Yield, Leaf Mineral Content, and Quality Properties of Hayward kiwifruit as Influenced by Different Fertilization Methods

Kiwifruit requires a high quantity of nutrients that must be supplied through fertilization to obtain an optimum yield on a sustainable basis. This research was conducted to evaluate different fertilization methods including broadcast application (as control), deep placement of the fertilizer and fertigation, alone or in combination with foliar application and their effects on the yield, leaf mineral contents, and some quality properties of kiwifruit (A. deliciosa cv. Hayward). Results showed that fertilization methods had a significant effect on yield and the highest level of yield (76 Kg tree-1) was obtained in the combination of fertigation with foliar spray. In addition, foliar application significantly increased leaf mineral contents of kiwifruit in all treatments. Furthermore, the fertilization method had significant effects on phenol, ascorbic acid contents, and antioxidant capacity of fruits. The highest levels of antioxidant (70.9%), phenol (103.6 mg 100g-1), and ascorbic acid (54.2 mg 100 g-1) in fruits were recorded in ‘soil application’ method. Total soluble carbohydrate and starch contents of the fruits were reduced following foliar nutrition in all treatments. However, foliar nutrition significantly increased fruit crude protein. In conclusion, based on obtained results, fertilization method directly influenced the yield and leaf mineral status and indirectly influenced the fruit chemical composition of Hayward kiwifruit. In fact, the supplemental foliar application reduced some fruit quality attributes (lower antioxidant activity and carbohydrate content) but enhanced the yield of kiwifruit.

Keywords:

antioxidant capacity , Carbohydrate , phenol , starch