Mohsen Mozaffari - Department of Horticulture Sciences, Faculty of Agriculture, Zanjan University, Zanjan, Iran
Farhang Razavi - Department of Horticulture Sciences, Faculty of Agriculture, Zanjan University, Zanjan, Iran
Vali rabiei - Department of Horticulture Sciences, Faculty of Agriculture, Zanjan University, Zanjan, Iran
Azizollah Kheiry - Department of Horticulture Sciences, Faculty of Agriculture, Zanjan University, Zanjan, Iran

Fulvic acid is a principal component of humic substances, which are the fraction of naturally occurring organic materials commonly found in soil, sediments and natural waters. The research was carried out to evaluate the effect of foliar application of fulvic acid at four levels (0, 2.5, 5, and 10 gr/l) on the nutritional quality of grape cv. Fakhri. The experiment was conducted based on randomized complete block design (RCBD) with three replications. The vines were sprayed at three stages (Berry formation, Lage phase, and Varaison) some traits such as leaf chlorophyll, soluble solids, vitamin C, soluble sugars and potassium element were studied. The results showed that the application of fulvic acid increased the amount of total chlorophyll, soluble solids, vitamin C and leaf potassium .The 2.5 gr/l of fulvic acid concentration showed the highest impression on of all traits. With increasing fulvic acid concentration its effect on evaluated traits decreased So that 10 g/l fulvic acid treatment did not significantly affect the quality improving of grape. As the final result, 2.5 g/l fulvic acid treatment had an important effect on improving the qualitative of Fakhri cultivar

Humic Material, Potassium, Soluble Sugar, Vitamin C