Seeding Soybeans 201

By Ron Friesen

The cost of seed treatment for soybeans adds up quickly, depending on what you buy.

Stand-alone fungicide seed treatment costs $6 to $7 an acre. Fungicide and insecticide treatment together cost $12 to $14 an acre. Liquid inoculant on seed will run you around $6 an acre, plus another $10 an acre for granular inoculant banded in the furrow during seeding.

Take the price of the seed itself, add in the various seed treatments and you’re paying between $105 and $110 an acre.

Is it worth the money? Yes, says Rick Storoschuk.

“My recommendation is seed treatment,” says Storoschuk, sales agronomist for GJ Chemical Co., an agri-retailer in Arnaud, Manitoba. “It’s insurance. The discussion I have with my customers is when you’re putting that seed in the ground, why would you put it in halfway? If you already have the investment on the seed, why not give it the very best possible start?”

Seed treatment, inoculation, and added nutrients are considered standard practice for soybean growers. However, according to Storoschuk, some growers have moved away from seed treatment in the last few years, mainly because of the cost. But, he still recommends the practice because it promotes germination.

Storoschuk suggests soybean growers pay more attention to emergence rates, which are often lower than people realize. In the United States, optimum stands include 140,000 to 150,000 plants per acre. But American producers grow more aggressive varieties, which are bushy and produce higher yields. In Manitoba, producers grow varieties more suited to local conditions. These plants are smaller and more erect with less branching. For that reason, seed treatment is important to produce germination rates as high as possible.

Storoschuk puts the goal for germination at 170,000 to 180,000 plants per acre. Right now, that’s not always happening.

“I think a lot of farmers would be surprised what their actual stand is when they’re planting 200,000 seeds per acre. I’ll bet in a lot of cases it’s 140,000 to 150,000. It should be 170,000 to 180,000.”

Seed treatment is particularly important this year when growers face the possibility of seeding late into cold soil and increasing the risk of root diseases, says Storoschuk.

Treating seed won’t necessarily increase germination rates, but it will protect the seed against root diseases such as Pythium, Phytophthora, and Rhizoctonia. Untreated seed will pick up a disease and die, resulting in a lower overall germination rate and, ultimately, lower yields, explains Storoschuk.

Double inoculant on seed was common when soybeans began to take off in Manitoba 10 to 12 years ago. Storoschuk says rhizobium (bacteria that fix nitrogen inside root nodules) for soybeans was not natural to our soil. As a result, growers were encouraged to add rhizobium to their seed to promote nodulation. Double inoculation (using two different forms of inoculant) was recommended when planting into soil that had never seen soybeans before. That involved applying a liquid inoculant directly on the seed, as well as a peat inoculant which comes in the form of a powder. Alternately, growers can use a granular form of inoculant banded alongside the seed in the furrow.

As for fertilizer, it’s simply not true that soybeans don’t need added nutrients because they fix their own nitrogen. Storoschuk says soybeans are big phosphorus users and require adequate P levels in the soil. Potassium is also necessary in some cases. Soil tests are essential to determine levels of P, K, and other nutrients.

Foliar fertilizers are another input soybean growers can add to their fertility packages. Most foliars contain micronutrients which may or not be helpful to growing plants. Most Manitoba soils are sufficient in micronutrients, so Storoschuk advises growers to “walk before you run” by first trying foliars on a few acres to see the result before applying them more widely.

In short, Storoschuk recommends following the basics of seed treatment before going further.
“If I’m sitting down with a guy and we’re talking about managing our dollars on soybean acres, it’s going to be seed treatment and inoculant. Then we can talk about the other stuff.”