Dear Jinzhong Yang.

You can not have SDATE come after (be larger than) harvest code date, and
should not have it after any growth sampling dates.  That is
illogical.  You must start the simulation prior or on the date of sowing,
and prior to any sampling.

Also, START should nearly always be set to "S".  I have never used it set
to "I".  I don't know if that works.  Done properly, you should either have
initial conditions be on the day of sowing in which case you can set SDATE
same as sowing date and SDATE is S.  Or take initial conditions prior to
sowing, in which case you set SDATE as the same as the date of initial
conditions and still set SDATE to "S".

Don't get too fancy on all those other codes.  Also, I recommend that you
try to take one of the training courses to avoid all these
difficulties.  There is one planned by Dr. Hoogenboom in Georgia in
December 2002.

Ken Boote


At 04:43 PM 2/6/02 -0500, you wrote:
>Dear Gerrit and others:
>
>Thank you for your immediate and valuable reply.
>
>The problem reported in my last message disappeared after following your
>guide. However a new problem rises. If START is set to "I" and SDATE to any
>number larger than the largest among harvest date codes in Harvest Details
>Section in FILEX, then the model will output 0's for almost all growth
>traits such as LAI, SEED YIELD and BIOMASS etc. without warnings or errors
>reported by the model. However, if HARVS is changed from "R" to "A" in "Line
>4: Management" in Simulation Controls Section, the problem will disappear.
>
>I want the model to use my measured harvest dates rather than ones
>"automatic when conditions satisfactory."  Could you or somebody else help ?
>
>Jinzhong Yang
>
>----- Original Message -----
>From: "Gerrit Hoogenboom" <[log in to unmask]>
>To: <[log in to unmask]>
>Sent: Wednesday, February 06, 2002 9:01 AM
>Subject: Re: Simulation Start Date Code in Simulation Controls Section in
>DSSAT3.5
>
>
> > Dear Dr. Yang and others:
> >
> > On page 15 and the examples on page 30 of DSSAT version 3 volume 2 Start
>of
> > simulation is defined as a critical input to be able to run the crop model
> > and has to be defined.  In your case you also need to define the Initial
> > Conditions sections and ICDAT, the date that your initial conditions were
> > measured.  If you set the Start to I, the model will check if ICDAT <
>SDATE
> > and will use the smallest of the two numbers.
> >
> > Regards,
> >
> > Gerrit Hoogenboom
> >
> >
> > At 08:19 AM 2/6/02 -0500, Jinzhong Yang wrote:
> > >Dear members,
> > >
> > >I am using DSSAT35 for simulating the rainfed growth of soybean in
>coastal
> > >plain soil in Virginia. I have soil moisture measured before planting so
>I
> > >prefer starting simulation at the time "when inital conditions measured."
> > >to other "Suggested codes."   But, whenever I set Header START(Start of
> > >Simulation, code) as "I"(I=When initial conditions measured) and leave
> > >SDATE as blank in "Line 1: General" in Simulation Controls Section in
> > >FILEX, the model will always take "Jan. 0, 1900" as  simulation start
>date
> > >no matter what is the actual experiment year , even though if I set
>Header
> > >START as "P" and leave SDATE as blank in "Line 1: General" in Simulation
> > >Controls Section in FILEX, the running of the  model will prove
> > >successful. This means that "I" as "Suggested codes" doesn't work as
>expected.
> > >
> > >Can you help please?
> > >
> > >--------------------------------------------------------
> > >Jinzhong Yang, Ph.D
> > >Dept. of Crop and Soil Envir. Sciences
> > >Virginia Tech
> > >Blacksberg, VA  24061-0404
> > >Office Phone: +1 540-231-7893