The Use of Soil Amendments in the Revegetation Process of Smelter-Affected Soils.

Revegetation of forest soils affected by mining and smelting activities is challenging as these soils frequently have high levels of heavy metals, altered organic matter accumulation, and low pH values. Our study examines the impact of four soil amendments on revegetation in soils affected by mining and activities in Flin Flon, Manitoba, Canada. The study was conducted in situ, on soils affected by a combination of smelting processes, forest fires, soil erosion and tree harvesting, all of which resulted in the loss of the natural boreal forest vegetation. The existing vegetation in the area is predominately a non-native metal tolerant grass community. Soil erosion has created regions that have only small areas of soil present in rock out-crop soil pockets. A community project in Flin Flon has spread dolomitic lime, which has aided in some revegetation of the area however some areas have not responded.

The objective of the study was to evaluate if the application of four soil amendment treatments improved survival and growth of two tree and two understory species. The amendments selected from a larger growth chamber study as having potential for increased growth and survival were meat and bonemeal biochar, willow biochar, municipal compost and an ecto and endo mychorrhizal product. This study included 12 sites, on which 240 Populus tremuloides and 240 Pinus banksiana trees and an understory cover comprised of Vicia americana and Deschampsia cespitosa were planted. The sites were planted and left to grow for one season and were then harvested after over-winter survival was examined. In addition to survival and growth measurements of the plants, the practicality of the soil amendments for use in revegetation was assessed.