Abstract

Rooted stem cuttings of ‘Carolina Sapphire’ smooth Arizona cypress [Cupressus arizonica var. glabra (Sudw.) Little ‘Carolina Sapphire’] grown in calcined clay in 3.8 liter (#1) containers were fertilized daily for 16 weeks with a complete nutrient solution containing 0, 20, 40, 80 or 160 mg N/liter supplied as ammonium nitrate. Plant heights and stem diameters were unaffected by N rate suggesting that a daily nutrient application of 20 mg N/liter was adequate for maximizing growth. Nitrogen fertilization increased heights and stem diameters by 71% and 56%, respectively, compared to the nontreated controls (0 mg N/liter). Even though shoot growth was unaffected by increasing N levels, foliage N concentration was positively correlated (r = 0.75, P < 0.0001) to N levels. As N concentration increased, total root area and total root length increased quadratically. Nitrogen fertilization increased root area and root length 119% and 108%, respectively, compared to the nontreated controls. Phosphorus concentration of shoots increased quadratically with increasing N levels. Nitrogen rate failed to affect K concentration of shoots. Shoot Ca and Mg concentrations decreased with increasing N levels.