Effect of Foliar and Soil Application of Humic Acid on Quantity and Quality of Pomegranate Fruit cv. Malas-E- Saveh

Humic acid, as an organic acid obtained from humus and organic sources without any environmental destructive effects, is used in the production of horticultural crops. In this study, the effect of foliar and soil application of humic acid treatment (as Humix 95, contains 68% humic acid, 12% fulvic acid and 13-15% potassium) at different concentrations (0, 1.7, 3.4 and 5.1 g pure humic acid per tree at each time) on quantity and quality of pomegranate fruit cv. Malas-e-Saveh performed in the complete randomized block design with three replications. Humic acid is used at pre-flowering, 30 and 60 days after fruit set. The results showed that humic acid treatment increased total fruits per tree, dry matter of aril, fresh weight of aril, aril/peel ratio, total phenolic and flavonoids content and antioxidant activity in compared with control. However, sunburn damage, cracking, aril paleness and fresh weight of peel were significantly lower than control fruits. While, mean fruit weight, total soluble solids (TSS), Titratable acidity (TA), TSS/TA and total anthocyanins content were not affected by humic acid treatment. Overall, humic acid application increased marketable fruits. According to these results, foliar application of humic acid was more effective in the improving quantitative properties and antioxidant activity of pomegranate fruits.