“I think farmers can do a real good job with what they’ve got – a 30-inch corn planter or their air seeder. They just need to look and decide how they can tweak it.”
– BRUCE BROLLEY, MAFRI
Planting soybeans in 15-inch rows instead of solid seeding will cut farmers’ seed costs and boost yields, but whether it pays to buy a new row crop planter depends on each farmer’s circumstances, according to the province’s pulse crop specialist.
“The long and short of it is both an air seeder and row crop (seeder) will work,” Bruce Brolley said in an interview March 26. “To invest in more iron you need to be getting a lot of yield or have more uses than just soybeans.”
Most Manitoba farmers seed soybeans with air seeders. And those using planters mostly seed in 30-inch rows, Brolley said. With seed costs increasing, farmers are looking for ways to save money, including cutting seeding rates if possible.
The recommended plant population for solid-seeded soybeans in Manitoba is 200,000 plants per acre. It varies from 160,000 for soybeans planted in 30-inch rows to 175,000 in 15-inch rows – a 12 to 20 per cent reduction in seed versus solid-seeded fields.
“That’s a cost saving right there,” Brolley said.
“With 15-inch rows you probably have a little higher seeding rate (than 30-inch), but you’d have more yield. At $8 a bushel it doesn’t take many bushels to justify the cost of extra seed.”
What’s harder to justify is spending big bucks on specialized seeding equipment if what’s being seeded represents only a small portion of one’s overall plantings. It makes more sense for farmers who grow large acres of corn and edible beans, as well as soybeans.
Thirty-inch corn planters do a great job evenly distributing seed within the row. Growers can cut their seeding rate by up to 20 per cent from solid seeding. But yields from fields seeded in 30-inch rows yield about the same as solid-seeded fields.
“The shorter-season soybeans grown in Manitoba don’t have enough growth to fill in between the 30-inch rows” Brolley said. “With 15-inch rows you’re going to get that complete row closure.
“The more sunlight soybeans can capture the more yield you’re going to get so we’re losing yield growing 30-inch rows.”
But the saving on seed alone makes planting with a 30-inch row crop seeder better than seeding with an air seeder, most of the time. There are exceptions, including the last two springs when many fields were too wet to support a corn planter but air seeders could get through, Brolley said.
EVALUATE AND ADJUST
While row crop seeders do a better job planting soybeans, air seeders can do a good job too, but they are often not as precise, Brolley said. Sometimes, two, three or more seeds will be too close together. When that happens some plants will dominate and others will behave like weeds. Normal-size plants will have 30 to 45 pods per plant; smaller plants, just eight to 10.
“If you can avoid the doubles, the triples and the big gaps, then you can cut down your seeding rate,” Brolley said.
Farmers need to check how well their air seeders distribute the seed within the rows, Brolley said.
“If they don’t make this evaluation, they don’t know they need to make adjustments to their seeder for next year,” he said.
Reducing seeding speed and using knives instead of shovel openers can improve seed placement too.
Not all air seeders are created equally. Some distribute the seed more evenly within the row than others.
“I think farmers can do a real good job with what they’ve got – a 30-inch corn planter or their air seeder,” Brolley said. “They just need to look and decide how they can tweak it.”
Manitoba Agriculture, Food and Rural Initiatives and the Manitoba Pulse Growers Association are running side-by-side demonstrations with row crop planters and air seeders this year. Farmers interested in participating can call MAFRI’s Brent Reid at 204-878-0317.
When soybean seed is cheap, higher seeding rates are good insurance, especially when seeding into cold, wet soils or in early June, which is later than desirable, Brolley said.
“We’re trying to reduce costs without sacrificing yield, but it is going to take work on the farmer’s part,” Brolley said.