Open Access. Powered by Scholars. Published by Universities.®

Agricultural Science Commons

Open Access. Powered by Scholars. Published by Universities.®

Grassland

Discipline
Institution
Publication Year
Publication
Publication Type

Articles 181 - 183 of 183

Full-Text Articles in Agricultural Science

Increasing Co2 From Subambient To Superambient Concentrations Alters Species Composition And Increases Above-Ground Biomass In A C3/C4 Grassland, H. W. Polley, Hyrum B. Johnson, Justin D. Derner Jan 2003

Increasing Co2 From Subambient To Superambient Concentrations Alters Species Composition And Increases Above-Ground Biomass In A C3/C4 Grassland, H. W. Polley, Hyrum B. Johnson, Justin D. Derner

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The glacial-to-present increase in atmospheric CO2 concentration is likely to have stimulated plant production, but experimental tests in natural ecosystems are lacking.


Gas Exchange And Photosynthetic Acclimation Over Subambient To Elevated Co2 In A C3-C4 Grassland, Laurel J. Anderson, Hafiz Maherali, Hyrum B. Johnson, H. Wayne Polley, Robert B. Jackson Jan 2001

Gas Exchange And Photosynthetic Acclimation Over Subambient To Elevated Co2 In A C3-C4 Grassland, Laurel J. Anderson, Hafiz Maherali, Hyrum B. Johnson, H. Wayne Polley, Robert B. Jackson

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Atmospheric CO2 (Ca) has risen dramatically since preglacial times and is projected to double in the next century. As part of a 4-year study, we examined leaf gas exchange and photosynthetic acclimation in C3 and C4 plants using unique chambers that maintained a continuous Ca gradient from 200 to 550 µmol mol-1 in a natural grassland. Our goals were to characterize linear, nonlinear and threshold responses to increasing Ca from past to future Ca levels. Photosynthesis (A), stomatal conductance (gs), leaf water-use efficiency (A/gs …


Net Grassland Carbon Flux Over A Subambient To Superambient Co2 Gradient, P. C. Mielnick, W. A. Dugas, H. B. Johnson, H. W. Polley, J. Sanabria Jan 2001

Net Grassland Carbon Flux Over A Subambient To Superambient Co2 Gradient, P. C. Mielnick, W. A. Dugas, H. B. Johnson, H. W. Polley, J. Sanabria

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Increasing atmospheric CO2 concentrations may have a profound effect on the structure and function of plant communities. A previously grazed, central Texas grassland was exposed to a 200-µmol mol-1 to 550 µmol mol-1 CO2 gradient from March to mid-December in 1998 and 1999 using two, 60-m long, polyethylene-covered chambers built directly onto the site. One chamber was operated at subambient CO2 concentrations (200-360 µmol mol-1 daytime) and the other was regulated at superambient concentrations (360-550 µmol mol-1). Continuous CO2 gradients were maintained in each chamber by photosynthesis during the day and …