Soybean School: 15″ versus 30″ rows — the great debate

OMAFRA soybean specialist Horst Bohner.

Should growers plant soybeans in narrower 15-inch rows or should they go wide and plant at 30 inches?

Ontario Ministry of Agriculture, Food and Rural Affairs soybean specialist Horst Bohner has been listening to the debate for years, and rather than taking sides, he likes to focus on the fact that growers can choose an option that’s best for their farm.

On this episode the RealAgriculture Soybean School, Bohner notes that Ontario row-width research conducted over the years does show narrow rows typically out-yield wide rows by about four bushels per acre. But research also indicates that the yield gap closes when growers “do things right” when managing 30-inch rows. That includes feeding the crop, choosing the right variety, planting early and selecting good soil types and yield environments.

Bohner admits growers will have to invest in feeding the crop to eliminate the yield gap but they also need to consider the benefits of wide rows in areas of high white mould pressure.  (Story continues after the video.)

In 2022, Bohner conducted research trials to help identify management decisions that could help shrink the yield gap. One way to make wider rows more yield competitive is to plant longer-season maturing varieties within a specific growing area. In the trials, longer-season varieties planted at 30 inches lost only two bushels per acre when compared to the same variety planted at 15 inches. Shorter-season varieties planted in a similar trial lost six-bushels per acre in 30 inches versus 15.

In the video, Bohner also shares results from 2022 research where he compared how the two-row systems performed with more intensive management, including 10 gallons per acre of 28% nitrogen beside the row at planting as well as a foliar fungicide at the R 2.5 growth stage. In this case, the wide rows gained a small edge, but not enough to compel growers to make the switch to wider rows.

Bohner says he’ll be replicating his trials again in 2022, but for now he says 30-inch rows can do well in high yield environments with the right variety but 15-inch rows are tough to beat.

Click here for more Soybean School videos.

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