The model versions released with DSSAT3 do not contain subroutines for
simulating the mineralization of animal manures. The N sources that are
simulated include soil organic matter, certain N fertilizer sources, and
plant residues (e.g. crop residues, plant roots, and green manures). Please
refer to Godwin and Jones (1991; in Modeling Plant and Soil Systems, J.Hanks
and J.T. Ritchie, eds), Bowen et al. (1993; Agron. J. 85:153), and Quemada
and Cabrera (1995; Soil Sci. Soc. Am. J. 59:1059) for more details on model
assumptions regarding the N balance.
Although the FILEX may contain codes for other N sources, e.g. animal
manure, those codes are not presently implemented. The FILEX structure was
set up to accomodate future improvements and enhancements in the models, but
please note that not all of those options presently work. When in doubt, and
one does not have access to the code, run the model with the different
options to see if it makes a difference. For example, if you were to set up
a FILEX with a green manure source of N compared to an animal manure source
with the same dry matter and N content, you will notice no difference; of
course the availability of N in green manures versus animal manure is not
the same. Some work has been published on the possible structure of
subroutines to describe N made available from animal manures--Hoffman, F.
and J.T. Ritchie, 1993, J. Agron. & Crop Sciences 170:330.
Please feel free to contact me if you have any other questions.
==============================
Walter T. Bowen
CIP/IFDC
Apartado 1558
La Molina, Lima 12
PERU
Tel: +51-1-436-6920
FAX: +51-1-435-1570
E-mail: [log in to unmask]
USA satellite connection:
Tel: (415)833-6635
FAX: (415)833-6636
==============================
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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
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