Stima della produttività di Vitis vinifera L., tramite un modello big-leaf

In order to assess primary productivity and transpiration of plant communities several approaches are used. Here a modification of the model developed by Vitale et al., based on the ‘big leaf’ approach, has been used to model functional behaviour of Vitis vinifera L. Model inputs are: latitude; mean temperature on monthly basis; maximum photosynthesis rate; Quantum Yield as a temperature function; leaf angle; reference temperature for respiration. Field gas-exchange measurements were carried out at leaf level and it was necessary to make some assumptions on canopy structure in order to avoid overestimation of biomass production. These assumptions are required since canopies structure in known to influence productivity and to determine canopy conductance. The model estimates a crop net production of 186 g dry weight/m2, in accordance with field data. The model also highlights the relationship between biomass production and canopy structure in accordance with those productivity models based on allometric relationships