Effects of liquid fertilizer application on the morphology and outplanting success of container longleaf pine seedlingsThis article is part of a larger document. View the larger document here.
Of a range of fertilization rates (0.5, 1.0, 2.0, 3.0, and 4.0 mg nitrogen (N) per seedling per week) applied for 20 weeks, the 2.0-N and 3.0-N seedlings produced good root collar diameter (RCD) growth (6.9 and 7.1 mm, respectively) and needle length = 30 cm. Root collar development did not differ significantly in seedlings receiving the 4.0-mg-N treatment from those receiving 2.0-mg or 3.0-mg, but needles grew to 35 cm in 4.0-N, surpassing the 30-cm limit to avoid clipping. Seedling survival (95 percent) was higher in 3.0-N seedlings one year after outplanting. RCD growth in 3.0-N was 14 percent greater than 2.0-N seedlings, but not different between the 3.0-N and 4.0-N seedlings. Height and RCD growth remained statistically similar between 3.0-N and 4.0-N seedlings after 2 years. Emergence from the grass stage increased as the amount of fertilizer increased, but given similarities in field performance between the two highest N rates, the extra 1.0-mg N per seedling per week was not economically justified.