Nitrogen, flowering and production of lychee in Florida.

摘要

Lychee (Litchi chinensis) is gaining popularity in American markets and is becoming a high value crop in south Florida. However, unreliable flowering and yield seriously impact on lychee production in this area. Flowering normally follows cold or drought stress. Under warm weather, high rainfall and excessive nutrients cause unreliable flowering and fruit set. Although growers have no control over the weather, they can optimize flowering by managing the vegetative vigour of trees. In an experimentconducted during 1998, the effects of N fertilizer (rates and application date) on lychee cultivars Brewster and Mauritius were studied. When excessively watered and fertilized, lychee trees grew vigorously and produced vegetative flushes every two or three months. The lack of maturity of late vegetative flushes in the late fall or early winter prevented flowering in January and February. Vegetative flushes in late fall can be prevented by restricting nitrogen in summer. Thus, through proper nitrogen fertilization, growers can achieve abundant flowering. Our results demonstrated that the timing and rate of nitrogen fertilizer significantly affected soil and leaf nitrogen status. High nitrogen concentrations in leaves were associated with vegetative flushing, and reduced flowering and yield.