An Experiment to Determine the Effective Time of Fertilizer Application for 'Kyoho' Grapes

The experiment was carried out with three years old 'Kyoho' grapevines planted on gravelled beds. Applications of aqueous fertilizer were started at different times from autumn to spring. Effectiveness of each application was determined by measuring vine growth and fruit productivity and also by analysing the nutrient contents in root, cane and leaf at several times. Applying fertilizer in autumn increased the N content of root and cane even during winter and resulted in earlier and more dud bursting and better development of flower cluster. Application from March or April caused a rapid increase in N content of root and cane at bud bursting. The greatest shoot length and the largest ovary size were measured at blooming, and a better crop with larger sized berries and good qualities was yielded on the vines fertilized in spring.