Soil development along an elevational gradient in the southeastern Uinta Mountains, Utah, USA

A silt mantle enriched in Ca is important in buffering soils on quartzitic terrane in the southeastern Uinta Mountains. We examined 32 pedons along an elevational gradient on the south slope of the eastern Uintas to determine the amount of the silt and its importance to pedogenesis. The pedons were in the upper montane forest (2700–3000 m), subalpine forest (3000–3400 m) and alpine tundra (3400–3850 m) on stable sites. There were no significant differences in silt cap thickness or in profile quantities of silt (upper 100 cm) by ecoclimatic zone. Similar soils were found in all three ecoclimatic zones, including Eutrocryepts, Dystrocryepts, Haplocryalfs, Cryorthents, and Haplocryolls, in descending order of abundance. Profile quantities of clay, exchangeable cations, and extractable Al and solum thickness are greatest in the alpine zone, probably because the soils there are older than those at lower elevations and soil formation proceeds more rapidly. Base cycling is enhanced in alpine communities dominated by Acomastylis (Geum) rossii as evidenced by large profile quantities and high tissue concentrations of Ca. Profile quantities of total N and organic C are significantly greater (p≤0.05) in the alpine zone, reflecting greater below-ground production and lower rates of organic matter turnover than in soils at lower elevations.