The effects of nitrogen fertilizer application amounts and timing on the quality of barefoot loblolly pine (Pinus taeda L.) seedlings

The recommendation for nursery-grown bareroot loblolly pine ( Pinus taeda L.) seedlings is a total of 169 kg N/ha applied between April and August. A study was conducted to observe the effects of altering the amount of fertilizer at each application on seedling morphology and physiology. Six applications of ammonium nitrate were done over the course of the growing season. The treatments included an equal amount applied each time, an increasing amount each time, and a schedule characterized by low amounts, high amounts and low amounts. In addition, the seedlings were treated either in October or November with a one-time application of 56.4 kg N/ha or 112.7 kg N/ha.; Based on this study, it appears that by increasing the N fertilizer incrementally when applied over the growing season application, with the addition of 112.7 kg N/ha in October performance of bareroot loblolly pine seedlings can be increased. (Abstract shortened by UMI.)...