IVINE: a crop model for simulating pheno-physiological processes on vineyards, also from a climatic point of view

Several factors influence grapevine's quality and productivity; among them, there are weather and climate. Temperature, solar radiation, precipitation and soil moisture have relevant impacts on crop growth and yield. Recently crop growth models were used as tools to assess climate variability and change in crop yields and quality. Crop growth models are currently employed at a regional scale for agricultural needs, environmental applications, and/or for supporting the process of decision-making and planning in agriculture. Some crop growth models are adaptable to various crops and can simulate crop growth and plant development, as well as water and nitrogen balances. Specific crop growth models have also been developed to simulate grapevine growth and development. Generally, crop growth models include specific modules calculating the occurrence of phenological stages, that can also be used as stand-alone routines. Finally, grapevine phenology has recently been studied in connection with climate change by means of grape harvest dates used to reconstruct past climate and, more rarely, future climate. The numerical crop growth model IVINE (Italian Vineyard Integrated Numerical model for Estimating physiological values) was developed at our dept. to simulate grapevine phenological and physiological processes. The boundary conditions required by IVINE are hourly meteorological data related to some air and soil values (among which the more relevant are air temperature and soil moisture), while other inputs are initial conditions and parameters characterizing geography, soil texture, grapevine variety, and cultivation interventions. The main IVINE outputs are: the phenological stages (e.g. dormancy exit, bud-break, fruit set, veraison, and harvest), the leaf development, the yield, the berry sugar concentration, and the leaf water potential. The IVINE requires some experimental parameters depending on the cultivar, which have been evaluated through some calibration experiments for some popular Italian varieties. IVINE includes theoretical physically based equations for processes such as water balance and photosynthesis, and empirical equations for others. Long-term simulations carried out in Italian territory show, in the period 1980-2010, significant trends in almost all physio-phenological variables, as well as a reduction in interannual variability, correlated with the climate change still ongoing.
IVINE model performances depend on the quality of input data: the use of experimental data measured not far from the vineyard could improve the quality of the simulation, even if the model seems able to account for the interannual variability of the meteorological conditions, which reflects in the pheno-physiological trends interannual variability. During the presentation, the model will be introduced, and a sketch of the main results obtained will be discussed.