Dr. Xiong Wei

The origins of the CO2 function for maize in DSSAT came from a late 1980s
EPA project to Peart and Curry here at the University of Florida.  Here are
the publications that resulted.  Those publications may have information on
how the function was arrived at.  I know that function is somewhat
arbitrary, as it originated with early model versions as of the late 1980s
(and has not changed since), and it is based on very, very limited data on
maize available to that point.  Growth response data to CO2 was
particularly limited. As you know, CERES-Maize is an RUE-approach model, so
it basically requires a scaled reduction/multiplier factor on RUE, as a
function of CO2. The estimated reduction in ET was done a bit better in
terms of rigor, coming from known CO2 change in stomatal conductance which
in turn was put through an energy balance model (SPAM) by Dr. L. H. Allen
of USDA-ARS.  The Peart reference is probably most complete on the method,
but is a EPA project report that most of us will not have access to.

Let DSSAT users know if you or others have better information on growth
response to CO2 for maize.

Adams, R. M., C. Rosenzweig, R. M. Peart, J. T. Ritchie, B. A. McCarl, J.
D. Glyer, R. B. Curry, J. W. Jones, K. J. Boote, and L. H. Allen,
Jr.  1990.  Global climate change and US agriculture.  Nature 345:219-224.
Curry, R. B., R. M. Peart, J. W. Jones, K. J. Boote, and L. H. Allen,
Jr.  1990.  Simulation as a tool for analyzing crop response to climate
change.  Transactions of the ASAE 33:981-990.

Curry, R. B., R. M. Peart, J. W. Jones, K. J. Boote, and L. H. Allen, Jr.
1990.  Response of crop yield to predicted changes in climate and
atmospheric CO2 using simulation.  Transactions of the ASAE 33:1383-1390.

Peart, R. M., J. W. Jones, R. B. Curry, K. J. Boote, and L. H. Allen,
Jr.  1988.  Impact of climate change on crop yield in the Southeastern
USA:  A simulation study.  In:  J. B. Smith and D. A. Turpak (eds.).  The
Potential Effects of Global Climate Change on the United States.  U.S.
Environmental Protection Agency.

At 06:02 PM 3/6/04 +0800, you wrote:
>Dear All
>
>I have been trying to simulate the maize yield in a enriched CO2
>environment by the new DSSAT-4.the yield will increase more than 13% if
>the 725 ppmv CO2 concentration is added into "ENVIRONMENTAL
>MODIFICATIONS". I knew that the higher CO2 will increase photosynthesis
>and WUE of plant. but how does the CERES model considered the CO2 direct
>effect in the model, are there some related references talking about the
>fuctions used in the CERES model to take account of the CO2 effect. Any
>help will be greatly appreciated
>
>Thanks in advance.
>
>Wei
>
>Dr. Xiong Wei
>The Institute of Agricultural Environment and Sustainable development.
>Chinese Academy of Agricultural Sciences.
>#12 Zhong Guancun south street, 100081. Beijing.
>Telephone: +81 10-62119681
>E-mail: [log in to unmask]