Fertilization to accelerate tree growth and land reclamation in the oil sands

This project aimed to improve the successful establishment of tree seedlings on reclaimed mine lands by examining how fertilizer use and cover crops (barley and oats) affect seedling growth and survival. It focused on the challenges of low soil nutrients and weed competition, particularly under conditions common in the Oil Sands Region. Researchers investigated how fertilizer and organic amendments influence nutrient availability—especially phosphorus and potassium—and how these interact with weed competition and soil moisture. Through both greenhouse and field experiments, the study evaluated the effects on trembling aspen and white spruce seedlings, with the goal of refining fertilizer recommendations to optimize seedling performance while minimizing environmental impacts like nutrient leaching.

This study examined how fertilizer type and rate, along with cover crops (barley and oats), affect the early survival and growth of trembling aspen and white spruce seedlings on reclaimed mine lands. Fertilizer improved seedling growth in greenhouse conditions but had little benefit in the field due to increased weed competition. Trembling aspen was more negatively affected by this competition than white spruce. Controlled-release fertilizer (CRF) supported similar or better growth than conventional fertilizers while using 90% less nitrogen and generating less weed pressure. First-season growth was generally improved by fertilization, but second-season responses were inconsistent, with white spruce benefiting most from low CRF rates. Overall, immediately available fertilizer had limited value for early seedling establishment in the field. The use of low-rate CRF appears more effective and environmentally sustainable.