Interactions of CO{sub 2} with temperature and other climate variables: response of vegetation. Final report

Technical Report · Tue Feb 28 04:00:00 EST 1995

DOI:https://doi.org/10.2172/6635· OSTI ID:6635

Knipling, E B ^[1]

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1. USDA, ARS, SAA, CGER

The overall objectives of this project were: (1) to examine experimentally, for major crop species, the interacting effects of CO{sub 2} concentration, temperature, and water availability on plant growth and development, (2) to model these interactions, and (3) to continue developing physiologically-based mechanistic models for predicting crop response to increased CO{sub 2} concentration and future global climate change. To meet these objectives, controlled-environment studies were conducted on cotton, lemon, rice, and soybean and a long-term open-top chamber study was continued on orange. Much progress was made on development of plant growth models for cotton, wheat, rice, and soybean. In addition, there were two special modeling efforts which have the potential for contributing to all of the crop models. These efforts are concerned with modeling root growth and physical and chemical processes in soil and with modeling the effect of stomatal aperture on photosynthesis and transpiration rates as a function of CO{sub 2} concentration, temperature, and vapor pressure deficit. The root growth and soil process modeling is important because it enables us to estimate the water available to the plant. The modeling of effects of stomatal aperture on photosynthesis and transpiration rates enables them to estimate dry weight gain and water use by the plant. These are both important components of the interaction of CO{sub 2} concentration with temperature and water availability. The work on stomatal aperture, photosynthesis, and transpiration has the added benefit of allowing us to improve predictions of energy partitioning by the terrestrial biosphere. The lack of realistic energy partitioning is a serious deficiency of the present general circulation models which are used to predict how climate will change. An additional important aspect of the rice experiments is a study of methane emissions of paddy-grown (i.e., flooded) rice grown under two levels of CO{sub 2} and three temperature regimes.

• Research Organization: USDA, Beltsville, MD (US)
• Sponsoring Organization: USDOE Office of Energy Research (ER); US Water Conservation Laboratory (USWCL); Western Cotton Research Laboratory (WCRL); Univ. of Florida (UF); Systems Research Laboratory (SRL); USDA (US)
• DOE Contract Number: AI02-93ER61720
• OSTI ID: 6635
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CLIMATES
CLIMATIC CHANGE
CROPS
GENERAL CIRCULATION MODELS
PHOTOSYNTHESIS
PLANT GROWTH
TRANSPIRATION
VAPOR PRESSURE
WATER USE