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ARS Home » Pacific West Area » Burns, Oregon » Range and Meadow Forage Management Research » Research » Publications at this Location » Publication #197740
Title: INFLUENCE OF SOIL NITROGEN AND PHOSPHORUS ON THE COMPETITIVE RELATIONSHIP BETWEEN MEDUSAHEAD AND SQUIRRELTAIL

Author
item YOUNG, KERT - OREGON STATE UNIVERSITY
item Mangold, Jane
item BORMAN, MICHAEL - OREGON STATE UNIVERSITY
item CARPINELLI, MICHAEL - NRCS
item KLING, JENNIFER - OREGON STATE UNIVERSITY

Submitted to: Society of Range Management
Publication Type: Abstract Only
Publication Acceptance Date: 1/20/2006
Publication Date: 2/15/2006
Citation: Young, K., Mangold, J.M., Borman, M., Carpinelli, M., Kling, J. 2006. Influence of soil nitrogen and phosphorus on the competitive relationship between medusahead and squirreltail. [abstract] Society of Range Management. Paper No. 404.

Interpretive Summary:

Technical Abstract: Medusahead (taeniatherum caput-medusae ssp. asperum (Simk.) Melderis) is an invasive, nonnative, winter annual grass that is rapidly displacing desireable rangeland plants in western North America. Evidence suggests that the native perennial bunchgrass squirreltail (elymus elymoides (Far.) Swezey) may be able to displace medusahead under certain conditions, but the role of soil nutrients in this process is not well understood. We performed growth analysis and competitiion experiments in a greenhouse to determine if soil nitrogen (N) and phosphorus (P) alter the competitive relationship between medusahead and squirreltail. All plants wre grown in pots containing a one-to-one mixture of sand and field soil from a site containing medusahead and squirreltail. In the growth analysis experiment, we compared the relative growth rates (above-and belowground and biomass, leaf area, total root length, and soil depth penetration) of isolated individuals harvested at 2-week intervals over a 70 day period. In the competition experiment, we grew medusahead and squirreltail in all possible density combinations of 0, 1, 5, 25, and 125 plants per species per pot at 4 levels of N and P (low N, low P; low N, high P; high N, low P; high N, high P). We harvested all post-senescent aboveground biomass and quantified the intra-and interspecific interference, relative competitive ability, and niche differentiation.