Hiroshi;

CropTest uses the batch files (*.DV4) that are created by the DSSAT4
shell program.  By default it will look for D4BATCH.DV4, but the user
can specify a different file.  The DSSAT4 batch file will be converted
to a DSSAT v3.5 batch file as needed.

Regards,
Cheryl

-----Original Message-----
From: DSSAT - Crop Models and Applications
[mailto:[log in to unmask]] On Behalf Of [log in to unmask]
Sent: Wednesday, December 22, 2004 6:57 PM
To: [log in to unmask]
Subject: Re: Q about different versions


Hi Arjan,

Thank you for your informative response. I meant to email to the DSSAT
list server. Sorry.

Let me ask you more about Q2. I am interested in changing composition
(CARB, CELL, LIGN) and decay rate constants of fresh organic matter
(FOM) such as cover crop residue or maize residue and cattle compost for
simulating short-term N dynamics (14 months) in bare fallow. If I want
to compare model predictions between versions 3.5 and 4.0 after the
incorporation of FOM or compost, do I need to conduct following steps?
  1) Prepare a FileX.
  2) Put measured or estimated parameters in SOILN980.SOL for version
3.5 and in SOILN040.SOL for version 4.0.
  3) Go to CropTest to conduct simultaneous runs of version 3.5 and 4.0.
Where can I choose FileX prepared for CropTest?

Best,

Hiroshi

>2.  One of the major differences between v3.5 and v4.0 is that the
>latter has a new SOM/residue module that was based on the CENTURY model

>(see: Gijsman et al. 2002 Modifying DSSAT for low-input agricultural
>systems, using a SOM/residue module from CENTURY. Agron. Journal.
>94:462-474). The original SOM/residue module of DSSAT is also still
>included, so that who did many simulations with v3.5 does not suddenly
>get different results with v4.0 (the two SOM modules do give quite
>different results, as shown in Fig. 5 of the article).
>
>The file SOILN980.SOL only serves for the original module. In v4.0 this

>file has been updated and is called SOILN030.SOL. If you want to change

>some parameters of the CENTURY-based module, then you have to go to the

>file SOMFIX_C.SOL This has many parameters (about 130) but no parameter

>explanation (we should add that).