Acta Horticulturae

Commission Engineering
IV International Symposium on Models
for Plant Growth and Control in
Greenhouses
The ISHS Working Group Plant Growth, Environmental Control and
Greenhouse Environment of the Commission of Horticultural Engineering
and the Commission on Protected Cultivation met in conjunction with the
Biological Systems Simulation Group (BSSG), a group of scientists affiliated
with the Agronomy Society of America. The meeting, entitled Modeling for
the 21st Century: Agronomic and Greenhouse Crop Models, was held in
Beltsville, Maryland, USA on March 25-29, 2001. The organizers of the
meeting were Dr Jeff Baker (USDA/ARS, Beltsville) and Prof Heiner Lieth
(University of California). Approximately 90 scientists attended the meeting
(50% as ISHS members, 50% as BSSG members).
The meeting focused on basic aspects of
crop model development as well as creation
and dissemination of applications.
The former types of presentations were
scheduled for early in the meeting while
the more-applied aspects were presented
later. Each day consisted of various oral
sessions in the morning and early afternoon,
concluding with an overview/discussion
session where the participant
could raise questions and discuss issues
related to crop modeling. This facilitated
discussions between those working on
field crops and those working on greenhouse
crops. The interaction of the two
groups (agriculturists and horticulturists),
that normally do not directly interact,
appeared to be quite successful, since
there appeared to be far more problems
and solutions in common than one would
have expected.
One special feature of the meeting was a
hands-on workshop (presented by Prof
ISHS • 6
Heiner Lieth) on programming in the programming
language Pascal using the software
package Delphi. This consisted of an
overview presentation followed by an
evening session where attendees could
bring laptop computers for a hands-on
experience. The exercises led the attendees
through the rudimentary aspects of
this type of programming, culminating in
a simulation model with built-in graphical
display of output data.
There was some concern about the
apparent lack of practical applications of
crop models in agriculture and horticulture.
It was recommended to enhance
activities to implement models in practical
tools, to stimulate the interest of policy
makers in crop modeling research. To
obtain such tools it is important that there
is sufficient involvement of the software
industry, and that critical success factors,
such as cost-benefit balance, flexibility,
integration and relevance of information,
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reliability, simplicity, interface and input
requirements are adequately incorporated
in the design of such systems.
Besides the tendency to use relatively
simple models for practical applications
with a high added value, there was also a
trend towards the development of rather
complex models that combine agronomic,
economic and environmental issues.
Society oriented agricultural production
systems need such tools to find a proper
balance between different conflicting
objectives.
At the ISHS Working Group Business
meeting on the last day, it was decided
that the next meeting of the group would
be held in Berlin, Germany in 2003,
organized by Prof. Matthias Fink.
For more details, including the program
details, see the web page
http://lieth.ucdavis.edu/ishs/
Heiner Lieth, Environmental Horticulture, University of
California, Davis CA 95616-8587, USA, Phone: (1)530-
752-7198, Fax: (1)530-752-1819, e-mail:
jhlieth@ucdavis.edu
and
Hugo Challa, Horticultural Farm Technology,
Wageningen University, e-mail:
hugo.challa@user.aenf.wau.nl