Biomass crop summary has indications for Michigan’s bioeconomy

Preliminary data from Illinois Biomass Crop Study indicates promising feedstock species for Michigan’s bioeconomy.

There are many different biomass crops that are being evaluated as potential feedstock sources for cellulosic ethanol production. Different crops are adapted to particular soil and climate conditions existing across the country. Here in the Midwest, there are a number of potential crops we could grow to achieve bioenergy goals.

A recent study conducted by the Energy Biosciences Institute at the University of Illinois revealed the most promising biomass species for the north central United States. The trial included woody plant species and prairie (grasses and forbes) species. In Michigan, we grow both woody and grass biomass crops, but production varies by region. Due to historical land use patterns and existing infrastructure, the Northern latitudes are generally dedicated to woody species and Southern areas to grasses. The results of the study conducted in Illinois are quite applicable to Michigan due to our geographic proximity and somewhat similar growing conditions.

The woody species evaluated in this study included 21 species of short rotation woody plants. Yields from the top five performing species are listed in Table 1. Trees were planted in a 5-foot by 6-foot spacing. Alfalfa was used as a cover crop to help control weeds in the establishment year (2010). Weeds within the rows were controlled with pre-emergent and non-selective herbicides, as well as mechanical means. Two-year-old plants were harvested in winter 2012.

Table 1. Top five woody species planted at University of Illinois research plot.

Species

Bone dry U.S. tons/acre

Black Locust

5.2

Northern catalpa

1.9

Flameleaf sumac

1.7

Silver maple

1.6

Sycamore

1.2

Prairie grasses and forbes were planted in the spring of 2010 in small plot trials. The grasses were drilled with a small plot seed drill. Forbes were transplanted by hand from 2-inch square pots started in the greenhouse. Mechanical weed control was used in the establishment year. Plots were also irrigated as needed in the first year to help ensure establishment. Plots were harvested in 2011 and 2012. Yields of the top five forbes and grasses are listed in Table 2.

Table 2. Top five grasses and forb species planted in 2010 at University of Illinois research plot.

Species

2011 Yield

2012 Yield

Dry U.S. tons/acre

Dry U.S. tons/acre

Switchgrass Blade 1102

5.8

6.5

Switchgrass Blade 1101

5.7

6.1

Indiangrass Scout

4.3

3.1

Switchgrass NE-54

3.8

3.0

Switchgrass Kanlow

3.3

3.8

Cupplant

3.1

1.5

Sawtooth sunflower

2.0

1.5

Illinois bundleflower

1.4

1.2

Virginia mallow

1.3

0.9

Late goldenrod

1.0

0.9

Notice that the yields of the prairie grasses were significantly higher than the forbes. While planting forbes has biodiversity benefits, their lower yields could be a deal breaker for biomass production. Prairie grasses take three years to fully establish, so this study needs to be continued for at least two more years to draw solid conclusions. Weather variability from year-to-year can also have a big impact on how each species performs. Therefore, long-term data is essential when deciding what species to plant.

There is a great deal of biomass crop research underway in private and publicly funded trials. While this study is not completed yet, it gives us a snapshot of how these plant species are performing during the first two years.

For more information, contact Michigan State University Extension’s Dennis Pennington at .(JavaScript must be enabled to view this email address) or 269-838-8265.

Reference

  • “Short Rotation Woody and Prairie for Biomass Crops,” 2013 Bioenergy Feedstocks Symposium

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