Canadian Forest Service Publications
Growth response of aspen and alder to fresh and stockpiled reclamation soils. 2018. Omari, K.; Das Gupta, S.; Pinno, B.D. Forests 9(12):731.
Issued by: Northern Forestry Centre
Catalog ID: 39433
Availability: PDF (download)
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Soil stockpiling is a common reclamation practice used in oil sands mining in the boreal forest region of Canada to conserve soil resources; but stockpiling may have detrimental effects on soil quality and plant growth. We examined growth response of trembling aspen (Populus tremuloides Michx.), a fast-growing early successional tree, and green alder (Alnus viridis (Chaix) DC. ssp crispa (Ait.) Turrill), a nitrogen-fixing shrub, to stockpiling and fertilization treatments on two reclamation soils (forest floor mineral mix (FFMM) and peat mineral mix (PMM)). Aspen and alder seeds were planted and their growth monitored for four months in the greenhouse. We found that unfertilized stockpiled FFMM supported significantly higher aspen and alder aboveground biomass than the other fresh and stockpiled soils. Phosphorus and potassium supply rates were highest in stockpiled FFMM and were positively correlated with aboveground plant biomass. There was no significant difference in aspen and alder aboveground biomasses between unfertilized fresh FFMM and PMM soils. Aspen grown in combination with nitrogen-fixing alder did not experience competition or facilitation except on fresh PMM, where aspen height declined. Fertilization increased both aspen and alder growth and eliminated differences in growth between soil types and stockpiling treatments. Our study showed that individual soil properties are more important for revegetation purposes than type of soil or stockpiling treatment.
Plain Language Summary
Before oil sands mining begins at a site, the soil is removed and stockpiled for later use in reclamation when direct placement is not possible. In this study we examined the effects of stockpiling and fertilizing on the growth of aspen and alder in two different types of reclamation soils (forest floor mineral mix and peat mineral mix). We conducted our experiments in a greenhouse with controlled environmental conditions. In our experiments without fertilization, trees grew better in stockpiled forest floor mineral mix than in the fresh soils and the other type of stockpiled soil. Fertilization increased plant growth and eliminated the differences in growth between soil types and stockpiling treatments. We conclude that it is important to assess the individual properties of reclamation soils to determine their suitability for revegetation purposes rather than basing decisions on the general soil type or duration of soil storage. Our findings will contribute to effective planning of land reclamation efforts.