Topographically controlled grassland soils in the Boreal Cordillera ecozone, northwestern Canada

Abstract

Properties and ecological relationships of grassland soils were examined at three widely separated sites (Stikine River Valley, British Columbia, and Carmacks and Kluane Lake, Yukon) in the Boreal Cordillera ecozone of northwestern Canada. At these latitudes (58 to 62°N), grasslands are largely restricted to south-facing aspects, and usually occur as islands within the boreal forest. The grayish and yellowish brown, base-rich, Ah horizons had a thickness-weighted mean organic carbon concentration of 19.5 g kg-1. Ah horizons exhibited a range of microstructures similar to that documented in grassland soils in the southern Cordillera and Great Plains, ranging from spongy to massive in the young loess-derived Kluane Lake pedon to well-developed crumb microstructure in the finer-textured Stikine pedon. These pedons met the morphological and chemical criteria, and likely the soil climate requirements, for the Dark Brown and Brown great groups of the Chernozemic order of the Canadian System of Soil Classification (3rd ed.). Key words: Grassland, Boreal Cordillera, Chernozem, soil micromorphology, soil genesis, soil classification