Fertilizer Dose Response Studies

Revegetation in oil sands reclamation is often hindered by poor seedling survival and growth due to low soil nutrients and competition from other vegetation. The Fertilization Dose Response project explores nutrient loading in nurseries as an alternative to field fertilization, aiming to improve early establishment of aspen, white spruce, and jack pine. Nutrient-loaded seedlings have greater internal reserves, enhancing root growth, nutrient uptake, and competitiveness in nutrient-poor, weedy soils. The study tests these seedlings in the field to evaluate their growth, survival, and nutrient retranslocation efficiency compared to conventionally grown seedlings.

We conclude the following: 1) Enhanced accumulation of nutrient reserves and increased nitrogen retranslocation contributed to the improved growth of exponentially fertilized aspen seedlings outplanted for oil sands reclamation. Operational trials of exponential fertilization for aspen should be conducted to evaluate its potential for large-scale reclamation efforts in the oil sands region. 2) Exponential fertilization significantly improved the early growth of jack pine seedlings, suggesting it can be a useful strategy for promoting revegetation on disturbed oil sands sites. 3) Vegetation management through the removal of competing understory vegetation enhanced the early growth of white spruce seedlings in reclaimed soils, supporting its use in land reclamation. However, the benefits of exponential fertilization for white spruce in nursery conditions require further study to optimize its effectiveness.