Soybean yields: plateau or grow?
By Top Crop Manager
Is management the issue that holds back growers?
According to data gathered in Ontario, corn yields have increased an average
of 1.5bu/ac in the past 15 years. While that is great news for the corn sector,
some use it as a reflection of yields and management practices in Ontario's
In large part, growers have maintained corn acres across the province during
the early to mid 2000s. This in spite of rising surpluses that have depressed
prices. Yet, the reported yield increase has Cargill AgHorizons field agronomist
Pat Lynch asking why soybean yields are not rising at the same rate.
Lynch looks back on 2001 when agronomists and advisors adopted various approaches
to boost corn yields. "We said, 'We need corn in Ontario; we're importing
the stuff and we should be self-sufficient'," explains Lynch, who speaks
to growers across the province each year. "Probably the biggest thing was
collectively agreeing to plant early, and by planting earlier we have raised
A similar trend took place in the 1970s when George Jones established a set
of practices to show continuous corn could be economical. Lynch wonders why
the same approach has not come forward with soybeans. "When I see the type
of things that are going on in the soybean field, we still have that 1960s to
'70s attitude, where things haven't changed and there's been no leading force,"
he says, adding that soybean seed still is sold by the pound, not by seed count.
"It's the mentality of 'Oh well, it's the soybean crop, it's the ugly sister
and maybe nobody will notice that we're not paying it any attention'."
What Lynch would like to see is a collaborative approach within the soybean
sector similar to the 2001 effort in corn. "We need a group to look at
the best practices to increase yield while growing soybeans under continuous
soybean conditions," says Lynch. Issues such as early planting, certified
seed, seed treatments and improved scouting could be addressed through the group.
Another factor that could detract from advancing yield is dissension in the
ranks. Disagreements between agronomists, company representatives or government
extension personnel are fine, but not in public. "When I look back at what
we did with forages, intensive cereal management and corn, we all got together
and if we disagreed, we did it behind closed doors," says Lynch. "We
did not bring these out into the media to show the dissension among the different
people working on the same crop, and that attitude probably has to change if
we're going to go forward with this soybean crop."
One aspect that might benefit from a united front would be seed treatments.
In corn, they are a part of the cost of the crop. But with soybeans, notes Lynch,
chemistries that are standard in the US are being delayed for registration in
Canada, with no apparent reason. "With some of the products they have in
the US, if we stuck together, we could be forcing the federal government to
allow these products into Canada," says Lynch.
Crops and practices too varied
However, others interested in advancing soybean yields insist significant progress
is being made. According to Horst Bohner, soybean specialist with the Ontario
Ministry of Agriculture, Food and Rural Affairs, there are certain unique qualities
that must be acknowledged when considering changing management practices. For
- soybeans are being challenged by newer and more diverse pest and weed species;
- a soybean seed is composed primarily of oil and protein, which require more
energy to produce. In corn, the main component is starch, which requires less
- the varietal choice in soybeans has escalated in the past decade –
from 20 to 30 to more than 250;
- more of the public sector's research initiatives have focussed on enhancing
specific traits in soybeans (like fatty acid profiles, isoflavones), lending
itself to more work on quality issues;
- the soybean sector has been working within identity preservation (IP) protocols
for decades ahead of corn or wheat.
Yields not dropping
As far as any stagnation in provincial soybean yields, Bohner counters talk
of a yield plateau, noting the steady incline in long-term averages. "It
all depends on the number of years you look at, and whether there's even a yield
plateau is a point that can be debated," he says, noting there are many
who insist yields of the past 10 to 15 years are insufficient to make long-term
"We are making significant progress because when you plant a variety of
30 years ago with one of today's, there's no comparison. The average provincial
soybean yield for the 1970s was 30.9bu/ac. For the '80s it was 34.5, for the
'90s it was 38.3 and I expect this trend will continue for the present decade,
and the vast majority of these yield gains are due to plant breeding."
Yield increases not uniform
Another point Bohner raises on the yield plateau issue is the impact of the
migration of Ontario's soybean crop. "In the newer soybean growing areas
to the north and east of London, breeding has brought us better yields at faster
rates while further south and west, yields are still up but not at the same
rate," he says.
On the subject of early planting, Bohner notes emergence is of vital importance
but that the trend overall is to continue to challenge that late May planting
recommendation. "Once soybeans are out of the ground, things usually aren't
that bad," says Bohner. "But I would also make the argument that 15
or 20 years ago, there were still a lot of people who wouldn't consider beans
before the 24th of May or even into June. Today, the most consistent yield response
is planting before the middle of May."
Roundup Ready has hurt progress
Another issue seldom considered is the popularity of, and over-reliance on,
Roundup Ready technology. "It's been great for production in some ways
but in others, it's hurt us, because we don't do a good enough job on weed control
because we leave the weeds too long," says Bohner. "And the breeding
and back-crossing of Roundup Ready slowed us down for a while, but we're passed
that point, too."
When referring to back-crossing of developing new traits and varieties, Lynch
maintains universities and ministries should be training new breeders. Varietal
development should be left to private companies instead of using taxpayer dollars.
But worse still is the perception that government must use those same funds
to protect farmers from 'big business'.
"Farmers are a highly intelligent group of business people and they do
not have to be protected from agri-business," says Lynch. "Who's protecting
the public from the unscrupulous people in the equipment industry, the insurance
industry and the housing industry? Why do we have this group in crop production
that believes they must protect the public?"
Choice and opportunity for smaller companies
The issue is not one of protection for Dr. Istvan Rajcan but of grower's having
more choice. In the past decade, breeders from universities or government have
basked in the success of varieties like OAC Bayfield. For smaller companies
that cannot afford their own breeding programs, that is a vital service.
"We have continued to develop new varieties, making crosses between the
best parental lines that we could get our hands on, including varieties from
public and private breeding programs," explains Rajcan, soybean breeder
with the University of Guelph's Department of Plant Agriculture. Since the late
1990s, he has gathered germplasm from Croatia, Argentina and China and incorporated
them into his program. "We're still capable of releasing high quality,
high yielding varieties, but we are not in the business of seed sales. The varieties
that we develop always wind up in the hands of the private companies."
Since the release of OAC Bayfield, a number of even higher yielding varieties
has been released by breeding programs from University of Guelph or Agriculture
and Agri-Food Canada. "One clear example is OAC Wallace that has topped
the 2600CHU charts four years in a row now," says Rajcan. To look at any
CHU zone, a grower would find publicly developed varieties are among the top
of any table, so why would growers want to stop that trend?
As for suggesting university or government breeding programs favour traits
ahead of yield, Rajcan and Bohner insist otherwise. Yield is and always will
be important. "Even with a tofu variety or an IP variety, you still want
the best yielding," says Bohner. "You'll get clobbered on a production
level unless you put your trait into a very high yielding bean."
For Rajcan, yield is seldom mentioned in research proposals for groups like
the Ontario Soybean Growers. "Yield is implied but it's not really spelled
out as a major objective," says Rajcan. "And it's not been easy to
get funding by just mentioning yield alone. We've always been aware that yield
is what the farmers get paid for, and we canÕt sacrifice yield for a novel trait
that we incorporate." -30-