Many producers in the soybean growing areas of the Great Plains also grow corn, which undoubtedly means they have a planter capable of singulation. It’s common practice in these areas to load up the planter with soybean seed and head out to the field. Perhaps this is the only seeding tool there is on the farm and therefore this makes perfect sense.
But what if there is an air drill on the farm that is used to seed wheat or cover crops? Can the use of a narrow row spaced drill provide more value to the farm when it comes to getting soybean seed into the ground?
The popularity of planting soybeans using singulation on wider row spacing (>15”) seems to be a product of using a corn planter because it is already on the farm. The advantages of narrow row spacing may outweigh the advantages of using a planter in your operation.
Soybeans are not like corn in that there is a lower importance of having exact spacing and emergence timing to ensure the highest yield potential. Soybeans are actually more like canola in that they are capable of branching out and fi lling in space to achieve yield. They are much more adaptable to their conditions than corn.
Research from Ontario’s Ministry of Agriculture, Food and Rural Affairs (OMAFRA) did a 3 year study from 2008 to 2010 comparing the volumetric metering of a drill to the singulation metering of a planter on the yield of soybeans. They found a slight yield advantage to using a vacuum planter compared to a no-till drill.
However, this is not the only consideration when looking at seeding equipment. Row spacing is also an important difference where planters typically come in wider row spacing than drills. Optimal row spacing in soybeans will differ from region to region based on climate and soil type. Shorter growing seasons favor narrow row spacing, whereas wider row spacing has been used successfully in longer growing seasons.
Wider row spacing can be advantageous in heavy clay in dry conditions that have created a crust layer on top. Having a higher concentration of seed in the seed row due to wider rows will allow the emerging seedlings to work together and push the crusted soil out of the way. Wider row spacing also allows for more air fl ow between the rows, which could potentially lower the humidity and disease incidence; or it allows for spores to spread more freely within the crop, which is not desirable.
Narrower row spacing advantages include quicker canopy closer, which allows for better weed competition and may reduce a two pass herbicide system down to a single pass system. The quicker canopy closure means there is more sunlight utilized to grow the crop.
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Manitoba Pulse & Soybean Growers conducted multiple trials over the years on row spacing.
Here’s their summary:
“Narrow row spacing results in soybean yields that are similar to or greater than wide rows according to research conducted in Manitoba. In small-plot research, where narrow rows of 10" were compared to wide 30" rows, narrow rows had a consistent yield advantage (+1.5 to +11.6 bu/ac). Where intermediate 16-24" rows were compared to narrow 10" rows, yields were similar between row spacings. MPSG’s On-Farm Network has conducted 19 row spacing trials on-farm since 2019. Nine trials compared narrow 7.5-10″ rows to intermediate 15-20″ rows and 10 trials compared intermediate 15″ rows to wide 30″ rows. Seeding rates were held constant between row spacings. Soybean seed survival was 7% lower in 30″ rows. Narrow rows improved yield over intermediate rows 44% of the time (on average by 1.8 bu/ac). Intermediate 15″ rows improved yield over 30″ rows 20% of the time.”
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Retrieved November, 2023 from www.manitobapulse.ca
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Becks Practical Farm Research (PFR) based out of Indiana also showed a positive response to 10” spacing compared to 15, 20, and 30” row spacing.
OTHER CONSIDERATIONS OF USING A PLANTER:
- Planters typically use some sort of disc opener that requires some type of tillage to manage the residue, which ensures good seed to soil contact. These openers are very good at placement, but not necessarily in a no-till situation;
- Fertilizer often requires a separate field application, whether that be deep banding or broadcast.
It may be time to consider other combinations of seeding equipment on the farm that could serve your crops and your operation better. Perhaps a corn planter will always be necessary, but the drill has the potential to serve a larger role by not only seeding cereals and cover crops, but take on the responsibility of soybean seeding as well.
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By Curtis DeGooijer, PAg, CCA
Agronomy Team Leader
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