Modelling grapevine responses to different training systems

Modelling represents a useful tool to analyse grapevine (Vitis vinifera) responses to environment and field practices. Their effect on quality and quantity of growth and development can be simulated, providing users with information concerning the best combination of variables to improve the final production. With this aim, vegetative, productive and ecophysiological behaviours of Sangiovese grapevines have been evaluated in a Tuscan vineyard in response to different training systems: single cordon and lyre. The grapevines were spur pruned and planted at the same density (6667 vines/ha). Research was carried out in 2002. The two trellising systems were distributed in a randomised block design with 4 replications of 3 rows each. Measurements of light interception, photosynthetic efficiency, vegetative and productive characteristics were collected from the central row. Agro-meteorological variables were measured by an automated station located close to the experimental vineyard. The simulation was obtained using a model implemented with the language STELLA. The model is composed of three sub-modules, i.e. photosynthesis, respiration and biomass accumulation. The results showed that the model can satisfactorily simulate the growth of grapevine under the single cordon system, while growth of lyre vine was strongly underestimated. This was probably due to the characteristics of lyre canopy, allowing a better utilisation of direct and diffuse solar radiation, that was not well described by the input data and the equations used in simulation model.