Ontario soybean growers wondering whether to plant deep or wait for rain

With the corn crop pretty much planted in Ontario, growers are pushing to finish soybeans as increasingly hot, dry weather depletes soil moisture.

With only small, isolated rain events forecast for the week ahead, growers are wondering how deep they should plant seed for their remaining soybean acres. With many already planting at the 2″ and 2.5″ depths — below the preferred 1.5″ — many are wondering whether they should push depths to three inches to find moisture or park the planter, watch the forecast and get beans into the ground at shallower depths ahead of a rain.

It is a challenging situation for growers says Greg Stopps, Corteva Pioneer agronomist based at St. Marys, Ont. During Tuesday’s virtual Ridgetown/Simcoe agribusiness breakfast meeting, Stopps and other agronomists on the call tackled the “tricky” situation many growers find themselves in.

Stopps said growers could push lower to 3″ on lighter ground, but if it’s still dry at that level his choice is to hold off, go shallower and wait for a forecast rain. “When you’re that dry, it all becomes a bit of a gamble,” he added.

RealAgriculture agronomist Peter Johnson noted that some soybean varieties struggle with hypocotyl extension and would be hard pressed to make it up to the soil surface from three inches. He added that soybeans planted at this depth in double crop soybean systems do emerge effectively in summer soil temperatures, but this could prove challenging in cooler spring soils.

Stopps acknowledged that some varieties will struggle but there are varieties that will push well. Overall, he’s not a fan of going to 3″ if it can be avoided.

Sevita International product development and agronomy manager John Van Herk said he’s not worried about planting depth. He’s planted a lot of beans over the years in the Niagara peninsula at 2″ and 2.5″ and hasn’t worried too much about it. “For the most part, find the moisture and get in there and get it done,” said Van Herk. “That’s a better plan than planting shallow and waiting for the moisture to come.”

Johnson noted that soil conditions are changing rapidly as heat, accompanied by drying winds, accumulates. In early May, soil worked up nicely in cooler conditions and low evaporation helped retain moisture, but when the higher temperatures arrived last weekend “it is a just a total different world,” said Johnson. He’s concerned that quick-drying soils may have snuck up on some farmers who now have soybeans sitting above the moisture. That could lead to some spotty stands, he adds.

Stopps is reminding growers to be careful when working soil too aggressively ahead of planting. He said it’s best to plant as quickly as possible after tillage, roll with the packer and “seal some of that moisture in if you can.”

Van Herk also offered a watch out for specialty soybean growers when planting deeper. He noted that natto soybean hypocotyl lengths “tend to be a little bit tricky.”