1. General Model Information


Acronym: SHEEP

Main medium: terrestrial
Main subject: biogeochemistry
Organization level: ecosystem
Type of model: compartment model
Main application:
Keywords: grassland, domestic herbivores, plant growth, forage, sheeps, grazing


J.D. Hanson

W.J. Parton
Fax :



Domestic herbivores are the primary concern of this model, thus a plant growth routine is included only so grazing material is available. Those parts of the plant that cannot be consumed by livestock are ignored. Plant growth is subsequently determined as the daily increase in weight of the forage divided by its initial weight (relative growth rate). This type of forage approximation may be appropriate considering the objectives of the study. However, there is no mechanism in this model to investigate the response of plant species to grazing, thus the model is of little use when considering the entire system.

Aboveground processes simulated in the SHEEP model:

  1. Growth (soil water, temperature)
  2. Carbon allocation (fixed allocation).
No belowground processes were simulated in the SHEEP model.

(from: Hanson, J.D.; Parton, W.J.; Innis, G.S.; 1985 : Plant growth and production of grassland ecosystems: A comparison of modelling approaches. Ecological Modelling (29), P. 131-144.)

II. Technical Information

II.1 Executables:

Operating System(s):

II.2 Source-code:

Programming Language(s):

II.3 Manuals:

II.4 Data:

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

III.2.1 Input

III.2.2 Output

IV. References

Hanson, J.D.; Dye ,A.J.; 1980: Diurnal and seasonal patterns of photosynthesis of honey mesquite.Photosynthetica, (14), P. 1-7.
Hanson, J.D.; Skiles, J.W.; Parton, W.J.; submitted. A multispecies model for spatially heterogeneous rangeland plant communities. Ecological Modelling.
Hanson, J.D.; Parton, W.J.; Innis, G.S.; 1985: Plant growth and production of grassland ecosystems -A comparison of modelling approaches. Ecological Modelling (29), P. 131-144.
Skiles, J.W.; Hanson, J.D.; Parton, W.J.; 1983: Simulation of above- and belowground carbon and nitrogen dynamics of Bouteloua gracilis and Agropyron smithii. In: W.K. Lauenroth; G.V. Skogerboe; M.Flug (Editors),Analysis of ecological systems : State-of-the-Art in Ecological Modelling. Developments in Environmental Modelling,(5), Elsevier, Amsterdam/Oxford/New York, P. 467-473.

V. Further information in the World-Wide-Web

VI. Additional remarks

Last review of this document by: T. Gabele: 08. 07. 1997 -
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:49 CEST 2002

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