BY: Chris Forsythe, On-Farm Network Agronomist, Manitoba Pulse & Soybean Growers
Last year many farmers told us they were curious to know the effects of increasing soybean seeding speed on seed placement, plant stand and yield.
Advancements in seeding and planting equipment technology are allowing farmers to seed faster – to a point – without reducing plant stand or sacrificing yield. Every field and seeding tool is different, but when conditions are ideal, it may be advantageous to get as many acres seeded as possible within an optimal soybean seeding window to maximize yield. Current Manitoba recommendations suggest seeding soybeans the second and third weeks of May to maximize soybean yield while reducing the risks associated with cold soil and late spring frost.
Of course, air seeders and planters, and even different models within each equipment type, have different optimal speed ranges. So, it’s important to know the speed capability of your equipment and match your ground speed with the soil conditions and a tractor with the appropriate horsepower. Seeding faster usually requires more horsepower and soil type and conditions may not allow faster seeding.
In 2025, the On-Farm Network (OFN) established eight soybean seeding speed trials with farmers using their own fields and equipment. The objective was to do an in-depth investigation into what exactly are the effects of varying seeding speed on seed placement and yield.
Three sites tested seeding at 5 mph versus 7 mph, and five sites tested 5 mph versus 7 mph versus 9 mph. To be noted, the 7 mph at each site was considered the farms’ traditional speed with the slower and faster comparisons. Six of those trials were established with a planter, and two were established with an air seeder or an air drill.
First, we looked at seed depth by doing a post emergent seed depth assessment. Seedlings were dug up and we measured the white space along the hypocotyl stretching from the root hairs to where the green tissue starts as this is the soil line. Across the three seeding speeds, we didn’t detect any differences in seeding depth at any site.
Next, plant counts were recorded at early season vegetative growth stages. The same areas were revisited later in the season at reproductive growth stages. Changing seeding speed didn’t affect plant stand establishment or late season plant survivability at any site.
At the same time as the early season plant stand counts, we measured plant-to-plant spacing, or how uniformly spaced the plants are at each seeding speed. Plant-to-plant spacings were lowered significantly when going from 7 mph to 9 mph at only two sites and, at both, planters were used. Plant-to-plant spacing at those two sites were similar when going from 5 mph to 7 mph. There were no differences in plant-to-plant spacing among the different speeds at the other six trial sites.
Finally, when we did yield measurements, finding that regardless of seeding equipment or speed, there were no significant yield differences between the three seeding speeds of 5 mph, 7 mph and 9 mph at any trial site.
It’s important to note that, due to the ability of soybeans to compensate for yield in less-than-ideal conditions, seed singulation in soybean production isn’t as important as it is for corn for maintaining yield potential. This is one reason why soybeans can be grown successfully with a planter or with an air seeder.
The economics of changing seeding speed were not quantified but preliminary fuel consumption data determined for each tractor used in this study showed that total fuel consumption per quarter section was reduced when increased seeding speed from 5 to 9 mph. Fuel efficiency in gallons per hour decreased when seeding faster but the time required to cover the same area was decreased, which more than compensated for the increased fuel consumption per hour and total fuel used per acre.
This is one on-farm trial type where a non-response to a treatment – in this case varying seeding speeds – is a useful outcome. Seeding at faster speeds may not always be warranted due to wear and tear on equipment, and it requires more horsepower. However, knowing that when seeding faster, quality and yield may not fall off a cliff is important when you need to get that quarter section in quickly.
Please note that with only one year of data, more testing is required to inform any potential future soybean seeding speed recommendations. We hope to replicate this trial this year. If you’re interested in participating, please get in touch with us.