Effects of ringing treatment on the numbers of flower, fruits set and leaf-nutrients in young "Maekawajiro" kaki (Diospyros kaki Lim. f.) growing on the andosols of non-volcanic ash material
1998
Ooshiro, A. (Shizuoka-ken. Citrus Experiment Station, Shimizu (Japan)) | Fukuyo, K. | Murakami, T.
To clarify the cause of low production of the fruits of Japanese persimmon (cv. Jiro) (6-year-old trees) in an orchard, the physico-chemical properties of orchard soil (the Andosol of Non-volcanic ash material) and leaf nutrient were investigated. At the same time, the effects of ringing treatment on the fruit set and the relationship between the number of late drop and leaf nutrient contents were studied. 1) As observed in common Andosol, humus and nitrogen contents of the soil of the tested orchard wee abundant and the ratio of liquid phase, and solid phase were also high. The thick Andosol existed up to the depth of 1 m. The leaf nitrogen contents early in October were somewhat high in comparison with common orchard trees. As the leaf nitrogen contents went higher, canopy volume also went larger and the numbers of flower became fewer. Therefore the low productivity might due to the results of surplus absorption of nitrogen nutrient. 2) By ringing of 2 mm width in early June, the numbers of flower in the next year were clearly high, causing increase of the numbers of fruit set. The amount of the 5 largest elements of leaf nutrients decreased in the year of the ringing, and recovered to the comparable level to the non-ringing control plots in the next year. Just after ringing, the color of the developing leaves tinged with red, and some leaves turned purple. The purple coloration of the leaves were thought to reflect strength of the ringing and may become an index for adequacy of ringing. 3) In the ringing treatment plots, numerous late drops of fruits were observed in the second year. It was considered that late drops were promoted by the high nitrogen contents of the trees caused by their vigor and soil fertility
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