1. General Model Information
Name: Range Plant Profiles
Main medium: terrestrial
Main subject: biogeochemistry
Organization level: ecosystem
Type of model: compartment model, ordinary differential equations
Keywords: rangeland ,range grass growth, grassland dynamics
Southern Plains Range Research Station
USDA-ARS-SPRRS 2000 18th Street Woodward, OK 73801
Fax : 405-256-1322
Developed by USDA-ARS Southern Plains Research Station in Woodward, Oklahoma
RAPPS is a process-oriented, range grass growth simulation model. The model
simulates the response of rangeland grasses to different climates and soils.
RAPPS uses hourly temperature data to calculate net carbon assimilation and
water loss through leaf stomata. These weather data can be input or generated
using a weather simulation model. The carbon, water and nitrogen is then
allocated to various tissues within plant.
RAPPS model output includes net photosynthesis, number of tillers in vegetative
or reproductive status, number of leaves and roots, root length, density by
depth, leaf area index, biomass of several plant organs, reserve carbohydrates,
plant and soil water potential, nitrogen content of plant organs, and
transpiration. The model currently simulates a single plant and extrapolates
to the field level for a single growing season.
Validation Procedures: The leaf gas exchange portions of the model are being validated in the
field. Within the next two years the plan is to validate the biomass production aspects of the model
for several grasses.
How Model Functions: RAPPS uses hourly climatic data to calculate net carbon assimilation
and water loss through leaf stomata. Climate data and soil physics submodels interact cyclically
with the model to calculate the amount of water and nitrogen taken up through roots. The carbon,
nitrogen, and water is then allocated to the various plant tissues based on the plants morphological
status. Currently, RAPPS operates only for one growing season and with one grass species. Our
goal is to implement RAPPS as a multi-year, multi-species model.
Author of the abstract:
CIESIN (CONSORTIUM FOR
INTERNATIONAL EARTH SCIENCE INFORMATION NETWORK):
II. Technical Information
Operating System(s): DOS or Windows
Programming Language(s): FORTRAN
III. Mathematical Information
RAPPS requires coefficients describing the relationships
RAPPS requires coefficients describing the relationshipsbetween environmental variables and photosynthesis and stomatal conductance. Realistic outputalso requires stress tolerance information and data relating the phenological status of the plant tothe environment. Hourly climatic data is used as an input or can be generated automatically usinglongitude and latitude input.
Model Input Data Source: Laboratory data was used to parametrize the leaf gas exchangeportion of RAPPS. Empirical field data concerning the phenological above and below grounddevelopment of grasses was also used. As more mechanistic information is acquired it will beassimilated into the model. Some of the output of RAPPS includes net photosynthesis, number of tillers
Some of the output of RAPPS includes net photosynthesis, number of tillersin vegetative or reproductive status, number of leaves and roots, root length, density by depth, leafarea index, biomass of several plant organs, reserve carbohydrates, plant and soil water potential,nitrogen content of plant organs, and transpiration.
Temporal Scale: RAPPS is currently setup to simulate a single growing season.
Spatial Scale: RAPPS simulates a single plant and extrapolates to the field level.
Dougherty, R.L., J.A. Bradford, P.I. Coyne, and P.L. Sims. Applying anEmpirical Model of Stomatal Conductance to Three C-4 Grasses. (In Press)
V. Further information in the World-Wide-Web
VI. Additional remarks
This model can be used to examine the effects of climate change oncentral United States grassland dynamics.
Last review of this document by: T. Gabele: 08. 07. 1997 -
Status of the document:
last modified by
Tobias Gabele Wed Aug 21 21:44:48 CEST 2002