Make Way for Miscanthus

Genetic improvements and advancements in growth and harvest techniques are moving miscanthus closer to becoming a commercial energy crop.
By Anna Austin
Research on miscanthus as an energy crop took off in the U.S. in the mid-'90s, but interest in the grass has peaked during the past few years. Though steady progress is being made in all dimensions of utilizing miscanthus as a biomass crop-from breeding to planting to harvesting to pest control-there are still some challenges to overcome.

Because miscanthus is naturally sterile, it must be grown by planting its root-like stems called rhizomes, a process similar to potato planting. While some groups have focused on developing rhizomes to provide to future growers, which takes about three years to accomplish, others are concentrating on genetic improvements such as seeded varieties of the crop.

Mississippi State University researchers have spent more than a decade isolating, identifying and developing genotypes of giant miscanthus that would be most suitable for commercial growth in the South. Their work has led to the development of a new strain dubbed Freedom. During MSU variety trials, Freedom demonstrated yields of 25 tons per acre and grew to 12 feet, outperforming switchgrass by a ratio of at least 2:1.

Soperton, Ga.-based SunBelt Biofuels is taking MSU's research to the next level. The company obtained an exclusive license for Freedom a few years ago, and has since been working to produce plant material to sell to growers, according to SunBelt Biofuels President Phillip Jennings. The company currently has 250 acres of Freedom in Georgia and Mississippi, and plans to have rhizomes available for sale this year.

Miscanthus Milestone

It has taken time and dedication to get to the point where SunBelt is able to supply miscanthus rhizomes to growers, according to Jennings. "For the past three years, our concentration has been on a series of studies involving the actual growing of rhizomes so we're able to furnish grower manuals, since it's a new crop," he says. "We're continuing to do numerous studies with major universities in the Southeast to learn more about the genetics of the plant."

Beyond the region's ideal climate, longer growing season and daylight hours, the Southeast, which is a region of focus for SunBelt, offers another advantage to growers-ample idle, available land. Georgia and Alabama each have a little more than 1 million acres of land not currently being utilized, according to Jennings, and South Carolina has 500,000 acres. Additionally, it costs considerably less to rent land in the Southeast than in other regions of the U.S. "Cash rent in Illinois is $200 to $400 an acre, and in Georgia its $50 to $70 an acre," he says. "Land that doesn't produce a profitable food crop-we want that land to host miscanthus." However, that doesn't mean miscanthus can't be grown in other areas from Florida to Canada, Phillips adds, the economics just fit better in the Southeast.

Freedom out-yields switchgrass because of the ideal growing conditions, while growers in other areas may fare better planting switchgrass. "[In the Southeast], we're going to get four times the amount of cellulose to the acre per year than you'd get with switchgrass," he says. "It's exceedingly hard to produce a stand of switchgrass in the Southeast, and after about three years, stands need to be replanted. It's a wonderful crop for the prairie lands where it is native, but you can't economically, feasibly reach yields that justify what we've got to do with cellulose. Cellulose buyers cannot afford to pay a switchgrass producer what it costs to grow tons of switchgrass in the Southeast-it's pure economics."

Though it's possible for growers to use the same equipment used to harvest hay, Jennings says those contracted for large acreages will likely require something more automated. "There hasn't been a lot of technologies developed surrounding miscanthus-we're surprised at that-but we're in the process of developing and will soon have a precision planter that will plant miscanthus the same way corn or soybeans are planted, and we also have developed a mechanical digger."

Others are also working to automate miscanthus planting and harvesting. The University of Illinois in partnership with Tomax Ltd. and Bermuda King USA, recently unveiled a miscanthus rhizome regeneration harvester and planter system after three years of collaboration. According to the university, the planter demonstrates a more uniform stream of rhizomes, enabling placement at a rate that matches rhizome weight, quality and ground conditions. The four-row planter incorporates separate feed hoppers and placement channels so it can be used for two-row nursery work and larger scale plantations.

The harvester lifts the rhizomes on a continual basis with a one-pass digging head and oscillating de-soiler. The rhizomes exit via a bulk side discharger that conveys the rootstock to an adjacent trailer. The equipment will be available for licensing this year.

For those who aren't sold on the idea of establishing and planting rhizomes, California-based Mendel Biotechnology Inc. is developing seeded varieties of miscanthus, a route it believes will serve as a long-term solution for commercial production of miscanthus.

Planting a Seed

When a company specializes in plant breeding its long-term fundamental asset is the scope and diversity of the gene pool that it can draw on to create commercial varieties, says Mendel Biotechnology President and CEO Neal Gutterson. "So what Mendel did early on, through the acquisition of a breeding program in Germany, was collect miscanthus accessions to put together what we think is the world's best and most robust miscanthus germplasm pool. That pool now has 2,000 accessions; quite a few natural accessions, and some developed varieties."

Why so many accessions? Gutterson says most of the accessions are not actually under development for commercial use in the next two to four years, but serve as assets to build on in the long term. "In the short term, we're focused on sterile varieties like many other people, and our approach at the moment is to propagate those with partners and to deliver them to farmers and growers in the form of transplant plugs," he says. "Establishing plugs is quite a reliable form of delivering planting material. Like the rhizome system, it's still rather expensive all-in-all, and although Mendel does have a proprietary clone, we don't see that as a long-term solution for a scalable miscanthus industry. For the long term, we're working toward creating varieties that can be reproduced from seeds. A seed production system is less expensive than a rhizome or plug system."

