Nitrogen Nutrition of Containerized Cryptomeria japonica ‘Elegans Aurea’

Containerized, rooted stem cuttings of ‘Elegans Aurea’ Japanese cedar [Cryptomeria japonica (L.f.) D. Don ‘Elegans Aurea’] grown in calcined clay, were fertilized three times weekly for 14 weeks with a complete nutrient solution containing 0, 25, 50, 100, or 200 mg N/liter supplied as ammonium nitrate. Top and root dry weights were not affected by N rate suggesting that 25 mg N/liter was adequate for maximizing growth. Nitrogen fertilization increased top and root dry weights by 149% and 20%, respectively, compared to the nontreated controls (0 mg N/liter). As N concentrations increased, root area and total root length decreased linearly. Nitrogen fertilization decreased root:top ratio by 50% compared to the nontreated controls. However, the root:top ratio was not affected by N rate. Percent top N concentration was increased by N compared to the nontreated control. Percent top K, Ca, and Mg decreased linearly with increasing N rates. There was a quadratic response in percent top P with a maximum at 50 mg N/liter.