Effects of ¹⁵N-Urea Application to Trunk or Spurs after Peeling the Bark on Shoot Growth of ‘Pione’ Vines under Forced Condition

Abstract

Eight-year-old ‘Pione’ vines were grown in plastic containers under forced conditions. Twelve vines, that were trained to cordon with spur pruning, were used for the experiment. Bark was peeled by high-pressure water two weeks after forcing. After that, 10% ¹⁵N-urea solution was applied to the trunk or spurs. In the control vines, tap water was applied to all trunks and spurs.
There was no difference in the date of bud-break among the three treatments. At the second leaf-expansion stage, total nitrogen and ¹⁵N contents of shoots were higher receiving in vines application to the trunk than in vines receiving application to spurs or in controls. When the trunk of vines was treated with ¹⁵N-urea, shoot growth was the most vigorous. The chlorophyll contents in the leaves at the third and fifth node in vines receiving application to the trunk were higher than in those vines receiving application to the spurs or in controls.
These results show that nitrogen absorbed throughthe surface of the trunk is effective for growth immediately after bud-break.