PHYSICALLY BASED HYDROLOGICAL MODEL TO SUPPORT WINE-QUALITY PRODUCTION

The role of soil water status on crop vine responses in terms of grape quality responses (sugar, acidity, poliphenols, antocians, etc.) is widely discussed inliterature, but the ensemble of processes involved, their quantification and management options is generally not examined. For these reasons the use ofphysically based soil-plant-atmosphere hydrological model can represent an useful tool to study and evaluate effects of soil-water and plant processes in order to (i) analyse the crop water stress, (ii) relate it to wine quality and therefore (iii) improve the classification of landscape addressed to the grapevine and wine with high quality suggesting also management options. In this way we tested a new physically oriented approach to terroir analysis, based on the use of the soil-plant-atmosphere simulation models in viticultural zoning. The study was conducted in the farm Quintodecimo located in Mirabella Eclano (AV), Southern Italy, and devoted to quality wines production (Aglianico DOC). The soil spatial distribution was recognized through geophysical analysis and classical methodologies; then the soil-plant water status was monitored in two experimental plots from two very different soils spacing 60 meters apart along a slope. Hydraulic properties of the soil horizons were measured in the laboratory by the Wind's method. Daily soil water variables (through TDR probes and tensiometers installed at different depths), crop development (biometric and physiological parameters) and daily climate variables (temperature, solar radiation, rainfall, wind) were monitoredalong two years. The agro-hydrological model SWAP was calibrated and validated on the soil water content data. Then it was applied to estimate soil-plant water status in different crop phenological stages, being anyone of these stages crucial for specific grape quality responses. The effects of crop water status on crop response and wine quality was evaluated in the two different soil types occurring in two different geomorphic settings (upslope and downslope positions), comparing the crop water stress index with: crop physiological measurement (leaf gas exchange, chlorophyll-? fluorescence, leaf water potential, chlorophyll content, LAI measurement), grape bunches measurement (berry weight, sugar content, titrable acidity, etc.) and wine quality (aromatic response).