Nitrogen, Phosphorus and Potassium Recovery of Container-Grown Red Oak and Blackgum Seedlings Under Different Fertilizer Application Methods

Abstract

Red oak ( Quercus rubra L.) and blackgum ( Nyssa sylvatica L.) seedlings were grown under five fertilizer application methods: 60 or 30 g slow release fertilizer (21N-1.8P-8.3K: Woodace 21-4-10) with a daily application of 3.8 liters of 25 mg/liter N from a water soluble fertilizer (15N-6.9P-14.1K: 15-16-17 Peter's) or not, or 3.8 liters daily application of 25 mg/liter N from a water soluble fertilizer. The largest red oak and blackgum seedlings were grown under a combination of water soluble plus 60 g slow release fertilizer. Red oak N, P and K recovery rates ranged from 4.1 to 8.6%, 4.5 to 8.8% and 4.2 to 16.5%, respectively. Blackgum N, P and K recovery rates ranged from 12.1 to 19.2%, 15.5 to 23.6% and 13.7 to 37.8%. Plant growth (both dry weight and height) was more highly correlated with total plant nutrient content (mg N/plant) than with whole plant nutrient concentration (mg N/g dry weight), except for K in blackgum seedlings. The results suggest that red oak and blackgum seedling N and P nutritional status is more accurately predicted by plant height or dry weight than by tissue concentration.