Soil water regimes of reclaimed upland slopes in the oil sands region of Alberta

Abstract

Leatherdale, J., Chanasyk, D. S. and Quideau, S. 2012. Soil water regimes of reclaimed upland slopes in the oil sands region of Alberta. Can. J. Soil Sci. 92: 117–129. Large oil sands deposits in the Athabasca oil sands region of Alberta, Canada, are recovered through surface mining, creating a large-scale disturbance. Reclamation requires reconstruction of soil profiles to return the land to equivalent land capability and support the required end land use. Soil water regimes must be understood to allow for planting of appropriate vegetation species. This study quantified soil water regimes on reclaimed upland slopes of various reclamation prescriptions and determined whether soil water was affected by slope position. Slope position did not have a consistent effect on soil water. Spatial variability in soil characteristics and vegetation distribution likely had a greater influence on soil water than did slope position. The upper slope soil profiles had highly dynamic water regimes and a greater response to precipitation events than the lower soil profiles. Differences in water-holding capacity among sites were attributed to differences in clay, sand and organic matter content. Overwinter soil water recharge varied dramatically by site. Capillary barriers resulting from the textural discontinuities created by the reclamation prescriptions enhanced soil water retention within the profiles in at least two sites, and hence are desirable in reclamation scenarios, especially where reclamation material is coarse textured.