Some soybean crops in Saskatchewan are struggling to make the minimum protein
by Lyndsey Smith
No matter what the crop, the quest for protein comes at the expense of yield. That said, some Prairie soybean growers struggled with harvesting soybeans that achieved an acceptable protein level for buyers even when yields have not been impressive.
There are several unknowns currently under review, but here is what we do know — the closer you farm to the equator, the higher the protein content of soybeans. That is not likely incentive enough to pack up and move south, but it does offer us the first clue in the protein problem.
“Unfortunately, we have more questions than answers on why some soybean crops are not achieving the industry standard,” says Glenda Clezy, Agronomy Specialist with Saskatchewan Pulse Growers (SPG).
If you compare with the traditional soybean growing area in Canada — Southern Ontario — average protein content drops as you move north and west. “It leads us to believe that (low protein) is the result, in part, of environmental factors,” she says. These less traditional soybean growing regions also use short to very short season varieties which may be another factor.
Garry Hnatowich, Research Director for the Irrigation Crop Diversification Corporation, says that, very likely, it is all of these things and more working in combination.
Developing shorter season soybean varieties that will actually mature in Western Canada has been an impressive achievement of plant breeders. A breeding program focused on bringing one major trait forward has to do so with several other factors, yield being the biggest. Yield and protein always exist in an inverse relationship, and the same is true for soybeans.
“We bred for short season beans. Is the maturity shutting the plant down before the line is fully able to put protein into the seed? That is possible,” he says. Breeding for higher protein potential is likely the biggest factor in success, but that is a long‑term game.
That said, Hnatowich is not sure there is not another agronomic factor at play — that perhaps the window between nodulation and maturity is just too small to get adequate nitrogen fixation. Could the rhizobia bacteria strains used to inoculate soybeans in Saskatchewan be good, but not quite what is needed for the compressed, cooler growing season?
“My gut tells me we can address this challenge agronomically,” he says, “but the increases are probably incremental and not enough to get us to high protein levels.”
All About That Nitrogen
Protein is roughly 16 per cent nitrogen. It makes sense, then, that agronomic management of nitrogen has been a major focus when addressing this seed-protein challenge. Recent research funded by SPG has shed at least some light on the subject, but the findings are preliminary.
Chris Holzapfel, Research Manager for the Indian Head Agricultural Research Foundation, says he is still crunching through the 2017 data, but a few interesting findings from the 2015 and 2016 data have popped up.
For starters, what is good for yield is generally good for protein, says Holzapfel. Proper inoculation is key. In the trials, all seed was treated with liquid inoculant, and dual inoculation showed to have an advantage when talking final protein numbers. He cautions, however, that the response was not necessarily an economic one.
“Environment itself seems to be important with overall averages ranging from 3.3 per cent to 6.3 per cent nitrogen (about 19 to 36 per cent protein),” he says. The low end of that scale was at Outlook in 2016, but it is a bit of an outlier, he says possibly
because it was a wet, very high-yielding year. Interestingly, this was the only site with previous soybean history and also the only site where we did not see a yield benefit to dual inoculation, he says.
Starter nitrogen either had no effect on protein or a slight, but significant, negative effect, says Holzapfel, but it was never beneficial. There were no yield benefits to starter nitrogen either, according to the research.
When looking at adding late-season nitrogen, the study suggests that when nodulation is poor, late-season nitrogen sometimes increased yield, but had inconsistent effects on protein. One year (2015), there was no effect at the Indian Head site, but it did offer a slight increase in protein at the same site in 2016.
New Crop, New Challenges
Hnatowich, who has been involved in the multi-site soybean research, says that results suggest that either nitrogen is not available to the plant or is there but is not being turned into protein. Hnatowich suspects this is a factor of that compressed season.
“Soybean is where canola was 30 years ago,” he says. “We have only recently grown enough acres to really even get a sense of what the challenges are in growing the crop.”
Sound agronomic practices are the baseline for what this crop can do, but Hnatowich says there is a complicated interplay between existing varieties, Saskatchewan soil and climate conditions, the length of the growing season, and more. “Soybean is still a new crop for Saskatchewan. When North Dakota began growing soybeans, their farmers struggled with achieving high protein, too,” he says.
“It is a matter of matter of exploring all factors together. We need the breeding component, the agronomy, the inoculation question, all of it to be looked at together,” Hnatowich says. “It is a long‑term, big‑picture challenge that will require a coordinated approach to solve.”