1. General Model Information

Name: winter wheat model


Main medium: terrestrial
Main subject: biogeochemistry
Organization level: Populations
Type of model: compartment model
Main application:
Keywords: ontogenesis, agroecosystem, biomass, grain yield, winter wheat plant,


Dr. Thomas Kartschall
Potsdam Institute for Climate Impact Research
P.O. Box 601203
14412 Potsdam, Germany
Phone: ++49-331-288-2529
Fax : ++49-331-288-2640
email: Thomas@Pik-Potsdam.de


Susanne Grossman
C. Fruehauf
Dr. Thomas Kartschall
E. Matthaeus
Frank Wechsung


contents of the model
The winter wheat model TRITSIM is developed to describe the main processes of development, growth, senescence and grain filling, but also to reflect the reaction on man-controlled factors and strategies of winter wheat. It is part of the agroecosystem model system DEMETER. DEMETER consists of the winter wheat model TRITSIM, the soil dynamics model SOIL\_MOD and the root dynamics model ROOT\_MOD and investigates the water and nutrient flows in an agroecosystem.
principles of the model
The model proceeds in discrete time steps (1 day resp. daily light and dark periods) and in a hierarchical sequence. The most important state variable is ontogenesis (Y_E). It depends mainly on environmental driving forces (resp. phototemperature). This variable controls the internal development as a kind of biological age of the crop. The model consists of three compartments: above ground vegetative biomass, roots and grain. Assimilation is takes place only within the vegetative biomass. The assimilates are used by different processes to maintain the plant metabolism (maintenance respiration) and to enable growth of roots, vegetative biomass and grain. A small part of them is exuded by the roots into the soil.

Author of Abstract: UFIS - Environmental Research Information System

II. Technical Information

II.1 Executables:

Operating System(s):

II.2 Source-code:

Programming Language(s):

II.3 Manuals:

Complete model documentation: Matthaeus, E.; Kartschall, Th.; Fruehauf, C.; Grossman, S.; Wechsung, F.: The agroecosystem model winter wheat DEMETER, Forschungsbericht, Potsdam-Institut fuer Klimafolgenforschung (1992).

II.4 Data:

III. Mathematical Information

III.1 Mathematics

This is a list of model equations sorted by their characteristics with hypertext links for more details.

III.2 Quantities

This is a list of model quantities sorted by their characteristics with hypertext links for more details.

III.2.1 Input

III.2.2 Output

IV. References

Matthaeus, E., Kartschall, Th., Fruehauf, C., Grossman, S., Wechsung, F., 1992.The agroecosystem model winter wheat DEMETER. Forschungsbericht, Potsdam-Institut fuer Klimafolgenforschung.

Milthore, F.L., Moorby, J., 1970.An introduction to crop physiology. Cambridge University Press 1970, pp. 304-305.

Frank, A.B., Bauer, A., 1983.Effect of temperature and fertilizer N on apex development in spring wheat.
Agronomy J. 75, 504-509.

McGree, K.J., Sisbury, I.H., 1978.Growth and maintenance requirements of subterranean clover.
Crop Sci. 18, 13-18.

Thornley, I.H.M., 1977.Growth, maintenance and respiration: A reinterpretion.
Ann. Bot. 41, 1191-1203.

Porter, J.R., Travis, K.Z., Day, W., 1988.Modelling the timing of the early development of winter wheat.
Agricultural and forest meteorology 44, 67-79.

Darwinkel, A., 1978.Patterns of tillering and grain production of winter wheat at a wide range of plant densities.
Neth. J. Agric. Sci. 26, 383-398.

Thornley, I.H.M., 1970.Respiration growth and maintenance in plants. Nature 227, 304-305.

V. Further information in the World-Wide-Web

VI. Additional remarks

Additional information
Last review of this document by: R. Patzak : 1. October 1997 -
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:41 CEST 2002

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