Growth and Inorganic Nutrient Absorption of 'fuyu' Persimmon Trees as Affected by Different Fruit-Loads

This experiment was conducted to investigate growth and nutrient absorption of 3-year-old 'Fuyu' persimmon as affected by different levels of fruit-load. The final leaf-to-fruit ratios of container-grown trees were adjusted to 10, 20, 30, and 60 on July 5. The higher the fruit-load the higher the yield, but the lower the fruit weight, soluble solids, and fruit color. Dry weight of aerial woods and the root increased significantly with decreasing fruit-load. However, total dry weight inclusive of the fruits was higher in the high than in the low fruit-load trees; the weight of a tree that had maintained the ratio at 10 was higher by 22% compared with a tree with the ratio at 60. Fruits accounted for 48% of total dry weight when the ratio was 10, but 18% when the ratio was 60. The amount of nutrients increased in tree parts were calculated by subtracting the contents at the time of bud-break from those at the end of the season. On a tree basis, different fruit-loads did not significantly affect the total amount of inorganic elements absorbed. As fruit-load was higher, however, the amount in the fruits amounted to 41%, 86%, and 69%, respectively, of the total uptake of N, P, and K when the leaf-fruit ratio was 10. The result suggested the necessity for nutrient supply that should correspond with the level of fruit-load since the nutrient in the fruits are permanently removed from the tree.