Articles
POST HARVEST IRRIGATION RATES AND CUT-OFF DATES AFFECT BUD BREAK, BUD NECROSIS AND YIELDS OF ‘PERLETTE’ GROWN AT THE HOT JORDAN VALLEY OF ISRAEL.
The vineyards at the Jordan Valley are irrigated with 10,000–12,000 m3/ ha each season, half of which is applied after harvest.
The environmental conditions and the amount of water induce excessive vegetative growth, severe shading, late cane maturation and delayed defoliation.
Cessation of irrigation from the end of October till pruning is commercially practiced, but decreasing post-harvest irrigation rates, or hastening cut-off date might cause salinization of the soil and vines.
This study was initiated in 1992. Three post-harvest irrigation rates: 50, 75 and 100% of currently recommended water amounts were applied to a 1.2 acre ‘Perlette’ plot, with 3 cut-off dates: the end of August, September or October, as sub-plots.
There was no increase in soil or vine salinity in any of the treatments.
The higher amounts of water and the later cut-off dates caused more vegetative growth, and more shade.
Yields at the seasons: 93, 94, 95, following the treatments were lowest after irrigating at 100% rate.
The cut-off date had no significant effect on the 3 yields’ average, but full irrigation induced significantly lower yield than 75 and 50%. At each cut-off date the 3 seasons’ average of % bud necrosis increased with increasing water amounts.
Percent bud necrosis was lowest in September cut-off date and was doubled in October.
The treated vines were sprayed with 5% Dormex and still there was a small but significantly higher percent bud break with the lowest irrigation rate than with the highest.
Bud break occurred insignificantly later at the October cut-off date than in the 2 earlier ones.
The physiological and practical implications of those results will be discussed.