Richard Moore is executive director of the Environmental Sciences Network and associate director for academics in the Office of Energy and the Environment.
Is climate change really happening and how does corn fit into the picture?
This month the American Association for the Advancement of Science published “What We Know” (whatweknow.aaas.org). It shows that 97 percent of scientists agree that human-caused climate change is happening. Many of them can cite evidence from their own research. Average global temperature has increased and continues to increase. The sea level is rising, coral reefs are dying, the glaciers are melting and we are seeing more extreme weather events, both in number and intensity. It is what we don’t know that is more disturbing. We are at risk of pushing our climate systems toward abrupt, unpredictable and potentially irreversible changes. Accordingly, the focus is starting to shift from “Is climate change happening?” to “Are there tipping points of irreversible change?”
One area of particular concern is the high level of greenhouse gases, which include methane, carbon dioxide, nitrous oxide and fluorinated gases. When greenhouse gases are trapped in the atmosphere, it warms the surface of the Earth via infrared radiation. One of the “tipping points” scientists are worried about is the constant rise of carbon dioxide levels.
Corn is the leading commodity crop in the United States and is usually rotated with soybeans. Cash receipts for the two combined was about $100 billion in 2011, two-thirds of the total for all crops. Growing corn releases carbon dioxide gases by driving tractors fueled by fossil fuels or by tilling the soil. When we till the soil, the soil carbon built up through the decomposition of organic matter becomes oxidized, creating carbon dioxide. Since the 1960s, American farmers have applied much higher levels of chemical fertilizers resulting in higher yields but also higher levels of nitrous oxide.
What are some of the goals and major findings of your research?
Currently, I am working on a $20 million USDA grant, “Climate Change, Mitigation and Adaptation in Corn-based Cropping Systems,” along with OSU faculty members Rattan Lal, Warren Dick and Kristi Lekies. Our goals are to increase the retention of soil carbon to improve soil quality and reduce greenhouse gas emissions, limit the loss of nitrogen, stabilize soil and nutrients during periods of water saturation, find more efficient use of water during drier periods and transfer our findings to farmers, scientists and local citizens. Our grant is the first effort to systematically measure greenhouse gases and carbon sequestration from corn. We use the same methodology to collect our data by the 11 participating institutions across the Corn Belt. We also interviewed many farmers regarding their attitudes about climate change. We are finding the use of cover crops improves soil structure, especially on hilltops and side slopes. This results in greater organic matter and carbon sequestration over the long term. Certain conservation practices, such as no-tillage and cover crops, can increase soil carbon.
Using nitrogen-sensing equipment to determine application rates results in a reduction in nitrogen fertilizer use, nitrous oxide emissions and soil nitrate leaching. This new technology has the potential to reduce energy consumption and emissions based on a life cycle assessment. Nitrous oxide emissions from the soybean phase of a corn-soybean system are low overall with emissions similar to corn grown with no nitrogen fertilizer. Managing the tile drains that are buried under the fields can reduce nitrate losses from fields into surface waters.