In a unique farm-level study, researchers at Colorado State University and the University of Minnesota and have shown that best farming practices can significantly reduce the carbon footprint of corn production.
Detailed production data from farmers in and around southwest Minnesota were analyzed to model carbon emissions under various scenarios while maintaining high yields. The study evaluated thousands of scenarios and found that by applying fertilizer at optimal rates and using tillage practices that minimally disturb the soil, greenhouse gas emissions from corn production can be dramatically reduced.
In 2011, researchers collected and analyzed detailed, three-year survey data from 40 large, family owned farms supplying corn to a biorefinery in southwest Minnesota. The original study showed the respondents had a 25 percent lower carbon footprint than the U.S. average.
In the current study, CSU used the data from these farms in its DayCent model to assess the effect of thousands of best management practice scenarios. Greenhouse gas emissions could be reduced by 46 percent simply by limiting nitrogen fertilizer application from current rates of 225 kg per hectare (ha) to the optimal rate of 150 kg. In addition, by using minimal tillage practices, carbon emissions could be reduced 65 percent compared to current practices. If fertilizer application rates were managed at the 150 kg/ha rate and no-till practices were used, the CSU model showed carbon sequestered at the rate of 55g of carbon per bushel of corn.
“A lot of studies have been done to develop recommendations for what corn farmers should do to be more sustainable,” said John Sheehan, a researcher in the Department of Soils and Crop Sciences at CSU who was the principal author of the study. “For these studies, we started by asking them what they were doing and found that some farmers were already managing their land in ways that lead to greatly reduced and even negative carbon footprints. In the modeling study, we analyzed what would happen if all farms in our original survey adopted the best of these practices.”
The CSU team, led by CSU soil and crop sciences professor Keith Paustian, included Kendrick Killian and Stephen Williams of the Natural Resources Ecology Laboratory in the Warner College of Natural resources at CSU. A review panel included experts from the World Wildlife Fund, The Nature Conservancy and the Environmental Defense Fund. The study was sponsored by Huttner Strategies, LLC, with funding provided by The Coca-Cola Company.
Links to the studies
“Measuring the carbon footprint of Gevo, Inc.’s Luverne MN corn supply,” November 2012, Sheehan, et.al., Institute on the Environment, Univ. of Minnesota, Colorado State University. http://iree.environment.umn.edu/wp-content/uploads/2014/03/Gevo-final-report-1.pdf
“Scenarios for low carbon corn production,” March 2014, Sheehan, et.al., The Natural Resources Ecology Laboratory, Colorado State University
DayCent is a daily time series biogeochemical model used in agroecosystems to simulate fluxes of carbon and nitrogen between the atmosphere, vegetation and soil. It was developed at Colorado State University. The U.S. Environmental Protection Agency and U.S. Department of Agriculture are currently using DayCent to report national annual inventories of agricultural carbon dioxide and (nitrous oxide emissions to the Intergovernmental Panel on Climate Change (IPCC) associated with the United Nations Framework Convention on Climate Change.