Dear Juan,

In 1990, Robert Caldwell and I developed a multiple cropping systems
(intercrop and sequential cropping) model, CROPSYS, that incorporated
all of the DSSAT sole crop models available at the time.  We included a
hedgerow solar radiation interception/competition model, and a rational
approach to modeling competition for below-ground resources.  We mades
sure that CROPSYS exactly reproduced the simulations of the component
DSSAT models under sole-cropping conditions.  The necessary process of
decoupling ecological (i.e., resource balance and capture) and
physiological (i.e., resource use) processes in the existing crop models
in a consistent manner was very time-consuming given the structure of
the crop models at the time, and prevented us from maintaining CROPSYS
in the face of ongoing modifications to the sole crop models.  CROPSYS
did a reasonable job of predicting intercrop yields in field
experiments.  However, intense intercrop competition significantly
altered phenology in a manner that CROPSYS and its component DSSAT
models could not capture.

The best description of our modeling approach is in:

Caldwell, R.M. and Hansen, J.W., 1993. Simulation of multiple cropping
systems with CropSys. Pp. 397-412 in: Penning de Vries, F.W.T., Teng,
P., and Metselaar, K. (Eds.), Systems Approaches for Agricultural
Development, Vol. 2. Kluwer Academic Publishers, Dordrecht, The Netherlands.



JUAN PABLO MONZON wrote:

>
>
> Dear all
>
> I am trying  to simulate intercrops with DSSAT, to  do so, I am
> changing the  initial water content and  the incident radiation of one
> crop (soybean) with the results from the other crop (wheat). This is
> working fine, but it  would be better to have both models (CERES-Wheat
> and CROPGRO) interacting, i.e. the input incident radiation and soil
> water content in soybean would be extracted from the wheat model.
>
> I wonder if there is a program that allows for this models interaction???
>
> Regards
>
> Juan Pablo Monzon
>
> ARGENTINA
>

Regards,
--
James W. Hansen, Ph.D.
Research Scientist - Agricultural Systems
The International Research Institute for Climate and Society
The Earth Institute
Columbia University, Lamont Campus
61 Route 9W, Monell Building
Palisades, NY 10964-8000
USA

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