HJA newt logoHJ Andrews
Login Donate
 
 
  Home > Publications > Search Bibliography > Publication Abstract

Publication Title:   Dinitrogen fixation by a mature Ceanothus velutinus (Dougl.) stand in the western Oregon Cascades

Year:  1983     Status:  Published     Publication Type:  Journal Article

H. J. Andrews Publication Number:  650

Citation:  McNabb, D. H.; Cromack, Kermit Jr. 1983. Dinitrogen fixation by a mature Ceanothus velutinus (Dougl.) stand in the western Oregon Cascades. Canadian Journal of Microbiology. 29(8): 1014-1021.

Online PDF:  http://andrewsforest.oregonstate.edu/pubs/pdf/pub650.pdf

Abstract:  MCNABB, D. H., and K. CROMACK, JR. 1983. Dinitrogen fixation by a mature Ceanothus velutinus (Dougl.) stand in the WesternOregon Cascades. Can. J. Microbiol. 29: 1014-1021. Dinitrogen fixation was measured in a 17-year-old snowbrush, Ceanothus velutinus var velutinus (Doug! ). stand in theWestern Oregon Cascades. Diurnal and seasonal rates of nitrogenase activity were measured in the field using the C2H, reductiontechnique. Snowbrush had a total biomass, estimated with equations developed. of 42 680 kg • ha-I, including 750 kg • ha-1 ofnodule biomass. Snowbrush fixed N2 for approximately 240 days annually. Except during precipitation events or periods of lowxylem pressure potentials, C2H2 reduction rates in the summer and fall were significantly correlated with soil temperature (R2 =0.93**, n = 6). A diurnal variation in nitrogenase activity also was measured. The annual N2 fixation rate was estimated atapproximately 101 kg N • ha-1 (C2H2). Sustained periods of precipitation suppressed nitrogenase activity and reduced theestimate by about 19%. The annual N2 fixation rate is higher than previously reported for other mature stands and primarily isattributed to the maintenance of a large nodule biomass.

Personnel and Keyword Links

Author Links
McNabb ,  David   H.
Cromack Jr. ,  Kermit  


Theme
Biomass (vascular plants)
Dinitrogen fixation
Leaf area
Moisture stress
N-fixation
Nitrogen
Nitrogen dynamics
Nitrogen fixation
Precipitation
Soil temperature

Place
Oregon
Oregon Cascades
Western Oregon Cascades
Western Oregon

Taxa
Ceanothus velutinus