Like it or not, corn and corn ethanol production are large, established industries in the U.S. While they provide significant economic, energy, and environmental benefits for our society, they also come with significant costs. Looking ahead, the question is how can we do corn and corn ethanol better, with reduced environmental costs, and start doing better than corn, by transitioning to more sustainable, diverse, multi-functional agricultural systems. Here are some recent developments in the field.
Doing corn better. . . One way to do this would be to get more value out of each corn plant. Using a portion of the cobs and leftover stover to produce cellulosic biofuel or heat and power would help displace more fossil fuels with renewable bioenergy. However, removing stover has to be done sustainably. Soil and water conservation and soil carbon and nutrient balances need to be maintained. Every field is different, depending on the amount of stover produced, soil type, climate, slope, etc. This was the topic of a conference in Washington, DC, this past week. Stay tuned for future reports. . . Another way to do corn better is to practice no-till farming. USDA research, published in the December 2012 edition of Bioenergy Research , has found that using no-till in corn production can increase the amount of carbon stored in soils significantly more than previously estimated. The study was conducted over ten years. No-till also reduces soil erosion, conserves water, and reduces the amount of fuel used in producing corn. . . . Also in the news this month, Biomass Magazine reports that the BioNitrogen Corp. is developing a commercial scale bio-based urea production plant in Florida. The plant will gasify waste vegetation and turn it into nitrogen fertilizer. Corn requires a lot of nitrogen fertilizer. Most nitrogen fertilizer today is made from fossil natural gas. However, if renewable technologies like this can be installed across corn country, using sustainably produced local biomass or corn stover, the carbon footprint of corn and corn ethanol production could be reduced further. Of course, state-of-the-art nutrient management techniques also need to be adopted much more widely across corn country to reduce the amount of fertilizer that is used and to reduce nitrous oxide emissions and nitrate leaching. . . . One way to reduce nitrous oxide and nitrate pollution is to buffer the boundaries of cornfields with perennial grasses and plants. This was reported on in a study released in January, "Reduced nitrogen losses after conversion of row crop agriculture to perennial biofuel crops" , in the Journal of Environmental Quality. C. Smith and colleagues report that deep-rooted, perennial biomass crops such as miscanthus, switchgrass, and mixed prairie plants can quickly reduce the flow of nitrate in groundwater and tile drainage systems and reduce N2O emissions into the air. . . Finally for this week, the January 11 issue of Biofuels Digest reports on several ways the corn ethanol industry is innovating and adapting, including using new feedstocks such as sorghum and corn stover; extracting corn oil (a co-product) more efficiently; developing new enzymes that reduce water and energy use; producing more energy-dense biobutanol; and using the CO2 from ethanol plants to co-produce algae for biofuels or nutra-ceuticals.
On the subject of "doing better than corn," a couple of links from last week’s SBFF are highlighted again. . . In a recent article in Nature, "Sustainable bioenergy production from marginal lands in the U.S. Midwest" , I. Gelfand and colleagues find that growing and harvesting successional vegetation on marginal lands could produce as much or more renewable fuel per hectare as corn while also absorbing (rather than releasing) carbon from the atmosphere into plants and soils. . . Similar findings are reported in another recent paper. In "Impact of second-generation biofuel agriculture on greenhouse-gas emissions in the corn-growing regions of the U.S." , published in Frontiers in Ecology and the Environment, S. Davis and colleagues found that "If cellulosic feedstocks were planted on cropland that is currently used for ethanol production in the U.S., more ethanol (+82%) and grain for food (+4%) could be produced while at the same time reducing nitrogen leaching (−15 to −22%) and greenhouse-gas (GHG) emissions (−29 to −473%). The GHG reduction was large even after accounting for emissions associated with indirect land-use change. Conversion from a high-input annual crop to a low-input perennial crop for biofuel production can thus transition the central U.S. from a net source to a net sink for GHGs."