In regions with severe water shortages in the summer period, associated with values with high temperature limiting photosynthesis, yield and the quality of grape must are often affected negatively reflected in the profitability of the vineyard. For these situations there is huge lack of data to guide criteria irrigation standards: global appropriation and piecemeal during growth in function of the potential evapotranspiration, watering times depending on the physiological activity of the vine and its amounts.
In the Douro DOC the white varieties have a very significant weight, whichever is the need to produce the best wine grapes leading to wines of choice, with implementation and competitiveness in a market currently favours red wines and is very selective about the quality white.
The malvasia fina is one of the most appreciated, either in DOURO DOC or in other wine-growing regions of the country. Therefore require a detailed study of its leading in order to extract the best of its high quality potential, particularly for irrigation, which is currently being regulated by the Interprofessional Committee of the Douro Region (CIRDD).
- Get concrete data to define criteria for irrigation (watering times and appropriation) to apply in vineyards in Douro DOC, in order to optimize the relationship x production quality.
- Acquire data on the behavioural characteristics of Malvasia Fina in situations of non-irrigation and different irrigation systems.
- Extrapolate the concepts acquired by testing other castes, including red ones, as a first approximation to the rationalization of vineyard irrigation, particularly in the Douro DOC.
- Provide conclusive evidence tending to CIRDD the regulation of irrigation in the region.
The test is installed in a portion of the vineyard of Quinta de Nª Sª de Lourdes, belonging to UTAD, included the demarcation of Douro DOC, with an area of 1.1 ha. The vineyard is conducted on cord with vegetation amounts, 2 x 1,2 with 6 years, grafted with malvasia fina under S04, in a schist cryept soil moderately fertile, with pH (H2O) = 6, after correction.
The experiment is in split-plot, with the following modalities:
A – Irrigation from setting off to harvest.
A1 – Irrigation to 100% of ETP
A2 – Irrigation to 50% of ETP
A3 – Irrigation to 25% of ETP
T – Control without irrigation
B - Irrigation from setting off to berry coloration
B1 - Irrigation to 100% of ETP
B2 - Irrigation to 50% of ETP
B3 - Irrigation to 25% of ETP
T - Control without irrigation
1. Evolution of maturation - weekly harvest of berries to analyze, in early September to early October:
- Degree refractive
- Total acidity by titration
- pH by potentiometer
- glucose, fructose, tartaric acid and malic acid CLAE
2. Physiological determinations weekly – from berry coloration to harvest:
- water potential from base and noon– Scholander Bomb
- transpirations, stomatal conductance, CO2 fixation e QUE – IRGA
3. Vinic determinations
- phenological stages - flowering, berry coloration, physiological maturity and leaf fall;
- production per plant and average weight of the bunch;
- pruning weight and ratio production / weight pruning.
4. Oenological determinations
- Microvinification by modality
- Wine analysis - alcohol degree, total acidity, volatile acidity and pH
- Organoleptic tes
50 vines per modality and repetition for physiological measurements.
Duration of test:
From 2002 to 2004, with annual disclosure of results and final publication in 2004.