Lithosequence of Soils and Associated Vegetation on Subalpine Range of the Wasatch Plateau, Utah

Phosphorus (P) and sulfur (S) in soil and parent material are important in the accumulation of nitrogen (N) and organic carbon (C org ) in soils. In an observational study, the role of P and S in soil development was explored on a small knoll in the Wasatch subalpine summer range of central Utah that had been severely eroded during uncontrolled grazing in the late 1800s. Vegetation, litter, soil, and parent material were sampled along a transect across six strata forming highly visible narrow, concentric rings around the knoll. Even-numbered strata were characterized by large amounts of surface rock and sparse vegetative cover. Odd-numbered strata had less surface rock and visibly greater vegetative cover. Data for vegetation, litter, and soil surface properties displayed highly consistent peak and valley patterns for oddand even-numbered strata with significant differences for 9 of 10 of these properties between the two strata groups. Organic C, potassium (K), and S of the parent material, and available N (N av ), P (P av ), and S (S av ) and exchangeable K (K ex ) of the 0to 15-cm soil layer also displayed peak and valley patterns. Multiple regression of herbage yield on C org and S of soil parent material, and P av and (K ex ) of the solum gave high Rs of 0.94 and 0.93. Multiple regression of grass yield on C org and K ex of the 0to 15-cm soil layer had R = 0.95. Based on results, the hypothesis that P of the parent material has influenced soil and plant development of these strata was rejected. The data subtly suggest that sulfur may play a key role in the development of these soil-plant systems. Stipa lettermanii Vasey and Cymopterus lemmonii Welch were strongly, but oppositely, correlated with most attributes studied, thereby suggesting these species may play important indicator roles of soil-vegetation development.