[CTRL] Agriculture After Global Warming

[William Shannon]

http://news.nationalgeographic.com/news/2001/07/0711_wiresoybeans.html Scientists Test Crop Growth in Climate Forecast for 2050 Environmental News Network July 11, 2001 Researchers at the University of Illinois in Champaign are raising soybeans in the kind of atmospheric conditions forecast for the year 2050. By 2050, carbon dioxide (CO2) levels are expected to be about 1.5 times greater than the current 370 parts per million, while daytime ozone levels during the growing season could peak on average at 80 parts per billion—now 60 parts per billion. Most scientists agree that the levels of the greenhouse gas CO2 in the atmosphere are rising due to the burning of coal, oil, and natural gas. Since the Industrial Revolution, the CO2 concentration in the atmosphere has increased from approximately 290 parts per million by volume (ppmv) to greater than 370 ppmv today. One unknown effect of this concentration is how well food crops will grow in a CO2-rich atmosphere. The conversion of sunlight through the green pigment chlorophyll in plants uses carbon dioxide and water and releases oxygen. Portions of 40 acres (16 hectares) of University of Illinois farmland this summer are sprouting soybeans grown in the presence of higher CO2 levels. Next summer, elevated levels of ozone will join the mix in an experiment called SoyFACE that is the first of its kind. Global Food Security "When you consider the importance of the Midwest in terms of global food security, it is important to do this research here," said Stephen Long, a photosynthesis professor of plant biology at the University of Illinois. "Up to now, experiments related to global warming on many crops have been done in locations on the periphery of major food production areas," he pointed out. SoyFACE (Free Air Gas Concentration Enrichment) is the first test of crop growth in the presence of both increased carbon dioxide and ozone. Researchers want to know how soybeans may be affected, and what scientists might do to assure the integrity of yields and quality as the climate changes, the university said in a statement July 2. Five University of Illinois departments, the Agricultural Research Service of the U.S. Department of Agriculture, and Illinois State Water Survey, as well as researchers from four other nations and two other U.S. universities are participating this summer. FACE research projects are being conducted in many places across the United States and around the world. In Oak Ridge, Tennessee, a sweetgum plantation is being grown in a CO2-rich environment, while in Rhinelander, Wisconsin an aspen forest is getting the CO2 treatment. Swiss scientists are testing grasslands and a bog in high CO2 concentrations, while in Brazil a tropical rain forest is being fed a CO2-rich diet. In Champaign, Illinois, four control and four experimental 70-foot-diameter (21-meter) rings now surround 24 varieties of soybeans. The experimental rings have vertical plastic pipes that deliver at crop level a precisely regulated flow of carbon dioxide, based on wind speed and direction, pumped from a 50-ton solar powered tank. Next summer, soybeans will grow on an adjacent 40 acres (16 hectares) dotted with 24 of the octagon shaped rings. Four rings will pump carbon dioxide, four will provide just ozone, and four will provide ozone and carbon dioxide. Natural conditions will exist in an equal number of control rings for each test. Next summer, eight more rings, including four experimental rings delivering CO2, will be placed among corn on the same 40 acres (16 hectares) being used this year for soybeans. 50 Percent Loss in Yield Soybeans are sensitive to ozone. In August 1999, for instance, ozone levels in central Illinois exceeded the crop threshold for damage on 28 days. Greenhouse experiments suggest a 50 percent loss in crop yield under constant 2050 levels. But under elevated CO2 levels, greenhouse work has shown increases in yields. This SoyFACE experiment, Long said, will provide insight as to what happens in real field conditions. Studies earlier this year by researchers at the U.S. Department of Agriculture Research Service (ARS) found that cropland and grassland in the United States could potentially store enough carbon to offset up to 14 percent of the carbon dioxide emitted from vehicle tailpipes and industrial smokestacks in this country. The first national estimate of how much carbon these lands are storing and how much more they could store was developed by Marlen Eve, an ARS soil scientist in Fort Collins, Colorado. Eve and colleagues developed the actual storage estimate for use in international climate change agreement discussions: 20 million tons of carbon a year. If crops of the future utilize more CO2 than plants of today, that carbon storage estimate could rise.