Since the early 1990s, most producers have been gradually moving toward wider row spacing. Farmers have come to recognize the advantages of lower machine investment, less soil disturbance, plus the savings on diesel with the reduced power requirements.
But lately, wheat stem sawfly has altered those plans.
Producers who had grown comfortable with having their seed rows 12 inches apart now feel compelled to take a step backward to nine or 10 inch spacing.
Wide row spacing works fine when the straw is strong and the crop can be straight cut.
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But sawfly weakens the straw and forces the producer to swath, and the wide gap between 12 inch seed rows does not support a swath.
Producers who want to switch to wider row spacing because of economics and moisture conservation find themselves stuck with narrow row spacing.
Pat Beaujot knows the situation well. The Langbank, Sask., farmer is president and chief designer at Seed Hawk.
“I know it sounds backward, but the fact is that the demand for narrow spacing is actually increasing lately, despite all the proven advantages of wider row spacing.”
Beaujot said a farmer can save 20 percent on fuel by converting his drill from 10 inch row spacing to 12 inch. But if they need to swath again because of the sawfly, they need the rows closer than 12 inches.
The situation creates an obvious need for a low disturbance opener with a 12 inch spacing measured shank-to-shank, but a nine inch spacing measured row-to-row. Nine inches is close enough to support a swath.
Although the logical answer was some form of the tried and true paired row opener, Beaujot had reservations because of the size of such openers and the resulting soil disturbance.
“Seeding with a paired row opener is like dragging a football through your soil,” Beaujot said.
“It takes more horsepower. It consumes more energy and it leaves your field very rough. We didn’t want that. That’s contrary to everything we’ve been saying all along. But the idea of a paired row opener still made sense to us.”
A year and a half later, the Seed Hawk team had some small paired row openers that met their criteria.
“We slimmed it down as much as possible. It’s whittled down so it slices through the soil more like a knife, not a football.
“If you were to study the field surface after we passed with our regular side bander next to the new paired row opener, you’d have trouble figuring out which is which.
“I won’t say it’s a true low-disturbance opener, but it’s surprisingly close to what we now achieve with our side bander.”
Beaujot’s new Twin Wing paired row system is based on the same engineering as the original side band opener. The half-inch wide fertilizer knife is mounted on the same arm as the seed opener, but the fertilizer knife is in front to break the soil and lay the fertilizer deeper into the centre trench.
Mounted behind that on the arm comes the Twin Wing seed opener. The prototypes use the same half-inch hardened tip as the fertilizer opener. Beaujot plans to design a new, sleeker tip for the production run Twin Wing openers.
On Seed Hawk side band drills, the seed opener shank was mounted 1 1/2 inches to the side of the fertilizer knife. On Twin Wing units, the seed opener shank is centred behind the fertilizer knife, with each seed opening off centre by 1 1/2 inches.
“When we line up the two knives like this, the straw flows through the machine so nicely compared to our side bander where the seed openers are offset. It’s a big improvement in straw flow. If we can get up to a 15 inch row spacing, it’ll be even better.”
The in-line positioning of the shanks also reduces soil disturbance. Beaujot said the Twin Wing arrangement still places the fertilizer band 3/4 of an inch deeper than the seed. The paired seed rows that straddle the fertilizer trench are three inches apart.
The four-inch-wide packing wheel pushes the fertilizer into the central valley and presses the seeds into their seedbeds 3/4 inch higher, closer to the tops of the valley walls.
Beaujot said all Seed Hawks have a four-inch-wide packing wheel. He wanted any new opener system to be retrofitted on existing drills with a minimum of investment and labour. Consequently, he wanted the new Twin Wing to work with the original four inch packer.
By spring 2006, Seed Hawk’s new slimmed-down paired row prototypes were ready for field testing.
Beaujot knew the opener was not ready for production.
He suspected that keeping the two seed rows from collapsing into the fertilizer valley in the middle might be the biggest challenge.
“I always do the R&D on my own farm,” Beaujot said. “If we screw something up, I’d rather do it on my own land.
“So I seeded my entire farm this spring with these new openers, but they didn’t have the trailing wing attachments at that time. We didn’t experience any significant amount of seed-fertilizer mixing, but we knew this could be the major drawback in some situations.
“What we did see was that we weren’t getting the seed all the way out to the edges. We weren’t getting the true three inch gap between the paired rows.
“And that meant we weren’t getting the true nine inch space between the right hand seed row of one pair and the left hand seed row of the neighbouring pair.
“That nine inch row space is what we needed. That’s what we were looking for.”
If the seed was not deposited all the way to the tips of the seed opener, it was not going onto undisturbed soil.
Beaujot said Seed Hawk has always emphasized the need for seed to be placed on firm soil that has seen minimal disturbance. On its new opener configuration, that firm soil is at the tips, way out to the left and right sides. If the new opener couldn’t achieve that, it would go no further than the scrap pile.
Because the seed shank follows directly in the path of the fertilizer shank, the company staff knew the main soil disturbance was limited to the centre. These narrow shanks did not disturb the sides of the fertilizer valley.
However, the two wing tips were not cutting into the sides of fertilizer valley and depositing seed on firm soil the way Beaujot had planned.
“It looked like we were flaking away at both sides of the fertilizer trench. That’s what we needed to address.”
The solution was a U-shaped piece of plastic that resembles a pair of wings and is bolted to the back side of the new paired row opener. The opener officially became the Twin Wing opener.
The three-inch-long trailing plastic wings glide through the disturbed soil and gently push some of it outward toward the two walls of the fertilizer valley.
This action causes the two seed openings to deposit seed in the desired location, a full three inches apart and in undisturbed soil.
“It’s so simple. The wings just prevent the seeds from bouncing or being swept into the middle trench by the soil flow,” Beaujot said.
“They run behind the opener, in loose soil, so there’s no additional friction or resistance. And they’re not cutting fresh soil or taking direct hits from the rocks, so they don’t show any sign of damage or wear.
“In October (2006) we did a field test in one of our fields that has lots of rocks. We did the equivalent of 3,000 acres on a 50 foot drill. There’s no damage to the opener or the wings.”
Beaujot said some customers in severe sawfly areas have asked for the new Twin Wing setup on 10 inch row spacings, so they have a seven inch gap between rows.
Beaujot’s answer is a definite no.
“I’m sorry, but I’m only comfortable with 12 inches. I won’t sell a Twin Wing drill with 10 inch row spacing. The nine inch gap is enough to support a swath. Going to closer row spacing is a big step backwards.”
In addition to abandoning the economic and agronomic benefits of 12 inch spacing, the 10 inch setup creates a new set of problems for paired row openers.
Such a setup would bury the front seed rows.
Beaujot speculates this may be why some high disturbance paired row openers have gone to 15 inch row spacing.
Farmers will likely find 15 inches is the best row spacing because all the benefits from 12 inch row spacing are multiplied, he said.
“I did paired row 15 inch spacing on my canola, but without the plastic wings. I put down 90 pounds of nitrogen, 35 lb. of phosphate and 15 lb. of sulfur. We had terrific emergence and no sign of seed damage. The plastic wings can only make it that much better.”
Beaujot said more research is needed on 15 inch row spacing because of the nitrogen concentration in the fertilizer band.
“Right now we have 700 customers with side-band Seed Hawk drills and some of them are putting down 80 lb. of ammonia without burning the seed. The Twin Wing will only serve to increase that safety margin.”
For more information, contact Pat Beaujot at 800-667-4295.
