Study the effect of humic acid and zinc on the quantity and quality of fruit, photosynthetic pigments and mineral concentrations of grapevine cv. Asgari

In order to evaluate the effect of humic acid and Zn on the grape yield and mineral concentration, a factorial experiment was conducted based on a randomized complete block design with three replications. The study was done on 20 years old grapevines in the Farsan region from Chaharmahal and Bakhtiari province in 2013-2014. Each of the factors, humic acid and zinc sulfate, were applied in three levels zero, 0.1 and 0.2 weight percent, in two periods including before of flowering and two weeks after full bloom. Results showed humic acid, zinc sulfate and their interaction effects significantly affected on fruit yield, concentration of nitrogen, iron and zinc and also leaf chlorophyll content. The highest fruit yield (8.31 kg per shrub) and the lowest fruit yield (6.12 kg per shrub) obtained in humic acid 0.2 percent and control treatments, respectively. The highest leaf zinc element (49.1 mg per kg dry leaf) obtained in 0.2 present zinc sulfate. Also the results showed positive correlation between zinc concentration and some index such as fruit yield (r = 0.46), cluster weight (r = 0.45), total leaf chlorophyll (r = 0.53) and fruit TSS (r = 0.49). Based on these results, it seems to enhance the yield and improve the quality of grapes, spraying humic acid and zinc sulphate at a concentration of 0.2 percent each to be useful.