The research by the CSU team also found that a group of farmers reduced carbon emissions by 65 percent by tilling less often.
The findings come from a three-year study by CSU researchers on farming techniques in southwestern Minnesota, where a group of progressive farmers has taken steps to lower greenhouse emissions during corn production. The study, funded by Coca-Cola Co. (NYSE: KO), looks at carbon pollution emitted during corn production on 40 family farms that supply corn to a biofuel refinery operated by Englewood-based Gevo Inc. The farmers have 25 percent lower carbon output than the average U.S. farmer. In all, agriculture represented about 10 percent of greenhouse-gas emissions in 2012, according to the U.S. Environmental Protection Agency.
Coca-Cola was interested in looking at corn production as part of efforts to learn more about emissions tied to making beverage bottles from corn. Gevo also was curious about its emissions from production of corn used to make the biofuel isobutanol in its refinery in Luverne, Minn.
“Companies like Coca-Cola in particular are so international in scope that they cannot afford to ignore things like greenhouse-gas emissions,” said John Sheehan, a researcher in the Department of Soils and Crop Sciences at CSU and principal author of the study. “The U.S. may not be moving very quickly in that area, but (companies) are feeling the pressure pretty strongly in the rest of the international market.”
Indeed, nations throughout the globe have mandated greenhouse-gas emission reductions from a variety of pollution sources, and the United States has followed up with its own regulations.
In the study, the CSU team looked at practices by the Minnesota farmers to calculate how much pollution they could avoid if they combined their techniques onto one farm.
David Kolsrud’s family has farmed in the region since the 1870s. Kolsrud, who farms corn and soybeans, and other farmers today lease the biofuel refinery to Gevo.
“This is just the beginning,” Kolsrud said. “We’re starting to head into an era where a lot of companies are looking at sustainability.”
Northern Colorado farmers such as Richard Seaworth of Seaworth Farms in Wellington also are taking steps to reduce emissions, although it’s aimed at reducing fuel and fertilizer costs.
Seaworth said he strip-tills, a technique he uses to till fewer times.
“It saves water, it saves fuel, it saves man hours,” he said. “It will save some fertilizer.”
CSU researchers found that farmers can reduce their carbon emissions by 46 percent if they applied two thirds of the amount of fertilizer they normally use per acre.
Applying less nitrogen fertilizer was one of the main ways Minnesota farmers reduced their emissions, Sheehan said. Nitrogen fertilizer not only requires a vast amount of energy that leads to emissions during manufacturing, it also emits nitrous oxide, a potent greenhouse gas.
“Over-application of nitrogen fertilizer can add a lot of nitrous oxide, which has a huge greenhouse-gas impact,” Sheehan said.
Tilling also can cause emissions by releasing carbon trapped in soil into the atmosphere. Farmers can reduce tilling by using genetically modified seed, which withstands the herbicide Roundup without killing crops. Tilling less often also can save water, which can evaporate during the process.
The good news? Emissions-reduction practices do not require special technology and lead to lower costs when farmers use less fuel for tilling and buy less fertilizer.
“Some of it is getting farmers to break from tradition,” Sheehan said. “Some of it is getting farmers to be generally more careful.”
Steve Lynn can be reached at 970-232-3147, 303-630-1968 or firstname.lastname@example.org. Follow him on Twitter at @SteveLynnBW.
An earlier version of this story said that farmers could reduce carbon dioxide emissions by applying less fertilizer. Farmers can reduce nitrous oxide emissions by applying less fertilizer.