"There's a number of factors that would impact the profitability of growing these crops as opposed to growing corn and soybeans, which include the cost of establishing these grasses as well as maintaining, storing and transporting them," Khanna said. "Another issue is the cost of the land itself. A farmer who converts land from corn and soybeans to miscanthus or switchgrass is giving up his profits from corn and soy."
Unlike annual crops that provide a farmer with a crop every year, miscanthus and switchgrass require a lag of at least two years before harvesting. In addition, the cost of harvesting is nearly one-third of the cost of producing biomass, according to Khanna. In the U.S., such large-scale grass harvesting hasn't been attempted, making cost estimates difficult. The most comparable crops currently grown are hay and alfalfa, which have yields only one-sixth to one-tenth of the possible volume from miscanthus.
In addition, the costs very between switchgrass and miscanthus. Miscanthus has a much higher yield, but also a much higher initial cost. Miscanthus is planted from small sprouts called rhizomes, which are much more expensive than switchgrass seed. However, miscanthus has a longer lifespan, so planting would be less frequent. These are tradeoffs farmers would have to consider when deciding to cultivate biofuel grasses.
Ultimately, the study found that biofuel grasses could be a viable crop in the U.S. under certain conditions.
"We find it's more profitable to grow miscanthus and switchgrass in areas where the yield of miscanthus and switchgrass is high, but the yield of corn and soybeans is low," Khanna said. "In areas like southern Illinois or Missouri where corn is not as productive as in central and northern Illinois or Iowa, these grasses are likely to be more competitive."
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|Contact: Liz Ahlberg|
University of Illinois at Urbana-Champaign