Ten-Year Growth in Two Fertilization Experiments in a Semimature Jack Pine Stand in Northwestern Ontario

Abstract

Two fertilization experiments were established in a 55-year-old, relatively pure jack pine (Pinus banksiana Lamb.) stand on a Site Class III sandy site in northwestern Ontario. In both the following response variables were estimated after 10 years: mean DBH increment, BA increment (absolute and per cent) and total and merchantable volume increment. Data were analyzed by analysis of variance and Duncan's New Multiple Range Test. In the first experiment urea and ammonium nitrate at two levels of application were tested against controls. Significant increases over controls, in terms of BA and total and merchantable volume increments, occurred only with urea at 336 kg N/ha. With this treatment response was good; approximately 20 m3/ha extra merchantable wood over controls was produced over 10 years. In the second experiment N, P, and K were applied in fixed mixture, with and without lime, at five levels of application plus control. Response was generally poor with no treatment producing a statistically significant increase over control in relation to any variable. The best treatment, NPK at 1 120 kg/ha of fertilizer plus lime, produced an increase in merchantable volume over controls of less than 8 m3/ha over 10 years.