Hello Shrikant,
 
I'll try to answer as best as I can, but some of these will need to be
answered by some of the others above...
 
On Thu, 22 Jun 1995, Jagtap, Shrikant wrote:
 
> 1. What happens when number of files in wth.lst exceeds 99?
 
It cannot.  Gerrit may need to correct me on this, but I think the
WTH.LST only lists weather data in that current directory, not the entire
hard disk.  You could probably separate the weather data by site or
whatever to avoid exceeding 99.
 
>
> 2. DSSAT Vol 2 pg 18, Ammonium and nitrates units should read ug/g to reflect
> actually what happens in the models (refer to pg 132 overview file).
 
Maybe you miss-understand.  On pg 18, what is being described is the crop
model input file (FILE X).  On pg 132, is the file OVERVIEW.OUT, which is
a model OUTPUT.  So pg 18 is NOT describing the format for OVERVIEW.OUT
on pg 132, therefore no conflict.
 
>
> 3. In seasonal analysis, using historical measured data, how to account for
> missing years? For many countries in Africa, due to civil war data for
> certain years is missing.
 
I'm assuming you are talking about weather data...you would have to fill
in the data somehow.  I know the crop models now have the weather
estimators built-in and can fill in missing weather data "on-the-fly" as
it is running, but don't know if it can do it YEARS at a time...
 
>
> 4. The units on Total Nitrogen, Pg 18 (File X) and Pg 46 (File soil.sol)
> should be same.
 
Why?  The Total N on pg 18 is data entered by the user.  I assume g/Mg is
what the user would typically have for units of Total N.  The other Total
N stored in soil.sol are values from the SCS soil database, so I just
store the units used from there.
 
>
> 5. It is common practice to record -2 for trace rainfall in weather data
> files, now the models stop when this occurs. I think the models must not do
> so, or else, we have to alter many of our data files. I think this would
> cause a lot of problems for people who are not familiar with this project's
> history.  Minor problem with serious implications!!!
 
It has been accepted at DSSAT v3 standard to put -99 for missing data.
Any other value is treated as a REAL data value.  Therefore -2 would be
treated as -2.  I don't think it makes much sense for us to modify crop
models to accept -2 as a special code for trace values.  We could have
problems if some other institute used -4 for trace or the letter "T" for
trace.  We can't just change the models because the data does not work.
 
That is why we have the minimum data set and the DSSAT standards.  By
getting the data into DSSAT MDS format, you can use any and all of the
components of the system.
 
In any case, it should not be too difficult to replace -2 with 0 for
trace, since I assume trace is some very small value approaching 0...
 
>
> 6. Pg 26, Vol 2, Automatic Planting management,
>  what is lowermost/uppermost soil water? does it refer to LL, DUL, available
> water or absolute soil water content?  Is it same as under Irrigation and
> water management section?
 
Gerrit or one of the modellers will have to answer this one.
 
>
> - N strees factoR? what does it mean? does it mean if plant is stressed to
> this value?
 
Values range from 0 to 1, 0 being the plant experienced no stress because
it had more than enough N and 1 being the plant experienced max. stress
because it did not have enough N at all.
 
>
> 7. Could you send me deatail definitions (mainly N:P:K composition as
> appropriate) for fertilizer codes. Fertilizer composition is one of the major
> issue as it refers to use efficiency. Are the models sensitive enough to
> capture these differences?
 
Gerrit or a crop modeller will have to answer this one.
 
Regards,
-Daniel
 
Daniel Imamura                         Computer Specialist
University of Hawaii-Manoa             Email: [log in to unmask]
2500 Dole Street, Krauss Hall rm 118   Phone: (808)956-8858
Honolulu, Hawaii 96822