EFFECTS OF NITROGENOUS FERTILIZER TREATMENTS AND HOT BRINE METHOD ON NITRATE CONTENT OF EDIBLE GRAPEVINE LEAVES

Nitrogen is an essential element for grapevine growth and development. Excessive nitrogen may accumulate in consumed parts of the plants, then pose serious health risks on human health. Grape leaves have traditionally been used to prepare stuffed leaves (Dolma) in Mediterranean countries. This study was conducted to determine the effects of increasing ammonium nitrate, ammonium sulphate and urea treatments on nitrate content of brined vine leaf of Narince grape cultivar (Vitis vinifera L). Three levels of different nitrogen forms (0-control, 5,10,15 kg N /da) were applied to Narince grape cultivar. In addition, effects of hot water brine treatments on leaf nitrate contents were also investigated. Vine leaves were harvested in four different periods with 8-9 day intervals during the growing season. Nitrate content of fresh and brined vine leaves were determined. Nitrate content of the vine leaves increased with increasing N levels. Nitrate content was higher in fresh vine leaves than in brined leaves. Nitrate content of vine leaves decreased with hot water brine treatments. Nitrate contents of fresh vine leaves were generally greater than the critical levels (3500-2000 mg kg-1). It was recommended based on present findings that nitrogen treatments should not be greater than 15 kg/da. Consumers were advised to prefer brined leaves. It was advised that small children should not consume stuffed vine leaf more than one serving a day.