THIS investigation was conducted for two successive seasons (2013 & 2014) in the vineyard of EL-Baramoon experimental farm. Hort. Res. Inst. Mansoura, Dakahlia Governorate, Egypt. The vines were of King Ruby cultivar. The chosen vines were fifteen years old, planted in a clay soil under surface irrigation system, spaced at 2 x 3 m apart using spur pruning under bilateral cardon trellis method with supporting by double T system. The aim of the present study was to investigate and evaluate the effect of addition two sources of soil conditioners and biostimulants such as Humic acid (HA) and Effective micro-organisms (EM) beside control with or without three spraying antioxidants treatments such as (ascorbic acid, citric acid and ascorbic + citric acid) on vegetative growth, leaf mineral content, yield and fruit quality of king Ruby grapevine cultivar. Humic acid and (EM) were used as a soil application at rate (10 and 20 cm3/vine), respectively and were added on two equal doses for two times, at growth start and full bloom. Ascorbic acid and citric acid were used as a spraying application at rate (500 ppm) and were sprayed on the vine for three times, at growth start, full bloom and 2 week after fruit set.
The obtained results showed that soil application of (HA) gave the highest values of cluster weight, yield, berry weight, berry length, berry width and vitamin C as well as the best vegetative growth parameters such as (shoot length and leaf area), leaf chlorophyll content, N, P and K content in leaf petioles as compared with (EM) application particularly in the first season. While no significant differences between (HA) and (EM) applications on SSC%, total acidity%, SSC/acid ratio in berry juice as well as total anthocyanin in berry skin were recorded. Concerning spraying application, it was observed that the treatment of ascorbic acid + citric acid gave the highest results in this respect followed by ascorbic acid and citric acid in descending order. Regarding the interaction between soil and spraying applications, the results indicated that the combination of humic acid + ascorbic acid + citric acid and (EM) + ascorbic acid + citric acid gave the highest values of cluster weight, yield, physical and chemical properties of berries and enhanced vegetative growth parameters, N, P and K content in leaf petioles in comparison with other combinations in both seasons of study.
The best results with regard to yield and fruit quality of king Ruby grapevines were obtained when the vines were supplying with humic