Juan,

The wheat model is not sensitive to row spacing, as it lacks row spacing 
impact on light interception or on the extinction coefficient for light 
interception.  It also does not predict height or width.

Ken Boote

At 11:13 PM 6/8/04 +0000, you wrote:

>Ken
>
>Thanks for your answer. I am reading a paper of M. Kropff. (Agri. Syst. 
>73: 173-203). I also have problems when I was trying to simulate wheat, 
>when I change the row distance from 18cm to 36cm the yield does not 
>change, even if I change it to 100cm.
>
>Juan Pablo Monzon
>
> >From: ken boote <[log in to unmask]>
> >Reply-To: DSSAT - Crop Models and Applications <[log in to unmask]>
> >To: [log in to unmask]
> >Subject: Re: Modelling intercrops
> >Date: Tue, 8 Jun 2004 08:57:13 -0400
> >
> >Juan,
> >
> >The present DSSAT models do not simulate intercrops or differential
> >height
> >competition for light interception (dry matter accumulation)
> >purposes.  So,
> >you can not do it in the DSSAT models.
> >
> >To do this correctly, you would need to predict the height of each
> >crop and
> >the corresponding (and competing) vertical LAI distribution of each
> >component.  I recommend that you see the approach followed in the
> >INTERCOM
> >model of Martin Kropff, Wageningen Agricultural University, The
> >Netherlands.  His model predicts those aspects of species
> >competition
> >nicely, but probably does not go to final yield like you would
> >like.  Martin Kropff did write one of those Wageningen special
> >publications
> >on the topic.  Either Pudoc Publications (Wageningen in-house) or
> >Halstead
> >Press.
> >
> >Can anyone give us the full citation of Kropff's book and where to
> >order?
> >
> >Ken Boote
> >
> >
> >At 11:37 PM 6/7/04 -0700, you wrote:
> >>  My name is Juan and I am trying to simulate the performances of a
> >>wheat/soybean intercrop.  The design of the intercrop (or relay
> >>intercrop) is 3:1 and has a distance of 75cm, I have 3 rows of
> >>wheat to
> >>17,5cm of distance and 1 row of soy to 17,5cm of distance from the
> >>rows
> >>of wheat and again the same design.  The soy is sown 30 days before
> >>the
> >>harvest of the wheat.  Because of the design, the wheat fails to
> >>capture
> >>the totality of the radiation and the soy grows inside the wheat
> >>during
> >>25-30 days until the wheat harvest and during this period the
> >>soy receives less radiation than the one that would receive it if
> >>sown alone.
> >>Any idea for this simulation is welcome.
> >>Greetings Juan Pablo Monzon
>
>
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