Modeling the effects of fruit load, shade and plant water status on coffee berry growth and carbon partitioning at the branch level

Preliminary results of coffee berry growth modeling at the branch level are presented. The model, RAMCAF, is based on an existing model developed for peach. Parameters such as light extinction within the coffee tree canopy and potential fruit and shoot growth rates were derived from an experiment conducted over a period of two years on dwarf arabica coffee trees in Costa Rica with varying fruit loads and contrasting light regimes. Equations of leaf fall versus time as well as net photosynthesis versus photosynthetically active radiation were also obtained from experimental data. Simulations illustrate over the production cycle the effects of fruit load, level of shade and plant water status on fruit growth and carbon partitioning between the vegetative and reproductive branch compartments. Future developments such as coupling RAMCAF with a 3-dimensional architectural model of coffee trees to improve calculation of light interception and carbon assimilation are proposed.