Features Agronomy Corn
Bin-busting corn yields in Manitoba

Grain corn has come a long way in the Keystone province.

Grain corn in some Manitoba fields now can average more than 150 bushels per acre. Photos courtesy of John Dietz.

Grain corn is getting better and better in Manitoba, in reliability and yield, according to the Manitoba Corn Growers Association. In fact, their annual production contest suggests it is possible to find bin-busting 250 bushel per acre (bu/ac) yields in some fields, without irrigation. Meanwhile, dryland no till corn growers 400 kilometres south win the North Dakota association’s yield contest with ‘only’ 202 to 207 bu/ac yields.

Why the discrepancy?

In the 2007 MCGA contest, McKnight Farms at Roland, Man., achieved a 248 bu/ac yield. It was the second highest recorded in 37 years of competition. In fact, all 10 MCGA finalists had marks of more than 215 bu/ac. McKnight Farms, using an old conventional John Deere 7000 corn planter, even beat North Dakota’s best ridge till production by almost 26 bu/ac.

The story lies in the fine print.

The two well established and similarly named events have different rules.

The North Dakota event measures production on 1.25 acres within a selected five acre plot; the Manitoba event measures yield on two adjacent, carefully selected, 50 foot rows. The North Dakota reality is that grain corn growers on dryland, in the southeast corner, are getting 140- to 150-bushel whole-farm averages, including marginal acres, says Tom Lilja, executive director, NDCGA.

Their best full-field yields are logging about 180 bu/ac on dryland.

Manitoba grain corn is coming on strong as an important crop in the Red River Valley.

Big yield increase
Theresa Bergsma, MCGA secretary-manager, estimated Manitobans planted 210,000 acres of grain corn in 2008. It was the highest planting level in recent years and a modest increase 2007. She estimates the number of corn growers, between grain and silage in Manitoba, is between 800 and 1000. “I don’t think we’re ever going to match up with Ontario or Illinois on their good years, but we’re seeing now more than 100 bushel provincial averages on a regular basis,” she says. “When I started, it was great when we got to the high 70s. Now, a couple times, we were higher than Ontario, when they had poor years.”

While McKnight was racking up a 250 bushel yield on a short strip in ideal conditions, whole fields and neighbour’s fields also were doing very well.

According to Manitoba Agricultural Services Corporation corn statistics for 2007, the 10 municipalities in the prime growing region averaged yields of 126.23 bushels per acre. On the west side the Red River, the Regional Municipality of Rhineland (Altona, Gretna, Plum Coulee) reported average yields from 128 to 157 bu/ac. In more detail, Rhineland had 192 farms growing 25,800 acres of grain corn by MASC records in 2007, using 15 corn varieties from Dekalb, Hyland, Pioneer and Quarry. One third grew Pioneer 39M27 with Bt tolerance. It yielded an average 140 bu/ac on 11,534 acres, about 40 percent of the corn acres in the RM.  

Those big yields are mostly occurring on farms with lots of corn history, Bergsma says. “I wouldn’t want a farmer beginning to grow corn to count on 110- to 120-bushel yields; corn is not the easiest crop to grow.”  In her 20 years with the MCGA, Bergsma says provincial average grain corn yields have increased at least 20 to 25 per cent.

Reliability also has increased. “In the 1980s, we could count on a blowout year every four to six years; we’d have a huge difficulty and lose a large part of the crop. The 2004 loss was the only time in 10 years.”

The 2008 crop is a prime example reflecting the improvements in varieties and management. She knows of farmers who sowed corn in late April and saw it emerge successfully four weeks later, once the ground had warmed and dried. “Ten years ago, that stuff would have been rotted and gone, but the new cold-tolerance production is really just making it better,” she says.  

Better technology
Harry McKnight planted the yield winning crop in 2007, 1999 (177.01 bu/ac) and 1996 (231.06 bu/ac). “Dad started growing corn in the 1960s. He and two other gentlemen from southern Manitoba, I think, were the pioneers of the corn industry in Manitoba,” he says. “There’s nothing special about our corn planter, except that we do have a liquid kit and we put down 7.5 U.S. gallons of 10-34 right on top of the seed when we plant. But, we’ve been doing that since the 1980s.”

The McKnights started working with GPS in 1989. They began using Real Time Kinematic (RTK) guidance in 2007, and have their own differential signal. Yield and elevation maps help them with field drainage, while soil tests and yield maps guide them with fertilizer management.

The big edge with RTK and autosteer, he says, is efficiency. “The most dramatic effect probably is that we spend less time on the field. We’re more efficient. We use less fuel, we don’t overlap. Our crop rows are straighter and no longer require any mechanical guidance. I know my equipment better now because I can turn around and watch it, see what’s happening with it. You catch problems sooner and you have less wrecks out there,” McKnight says.

He chooses three or four of the more than 50 grain corn varieties now available, and makes new choices each year. His farm, in Roland and Dufferin municipalities, is rated for about 2300 to 2500 corn heat units. His winning sample in 2007 was from Pioneer 39D97, a new line with added genetic traits for Bt, Roundup and Liberty-Link. It was his first year for using that line. “You have to be a little cautious with that variety. We watch heat units. We have about half our acres in a variety that we feel will make it, for heat units.” McKnight says Bt technology is the best he has seen in his lifetime and glyphosate-tolerance is “a beautiful way to control weeds in corn that couldn’t get any better.”

When he selects his site for the yield contest, he usually picks a few sheltered rows beside a yard. “I just look around the yard sites, basically; that’s where your heat units are. The corn next to your yard, as long as the trees aren’t robbing the nutrients, is where your best corn will be.”

The hand-selected rows probably will yield 50 to 75 bushels more than the yield maps will show later, and maybe 100 bushels more than the whole farm average. He says, “I think our whole farm average now is about 140, and that’s exceptional.”