Physical and Chemical Soil Properties of Three Big Sagebrush Subspecies

Abstract

AbstractThe three subspecies of Artemisia tridentata Nutt. typically occupy qualitatively different sites. Wyoming big sagebrush, A. t. ssp. wyomingensis, commonly grows in Aridisols; mountain big sagebrush, A. t. ssp. vaseyana, commonly lives in Mollisols at a higher average elevation; and basin big sagebrush, A. t. ssp. tridentata, occurs in deep soils of either order. This study evaluated some physical and chemical characteristics of surface and subsurface soil horizons of soils occupied by each subspecies in four widely spaced Oregon locations. Most soil chemical characteristics showed no significant differences between subspecies. Interaction between location and subspecies often indicated that analysis should proceed at each individual location. The Frenchglen location had the greatest elevational differences between sites and also had most statistically significant soil differences between subspecies. Many of the measured characteristics are interrelated and differences in them probably are influenced by elevation‐related variation in climate. Surface horizons of Frenchglen, A. t. ssp. vaseyana sites had lower pH, base saturation, and exchangeable Na+ and higher organic matter, cation exchange capacity, and water retention at −1.50 MPa than surface horizons of A. t. ssp. wyomingensis sites. Fewer surface soil characteristics of A. t. ssp. tridentata sites were significantly different. In deeper soil horizons at Frenchglen, A. t. ssp. vaseyana sites had lower pH and base saturation than A. t. ssp. tridentata sites.