SOIL-VEGETATION RELATIONS OF RECOVERING SUB-ALPINE RANGE OF THE WASATCH PLATEAU

On degraded subalpine range of the Wasatch Plateau, we examined the hy pothesis that recovery of vegetation, as manifested by its composition and biomass yield, was related to soil phosphorus (P) and sulfur (S) status. We sampled 6 topographic locations to determine the relationsh ip among composition and yield of grasses and forbs, litter cover, and soil characteristics including rock cover, organic carbon (C-o), tota l N (N-t), available nitrogen (N-av), total phosphorus (P-t), organic P (P-o), inorganic P (P-i), total potassium (K), total S (S-t), and el ement ratios. We also evaluated aspect effects. An alternative hypothe sis was that productive potential nas a function of depth of soil rema ining after the period of destructive grazing. Differences among locat ions were significant for all vegetal attributes and for all soil char acteristics except total K and C-o. Aspect was significant only for fo rb yield and P-t. Regression coefficients for yield and percentage com position of grasses were always opposite in sign to those for forbs. Y ield and composition of grasses and forbs as groups were oppositely an d strongly related to soil element ratios of C-o/P-t, N-t/P-o, C-o/P-t , and C-o/S-t but were not related to soil P-t or S-t. There was no cl ear support for acceptance of the hypothesis that soil P and/or S were major factors in recovery of this subalpine range after destructive g razing. Differences in regression coefficients and lower r-values amon g species within grass and forb groups, than for the groups themselves , to soil variables is a reflection of species individuality. This ind icated a need to examine soil/vegetation relationships at the species level. Percentage compositions of grasses and forbs were oppositely re lated to the depth of A + B horizon, lending support to acceptance of the alternative hypothesis.