A waist high sea of switchgrass, Indian grass, bluegrass, forages and legumes with small yellow flowers in full bloom ripples like waves from the cool breeze with colors jumping out from the bright sun; a great day to be outdoors at the University of Missouri Bradford Farm looking at future biofuels.
Tim Reinbott, superintendent of the MU Bradford Research and Extension Center, is spearheading a research project on the long-term effects growing various plants for biofuels has on soil quality and content. Reinbott is comparing monocultures plots with only one plant species, like corn, to diverse cultured plots that have three, ten or 18 different legumes, forages and grasses. The idea for this project arose when talk of cellulosic ethanol started to spread. Cellulosic ethanol is made from the dry matter of plants such as switchgrass, Indian grass, bluegrass, forages, legumes and wood.
The popularity of using these warm season grasses is because they are native to the Midwest and easy to grow. Switchgrass is popular because it establishes quickest, one year, and needs less help, while Indian grass produces more dry matter and therefore more ethanol.
“That’s a really good legume,” Reinbott noted as he picked the yellow flowering plant from the ground and inspected its nitrogen producing knolled roots. By not having to add nitrogen to the soil this lowers production costs and also makes the process “more carbon friendly” because fertilizers are made from petroleum. “When looking at the whole carbon footprint that’s tremendous. We don’t want to design anything with more carbon than before.”
“If you wait until after October to harvest [switchgrass] you won’t lose as many nutrients,” said Reinbott. When switchgrass dies for the winter, all if its nutrients go to the soil through the roots, which have a large underground system. Corn ethanol is going in the other direction. Ethanol plants are starting to make ethanol out of corn stover including the stalk and leaves, which is that much less nutrients being returned to the soil.
Miscanthus, an ornamental hybrid cross grass, is similar to switchgrass in that its nutrients go to its roots for winter. It has greater growth and therefore biomass potential and would require 1/3 less land than switchgrass. Switchgrass produces four tons of dry mass per acre while Miscanthus produces twelve tons per acre. The downside, being grown in a monoculture miscanthus is not as wildlife friendly as switchgrass.
“After three years we hope to see a difference in soil properties” said Reinbott, who expects to see a difference in the soil every year afterwards. The time is now. Reinbott’s three-year-old plot will be harvested for the first time this October, giving him data to compare the different types of crops for fuels like ethanol and biofuels and the impact on soil properties over time
“The seeds are just ideal,” said Reinbott as he picks a foxtail from a highly diverse plot. “We’re on the up and front on this wild life aspect. By looking at wildlife we’re staying ahead of the game. We don’t want that to blow up in our face.” Reinbott is working closely with the MU Conservation Department to see which types of plots attract which types and how much wild life. The Conservation Department is concerned about the monoculture plots, which often don’t provide wildlife with the food or shelter they need to thrive. “Ideally we want to produce as much biofuels as possible but with a more favorable base for wildlife.” By predicting and fixing problems before they occur, Reinbott hopes to have a smooth transition in biomass production for Cellulosic ethanol.
“It’s going to be very intense,” said Reinbott who sees the future of biofuels in the technology rather than new plant sources. Reinbott believes power analysis, which uses a system of heat and pressure to break down biomass to its basic elements, is going to be break through technology in the next five years. Currently, scientists are able to produce 70 gallons of ethanol for every ton of switchgrass, nowhere close to the theoretical 200 gallons per ton.
Another issue researchers are working on is storage. Forages are fluffier than corn and take up more space to store. Reinbott’s next research question, “In October what happens if fuel is stored in the field?” If storage isn’t an issue and little biomass is lost while in the field then farmers can take harvested biomass straight to the ethanol plant.
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