Biofuel: Focusing Solely On Biomass Yield Comes At A High Price
January 15, 2014

Biomass Yield Should Not Be Sole Focus Of Biofuel Production

Lee Rannals for - Your Universe Online

Corn may lead the pack in terms of biomass yield when it comes to biofuels, but this category shouldn’t be the sole focus of efficiency, according to a new study published in the journal Proceedings of the National Academy of Sciences.

Biomass yield is the ratio of the amount of biomass produced to the amount of substrate consumed. While this is an important factor when looking at biofuel production, it shouldn’t be the only consideration. Corn has always been a frontrunner for biomass yield, but scientists found that other biofuel crops, like native perennial grasses, actually score higher as viable alternatives.

"We believe our findings have major implications for bioenergy research and policy," Doug Landis, a biologist at Michigan State University (MSU) and one of the paper's lead authors, said in a statement. "Biomass yield is obviously a key goal, but it appears to come at the expense of many other environmental benefits that society may desire from rural landscapes."

For the study, researchers compared three potential biofuel crops, including corn, switchgrass and mixes of native prairie grasses and flowering plants. They measured the diversity of plants, pests and beneficial insects, birds and microbes that consume methane.

"Sustainability, food security, biodiversity, biofuel production--all are important to an increasing human population," said Saran Twombly, program director in National Science Foundation’s (NSF) Division of Environmental Biology, which funded the research through the LTER Program. "This is a superb example of how fundamental ecological research can assist human well-being."

Researchers found that methane consumption, pest suppression, pollination and bird populations were higher in perennial grasslands. They also saw that grass crops’ ability to harbor increased biodiversity is strongly linked to the fields’ location relative to other habitats.

Pest suppression is higher in perennial grass crops and is increased by 30 percent when fields are located near other perennial grass habitats. This finding suggests that coordinated land use should be a key factor when considering agricultural policy and planning.

"With supportive policies, we envision the ability to design agricultural landscapes to maximize multiple benefits," said Landis.

Rising corn prices are causing farmers to till and plant as much of their available land as possible, which hinders the idea of coordinated land use.

"If high commodity prices continue to drive conversion of these marginal lands to annual crop production, it will reduce the flexibility we have in the future to promote other critical services like pollination, pest suppression and reduction of greenhouse gases,” Landis said.