News Release
For Immediate Release — June 13, 2008
Herbicide Approved for Switchgrass
(Knoxville, Tenn.) - Growing grass got a little easier this week, as the Tennessee Department of Agriculture and the United States Environmental Protection Agency approved the use of herbicide AAtrex 4L for weed control in switchgrass that is grown for the production of biofuels.
“This is great news for the East Tennessee farmers that are growing switchgrass for the University of Tennessee Biofuels Initiative,” said Neil Rhodes, a plant sciences professor and UT Extension weed specialist at the University of Tennessee. “Switchgrass can be vulnerable to a variety of weeds in its establishment phase, so having an herbicide labeled for it will greatly increase the chances for a successful stand.”
AAtrex, made by agribusiness Syngenta, has shown to be an economical and effective option for providing residual control of many broadleaf weeds and some grasses. The new label allows for the broadcast application of AAtrex 4L at a rate of one to two quarts per acre after switchgrass has emerged.
The new label is a 24(c) Special Local Need Label, and it has been approved for East Tennessee counties that are likely to produce switchgrass for use in the region’s planned cellulosic ethanol biorefinery. Counties approved on the label include Anderson, Blount, Bradley, Cumberland, Hamilton, Knox, Loudon, Meigs, McMinn, Monroe, Morgan, Polk, Rhea, Roane and Sevier. Greene and Gibson counties were also approved for use due to ongoing research projects at the Greenville and Milan Research and Education Centers.
Despite growing robustly from its third year on, switchgrass is initially slow to establish and can be overrun by other grasses and weeds. For this reason, AAtrex has been approved for use on switchgrass in the establishment year and first year following establishment. Switchgrass that is treated with AAtrex cannot be grazed or cut for livestock feed.
In addition to AAtrex, UT researchers are pursuing other herbicide labels for switchgrass. Current possibilities include Accent, for its effectiveness against grasses such as johnsongrass and broadleaf signalgrass, and Paramount for combating crabgrass. “Ideally, we’ll soon have a system in place where we have at least one option for addressing each of the various grasses and weeds that can interfere with the successful establishment of switchgrass,” said Rhodes.
Switchgrass is a warm season perennial grass that is native to Tennessee. It was selected as the primary feedstock for the UT Biofuels Initiative because of its ability to produce large amounts of biomass, typically six to eight tons per acre or more.
More than 720 acres of switchgrass have been planted in East Tennessee in the past month. This is the largest amount of switchgrass in the country to be planted by farmers on their own private land using either their own equipment or equipment from a local farm supplier. After harvest, the switchgrass will be converted to cellulosic ethanol in the new biorefinery that’s being built as part of the UT Biofuels Initiative.
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Contact; Patterson Wilson, UT Office of Bioenergy Programs, (865) 974-5807, pattersonw@utk.edu
On the Web at www.UTbioenergy.org