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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #117108
Title: CARBON DIOXIDE FLUX IN THE MIXED-GRASS PRAIRIE

Author
item Haferkamp, Marshall
item Heitschmidt, Rodney

Submitted to: Advances in Terrestrial Ecosystem Carbon Inventory, Measurements Conference
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2000
Publication Date: 8/1/2000
Citation: HAFERKAMP, M.R., HEITSCHMIDT, R.K. CARBON DIOXIDE FLUX IN THE MIXED-GRASS PRAIRIE. ADVANCES IN TERRESTRIAL ECOSYSTEM CARBON INVENTORY, MEASUREMENTS CONFERENCE. p. 44. 2000.

Interpretive Summary: Research was initiated in 1994 to quantify role of Northern Great Plains rangeland ecosystems in regulating atmospheric carbon dioxide flux. The first experiment was designed to monitor carbon dioxide flux at a landscape level using Bowen Ratio technology on an ungrazed silty range site. The Bowen-Ratio unit is one in a network of several located in Texas, Oklahoma, New Mexico, Arizona, Colorado, Wyoming, North Dakota, Montana, Idaho, and Oregon. Soil properties, vegetation traits, and other data needed to infer cause and effect in flux variation are sampled periodically. In a second 3-year experiment we tested the hypothesis that seasonal grazing will appreciably alter CO2 flux on Northern Great Plains rangelands. Plots (15 by 15 m) were installed in a randomized block design with 4 blocks on a silty range site adjacent to the Bowen-Ratio unit site. Grazing treatments were 1) a nongrazed control, 2) grazed once by sheep in mid-May, and 3) grazed once by sheep in mid July. The same plots were used for treatments and measurements. During mid-April to mid-October, at about 30 days intervals, we sampled 1) standing crop by clipping to ground level, 2) leaf area with a point frame on clipped and nonclipped plots, 3) soil organic matter and root mass to a 30-cm soil depth, 4) diurnal concentrations of CO2 within 1- m**3 chamber per treatment plot, and 5) soil respiration from bare soil in a 1-liter chamber. Data from the small plot studies will be presented.

Technical Abstract: Research was initiated in 1994 to quantify role of Northern Great Plains rangeland ecosystems in regulating atmospheric carbon dioxide flux. The first experiment was designed to monitor carbon dioxide flux at a landscape level using Bowen Ratio technology on an ungrazed silty range site. The Bowen-Ratio unit is one in a network of several located in Texas, Oklahoma, New Mexico, Arizona, Colorado, Wyoming, North Dakota, Montana, Idaho, and Oregon. Soil properties, vegetation traits, and other data needed to infer cause and effect in flux variation are sampled periodically. In a second 3-year experiment we tested the hypothesis that seasonal grazing will appreciably alter CO2 flux on Northern Great Plains rangelands. Plots (15 by 15 m) were installed in a randomized block design with 4 blocks on a silty range site adjacent to the Bowen-Ratio unit site. Grazing treatments were 1) a nongrazed control, 2) grazed once by sheep in mid-May, and 3) grazed once by sheep in mid July. The same plots were used for treatments and measurements. During mid-April to mid-October, at about 30 days intervals, we sampled 1) standing crop by clipping to ground level, 2) leaf area with a point frame on clipped and nonclipped plots, 3) soil organic matter and root mass to a 30-cm soil depth, 4) diurnal concentrations of CO2 within 1- m**3 chamber per treatment plot, and 5) soil respiration from bare soil in a 1-liter chamber. Data from the small plot studies will be presented.