Effect of Fertilization and Vegetation Managementon the Growth and Survival of White Spruce Seedlings
Date
1998
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ORCID
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Degree Level
Masters
Abstract
In Saskatchewan, Forest Management License Agreement areas require 65% stocking with spruce seedlings being 50cm tall by year eight after harvest. Thus, there is interest in more intensive silvicultural treatments such as fertilization and vegetation management to increase white spruce (Picea glauca (Moench) Voss) seedling growth. The objectives of this study were to 1) determine the effect of manual vegetation manage merit,fertilizer applications,and site preparation on white spruce seedling growth, 2) quantify fertilizer use efficiency by white spruce seedlings and native vegetation using 15N, 3) quantify the influence of vegetation management on water use efficiency and plant stress by measuring the discrimination (L1) of l3C by white spruce seedlings, and, 4) determine the effect of pulp mill olivine ash application on soil properties and white spruce seedling growth.Various combinations of three fertilizers (broadcast ammonium nitrate (NH4N03) and two controlled-release products), manual vegetation management, Delta disc-trenching,and pulp mill ash were imposed in a random complete block experimental design on an Orthic Gray Luvisol soil. Tree growth and nutrient uptake and soil properties were measured throughout two growing seasons. The fate of applied
fertilizer N was determined using 15N labeled N�N03. The influence of vegetation management on L1l3C was measured in order to ascertain seedling moisture stress. Use of a controlled-release fertilizer product was more effective in increasing seedling development than NH4N03. However, combining vegetation management with fertilization had the greatest positive effect on seedling growth. Vector analysis determined that N was the main limiting resource at this site. Although vegetation management and site preparation significantly increased the fertilizer use efficiency of white spruce seedlings by limiting competition, <1 % of the applied fertilizer 15N was utilized by the white spruce seedlings after two growing seasons. Vegetation management decreased L1l3C, contrary to what was originally hypothesized. It appears that L1l3Cv decreased in response to increased photosynthetic draw, as opposed to differences in soil moisture. Application of 5 Mg ha-1 of ash increased the soil pH from 4.4 to 6.9, but reduced seedling growth due to increased soil salinity.These results suggest that
combining initial N fertilization and vegetation management has the most merit for increasing the early growth of white spruce seedlings.
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Citation
Degree
Master of Science (M.Sc.)
Department
Soil Science
Program
Soil Science