THIS STUDY was conducted during 2013 and 2014 seasons to elucidate the effect of single and combined applications of humic acid and potassium silicate each at 0.05 to 0.2% and selenium at 0.025% to 0.1% on growth, vine nutritional status, yield and quality of Early Sweet grapevines.
Single and combined applications of humic acid and potassium silicate each at 0.05 to 0.2% and selenium at 0.025 to 0.1% were very effective in stimulating growth characteristics, vine nutritional status, yield and quality of Early Sweet grapevines relative to the check treatment. Using humic acid, potassium silicate and selenium gave the best results with regard to yield and berry quality. The promotion on these parameters was related to increase the concentration of each compound. Using these compounds together was more effective than using each alone.
To improve yield and berry quality of Early Sweet grapevines grown under Minia region conditions, it is recommended to spray the vines three times at growth start (last week of February.), just after berry setting (Mid of April) and three weeks later (1
st week of May) with a mixture containing humic acid and potassium silicate each at 0.1% and selenium at 0.05%.