Colleagues:
                 Crop simulation models are composed of algorithms that
represent different processes. These processes may include: gross
assimilation, respiration, transpiration, soil evaporation, crop
development, growth of leaf area, leaf area senescence, plant height,
translocation of stored reserves, number of reproductive organs, mass of
reproductive organs, growth of roots, uptake of nutrients, partitioning of
dry matter between above and below ground components, etc. There isn't a
way to simulate any of these processes; there are several ways. How were
the algorithms that simulate these processes developed? Or, why do all the
things on the right hand of the equal sign, equal what is on the left hand
side of the equal sign? Of equal importance is integrating these processes
together into a whole-plant framework that responds to abiotic and biotic
stresses and management.
                 I am organizing a joint symposium for the next American
Society of Agronomy/ Crop Science Society of America meetings, which will
be held on 2-6 November 2003 in Denver, CO. A tentative title for this
symposium is "The Science Behind the Models". The presentation should
follow the following format: 1. Purpose or application of algorithm; 2.
Assumptions used in the development of the algorithm (validity of algorithm
across environments); 3. Approaches or techniques used to develop the
algorithm; 4. Results; 5. Improvements over existing algorithms; and 6.
Future directions.  If you would like to make a presentation to address any
of these or other processes, please provide me a title and a very short
outline of your presentation. If you have any questions or comments, please
do not hesitate to contact me. Also, please feel free to pass this message
on to anyone you feel might be interested in this symposium. Thanks for
your help.

         Albert Weiss
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         (402) 472-6761  (voice)
         (402) 472-6614  (fax)