More vigorous vines on soils with greater water retention
Amongst other results, it was shown that soils with the greatest capacity for retention of water (deposition and argillite soil) were those that developed the most robust vines. Hydric availability affected the unit production of the vine and the number of grape bunches on the deposition soil, although it was observed that, after one year of high production and number of grape bunches, there was a considerable drop in these variables the following year.
The research also revealed that the best conditions for obtaining a higher degree of probable alcohol are in years where there is less hydric availability during the setting to the vraison (onset of ripening) periods (middle of June to end of July) and greater hydric availability during ageing (August-September). This effect was clearly reflected with the different types of soil.
The temperature during the month of September prior to the harvest was one of the most influencing factors on the malic acid content of the must. High temperatures favoured the combustion of malic acid and, thus, the loss of this acid. The temperature of the grape bunch was influenced by the temperature of the air and the shade afforded.
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