The SIMBA model (Philippe Tixier)

 

The SIMBA framework is an innovative model dedicated to the simulation of the functioning of the banana agro-ecosystems. SIMBA includes simulation modules and indicators to evaluate agronomic, economic, and environmental performances. It is used to test in silico combinations of decision rules (ref) and to address issues related to the sustainability of banana plantations. The philosophy of SIMBA was to build a model that account for the specificities of the crop and to integrate all existing data. This model is also used to tackle more general question that deal with ecology of the agroecosystem. 

 

 

 

 General structure of the SIMBA model

 

Some modules of SIMBA:

 

• The core of the simulation model is the simulation of the dynamics of the banana population (SIMBA-POP, ref); it allows accounting for unsynchronization of the plant stages over the cropping cycles. The SIMBA-POP module is also used to predict the harvest dynamics and to optimize the planting date to maximize gross incomes (ref).
• SIMBA also includes a unique plant-parasitic population dynamics in interaction with the plant growth and development (SIMBA-NEM, ref). Inputs of the models are soil and climate data, and decision rules describing the simulated system. This module account for the effect of the variety of banana (ref).
• SIMBA-N is a nitrogen balance module that accounts for the specificities of banana field (ref): restitution of nitrogen between successive cropping cycles, dilution of nitrogen in biomass, and specificities of leaching in tropical soil and climate. 
• The SIMBA-IC module allows the simulation of the growth of inter-crop and the competition between the associated crop and the banana plant. More than 20 cover-crops were parameterized. Actually we develop a spatialized interaction between the banana and the associated crops.
• The Rpest indicator allows an evaluation of the pesticide risk (ref). Rpest is characterized by its link with outputs of the simulation modules, allowing a dynamic evaluation of pollution risk of waters, thus detecting the period of risk.

 

 

 Example of SIMBA out puts: nitrogen dynamics in four different zones of the banana fields

 

SIMBA was primarily developed on the Stella platform (HPS) but ‘easy to run’ modules were developed separately to answer practical questions of farmers or decision makers. Modules are available, please ask the author for further information, tixier (at) cirad.fr

 

Last update: September 2009