2008 Joint Annual Meeting (5-9 Oct. 2008): Impact of Vegetation on Nitrate Accumulation In Desert Vadose Zone

Recent studies have shown that soil profiles in the Spanish Springs Valley, northern Nevada have high a concentration (800-1000 mg l-1) of nitrate 2-3 meters below the soil surface. The aim of this study was to understand the role of the native vegetation (Artemesia tridentata and Chrysothamnus nauseosus) on the desert nitrogen cycle. Root samples were collected from 4 different locations (three sites with deep ground water and one with shallow ground water) 15 cm depth up to a depth of 45-60 cm using a root auger. Physio-chemical properties of soil were analyzed and foliar N content was determined. Our initial analyses indicated that the higher C/N in conjunction with shallow groundwater supports a higher root density with greater denitrification potential. In a year round observation showed a small, significant increase in foliar N in spring. The native vegetation played a significant role in regulating the organic carbon contents in the soil.