Development of a simulation model for studying kiwi fruit orchard management

Abstract

The paper presents a model designed for studying the effect of orchard management on fruit number and size in kiwi fruit plots. It summarises the submodels (previously published) that take place at different levels of organisation (flower/fruit, cane, plant) and compose the global model (flowering of female and male vines, pollination and fruit growth), explains their relationships and focuses on the way technical operations are incorporated. The characteristics of both planting scheme and choice of pollenisers are inputs of the flowering and pollination submodels. Winter pruning options (plant level) modify the inputs of the female flowering model. Thinning (plant level) influences the overlap of female and male flowering (outputs/inputs of the flowering/pollination models) and vine crop load that acts on fruit growth (individual fruit growth model). Irrigation scheduling participates with the rainfall regime to the calculation of a series of water stress effect at the plot level, which is used to affect individual fruit growth rates. After testing the model against real field data, simulations of the model are presented for sake of illustration. They include the effect of climate and of each technique (comparison of contrasted choices) with the other ones controlled on the performance of a reference plot, and an example with several techniques changed together. The results indicate that the model is sensitive both to climate and to changes in technical operations.