High levels of N are often used to produce a vigorous plant that is also aesthetically pleasing to the purchaser. Environmental concerns with the overuse of N raise the need to find the minimum N requirements necessary to produce a salable plant. Ilex opaca and Lagerstroemia indica plants growing in 1.5-gal containers were irrigated with nutrient solutions containing N concentrations of: 15, 30, 60, 120, 210, and 300 mg N/liter. After 4 months, data indicate that using solutions >60 mg N/liter for both plant species results in leachates with N concentrations higher than those in the applied solutions. Nitrogen leaching losses increased with applied N, ranging from ≈15% to 50% for the low and high treatments, respectively. Chlorophyll readings of leaf tissue were not significantly different for plants of both species receiving N solutions higher than 60 mg·liter–1. These results indicate that N levels lower than those typically used for production of these woody ornamentals will still produce salable plants while increasing N fertilizer-use efficiency.
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