Superior Seedless grapevines of 7 years old grown in a loamy sandy soil
(E.C_e = 3.7 ds/m) and drip irrigated (E.Ciw = 2.3 ds/m) were subjected to sulphuric
acid (2. 4 and 6 litre/feddan/2 weeks). humic acid (6. 9 and 12 litre/feddan divided
into 4 dosages), sulphur (25, 50 and 100 kg/feddan applied in winter), irrigation
water (30, 35 and 40 litre/vine at different intervals) and control. All treatments
increased leaf area, length of mature portion of the cane, internode length &
diameter; number & weight of clusters, berry weight & size and yield/vine. The best
results were obtained as a result of increasing irrigation water up to 40 litre/vine at
different intervals. Potassium was proportionally increased with increasing the rates
of any treatment. However, CI and Na took a reverse trend. Total free amino acids
were insignificantly affected by H2S04, humic acid or S, whereas increasing irrigation
water up to 40 litre/vine at different intervals followed in the vineyard itself reduced
total free amino acids. Increasing irrigation water up to 30-40 litre/vine at different
intervals reduced proline. Leaves contained more total free amino acids as well as
proline than shoots or roots. Humic acid and increasing irrigation water achieved
more carbohydrate storage in the canes. It was concluded that raising irrigation
water up to 40 litre/vine at different intervals was enough to reduce or counteract the
harmful effects of salinity on Superior Seedless vines in that region.