NORMAL, Ill. — Suggestions for overcoming today’s soybean production challenges, including “stressing” plants to produce more pods in certain situations, were front and center of a presentation by Crop-Tech consultant Ken Ferrie at the 2013 Illinois Soybean Profitability Summit.

During his presentation before hundreds of farmers, Ferrie predicted outstanding early production for soybeans in many regions of Illinois this year, due to residual nitrates left in soils following the 2012 drought, among other factors. But the focus of his talk was on overcoming new and historic challenges to profitability.

One historic challenge to soybean growers, Ferrie noted, was the number of herbicide rescue applications farmers had to employ to control late weeds in Illinois soybean fields during last summer’s severe drought.

“Knowing when you can burn a bean with a herbicide and when you can’t” made a big difference for producers in 2012, he told farmers. In fact, soybean yields could increase from pod stress under certain conditions.

“As we deal with more and more Roundup (glyphosate) resistance, we had to go back and clean some fields up (in 2012).  Because of the tough growing conditions we couldn’t close the rows, and we went to a lot of wide-row beans. Those wide rows had left us open to the possibility of late weed escapes,” Ferrie said of growing conditions his relatives – along with many Midwest soybean producers – faced last year.

“As these beans were stunted in the drought, it allowed for weed pressure. We did a lot of late-rescue applications, cleaning up waterhemp mainly, but can we do that without causing yield losses? When can we burn the bean? When you burn the bean, you’re going to trigger some stress. But in a lot of our plots we can actually increase yields by stressing the bean.”

Ferrie explained stressing soybeans in their vegetative stages triggers the release of a growth hormone to attempt to compensate for the stress. The process can actually serve to put on more nodes and, in turn, more beans, and often results in a yield increase.

Studies conducted since at least 2001 have confirmed the effectiveness of stressing soybeans with late-rescue applications of herbicides. Ferrie displayed results from some of the oldest and most recent studies on a large overhead projector during his presentation.

“What effect does this have on yield? You can see as much as a six-bushel yield advantage by tickling the soybean at the right times,” he said. “Looking at the growth stages of the bean plants, (in 2001) for the most part if we sprayed by (growth stage) R4, we had a yield increase.”

More recent studies, however, seem to suggest spraying no later than the R3 stage. “Any time you stress a soybean in the vegetative stage you’ll delay it’s maturity. When you stress it at the reproductive stage, you speed it up,” said Ferrie, adding that stressing soybeans already under stress from spider mites, aphids or other sources “works against you.”

He also advised that different varieties of soybeans such as “straight-line” or “bushy” will react differently to stresses such as late-rescue applications of herbicides.

For professional advice on stressing soybean plants to increase production, and other tips on increasing production, visit with an agronomist or crop consultant. Ferrie, who is co-owner of Crop-Tech Consulting in Heyworth, Ill., can be found at www.croptech consulting.com