Authors: Lin Wu ¹; Philippe De Reffye ; Bao-Gang Hu ²; François-Xavier Le Dimet ¹; Paul-Henry Cournède ³

• 1 System identification and optimization in physics and environment
• 2 Eco-informatics
• 3 Laboratoire de Mathématiques Appliquées [Paris]

GreenLab is a structural-functional model for plant growth based on multidisciplinary knowledge. Its mathematical formalism allows dynamic simulation of plant growth and model analysis. A simplified soil water balance equation is introduced to illustrate the interactions and feedbacks between the plant functioning and water resources. A water supply optimization problem is then described and solved: the sunflower fruit weight is optimized with respect to different water supply strategies in a theoretical case. Intuitive searching method and genetic algorithms are used to solve this mixed integer nonlinear problem. The optimization results are analyzed and reveal possible agronomic applications.