Soybean School: Measuring up the soybean stand

Agronomist Ryan Benjamins.

Scouting soybeans is a big part of any Ontario agronomist’s year. Emergence, a consistent plant stand, and seeding depth are the first few things to scout for in the field.

Ryan Benjamins, who owns and operates Benjamins Agronomy Services, gives tips for scouting soybeans and what to consider further along in the growing season, in this Soybean School episode.

“It starts with emergence and the number of healthy plants that have emerged per acre, and those come back to whether we need to do a re-plant or not,” says Benjamins.

From a plant population perspective Benjamins says that soybean is typically over-seeded. In the field that Benjamins and Tobin are in — a clay-loam soil and a no-till system — over 170,000 seeds per acre were seeded. “In this situation, as long as we have a consistent stand, over 100,000, we’re not going to do anything,” he says.

In the video, you’ll see a nifty trick that Benjamins uses to measure seed depth. Catch the full conversation between Benjamins and field editor Bernard Tobin, story continues below:

For seeding depth, Benjamins mentions some research that OMAFRA soybean specialist Horst Bohner has done that indicates the shallower the better for soybeans, as long as it’s seeded into moisture. Soil moisture can really dictate how deep to seed and it’s also important to note the condition of seedbeds at the time of planting so that other issues can be diagnosed as a result.

“Certainly beans that are deep, I think in this field, they’re coming. The shallow ones, we’ve had rain, they’ll germinate and will likely come too,” says Benjamins. To do a stand count, Benjamins recommends picking a few spots and using a hula-hoop or measuring six feet of row and using that as a multiplier.

Weed control can also be assessed at this time of year and the conventional, IP soybean field that the duo is in required a pre-seed burndown and then a residual herbicide.

“We just know, even in dry years, we get a lot better weed control with that herbicide down, than trying to do everything and target ten different weed species post-emerge that are germinating at multiple times throughout the year,” says Benjamins. “Even if we get only 80 per cent weed control here, we’re set up to have a lot cleaner field by starting clean.”

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