Selectively Salvaged B/C Horizons from A/B Ecosites

Surface horizons of sandy a and b ecosites may have unique properties (including higher levels of phosphorous) which may contribute to successful establishment of ecosites in the Athabasca Oil Sands Region. Using a greenhouse study, this research aims to understand if 1) selectively salvaged Bm or B/C horizons can be used as surface materials to enhance plant growth, and 2) how the use of these salvaged horizons as surface materials affect soil nutrients, specifically phosphorous availability, and soil microbial communities.

Eight soils varying in total nitrogen and available phosphorus were treated with no fertilizer (control), phosphorus and potassium (PK), nitrogen (N) and all three (NPK). Aspen and fireweed germination was not significantly different among soil types. However, soil had the greatest impact on seedling growth when no fertilizer was applied, with the best growth occurring on organic‐mineral material soils where growth was positively correlated with extractable and foliar potassium but not to nitrogen or phosphorus. Strong differences were seen between aspen and fireweed. Unlike the aspen, the fireweed grew very poorly on peat mineral mix. In addition, fireweed had very different nutrient concentrations in the foliage compared to aspen, indicating different uptake rates and abilities than aspen. Soil microbial biomass was found to be a better predictor of aspen height and biomass than soil organic carbon content.