the market which for which he then estimates the parameters.
John Sterman
MIT Sloan School of Management
E53-351
30 Wadsworth Street
Cambridge, MA 02142
617/253-1951 (voice); 617/258-7579 (fax),
jsterman@mit.edu
http://web.mit.edu/jsterman/www
perennial crop modelling
Posted: Mon Oct 20, 1997 12:55 am
by rjrahn@microtec.net (R. Joel Rah
Possibly Dennis Meadows book Dynamics of Commodity Cycles would be of some
help for your commodity crop. It should be available in a university library
or from Progress Press.
Good luck!
R. Joel Rahn
From:
rjrahn@microtec.net (R. Joel Rahn)
perennial crop modelling
Posted: Mon Oct 20, 1997 9:10 am
by rn_kickert@ccmail.pnl.gov (Ronal
Try contacting Wouter Gerritsma at:
Wouter.Gerritsma@USERS.AGRO.WAU.NL
and on the web:
http://www.spg.wau.nl/agro
esearch/pps05abs.htm
for information about his CASE2 simulation of cocoa growth and production. He
is with the Dept. of Agronomy, Wageningen Agricultural University, Netherlands.
The model is not implemented in the usual systems dynamics software
environments, but given the paucity of tropical crops simulations, at least you
can convert this to your favorite S.D. software if you so desire.
Ron Kickert
Battelle Pacific Northwest
Richland, Washington
From:
rn_kickert@ccmail.pnl.gov (Ronald N Kickert)
perennial crop modelling
Posted: Tue Oct 21, 1997 11:51 am
by Jim Hines
A further addendum to Johns note on Helmut Weymar.
Helmut Weymar went into commodities trading following his work at MIT in
system dynamics. He became one of the most successful commodity traders
ever. His sd work on commodities might indeed be worth a look.
Jim Hines
MIT
JimHines@interserv.com