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Book: Impact of Carbon Dioxide, Trace Gases, and Climate Change on Global Agriculture
Published by: American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America



  1.  p. 45-60
    ASA Special Publication 53.
    Impact of Carbon Dioxide, Trace Gases, and Climate Change on Global Agriculture

    Bruce A. Kimball (ed.)

    ISBN: 978-0-89118-319-8


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Effects of Carbon Dioxide on Photosynthesis, Plant Growth, and Other Processes 1

  1. Basil Acock
  1. Systems Research Laboratory, Beltsville, Maryland


The increasing concentrations of CO2 and other “greenhouse gases” are expected to change temperature, rainfall, and cloudiness. Since the late 17th century we have been collecting empirical information on crop response to all these climatic factors except CO2 concentration ([CO2]). The primary effects of high [CO2] are an increase in photosynthetic rate and a decrease in transpiration rate. The former response is more pronounced in C3 plants than in C4 plants. The extra C fixed increases the dry weight of all organs, with disproportionately more going to roots and stems in many plants. The sizes of most vegetative organs and the numbers of many organs increase unless limited by other environmental factors. The environmental factors that can limit plant response to high [CO2] include nutrients, water, temperature, and light, although the effects of some of these are ameliorated by high [CO2. These factors and [CO2] interact in a complex way, so it is necessary to understand the mechanism of plant response to [CO2] to predict growth and yield. The net result is that in a future high-[CO2] world, we can expect larger plants and higher yields whatever organs are harvested, with higher water use efficiency but higher fertilizer requirements. The C3 crops might displace maize (Zea mays L.) where water is adequate, because their yields will probably be stimulated more. However, the increased [CO2] might make maize more drought-tolerant.

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Copyright © 1990. Copyright © 1990 by the American Society of Agronomy, Inc., Crop Science Society of America, Inc., Soil Science Society of America, Inc., 5585 Guilford Rd., Madison, WI 53711 USA