This news piece by KBS LTER volunteer and retired journalist Bill Krasean.
If the United States is to develop sustainable biofuels such as cellulosic ethanol as alternatives to grain-based ethanol and the burning of climate-changing fossil fuels, there are still many questions yet to be answered.
Key among those questions is where best to grow biofuel crops without sacrificing valuable farm and forestland, says Jiquan Chen, Distinguished University Professor in Environmental Science at the University of Toledo and investigator in the U.S. Dept. of Energy’s (DOE) Great Lakes Bioenergy Research Center at Michigan State University (MSU).
Working with scientists at MSU’s Kellogg Biological Station (KBS) on Gull Lake, Chen’s post-doctoral student Michael Abraha collects and analyzes reams of data from seven so-called carbon dioxide (CO2) flux towers on land in Barry County north of the KBS Gull Lake site.
His is no easy task. The seven towers collect a variety of measurements continuously 365 days a year. The towers’ primary functions are to measure how much CO2 is captured by crops during photosynthesis for creating biomass for biofuel. The captured CO2 can also be released when respired by plants and microbes or stored in soil as soil organic matter
Chen said the answers are leading to a deeper understanding of economic, environmental and social issues about cellulosic biofuels—the broad question of sustainability.
Once a week or so, Abraha visits the towers and collects the measurements on flash-drives which he plugs into his computer.
“I analyze data from beginning to end,” Abraha said. “There are 10 measurements per second and I collate them and put the data in a graphic form that can be easily readable.”
Why such detail?
If you are building a bio-energy system, Chen said, you need to precisely measure the fate of the captured CO2: How much is turned into biomass for future biofuel use, how much is respired back to the atmosphere as CO2, and how much is stored in the soil as new soil organic matter.
Abraha’s data is available for free to other scientists or anyone who has a computer and interest in the subject.
Although the seven towers at KBS specifically target sustainable biofuel production, there are nearly 1,000 similar towers placed in the Great Lakes region and around the world. Each provides data for research in a wide variety of scientific studies.
They are called flux towers because, among other functions, they monitor the carbon cycle, the ebb and flow—the flux—of carbon in the atmosphere, the soil, and plant life adjacent to each tower.
The KBS towers are on seven parcels of land—three that have been used for agriculture for at least 20 years, three that have been Conservation Reserve Program (CRP) for at least 20 years, and one grassland parcel that has never been farmed.
G. Philip Robertson, professor of Ecosystem Science at KBS and lead scientist for DOE Biofuel Sustainability Research at MSU, said that CRP lands are former cropland retired from cropping for 10 years or longer. The contracts are 10 years in duration after which the farmer can put them back into farming or renew them for another 5 or 10 years.
The land has to be planted with approved conservation species such as brome grass, Robertson said.
Chen said that regions in Michigan and the Midwest in general are the most productive agricultural land in the world. With that in mind, Chen and the KBS team are trying to determine if the land can sustainably produce cellulosic ethanol and other biofuels while saving better farmlands for crops.
One study cited by Chen showed that converting CRP lands to soybean and corn for grain-based biofuels would have very limited climate benefit. Rather, it showed that it was much better to simply use the CRP grasses themselves to produce cellulosic ethanol.
The study, led by KBS researcher Ilya Gelfand, was published in the Proceedings of the National Academy of Sciences.
Chen and colleagues installed the seven towers in 2008. The sites were selected because they have similar microclimates, elevations, and slope. The parcel that has never been farmed serves as a baseline for the other six parcels, which are now converted to corn or cellulosic crops such as restored prairie and switchgrass. Cellulosic plants also include wood or other inedible parts of plants.
This is a long-term project, Chen said. All the data that Abraha is compiling will ultimately be used to determine the ultimate question of sustainability.
By sustainability he means that, given all the factors at play, what is the most economical way to produce biofuels that minimizes the release of CO2, methane, and other greenhouse gases, protects wildlife, makes maximum use of land, and is socially acceptable to people who live nearby.
“The theme of the project,” Chen said, “is addressing the question of whether there is enough water, enough nutrients, enough light to support the bioenergy system in an environmentally sustainable way. What kind of land and management is best suited for producing biomass for ethanol?”