Response to different amounts of applied nitrogen fertilizer including non-fertilization in Japanese persimmon (Diospyros kaki Thunb.) Tree 'Kaekawa Jiro'

To clarify proper N fertilization quantity and N fertilization induction to Japanese persimmon cv Maekawa Jiro for the production of a seedless fruits, this implemented a N fertilization quantity examination over the long time. 1) The number of normal flowers, yield without N fertilization was inferior to that with N fertilization and between the standard fertilization and the duple quantity, this didn't lead by the place to admit an influence over yield. However, as for the duple quantity fertilization, the year where there are more numbers of the normal flowers and lower with physiology fruit drop(%) than the standards were admitted. A difference isn't admitted to be duple quantity, that the trunk cross-sectional area, canopy volume are more attenuate without N fertilization than the standard and that they are small and this thinks that what there are rather much yield in early years influenced about the duple quantity. 2) As for the fruit quality, the fruit weight was small without N fertilization and the duple quantity was small in the single year when there is much result quantity. As for Brix in fruit juice, a difference was hardly admitted. As for a rind color this was good in non-N fertilization and a difference wasn't admitted at the standard and the duple quantity. The degree of hardness was low by 2 out of 3 years of investigation and this was low at the duple quantity when there are many numbers of the result in the single year. Brix in fruit juice was influenced by the number of fruit and by the leaf N content when the change of the fruit weight was small. It was recognized that the rind color was nearly similar to brix. 3) The leaf N content was low without N fertilization and it was thought that equal to or less than 2.1% was a lack area in July. A difference wasn't admitted at the standard and the duple quantity,