1. General Model Information
Main medium: terrestrial
Main subject: biogeochemistry
Type of model: not specified
Keywords: grassland, carbon, nitrogen, sulfur, growth, roots, shoots, photosynthesis, aging, ion uptake, nutrient allocation, translocations, respiration, senescence, litterfall
The plant component of SAGE simulates carbon, nitrogen and sulfur dynamics of
three categories of grassland plants.
Growth of roots and shoots is represented as an exponential function of young
tissue carbon content. This function is then modified by temperature and
moisture. Structural tissue is assumed to be synthesized with fixed carbon :
nitrogen and carbon sulfur ratios. Carbon growth requirements, therefore,
dictate nitrogen and sulfur growth requirements. ELM
and SPUR use a similar approach for simulating plant
nitrogen dynamics. Carbon growth is reduced if the nitrogen or sulfur levels
in the plant are suboptimal. The processes simulated by the model are
photosynthesis, aging, ion uptake, nutrient allocation, growth translocations,
respiration, senescence, and litterfall.
Aboveground processes simulated in the SAGE model:
Belowground processes simulated in the SAGE model:
- Photosynthesis (atmospheric CO2 concentration, phenology or leaf age,
temperature, solar radiation, leaf water potential)
- Growth (nutrient)
- Carbon allocation (variable allocation to nutrient ratio, phenology or
leaf age, leaf area).
- Death (phenology or leaf age).
- Carbon allocation (variable allocation to soil nutrient ratio)
- Root growth (soil water, soil nutrient)
- Death (soil water, soil temperature)
- Uptake (soil nutrient, sulfur)
- Respiration (soil water, soil temperature).
(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
III. Mathematical Information
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.
Lauenroth, W.K.; 1979: Grassland primary production : North American Grasslands. In : N. French (Editors), Perspectives in Grassland Ecology. Springer, New York, NY, P. 3-21.
Lauenroth, W.K.; Preston, E.M. (Editors), 1984: The effects of SO2 on a grassland : A case study in the Northern Great Plains of the United States. Springer, New York, NY, P. 207 ff.
V. Further information in the World-Wide-Web
VI. Additional remarks
Last review of this document by: T. Gabele: Tue Oct 7 1997
Status of the document:
last modified by
Tobias Gabele Wed Aug 21 21:44:49 CEST 2002