Although DSSAT in principle is able to handle manure as a source of nutrient
input, by including it in FILEX as residue and other organic inputs, I would
not put too much trust in the outcome of this. The DSSAT soil organic matter
(SOM) submodel is very limited and, for instance, only accepts residues that
are incorporated into the soil. Residues left on the soil surface (leaf and
stem litter, or surface-applied manure) don't do anything.
 
Particularly when modelling systems that are not (heavily) fertilized and
where the major nutrient flow comes from SOM decomposition -- such as most
developing-world agricultural systems -- DSSAT will therefore have limited
success. Since we are working in South and Central America with such
systems, we also ran into this problem, and I am presently trying to improve
the SOM submodel of DSSAT. It will, however, take a while before this is
well tested and can be made generally available.
 
Alternatively, one can have a look at the CENTURY model (Parton et al.,
1987: sssaj 51, 1173-1179 or Parton et al. 1988; Biogeochemistry 5, 109-131)
, that has a much more detailed SOM submodel and also allows crop production
simulations (at least in version 4.0 and later).
 
Arjan Gijsman
Centro Internacional de Agricultura Tropical (CIAT)
Cali
Colombia
 
 
 ----------
From: Octavio A Castelan-Ortega
To: Multiple recipients of list DSSAT
Subject: CERES NITROGEN  VERSION
Date: Wednesday, June 25, 1997 10:23AM
 
Could anyone tell me what is the minimu set of data to calibrate the
N version of the ceres-maize model. I also would like to know if the
DSSATv3 of ceres accepts manure as a source of fertilizer?
Thank you very much
Octavio A. Castelan-Ortega
Institute of Ecology and Resource Management
Scottish Agricultural College
West Mains Road
Edinburgh EH9 3JG
Scotland U.K.
e-mail: [log in to unmask]
Telephone: (0131)5354080