"Seeded varieties will dramatically change the cost structure of producing miscanthus for developers, growers, and power companies and refineries," Gutterson says. "That is our long-term goal, and we're well on the path to that."

Mendel is testing its clonal products on larger scales, as well as its seeded varieties that will come after the clonal products, on smaller scales. At its Kentucky demonstration site, the company has planted nearly 30 acres of miscanthus and expects to increase that to more than 50 acres this year. Outside of the Southeast, Patterson says Mendel is looking at the Atlantic Seaboard, southern parts of the Corn Belt, and has trials of different sizes at about 25 sites that extend into Canada in order to analyze issues such as cold tolerance and flowering control.

In the meantime, researchers and academia are covering other bases of miscanthus production, including possible hindrances.

Pondering Pests

Beyond innovations in yield, growth and harvest, perhaps one of the most overlooked aspects of developing new biomass crops is potentially negative scenarios such as disease, pests and effects on other crops. So far, SunBelt hasn't experienced any pest or disease problems in the Southeast that thrive on Freedom, Jennings says. "Our pathologists have injected our plants with numerous leaf diseases and they haven't taken," he tells Biomass Magazine. "We're not saying that Freedom is 100 percent resistant, but it was selected because it's a superior variety for the Southeast."

University of Illinois researcher Joseph Spencer, however, says those involved in or considering growing giant miscanthus should test the waters before jumping in, and fully understand pest possibilities and consequences. He is particularly concerned about the western corn rootworm (WCR). Although the WCR typically feeds on corn crops, Spencer's research indicates it could thrive on giant miscanthus. Just because corn isn't grown in regions that are ideal for giant miscanthus production, doesn't mean that a WCR infestation should be ruled out, Spencer says. "It is present in parts of the Southeast U.S.-in western North Carolina and Tennessee, as well as northern South Carolina, Alabama and Georgia-though this species has invaded these areas only in past 10 to 15 years," he says. "The WCR is a very adaptable and mobile pest. Pest managers in the Midwest know only too well that it can cause serious economic problems if ignored."

While Spencer agrees with Gutterson and Jennings that interest in farm-scale plantings of giant miscanthus is healthy, he emphasizes that it's not yet known whether the WCR will become a pest of giant miscanthus or whether giant miscanthus will become a source of WCR that will invade corn, or if giant miscanthus might actually benefit corn growers by acting as a refuge for WCR that are susceptible to transgenic corn hybrids. "If I were a grower I would want to go into my giant miscanthus commitment with a full understanding that pests and pest management costs may not be negligible," he says. "In the case of the WCR, it is our most significant pest of corn-it is adapted to a host plant that is available in the same field year after year; we were not surprised that the WCR could survive on a grassy biomass crop with a perennial growth habit. I think it is becoming clear that claims of a lack of pests on giant miscanthus are due to not looking for them, not because they are absent. That sort of hubris gets you in trouble with nature."

From Spencer's perspective, issues related to potential pests must be analyzed extensively for the future success of giant miscanthus. "Another issue that is often discounted is whether giant miscanthus may become invasive," he says. "People, who suggest caution in this regard, are painted as being obstructionist. Any time someone tells me that we don't have time to be careful my discomfort level goes up a notch or two. There are good reasons to work toward biofuel alternatives; this new and developing technology will certainly provide good jobs and profits to those involved. However, until we are willing to accept the responsibility for associated risks I don't think we can go �all in' on this."

As long as the proponents are mainly focused on profits and are unwilling to shoulder the risks, or adequately address them, it is a gamble, Spencer adds. "It's a lot like gambling with someone else's money-there's little need to be risk averse when it doesn't cost you anything to lose. Being thoughtful and thorough in the collection of data about a system's risks and benefits is far less costly than acting in haste and paying to clean up a mess down the road."

Fueling the Future

Developing new crops is never easy but miscanthus does have an advantage as a bioenergy feedstock-the Biomass Crop Assistance Program. Gutterson says he thinks programs such as the federal BCAP are essential in helping the industry get on its feet, but it needs to be extended. "Our view is that any program that is important to help an industry get on its feet shouldn't last for 20 years, but BCAP needs to be available longer than its current [duration, which is 2012]. I think if it's available out to 2016 or 2017, it will get the industry over the hurdle. At this stage, where there's a lot of speculative production and a pretty high cost of establishment, BCAP is essential to get this moving."

As always the industry struggles with its chicken and egg dilemma of what should come first the feedstock or the facility. "By the time the cellulosic ethanol people are ready, the [feedstock] needs to be here," Jennings says. "There's no reason to build the facilities until you have the [feedstock]. Our government has somehow gotten one ahead of the other-the area we need help in is the feedstock. Once we get that done, then the facilities will come. It's backwards to get these facilities up and then figure out what to feed them." BIO

Anna Austin is a Biomass Magazine associate editor. Reach her at [email protected] or (701) 738-4968.