Soil pH Effects on Selected Species of Boreal Plants

The study focuses on examining how elevated soil pH in oil sands reclamation areas affects boreal forest plants, especially acid-loving understory species. It aims to understand the physiological, growth, and survival responses of both pH-tolerant and pH-sensitive plants under controlled conditions. Key hypotheses include variability in plant sensitivity to high pH, the aggravating effect of high calcium levels, the role of calcium uptake control in alkalinity tolerance, and the mitigating impact of increased phosphorus and iron availability. The study also investigates whether plant resistance to high pH improves with age.

Experiments were carried out with six species of plants (blueberry, bearberry, dogwood and aspen, white spruce, and jack pine). These species were chosen via a pH tolerance study to obtain three relatively pH‐sensitive and three relatively pH‐tolerant plant species. The plant species that are more sensitive to high pH (aspen, jack pine, and blueberry) also showed greater sensitivity to high calcium concentrations at high pH. In these plants, 5 time and 10 times the Ca concentrations in Hoagland’s solution were beneficial to plant growth at low pH, but toxic at high pH. This may be an important mechanism contributing to high pH toxicity in alkaline soils with high Ca levels. Additional conclusions were expected to be published in 2013.