CHEMICAL ANALYSIS AND COMPARISON OF ARIDISOLS BASED ON VEGETATION AND ROCK TYPE IN THE WHITE MOUNTAINS, EASTERN CALIFORNIA

The goal of this study was to evaluate how three plant species affected soil chemistry overlying two different lithologies in the White Mountains in eastern California. The range is located in the rain shadow of the Sierra Nevada; consequently, the White Mountains experience a semi-arid climate, and the soils are dominantly aridisols. This study examined three plants that are common in the middle to upper elevations of the range: Great Basin sagebrush (Artemisia tridentata), mountain mahogany (Cercocarpus ledifolius), and bristlecone pine (Pinus longaeva). Soils for this study were collected from underneath each of these three plants and from out in the open on both granitic and dolomitic rock at elevations between 10,000 and 13,000 feet (3,000 and 4,000 meters) above sea level. X-ray diffraction (XRD) confirmed that the soils were locally derived, as the dominant soil mineralogy parallels the dominant bedrock mineralogy. The differences in whole sample major and minor chemical compounds were compared between dolomitic and granitic soils, as well as between the three plant types and open space using x-ray fluorescence (XRF). T-tests and ANOVA were performed on the data results (p < 0.05) to test the significance of the differences. Results showed significant dissimilarities between the two rock types for most chemical compounds analyzed. However, only very subtle differences were found in the same soils from beneath different plant types. Most of those differences were not statistically significant. On granitic soils only lanthanum, strontium, and magnesium were significantly higher in soils collected in the open than those collected beneath sagebrush. Comparing dolomitic soils collected under mountain mahogany, bristlecone pines, and open, only copper and sulfur were found in concentrations that were significantly higher underneath bristlecone pine trees and were lowest in the open. Results for soils collected underneath mountain mahogany plants consistently fell between the results for the open soils and the bristlecone pine soils. This could suggest that bristlecone pine has a greater impact on soil chemistry than mountain mahogany.