effect of interspecific competition on conifer seedling growth and nitrogen availability measured using ion-exchange membranes

• Published in: Canadian journal of forest research Vol. 34; no. 3; pp. 754 - 761
• Main Authors: Hangs, R.D, Greer, K.J, Sulewski, C.A
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 01.03.2004; National Research Council of Canada; Canadian Science Publishing NRC Research Press
• Subjects: Agronomy. Soil science and plant productions; ammonium nitrogen; artificial regeneration; Artificial regeneration. Forest nurseries. Planting; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; diameter; forest trees; Forestry; Fundamental and applied biological sciences. Psychology; interspecific competition; ion exchange resins; Ions; Mineral components. Ionic and exchange properties; nitrate nitrogen; Nitrogen; nutrient availability; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Picea glauca; Pinus banksiana; plant competition; Plant growth; seedling growth; Seeds; soil fertility; soil nutrients; Soil science; Sowing and planting; Trees; understory; vegetation management; Saskatchewan; Canada; North America; America; Growth; Forest regeneration; Available nutrient; Forest soil; SOIL CHEMISTRY; Inorganic element; Ion exchange membrane; Luvisols; Gymnospermae; Softwood forest tree; Interspecific competition; SOIL TESTING; Soil science; Quantitative analysis; Analytical chemistry; Boreal forest; Early phase; Bioavailability; Nitrogen; Seedlings; Measurement in situ; Analysis method; Forestry; Spermatophyta; Coniferales; Soil plant relation
• ISSN: 0045-5067; 1208-6037
• DOI: 10.1139/x03-229

During the early establishment phase, outplanted white spruce (Picea glauca (Moench) Voss) and jack pine (Pinus banksiana Lamb.) seedlings are vulnerable to lethargic growth or mortality because of interspecific competition for soil nutrients, particularly N. Accurately quantifying the degree of N competition is essential for supporting effective vegetation management (VM) decisions. This study evaluated the use of in situ burials of ion-exchange membrane (IEM; Plant Root Simulator-probes) for quantifying differences in soil N supply rate between different VM treatments and the relationship of this N availability index to early growth of conifer seedlings at four boreal forest sites. At most sites, the effect of noncrop N uptake on soil N availability was apparent, with smaller NH4(+)-N, NO3(-)-N, and total dissolved inorganic N (DIN) supply rates in control plots than in VM plots. Total DIN supply rate was correlated (R2 = 0.60 to 0.73, P < 0.01) with seedling height, root-collar diameter, and stem volume growth. Ammonium-N supply rate was better correlated than NO3(-)-N supply rate with conifer seedling growth, which is in agreement with preferential NH4(+)-N uptake by conifer species. The results of this study support the use of in situ burials of IEM for measuring soil N availability during the early establishment phase.