Soil pH Effects on Selected Species of Boreal Plants

油砂开采涉及到地貌的完全破坏和重建，对北方生态系统造成干扰。这种发展对环境的影响通过填海、重新造林和土壤封闭活动得到缓解。在许多油砂复垦区，土壤pH值比在该地区未受干扰的北方森林中测量的可比土壤层的土壤pH值更碱性。复垦土壤与未开垦森林土壤pH值的潜在差异会对森林生产力产生深远的影响。复垦地土壤初始pH值的差异对某些喜酸性林下植物物种来说可能尤为显著。在采取措施解决这些问题之前，了解高土壤pH值对植物的影响是必不可少的。在拟议的项目中，我们将研究根区pH值对阿尔伯塔东北部北方森林原生植物物种的生理、生长和生存的影响。在受控环境实验中，我们将研究耐pH和pH敏感植物的生长和生理反应，以了解它们的耐pH极限和机制。我们将研究以下假设：1)北方植物对高pH的敏感性不同；)高pH对植物的负面影响会因高钙浓度而加剧；3)植物的耐碱性与其控制钙吸收的能力有关；4)土壤磷和铁的有效性增加减轻了碱度的影响；5)植物对高pH的抗性随着年龄的增长而增加。拟议的研究将产生制定受高土壤pH值影响的油砂区复垦方案所需的知识。

Oil sands mining causes disturbance to boreal ecosystems as it involves complete removal and reconstruction of landforms. The impacts of this development on the environment are mitigated through reclamation, reforestation and soils closure activities. In many of the oil sands reclamation areas, soil pH is more alkaline than soil pH measured in comparable soil horizons found in undisturbed boreal forests in the region . Potential differences in pH between reclamation soils compared with that of undisturbed forest soils can profoundly affect forest productivity. These differences in the initial soil pH on reclamation sites may be particularly significant for some of the acid-loving forest understory plant species. Understanding the effects of high soil pH on plants is essential before undertaking steps aimed at addressing these concerns in reclaimed soils. In the proposed project, we will examine the effects of root zone pH on the physiology, growth and survival of plant species native to the boreal forest of northeastern Alberta. In the controlled-environment experiments, we will examine growth and physiological responses of pH-tolerant and pH-sensitive plants to understand their limits and mechanisms of pH tolerance. We will examine the hypotheses that: 1) Boreal plants vary in their sensitivity to high soil pH, ) Negative effects of high pH on plants are aggravated by high calcium concentrations, 3) Alkalinity tolerance of plants is related to their ability to control Ca uptake, 4) Increasing soil P and Fe availability alleviates effects of alkalinity, and 5) Resistance of plants to high soil pH increases with age. The proposed study will generate knowledge required to develop protocols for the reclamation of oil sand areas that are affected by high soil pH.