Responses of 'FuyiT persimmon trees to different supplemental nitrogen application times

摘要

This study evaluated the effect of different nitrogen (N) application times on tree growth and fruit characteristics in pot-grown 'Fuyu'. After application at 10 g N tree1 as 1% (w/v) urea in June, a total of 10 g N was additionally supplied to each pot in late July, late August, late September, early October, or mid-October. N application after late July caused reduction of soluble solids of the fruits. When N was supplied in late September and early October, fruit skin color tended to decrease indicating delayed fruit maturation with its increased N concentration. N concentration in dormant shoot significantly increased from 1.13% for the late July application to 1.29 and 1.24% for the early October and mid-October N applications. In the followingyear, number of flower buds was not affected by any N application time in the previous year. Shoot and leaf growth significantly increased for the early October N application of the previous year, which increased by 28 and 11%, compared those of the late July N application. In conclusion, supplemental N application in late September or early October after June N application increased reserve N of the shoots that promoted spring shoot growth and reduced June drop, but they could delay fruit maturation.However, excessive late N application during autumn should be avoided to promote coloration and sugars accumulation of the fruits.