Influence of Atmospheric CO{sub 2} enrichment on rangeland forage quality and animal grazing. Final technical report, September 1, 1989--August 31, 1992
Increased biomass production in terrestrial ecosystems with elevated atmospheric CO{sub 2}, may be constrained by nutrient limitations as a result of increased requirement or reduced availability caused by reduced turnover rates of nutrients. To determine the short-term impact of nitrogen (N) fertilization on plant biomass production under elevated CO{sub 2}, we compared the response of N-fertilized tallgrass prairie at ambient and twice-ambient CO{sub 2} levels. Native tall grass prairie plots were exposed continuously to ambient and twice-ambient CO{sub 2}. We compared our results to an unfertilized companion experiment on the same research site. Above- and below-ground biomass production and leaf area of fertilized plots were greater with elevated than ambient CO{sub 2}. Nitrogen concentration was lower in plants exposed to elevated CO{sub 2}, but total standing crop N was greater at high CO{sub 2} increased root biomass under elevated CO{sub 2} apparently increased N uptake. The biomass production response to elevated CO{sub 2} was much greater on N-fertilized than unfertilized prairie, particularly in the dry year. We conclude that biomass production response to elevated C{sub 2} was suppressed by N limitation in years with below-normal precipitation. Reduced N concentration in above- and below-ground biomass could slow microbial degradation of soil organic matter and surface litter. The reduced tissue N concentration higher acid detergent fiber under elevated CO{sub 2} compared to ambient for forage indicated that ruminant growth and reproduction could be reduced under elevated CO{sub 2}.
- Research Organization:
- San Diego State Univ. Foundation, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG03-89ER69028
- OSTI ID:
- 26683
- Report Number(s):
- DOE/ER/69028-T1; ON: DE95006399
- Resource Relation:
- Other Information: PBD: [1992]
- Country of Publication:
- United States
- Language:
- English
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