Vinegar and Iron Chelate Spray Affected Vegetative Growth and Yield of Grape cv. Thompson Seedless

In soils with high pH, iron is inactivated and bounded to the leaf apoplast developing leaf chlorosis. The inactive iron can be reduced artificially by lowering leaf apoplastic pH with spraying weak acid solutions, providing the symplast absorption of activated iron. The objective of this study was to determine the effect of vinegar spray, as an acidifying substance and iron chelate (Fe-EDTA) on iron nutrition and vegetative growth of grape vines (cv. Thompson Seedless) grown in high pH soils. Four years old grape vines of cv. Thompson Seedless which were grown in high pH soil (pH=8) were selected. Experimental design was a Randomized Complete Block Design (RCBD) with four spray treatments: 1) vinegar (0.8%), 2) iron chelate (0.2%), 3) combination of vinegar and iron chelate (0.8%, 0.2% respectively) and 4) distilled water (control). Vinegar treated plants had higher chlorophyll, active iron (Fe2+) and yield. Vinegar is a by product of grapes that can be easily produced by growers with very little cost and its application has effectively improved plant vegetative growth, yield and mitigated iron deficiency of “Thompson Seedless” grapes. Vinegar is very cheap compared to chelated iron. The vinegar spray has the potential to increases yield without increasing the cost for the growers, ensuring both profitability and sustainability of the production system.