Written By: Bruce Barker
Roundup Ready soybeans have long ruled the roost in Canada and the U.S., but more and more growers are turning to LibertyLink soybeans – primarily to help manage herbicide resistance. All things being equal, including yield, that trend may develop in Western Canada as well.
“We started to move to LibertyLink® soybeans a few years ago in response to glyphosate resistant weeds developing. We wanted to have an alternative mode-of-action in our rotation,” says Andy Beyer, of Beyer Seed Farm, Kent, Minnesota. “It works for us to do that.”
Beyer grew several LibertyLink soybean varieties in 2015, including NS0801NLL and NS0571NLL. While these NorthStar Genetics varieties have longer maturity than recommended for Western Canada, NorthStar Genetics has one suitable variety, NSC Mollard LL. NSC Mollard LL is a 2450 CHU (00.6 relative maturity) variety with a branchy plant architecture, very high IDC score, and mid-tall height with high pods for an easy harvest.
Beyer says he isn’t giving up any yield by moving to LibertyLink soybeans. The LibertyLink varieties have been his two best yielding varieties in each of the last four years.
At Drayton, North Dakota, Roger Weinlaeder of Weinlaeder Family Farms and Weinlaeder Seed Company has grown LibertyLink soybeans for the last five or six years. He also says yield is a primary motivation for growing LibertyLink soybeans.
“The number one reason is that the genetics in LibertyLink soybeans are excellent. They yield as well as any other Roundup Ready 2 soybean variety that we have grown,” says Weinlaeder. “If we grow both, LibertyLink stays with the Roundup varieties, and most of the time wins. That translates into more revenue per acre.”
Like Beyer, Weinlaeder also likes LibertyLink soybeans as a means to rotate to different chemistries to manage herbicide resistance. Glyphosate resistant weeds are becoming common across the U.S., including in the Midwest where palmer amaranth, tall waterhemp, common and giant ragweed, hairy fleabane, horseweed, and kochia, among others, have been identified as having glyphosate-resistant biotypes. In Western Canada, kochia resistance has been identified, and horseweed (Canada fleabane), common ragweed, waterhemp, and giant ragweed-resistant biotypes have been found in Ontario.
“Glyphosate resistance is occurring everywhere around the world, and we know there are some resistant weeds in the county. Our approach is to try to deal with it before it becomes a problem,” says Weinlaeder.
Dennis Lange, a pulse crop specialist with Manitoba Agriculture, Food and Rural Development (MAFRD) at Altona, Manitoba, says LibertyLink soybeans could have a fit in Manitoba, depending on the variety performance and crop rotation. In rotations with Roundup Ready canola, Lange says a LibertyLink variety could be a good fit for managing herbicide resistance, while also providing an opportunity to control Roundup Ready volunteer canola.
“If Roundup Ready crops are in your rotation, then a LibertyLink soybean may make sense,” says Lange.
David Kikkert, manager of soybean seeds and traits with Bayer at Guelph, Ontario agrees with Lange’s assessment on how LibertyLink soybeans can fit for Western Canadian growers. It can be a valuable tool as a rotational option for managing herbicide resistance, but only where it fits in with farmers’ cropping plans.
“If you are growing LibertyLink canola, our recommendation for managing herbicide resistance is to stay with LibertyLink canola and use a Roundup Ready soybean if soybeans are following your canola crop,” says Kikkert. “But if you have other Roundup Ready crops in your rotation, LibertyLink soybeans can be a good fit. Growers should also use additional pre- and post-emergent herbicides no matter what trait system is being used for more than one herbicide group coverage.”
Glufosinate, the active ingredient in Liberty herbicide used in the LibertyLink system (In Canada: Liberty 200 on soybean and corn; Liberty 150 on canola), has the same herbicide resistance development risk rating as glyphosate, which is low. While only Italian ryegrass has been found to be resistant to glufosinate in an Oregon orchard in the U.S., the potential of further glufosinate resistance is a real possibility. Likely the reason more glufosinate resistance hasn’t developed is that LibertyLink technology isn’t used nearly as intensively in crop rotations as Roundup Ready technology that has traditionally been used every year in the U.S. Midwest in a corn-soybean rotation, and glyphosate in pre-seed, pre-harvest, and post-harvest applications.
“The concept of managing herbicide resistance applies to LibertyLink and Roundup Ready crops. You want to rotate crops, herbicides, trait technologies, and have more than one herbicide group as much as you can to preserve the effectiveness of the technologies for as long as possible,” says Kikkert.
Weed control considerations
Looking at weed spectrum and effectiveness on weeds, glufosinate and glyphosate have different strengths and weaknesses. In Western Canada, glufosinate is known to be strong on broadleaf weeds, but a tank-mix is often added to boost grassy weed control. Conversely, glyphosate is strong on grasses, perennial weeds, and most broadleaf weeds, but needs a bit of help on wild buckwheat and kochia.
At Kent, Minnesota, Beyer has his weed control program dialed in on soybeans. He uses Valor herbicide (flumioxazin) pre-emergent over top all of his soybeans – Roundup Ready or LibertyLink – a day or two after seeding. Flumioxazin is registered on soybeans in Western Canada as Valtera. Valor provides four to six weeks of residual weed control of a wide spectrum of broadleaf weeds including water hemp and Palmer pigweed. In LibertyLink soybeans, he sprays Liberty 280 herbicide twice. The first when the beans are about four inches high and the second just before the crop goes into bloom.
“The biggest trick with Liberty  is to use 20 gallons of water and AMS [ammonium sulfate] additive to help with coverage. We also spray in the middle of the day when the sun is out and the plants warmed up,” says Beyer. “We’ve found way better success with this approach.”
Lange says most Western Canadian growers are familiar with Liberty weed control. In canola, he says many growers add a grass herbicide such as Centurion or Select (clethodim) to Liberty 150.
While Pursuit, Basagran Forte, FirstRate, Excel Super, and AMS are registered tank-mixes with Liberty 200 in Eastern Canada on soybeans, only the Liberty 200 + AMS tank-mix is registered on soybeans in Western Canada. Bayer does recommend a Group 1 herbicide tank-mix with Liberty on soybeans; speak to your Bayer representative for further information.
Why so few choices?
With NSC Mollard LL just entering the Western Canadian market, the question begs to be asked. Why has it taken so long? LibertyLink soybeans were just commercially launched in 2009 after global clearances were obtained, with the first variety introduced in 2010 in Canada. Kikkert says Bayer also approached the soybean market differently than canola where the company established its own breeding program. LibertyLink soybean technology was licensed out to MS Technologies at West Point, Iowa. Once LibertyLink germplasm is developed, it is broadly licensed out to seed companies like NorthStar Genetics for production and marketing.
Kikkert says getting LibertyLink soybean varieties into the Canadian market is a slower process. Plant breeders mainly focus their efforts on the biggest markets first. In Eastern Canada, six LibertyLink varieties are on the market, although that is substantially less than the choices available to growers in the U.S.
“One of the challenges with LibertyLink soybeans in Western Canada is acreage. We have smaller acreage, so less effort has been put into breeding 00 and 000 maturity beans, although we are starting to see some new germplasm coming, especially as acreage increases in these earlier maturity groups,” says Kikkert.
Lange says whether LibertyLink soybeans catches on in Western Canada will hinge on the yield performance and maturity of introduced varieties. He tested NSC Mollard LL a few years ago.
“From what I’ve seen, the yield potential looked pretty good. Maturity was in that mid-season zone. It will be interesting to see how it does,” says Lange.