Climate Fact: Wheat, Nitrogen and Carbon Dioxide
In Brief: Wheat grown under elevated ambient carbon dioxide levels is less nutritious that wheat grown under current levels.
Atmospheric carbon dioxide (CO2) is a key plant nutrient, as carbon is the primary building block of all life on Earth. Other building blocks, however, are just as essential. Nitrogen, for example, is the mineral that plants require in the largest quantity. As atmospheric CO2 concentrations have risen from 280 parts per million to 390 over the last few centuries, scientists have started to ask questions about what this change will do to plant growth. More CO2 appears to stimulate growth in some plants, notably parasitic climbing vines, poison ivy and weeds like Canadian Thistle. In other plants, which use different methods to convert carbon into plant matter, more CO2 can also affect a plant’s ability to absorb nitrate, the most common nitrogen compound found in agricultural soils. Experiments done on wheat show that when this crop is grown under CO2 concentrations of twice today’s levels, there is a 7.4 to 11 percent decline in the protein content of the wheat grains, making the grain less nutritious.
Seasons: Winter, Spring, Summer, Fall
Sources: Bloom, AJ et al. “Carbon Dioxide Enrichment Inhibits Nitrate Assimilation in Wheat and Arabidopsis.” Science 328 (2010): 899-903 and Phillips, OL et al. “Increasing dominance of large lianas in Amazonian forests.” Nature 418 (2002): 770-774 and “As CO2 Levels Rise, Plants—and Humans—Respond.” Agricultural Research Magazine. USDA Agricultural Research Service, Nov. & Dec. 2009. Web. Nov. 2009: Vol. 57, No. 10.
