TREE RESPONSES OF 'FUYU' PERSIMMON TO UREA NITROGEN APPLIED AT DIFFERENT TIMES DURING THE LATE SEASON

This study was conducted to assess the effect of different application times of urea nitrogen (N) on tree growth and fruit characteristics of container-grown, 4-year-old ‘Fuyu’ persimmon. The same amount of N at 36 g per tree was fertigated from July to October on a monthly basis. Fruit characteristics were not significantly affected by the N application times, except for the July-N trees that had higher soluble sugar concentrations. Different N application times did not affect carbohydrate concentrations of dormant shoots, whereas the August-N and September-N trees contained higher N and amino acids. N applications later than August significantly decreased the number of flower buds the following year, the difference being up to 5-fold between the August- and the September-N trees. Severe cold injury occurred in 54.2% of the shoots in the October-N trees, indicating that the N applied late in the season had rendered the trees to be highly susceptible to cold injury in Korea.