VINE RESPONSE TO THE IMPLEMENTATION OF PARTIAL ROOTZONE DRYING (PRD)
Dr Joan Girona
Growing vines for wine production presents a special challenge because of the effects of water supplied by irrigation. While necessary to obtain good yields, they should be moderate to avoid negatively affecting the final wine quality by excessive irrigation. This assertion is a reality with regards to the management of grape vines used for winemaking. However, on a more scientific level, the meaning of the word moderation is poorly defined.
Numerous studies have explained the effects of water deficiencies during different stages of the annual vine cycle, and its consequences on the production, vegetative growth and must composition (Matthews, et al., 1987 et 1990; Matthews et Anderson, 1988 et 1989; McCarthy, 1997 et 2000), which were reviewed by Goodwin (2002).
Besides providing pertinent scientific information, these studies also showed the possible practical advantage of applying moderate stress at certain stages of the annual cycle. With this in mind, various irrigation strategies have been proposed, and regulated deficit irrigation (RDI) (Chalmers et al., 1981; Mitchell et al., 1984), sustained deficit irrigation (SDI) (Girona et al., 2002a) and partial rootzone drying (PRD) (Loveys et al., 2000) appear to be noteworthy representatives.
All of these strategies aim at reducing the vegetative growth, improving the production and the quality of the musts, and at decreasing the consumption of irrigation water.
This current work reviews the existing information on PRD, and analyses the possible factors involved in the responses obtained.
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Published on 05/20/2006
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