Effect of humic acid on qualitative and quantitative characteristics of Kiwifruit cv. Hyward

In order to investigate the effects of humic acid concentration on quality indices of Kiwifruit cv. Hyward, an experiment based on complete block design with 4 replication was conducted during 2015-2016 in one of the Kiwifruit garden of Talesh city, Gilan province. Experimental treatments included soil drenching method and foliar spraying of different levels (control, 2, 4 and 6 Kg/h) of humic acid. In this study, some traits such as weight of fruit, yield, firmness, soluble solids, titratable acidity and vitamin C, pH of fruit juice and total phenol of fruit were measured. Results of ANOVA showed that different concentration of humic acid had significant effect on weight of fruit, yield, soluble solids, and vitamin C traits at 1% probability level and these treatments had significant effect on titratable acid it/at 5% probability level. However, the use of humic acid did not has significant effect on fruit firmness, total phenol and pH of fruit juice. Comparison of means showed that the leaf application of 4, 2 and 6 kg.ha-1 concentration from humic acid had the highest fruit weight and yield. The best result for soluble solids and titratable acidity was obtained from Humic acid at concentration of 4 kg.ha-1 with soil application. Also, the highest amount of vitamin C was recorded from leaf application of 4 kg.ha-1 of humic acid. In general, results showed that the leaf application of 4 kg. ha-1 of humic acid, was more effective in the most studied traits. The highest yield (61.65 kg per tree), fruit weight (145 g), soluble solids (5.57.5 Brix), and vitamin C (38 mg/ 100g Fresh weight) were obtained from the above treatment.