partial rootzone drying or PRD, Australian irrigation technique designed to control vine vigour and maintain wine quality with minimum interference to yield. PRD was developed by scientists Dry and Loveys from the University of adelaide and csiro, after observation of basic vine physiology in response to water stress. Initially using vines with divided root systems, they discovered that when only a portion of a vine’s root system was drying, transpiration was reduced and shoot growth was slowed as a consequence of the production of the hormone abscisic acid by drying roots.
