Researchers assessing benefits of converting grasses to biofuel
WASHBURN — University of Northern Iowa professor Mark Myers considered it a “theoretical exercise” when he assigned his wildlife ecology and management students to develop a habitat management plan for a local site.
But, said Myers, Jarrett Pfrimmer, 25, of North Liberty, “took the assignment to heart,” and a year later, prairie grass was growing on 20 acres of former cropland along a Cedar River tributary.
“I did not think he could make it happen in that short a time,” said Myers, who is working with Pfrimmer on another major project with the potential to restore natural functions of the Cedar River watershed — research to determine the feasibility of native prairie as a biofuel.
Pfrimmer, who will complete work on his master’s degree next month, said he worked with the Black Hawk County Soil and Water Conservation District to line up cost-share funding for the stream buffer project.
The Boone native said he also took advantage of expertise at UNI’s Tallgrass Prairie Center to plan and execute the 120-foot wide buffer strips on both sides of Dry Run Creek, which flows past the UNI campus en route to the Cedar River.
Seeded a year ago, the native vegetation will become well established next year, greatly reducing erosion from the former farm fields, improving the quality of the water flowing into the Cedar and providing habitat for songbirds, pheasants and other wildlife.
The absorbent grass also will play a small role in reducing the crest of future Cedar River floods.
“Every little bit helps” when it comes to watersheds’ ability to store and slowly release floodwaters, said State Sen. Rob Hogg, D-Cedar Rapids, a leader in legislative efforts to improve watershed management.
Small-scale improvements like the two Black Hawk County projects can help create a mindset and policies “that will help buy down flood peaks for those of us downstream,” Hogg said.
In addition to the Cedar Falls stream buffer project, Pfrimmer has worked with Myers and others to assess the benefits of converting cropland into a prairie biomass production site at the 593-acre Cedar River Natural Resource Area about 10 miles south of Waterloo.
On flood plain land that had formerly been leased for row crop production, the researchers established 48 test plots, each seeded with one of four types of native vegetation ranging from switch grass alone to a mix of 32 species of grasses, legumes, forbs and sedges.
Those plantings were equally distributed among three distinct soil types, enabling the researchers to control all key factors contributing to the productivity of native grass not only as a source of energy but also as habitat for birds, butterflies and other wildlife.
The research got off to a rocky start with the historic Cedar River flood of 2008 wiping out the initial seeding. The plots were reseeded in 2009, burned in 2011 and finally harvested in April, compressed into 550-pound rectangular bales, with an average yield of 4 tons per acre.
About 150 of those bales were later pelletized for an upcoming test burn by Cedar Falls Utilities. “We’re looking to find out how well it burns for energy generation,” said Daryl Smith of the UNI Tallgrass Prairie Center, a partner in the research.
Researchers have suggested that cultivation of low-input, high-diversity grassland biomass could have significant energy and environmental advantages over corn-based ethanol, according to Myers.
While it remains to be seen whether the energy yield would justify conversion of marginal farmland to production of native vegetation for use as an energy source, biofuel production with diverse mixtures of native prairie vegetation “contributes to the maintenance of biodiversity in agricultural landscapes,” the researchers concluded.
Grassland birds and butterflies quickly found and colonized the test plots, according to Myers.
Pfrimmer, who has led bird data collection efforts, will soon complete his master’s thesis on “Bird Use of Heterogenous Native Prairie Biofuel Production Plots.”
In each of the past two years, he has found at least 100 delicate nests hidden among the grass stems by species such as the sedge wren, dickcissel, grasshopper sparrow and lark sparrow. Pheasants and turkeys also have moved into the grass, he said.
“We are starting to see different bird communities established in the plots in accordance with their preferences for the vegetation mix and even the soil types,” Pfrimmer said.
Article taken From The Gazette Newspaper
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