PARENT SESSION
Contributed Oral Session 32: Soil Nutrient Dynamics and Acid Deposition
Monday, August 8, 1:30 PM - 5:00 PM, Meeting Room 521 A, Level 5, Palais des congrès de Montréal
Soil N and P storage and cycling in semi-arid shrublands exposed to high atmospheric N deposition.
Vourlitis, George*,1, Zorba, Gypsi1, Pasquini, Sarah1, 1 Biological Sciences Department, San Marcos, CA, USA
ABSTRACT- Expanding population has caused an increasing amount of atmospheric nitrogen (N) pollution to be deposited into semi-arid chaparral and coastal sage scrub (CSS) ecosystems of southern California. While the effects of N deposition on temperate deciduous and coniferous forests have been studied extensively over the last 1-2 decades, the effects of N deposition on semi-arid shrublands have only recently been investigated. This research investigated soil nitrogen storage in several areas of southern California, which received different levels of exposure to atmospheric nitrogen pollution. Soil samples from five sites of varying atmospheric deposition were analyzed for extractable N, mineralized N, total nitrogen, P, and C, and pH. The results indicate that surface (0-10 cm) and sub-surface (30-40 cm) soil exposed to high atmospheric N deposition had correspondingly higher levels of total and extractable N, lower pH, and a lower C:N ratio than sites with lower pollution exposure. These data suggest that atmospheric N deposition can significantly increase soil N storage and cycling in southern California shrublands.
Key words: Nitrogen, Fire, Biogeochemistry