Wide open

THE PROS AND CONS OF MOVING TO WIDER SOYBEAN ROWS

GROWERS IN ONTARIO are moving towards wider row spacing for soybeans in an effort to save time and money.


Wider row spacing is becoming a viable option in Ontario for a couple of reasons: it helps decrease the spread of white mould, and it saves money on the cost of seed — as much as $30/acre according to Horst Bohner, soybean specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs.

As well, opting for a row-unit planter rather than a drill to seed these wider rows offers better depth control, less crop trampling when fertilizer is put down, and allows you to get more acreage covered in a day compared to a 15-foot drill.

While this all seems like good news, Bohner warns wide rows aren’t for everyone.

“Like so many things, we like to over-simplify and this is one of those situations where for some growers and some fields, the right thing to do is grow 30-inch rows, for others it’s absolutely the wrong thing,” says Bohner.

WEIGH YOUR RISKS
He recommends assessing your situation; if you have tall, lush beans that are falling over, and you have problems with white mould, wide rows are a very good option. But for others who are using no-till and use shorter varieties, it would not be beneficial to make the switch.

“The grower needs to be really clear about the yield lag on average and then think about why they would want to move to wide rows,” says Bohner. He reinforces the only way yield will improve in wider rows is if you have white mould.

Once you’ve assessed the situation, in order to ensure a successful transition, Bohner says there are some basic things to do.

First, he suggests making a slow transition. Switching all soybean acreage in one shot “would be a bit extreme and you will be disappointed.”

AGRONOMY TIPS
Next, it is important to choose the right variety. “The soybeans have quite a range in terms of their genotypes, so you want tall, bushy varieties,” Bohner says. These varieties ensure the canopy fills as soon as possible so the plant can absorb all the available sunlight, rather than it being wasted on empty space.

It is also important to plant relatively early. “Soybeans are a sub-tropical species, they want sun, warmth and they’re relatively long-season crops, where we are the exact opposite,” says Bohner. Therefore, planting early helps extend the season and fills the rows as soon as possible.

Management also becomes even more of an issue; wider rows create the risk of more weeds, so the crop will need to be managed more carefully. As well, because each plant has to provide more yield, with fewer plants per acre, it’s important to feed those plants.

Finally, it is absolutely essential that any grower considering wide rows does some sort of tillage, whether it is complete or strip tillage; the plants need the opportunity to grow quickly. No-till is not an option because “it is a more stressful environment for the plant,” according to Bohner. Any obstruction is a challenge for the plant to grow swiftly and efficiently, so at a minimum, corn stalks need to be pushed out of the way.  

BOTTOM LINE
So why move to wider rows?

“I think at the end of the day the drill is on the way out for planting soybeans,” says Bohner. A row unit planter has better accuracy in terms of seed placement and seed quantity.

Aside from that, Bohner says growers who make the switch like that they can use a planter, have lower seed costs, and lower white mould risk. 

Across Ontario, the response varies, from sparse interest to a conviction that wide rows are the way of the future.

At the end of the day, though, it’s up to the grower to decide whether the reward of more time and money is worth the risk of losing a few bushels. •