Simulating grapevine phenology with IVINE and UTOPIA models: a case study on the Timorasso cultivar

Crop models such as IVINE (Italian Vineyard Integrated Numerical model for Estimating physiological values), developed at the University of Turin Physics Department since 2015, represent a sophisticated tool for simulating the complex interactions between vineyards and the atmosphere. These models are designed to accurately reproduce the phenology and key physiological processes that dictate crop growth and yield quality, including photosynthesis, respiration, nutrient uptake, and water use efficiency. Given that the precise identification of the main phenological stages is crucial for guiding the timing and intensity of various biological processes, the model must meticulously account for a wide array of fluctuating environmental factors. These include primary meteorological variables — temperature, humidity, wind speed, atmospheric pressure, and precipitation — as well as variables related to the surface layer and the root zone, such as soil water availability and energy content. Furthermore, the model incorporates detailed site-specific parameters, including soil texture, physical characteristics, and the specific morphological properties of the vegetation. A fundamental phase of this research involves the rigorous validation of the model for specific cultivars; this is achieved through experimental runs in distinct geographical regions, where simulation outputs are compared against high-resolution field measurements. Once validated, these models serve as reliable "numerical laboratories" for conducting predictive simulations under varying environmental scenarios. In this work, we present the results of simulations focused on the Timorasso grape variety, a traditional Piedmontese cultivar. The study compares model outputs with detailed field observations provided by a leading winery in the region, bridging the gap between theoretical modeling and practical viticulture. The meteorological input data were meticulously compiled into a dedicated database, integrating records from the regional agrometeorological network (RAM) and the ARPA hydro-meteorological network, with missing values filled through site-specific interpolation techniques. Soil-related variables were generated using the UTOPIA (University of TOrino land surface Process Interaction model in Atmosphere) model, while soil texture and organic matter content were retrieved from the international SoilGrids database to ensure a comprehensive characterization of the vineyard environment.