|Bates, Jonathan - Jon|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/13/2005
Publication Date: 11/9/2005
Citation: Bates, J.D., Svejcar, A.J., Miller, R.F. 2005. Precipitation timing effects to nitrogen mineralization in the sagebrush steppe [abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts.
Technical Abstract: Major shifts in climate as predicted by general circulation models have the potential to alter nutrient cycling process and effect ecosystem productivity. The impact of altered timing of precipitation to nitrogen dynamics was compared among four treatments in a sagebrush steppe community in southeastern Oregon using rainout shelters. Treatments included WINTER, SPRING, and CURRENT applications. The WINTER received 80% of its water between October and March; the SPRING received 80% of water between April and July; and watering in the CURRENT treatment matched the site’s long-term precipitation distribution pattern. A CONTROL treatment, placed outside each shelter replicate, received natural precipitation inputs. Nitrogen mineralization was determined using open top tube incubations. Over a three-year period few consistent differences were found among the treatments for in situ N mineralization, extractable soil NH4+, and root counts. Extractable NO3- was consistently greater in the SPRING compared to the other treatments. Aboveground herbaceous cover and productivity were significantly reduced in the SPRING application compared to the other treatments. The results indicate that large shifts in patterns of precipitation will likely be necessary to result in major changes to N cycling and ecosystem productivity in the sagebrush