Effect of Foliar Application of Iron and Zinc Micronutrients on Yield and Quality Properties of Sour cherry Fruit (Prunus cerasus L.)

Sour cherry is one of the most strategically important horticultural products in the Khorasan Razavi province that proper nutrition can improve the performance of the plant. This fruit is rich in vitamins, antioxidants, and soluble fiber, which is very useful for lowering blood pressure. Proper nutrition is one of the important factors in determining the quantity and quality of the fruit. In arid and semi-arid regions, micronutrient elements availability is one of the factors that limits growth, yield, and quality of fruit trees , because absorption of nutrients being limited due to the alkalinity of the soil. So, the use of an appropriate method to provide the required nutrients by plants is necessary. Foliar application of nutrient is one of the important ways in the food supply for plants. Hence, spraying is an effective way to reduce nutritional disorders in plants. Therefore, the objective of this study was to evaluate the effect of foliar application of iron and zinc micronutrients on the yield and physicochemical properties of sour cherry fruit

In order to investigate the effect of spraying of iron chelate and zinc sulfate on yield and qualitative characteristics of the sour cherry fruit, a factorial experiment was conducted in a randomized complete block design with 4 replications in the commercial orchard of Astan Quds Razavi, Mashhad, Iran. The first factor was spraying iron 6% Fe-EDDHA at 3 levels (0, 2 and 4 g l-1) and the second factor was spraying zinc sulfate at 3 levels (0, 2 and 4 g l-1). The treatments were applied in two stages, 20 days after the whole flowering stage and 20 days after the first spraying. Spraying chemicals was done in the morning when temperature and humidity were not high.. Fruit and leaves samples were collected, at the commercial maturity stage of fruit, from each tree include one kilogram of fruit and half kilogram leaves. Thereafter, healthy fruits and leaves of the same shape, size, and color were selected to determine the biochemical properties of fruit and chlorophyll leaves. In this experiment, 36 grilled cherry trees of 10 years old with a spacing of 3×4 m were used. The general conditions of the selected trees were similar to other garden trees, and irrigation (dripping), pest and disease control were applied uniformly to all treated trees. The studied traits included the fresh weight of fruit, dry matter percentage, fruit yield, fruit juice acidity, soluble solids, total antioxidant, trace related to chlorophyll content, iron and zinc concentration in leaves

The results showed that different levels of iron chelate, zinc sulfate, and their interaction increased fruit fresh weight, dry matter percentage, fruit yield and chlorophyll traits. An individual application of 4 g l-1 of iron or zinc, and also their combination application showed the greatest values on evaluated traits In addition, the soluble solids, total antioxidant, and iron leaf values were only affected by different levels of chelate iron, which improved with increasing spraying levels of the studied traits. Sprayed with zinc sulfate could increase the concentration of zinc in the leaves but the acidity of juice was not affected by the treatments. The results showed that different levels of zinc significantly affected all quantitative traits of sour cherry fruit than iron chelate. However, spraying with iron chelate had a significant effect on the quality traits of fruit, including total soluble solids and total antioxidants. Moreover, the combination effect of chelate iron and zinc sulfate in comparison to their individual application had a better effect on the quantitative and chlorophyll traits of the cherry leaf. The highest increase in both zinc and iron content of leaf samples were obtained in trees that were treated with 4 g l-1 of zinc or iron solutions, respectively. The results show that foliar application of high concentrations of both chemicals increased zinc or iron content of leaf samples about 30% compared to the control. Thus, not only higher yield but also quality improvement of sourcherry fruit occurred in treated trees. Our results was in accordance with the findings of previous studies on different fruit tress like grapes, pistachio and orange. According to the results, it can be concluded that spraying with zinc sulfate and iron chelate during plant growth season can increase yield and improve the physical and chemical properties of the sour cherry fruit