Dear Ken

Thank you very much

Wei Xiong
----- Original Message -----
From: "ken boote" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, March 18, 2004 12:43 AM
Subject: Re: help in CO2 effect in CERES-Maize


> 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]
>