Michael,
If I understand correctly, this is a good example of where you may find
it much more efficient to edit the file X directly, rather than work
with XBuild.
From the file list in the DSSAT shell, you can open the file X for
"viewing" rather than editing. Rather than opening XBuild, your file is
opened in the default ASCII editor (usually Notepad). You can edit the
file similar to any document, including cutting and pasting.
From your question, I am unclear whether you want to add treatments
and/or planting levels. Let's assume both.
FIRST, save the file with a new name or make a backup copy of the old
file. If you rename it, follow the DSSAT convention. Also, edit the name
at the top of the FileX.
For treatments:
1. You would select a treatment that is otherwise similar to the one you
want to create.
2. Copy the entire line twice, making sure you copy the whole line
3. Renumber the treatments. For 500 levels, you would be much happier
with an editor like UltraEdit that allows you to select, copy and paste
columns. Otherwise, you have a lot of typing to do.
4. Renumber the appropriate columns that link to the treatments of
interest, such as for planting.
5. Edit the names and treatment levels as appropriate.
For planting levels, the process is about the same:
1. Select the planting level that is most similar to what you want to
create.
2. Copy that line
3. Renumber as needed.
The index levels for planting have to be in order, but the treatments
can come in any order. Thus, you could just add new treatments at the
end of the list. But most often, there is some logic to how treatments
are specified (e.g., dates by density).

Save the file. Before running, you might want to reopen in XBuild to
check that the edits worked as intended. If you made a major mistake,
XBuild may report an error.

Editing the ASCII files can be much more efficient than using XBuild. I
often generate file Xs using SAS as a scripting language. We often have
discussed whether there would be interest in a sort of "power users"
workshop where people could share how the deal with applications that
are too complex to run efficiently through the DSSAT shell.
Best regards,
Jeff White
USDA ARS

-----Original Message-----
From: DSSAT - Crop Models and Applications
[mailto:[log in to unmask]] On Behalf Of Vassalos, Michael
Sent: Wednesday, September 15, 2010 4:15 PM
To: [log in to unmask]
Subject: Question

Dear all,

I was wondering if it is possible to add planting dates in-between the
ones that i have already input.

i.e. i have 500 different planting levels and i want to add 2 more
between the levels 38 and 39 is it possible?

When i hit add the next level is added on the bottom if i put the two
levels i want there instead between 38 and 39 would this affect the
result?

Thank you