Rangeland -- Plant responses to elevated CO{sub 2}. Progress report
Several broad conclusions which can be drawn from the work that was accomplished during the first 3-year phase of the study is described. In prairie ecosystems dominated by C{sub 4} grasses, it is likely that elevated atmospheric CO{sub 2} will increase ecosystem level productivity, with a greater increase in belowground productivity. The increased productivity will primarily result from increased water use efficiency due to the anti-transpirant action of CO{sub 2}. Fumigation chambers are directly confounded with elevated CO{sub 2} effects, in that both reduce evapotranspiration. The reduced evapotranspiration of the fumigation chamber is primarily through reduced wind speeds and reduced radiation. In very dry years, fumigation chamber effects are negligible, but in years with normal precipitation, chamber effects and elevated CO{sub 2} effects are essentially equal with respect to reduced evapotranspiration effects. Increased production under elevated CO{sub 2} results in reduced nitrogen concentration in the herbage and increased fiber concentrations. Consequently, digestibility of the herbage is reduced, and microbial degradation of surface litter and soil organic matter is slowed. On the negative side, ruminant productivity will likely be reduced substantially, but increased carbon storage in the soil may buffer against future rise in atmospheric CO{sub 2}. Tallgrass prairie will not likely change greatly in botanical composition, since the C{sub 4} dominants responded to elevated CO{sub 2} more than the C{sub 3} subdominants.
- Research Organization:
- Kansas State Univ., Manhattan, KS (United States). Dept. of Agronomy
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG02-84ER60253
- OSTI ID:
- 10184179
- Report Number(s):
- DOE/ER/60253-T5; ON: DE93000883
- Resource Relation:
- Other Information: PBD: 1992
- Country of Publication:
- United States
- Language:
- English
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Rangeland-plant response to elevated CO sub 2
Rangeland -- plant response to elevated CO{sub 2}. Progress report, 1993