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ARS Home » Research » Publications at this Location » Publication #106871
Title: CARBON DIOXIDE AND TEMPERATURE EFFECTS ON FORAGE DRY MATTER PRODUCTION

Author
item NEWMAN, Y. - UNIVERSITY OF FLORIDA
item SOLLENBERGER, L. - UNIVERSITY OF FLORIDA
item BOOTE, K. - UNIVERSITY OF FLORIDA
item Allen Jr, Leon

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/12/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Although grasslands occupy 25 percent of the Earth's land area, studies of climate change effects on grassland species are limited. A 3-yr study was conducted by USDA-ARS scientists at Gainesville, Florida to determine the effects of elevated carbon dioxide (CO2) and temperature on forage yield of bahiagrass and perennial peanut (a subtropical/tropical forage legume with a high quality similar to alfalfa). Both forage species were grown in fully irrigated natural field soil in temperature-gradient greenhouses under different CO2 (360 and 700 ppm) and temperature conditions (baseline [B], B+1.5, B+3.0, and B+4.5 degrees Celsius, where B is the entry air temperature). Averaged over all harvests over three years, doubled CO2 increased bahiagrass yields by 16 percent and perennial peanut yields by 26 percent. Averaged across species, yields increased 11 percent in 1996 and 1997 and 26 percent in 1998 as temperature increased from baseline [B] to B+4.5 degrees Celsius. Since forage yields increased with temperature to at least 4.5 degrees Celsius (8 degrees Fahrenheit), predicted global warming under Florida conditions should increase productivity of grasslands as long as rainfall is adequate.

Technical Abstract: Grasslands occupy 25 percent of the Earth's land area, but few climate change studies have been conducted on grassland species. We determined the effects of elevated carbon dioxide (CO2) and temperature on forage yield of the C3 legume 'Florigraze' rhizoma peanut and the C4 grass 'Pensacola' bahiagrass. Rhizoma peanut and bahiagrass were grown in well watered field soil in temperature-gradient greenhouses under different CO2 (360 and 700 ppm) and temperature conditions (baseline [B], B+1.5, B+3.0, and B+4.5 degrees Celsius, where B is the entry air temperature). Plots were harvested three times (June, August, and November) in 1996 and four times (May, July, August, and November) each in 1997 and 1998. Yields increased with the doubling of CO2 (27, 28, and 23 percent for rhizoma peanut; and 16, 23, and 10 percent for bahiagrass; for 1996, 1997, and 1998, respectively), with an average increase of 26 percent for rhizoma peanut and 16 percent for bahiagrass. Averaged across species, yields increased 11 percent in 1996 and 1997 and 26 percent in 1998 as temperature increased from B to B+4.5 degrees Celsius. Therefore, predicted levels of global warming under Florida conditions should increase forage productivity as long as rainfall is adequate.