After a bit of a false start this past spring, at least two Liberty Link soybean varieties will be available for 1999 planting.
Rick Mohan, soybean product manager for AgrEvo, says Croplan Genetics and Mark II both will have limited supplies of two late Group II varieties. There may also be a Group V variety for the Midsouth and Southeast.
Bob Hartzler, Iowa State University extension weed specialist, has observed Liberty Link soybeans in research plots for the past two years.
"Liberty Link may take a little better management than our historical weed control programs, in that some weeds are on the borderline of what Liberty can control, even at the 28-oz rate," he says.
Specifically, the problem weeds seem to be yellow foxtail and lambsquarter. Most others are controlled with 24, 20 and sometimes 16 oz, depending on the size of the weeds.
The label for Liberty, when used with Liberty Link soybeans, allows for two applications of up to 28 oz, or no more than 56 oz total for the growing season.
Hartzler says Iowa State weed researchers looked primarily at a straight Liberty program, rather than Liberty in combination with other herbicides.
"In our plots, control was very comparable to what we saw with Roundup Ready beans," he says, adding "we don't have a lot of yellow foxtail or lambsquarter in these plots.
"Liberty Link is a viable option, but I'd compare costs based on a couple of applications of something less than the full 28-oz rate," Hartzler advises. "For 1999, growers also need to consider whether the varieties available will be among the best-yielding for their area, since, in the end, yield is still more important than the herbicide program, providing costs end up being similar."