|Bolton, H., Jr. - PACIFIC NORTHWEST LAB.|
|Bailey, V. - PACIFIC NORHTWEST LAB.|
Submitted to: Soil Science Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2000
Publication Date: N/A
Technical Abstract: The semi-arid shrub-steppe is the largest grassland-type ecosystem in North America. The stability of the shrub-steppe including its biogeochemical cycles in highly dependent on the ecosystem's adjustment to changing environmental conditions such as would be experienced under global climate change conditions. Our overall objective is to increase our understanding of how changes in climate, specifically temperature and moisture regimes, affect the storage and cycling of carbon in semi-arid systems. Results from these studies will improve our ability to predict changes in terrestrial carbon cycling under different climate change scenarios. We investigated the effects of climate change and storage over a 500 m elevation transect. The parent material, loess, was deposited over the area at the same time, the climate has been stable for 3k years, and the vegetation is similar. The mean maximum temperature ranges from 30 C at the lower slope to 24 C at the upper slope, and the precipitation ranges from 180 mm to 270 mm. Both the total soil C and N increased as elevation increases due to the increased plant biomass and reduced decomposition. Particulate organic matter (POM) C and N increased significantly over the transect, however the mineral fraction C and N showed no trends. Under a changing climate to hotter, drier conditions total C and N will decrease mostly from the POM C and N fractions.