NISKU, Alta. Ñ Moving from a row space of nine inches to 12 inches has no effect on pea yield, according to results from a 2004 demonstration site for the Alberta Pulse Growers on-farm agronomy program.
Speaking at a Direct Seeding Advantage conference in Nisku late last year, Rick Taillieu, the Reduced Tillage Linkages, or RTL, agronomist at Camrose, said crop rotation, fertility and pest management will probably play a larger role in maximizing yields and profits than row spacing.
RTL worked with Hillcrest Acres farm near Camrose to set up the trial. Hillcrest Acres has two Flexi-Coil 5000 air drills equipped with paired row openers: a 51-foot unit on nine inch spacing and a 57 foot unit on 12 inch spacing.
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On April 30, a 65 acre field was direct seeded with Majorette peas. The two drills alternated passes across the field, providing 24 separate strips. Seeding rate was 180 pounds per acre, with JumpStart and liquid inoculant included at seeding.
Two half-acre strips were harvested from each row spacing on Sept. 7. The average yield of the nine inch spacing strips was 62.1 bushels per acre, while the 12 inch spacing strips averaged 61.4 bu. per acre.
Taillieu said visual observations and yield monitor readings indicated that field variability was more closely related to soil conditions and weed pressure than to row spacing.
Plant counts conducted by the Battle River Research Group found little difference in plants per sq. foot between the two drills. While the target population was seven per sq. foot, most counts were in the four per sq. foot range. Taillieu thinks this might have been the result of using common seed with no seed treatment.
“The wider row spacing was slower to form a canopy,” he said.
“The narrow row spacing closed the canopy approximately seven to 10 days earlier. But because of the thin plant stand, a thin canopy resulted regardless of spacing.”
Weed numbers similar
Taillieu said there was little visual difference in weed pressure when comparing the two systems before or after herbicide application. The field was sprayed June 4 with Select and a half rate of Pursuit.
He said both the opener design and the row spacing have an effect on the crop canopy. With single shoot openers that spread the seed, a wider opener on wider row spacing can allow the same seedbed use as a narrower opener on narrower rows.
A three inch spread tip on a nine inch row spacing will use 33 percent of the seedbed: the same amount as a four-inch spread tip on a 12 inch row spacing.
With double shoot openers, the distance between paired rows on the same opener will increase as the opener gets wider, but at the same time the distance between the two adjacent openers decreases.
Taillieu said interaction between the opener and row spacing will affect the amount of soil disturbed, amount of stubble left standing, moisture conservation and amount of fertilizer that can be safely placed with the seed. It will also affect how much residue the drill can seed through.
“Row spacing continues to be one of the most discussed, and disputed, aspects of a direct seeding system. Producers continue to weigh the pros and cons of wide versus narrow row spacing, while research continues to provide inconsistent results. Row spacing is often equated to stand density and canopy closure, but opener size and design also have to be factored in,” Taillieu said.
A search of the RTL Farmer to Farmer network revealed an equal number of producers seeding on nine inch and 12 inch spacing.
“It’s important to remember that direct seeding is a system, and the configuration of your drill is only one part of the whole management system,” Taillieu said.
