1. General Model Information

Name: Analysis of the cowpea agro-ecosystem in West Africa

Acronym: COWPEA

Main medium: terrestrial
Main subject: biogeochemistry, agricultural
Organization level: population
Type of model: not specified
Main application:
Keywords: crop growth, cowpea, demographic model, age structure, distributed delay model


Dr. Manuele Tamo
International Institute of Tropical Agriculture (IITA) -BCCA
B.P. 08-0932
Republic of Benin
Fax : +229-30-14-66


Dr. Manuele Tamo


Growth and development of a photosensitive cowpea variety are studied with the help of a demographic canopy model. The major driving variables are abiotic factors such as temperature, solar radiation, soil phosphate and water. The dynamics of age-structured populations of leaves, shoots, roots, peduncles and other reproductive organs having numbers and dry matter attributes is simulated by a time-varying distributed delay model with attrition. The delay subroutine is used to emulate stochasticity in growth, aging, and loss of population attributes. A modified functional response model from predation theory is used to estimate the daily photosynthates aquisition. Dry matter allocation is simulated by a matabolic pool model. Growth and yield formation of the plant are driven by the computed ratio between carbohydrates supply and demand. Demand parameters were estimated from detailed dry matter data of developing plant organs. Simulation results are compared with four sets of field data. Further, the model has been used to evaluate the effect of drought stress and different levels of available phosphate in the soil.

Model purpose
This model has been designed for research purposes, to be used as a tool for the exploration of the cowpea egro-ecosystem. It demostrates the suitability of the demographic approach for the analysis of cowpea growth and development. The model also permits the assessment of yield limiting factors, which is of great value as herbivory will be added to the model in the future.

Source of the Abstract:
Joergensen S.E., B. Halling-Soerensen and S.N Nielsen (Edts.) 1996: Handbook of Environmental and Ecological Modelling. CRC Press Boca Raton et al. 672 pp.

II. Technical Information

II.1 Executables:

Operating System(s): Apple MAC-OS current-system 7.1, min-system 6.0.5

II.2 Source-code:

Programming Language(s): Think Pascal 4.0.1

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

V. Further information in the World-Wide-Web

VI. Additional remarks

Last review of this document by: T. GabeleNov 21th 1997
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:41 CEST 2002

Go back to Register of Ecological Models (R E M)