Relationships between grape composition of Tempranillo variety and available soil water and water stress under different weather conditions

Resumen

The aim of the research was to analyse the relationship between grape composition of the Tempranillo variety, and available soil water along the growing cycle. The study was conducted in the Rioja DOCa (Qualified Designation of Origin (Spain). Grape composition (berry weight, acidity and phenolic composition) was analysed between veraison and maturity in non-irrigated vines and related to available soil water along the growing cycle. The available soil water (ASW) was simulated for the period 2008-2018, taking into account soil properties and the weather conditions recorded at each location. Soil water was simulated for each plot and year analysed, after calibration in one plot and the ASW was evaluated under the different conditions. The results showed that soil properties conditioned available soil water, which influenced berry weight, acidity, anthocyanins and total polyphenol index. Under the rainfed conditions in which the vines were cultivated, vines suffered from moderate to high water stress in some periods along the growing cycle. The results showed the most critical periods regarding water availability for grape composition. An increase in available soil water between one and three weeks after bloom and at the end of the ripening period increased acidity and decreased pH while an increase in available soil water content between two and seven weeks after bloom and at the ripening period increased berry weight and decreased anthocyanins and other phenolic compounds.