Growth, Dry Weight and Nitrogen Distribution of Red Oak and ‘Autumn Flame’ Red Maple Under Different Fertility Levels

Abstract

Red oak (Quercus rubra L.) seedlings and ‘Autumn Flame’ red maple (Acer rubrum L.) rooted cuttings were grown under different fertility levels: 0, 25, 50, 100, 200 or 400 mg/liter N from 20N–8.6P–17K water soluble fertilizer applied daily in two, 45-minute irrigation events. At one-month intervals from June to October, seedlings were harvested, and dry weights and N content of leaves, stems and roots determined. In October, red oak dry weight increased up to 400 mg N/liter fertigation. Red maple dry weight was greatest between 200 and 400 mg N/liter fertigation. For both species, as N fertigation level increased, relative stem dry weight increased while relative root dry weight decreased. There was little change in relative leaf dry weight. For both species, percent N in leaf, stem and root tissues increased with increasing N fertigation. N distribution in leaf, stem and root tissues was similar to relative dry weight accumulation. Red maple plants had greater morphological adjustment to increasing N fertigation than did red oak plants. At the highest fertigation levels, red maple plants could be N loaded, increasing N tissue concentrations without an increase in plant dry weight. Red oak plants did not exhibit N loading.