Features Agronomy Soybeans
Soybeans look promising in Saskatchewan

It was not that long ago that soybean acreage started to creep up in Manitoba from about 800 acres in 1996 to around 350,000 acres in 2007. Will the same happen in Saskatchewan? Adequate moisture and heat units will be the limiting factors in soybean expansion into Saskatchewan.

Elmy was able to harvest soybeans on October 2, despite a lack of heat units. Photo Courtesy Of Friendly Acres Seed Farm.

Kevin Elmy, of Friendly Acres Seed Farm at Saltcoats, in east-central Saskatchewan is big on the potential of soybeans. He grew 240 acres in 2007 in an area where many doubt that soybeans can be successful. “Most people say that you can’t grow soybeans in Saskatchewan,” says Elmy. “To average 24 bushels per acre in a year like we just had, I’m excited about their potential here.”

Soybeans like hot and wet weather, and for Elmy in 2007, that meant he was batting one-for-two. The season started off with plenty of rain in May, and his soybeans went into the ground on May 27 and 28. June was rainy, cloudy and cool. July was more favourable with some heat, and then August came back with cool, wet, cloudy weather. In total, Elmy received a little more than 2000CHU, 1300 growing degree days (GDD) and 15 inches of rain from May 27 to September 20 – not exactly great soybean weather.

Even more surprising is that the variety Elmy grew, LS0036RR from Quarry Seed, is rated at 2425CHU. With that type of rating, maturity should have been an issue, but Elmy was able to start combining on October 2.

Part of the reason that Elmy harvested a mature crop may have something to do with photoperiod (daylight) sensitivity. Ron Gendzelevich of Quarry Grain Commodities in Stonewall, Manitoba says that some soybeans react differently when grown in different regions. “What we have found is that as you move varieties from one area to another, they respond differently to daylight hours,” Gendzelevich explains. “A variety with a CHU of 2425 should not mature here, but if it is daylight sensitive, that seems to make the difference.”

Manitoba Agriculture, Food and Rural Initiatives’ (MAFRI) Bruce Brolley says there is something to photoperiod sensitivity. He explains that soybean plants will start to flower once the days start to shorten (after the summer solstice) with open flowers seen on the plant in early July (5 to 10). However, soybean flowers that are fertilized much beyond mid August have a slim chance of maturing before the killing frost.

“Soybeans can have photoperiod sensitivity at two stages. The first stimulates flowering, and the second is late in the fall during September when the plant starts to mature,” explains Brolley. “If they are photoperiod sensitive, they can finish filling pods that are mostly filled (late R6 stage) while other insensitive varieties just seem to stall and not advance in maturity.”

Brolley has seen a 2500CHU variety normally suited for the Morris area of the Red River Valley successfully grown northeast of Winnipeg at Beausejour. In another example, he brought up four varieties from the US and compared them in trials. In the US, all were within one day of maturity, but in Manitoba, three were very late maturing but one was mid season maturing several days earlier than the other three.

Another factor that may be at play is drought stress-induced maturity. Brolley says that in trails at Outlook, Saskatchewan, the dryland plots always mature before the irrigated plots. Of course, in normal years, dryland plots have lower yields than irrigated trials. There is also a relationship between early maturity and lower yields.

The University of Saskatchewan Plant Sciences Department has a small screening program to help assess soybean performance in Saskatchewan. Tom Warkentin says their emphasis is on early maturing varieties, and the University of Saskatchewan has plots at Saskatoon, Rosthern and Oxbow.

Kevin Elmy sees potential for soybeans in Saskatchewan. Photo By Bruce Barker.

Good agronomics help
Gendzelevich says that as soybeans move into different regions, agronomics evolve. When soybeans were first grown in Manitoba, the crop was seeded at 160,000 to 180,000 plants per acre, which was the recommended rate for row crop soybeans. Now, the recommended rate for solid seeded soybeans is a minimum of 200,000 plants per acre. Elmy targeted 220,000.
Elmy seeded with a Bourgault air-seeder on eight inch centres. Because the soil was wet, he used shovel openers and harrows for packing. Seeds were placed one inch deep with a four inch spread in the shovel openers. Normally, he would have seeded with 1-3/4 inch hoe openers.

Elmy conducted several strip trials to help assess different agronomic practices. He seeded the soybeans on summerfallow, alfalfa stubble, winter wheat stubble, oat stubble and soybean stubble. He also compared several different inoculants and seed treatments.

The best yields came from soybean stubble, which ran 35 bushels per acre. Next came oat stubble 24. Summerfallow yields varied on two different fields. One field ran 28 and the other 16. Elmy explains that the lower yielding summerfallow field is a silty loam soil with a waterway in it, which kept the soil cooler and delayed maturity. Alfalfa stubble yielded 21 bushels per acre, winter wheat stubble was 19 bushels per acre.

“Winter wheat was the worst because it had heavier trash, which kept the soil cooler,” explains Elmy. “We think the soybean stubble yielded the best because of the rhizobia in the field from the previous year.”

With inoculants, Elmy compared liquid Apex Pro to TagTeam granular, and also included a dual inoculation with the liquid and granular inoculants. Non-inoculated soybeans on canola stubble yielded 11 bushels per acre. A single inoculation of either Apex Pro or TagTeam ran 22 bushels per acre. When both Apex Pro and TagTeam were used in a dual inoculation, the yield was 32 bushels per acre.

Elmy also tried a Cruiser Maxx seed treatment because previous trials at Oakville, Manitoba had shown a four to five days earlier maturity and a small yield advantage. Cruiser Maxx is an insecticide/fungicide seed treatment combination that protects soybeans from a wide range of seedling diseases and insects. While Elmy did not see a maturity difference in 2007, Gendzelevich says that Cruiser Maxx may still be a good idea from a disease management perspective.

“Cruiser Maxx somehow tricks the plant into a stress reaction so that it grows faster and stands better,” says Gendzelevich. “But it also helps with stand establishment. If you plant 220,000 plants per acre of treated seed, you’ll get close to that type of emergence. But without Cruiser Maxx, your stand might drop to 150,000 to 180,000 plants per acre. So there is a definite benefit just from a stand establishment perspective.”

The no-inoculants check strip was clearly evident. Photo By Bruce Barker.

Economic returns bettered canola
While Elmy’s soybeans average 24 bushels per acre, his canola averaged 23 bushels per acre. He calculates his net revenue from soybeans at $118.50 per acre compared to $81.50 for canola.“With the price of fertilizer going up, that makes soybeans look even better. And the net revenue doesn’t even take into consideration the nitrogen rotational benefit for next year’s crop,” says Elmy.

Elmy estimates that in a normal fall, his yields could have reached as high as 40 bushels per acre. In 2007, he seeded 10 days later than he had hoped to, and his CHU rating was 10 percent lower than normal.

As a final word to Elmy’s optimism for soybeans, he plans to seed at least 390 acres in 2008, and if the price of fertilizer keeps going up and soybean prices remain strong, he would consider seeding 600 acres of his 1400 seeded acres to soybeans. -end-