|Goergen, Erin - UNIV. OF NEVADA RENO|
|Chambers, Jeanne - USDA-FS|
Submitted to: Ecological Society of America Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 12, 2006
Publication Date: February 12, 2007
Citation: Goergen, E., Chambers, J., Blank, R.R. 2007. The effect of water stress and nutrient availability on productivity, nodule formation and nitrogen contribution by Lupinus argenteus [abstract]. Ecological Society of America. Paper No. 90-7. Technical Abstract: Nitrogen fixing species can contribute to the nitrogen budgets of ecosystems, but background resource levels influence nodulation and fixation as well as plant growth. Understanding how nitrogen fixing species respond to varying levels of resources can provide insights into the role that these species play under different inherent resource levels and following disturbance. We conducted a greenhouse experiment to examine the separate and interacting effects of water and nitrogen on the growth, nodulation, nodule activity, and tissue N concentration of Lupinus argenteus, a legume native to sagebrush steppe. Plants were grown under a completely randomized block design with three levels of water stress (200ml every 3, 6, or 12d) and four levels of nitrogen (0, 5mM, 20mM, 100mM). Biomass was significantly affected by both water and nitrogen level (pL. argenteus is reduced but not inhibited under elevated N availability, and that this is the case even under low levels of water availability. Further, high tissue N concentrations combined with low C:N ratios indicate that upon senescence at the end of the growing season, L. argenteus can provide substantial amounts of N through litter decomposition. The ability of L. argenteus to affect nitrogen availability and cycling indicates that they have the potential to influence community composition and plant invasion processes within the sagebrush steppe.