Downy brome (Bromus tectorum L.) is an alien grass that dominates disturbed ground in shrub-steppe ecosystems of the western United States. Responses of downy brome to added nitrogen and water were evaluated using intact soil cores obtained from an old field. Gas exchange data were gathered at the leaf and canopy scales. Stomatal conductance and net photosynthesis rates were greater at the leaf scale than at the canopy scale, decreased with time from germination, and were weakly affected by treatments. Water-use efficiency was weakly related to time from germination and treatments. Biomass was greater in the nitrogen-plus-water (7.4 g) treatment, compared with water (3.6 g), nitrogen (4.5 g), and control (3.3 g) treatments. The leaf-area index varied like biomass at the end of the experiment. Shoot nitrogen was the same in the nitrogen (2.5%) and nitrogen-plus-water (2.5%) treatments, nearly twice the level in the control (1.5%) and water (1.3%) treatments. Nitrogen-use efficiency was highest in the control (67) and water (80) treatments and lowest in the nitrogen (41) and nitrogen-plus-water (43) treatments. The most significant conclusion of this work is that gas exchange was strongly related to the time from germination and little affected by water and nitrogen while growth characters were strongly affected only when water and nitrogen were added together. The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information. Migrated from OJS platform August 2020
Scholarly peer-reviewed articles published by the Society for Range Management. Access articles on a rolling-window basis from vol. 1, 1948 up to 5 years from the current year. Formerly Journal of Range Management (JRM). More recent content is available by subscription from SRM.