Tips For New Soybean Growers

Manitoba soybean growers faced cool and wet weather and aphid infestations in 2008. Yet Manitoba Agriculture says overall soybean yields in the province averaged an estimated 38 bushels per acre in 2008, compared to the long-term average of 30 to 32 bushels per acre. To help you get the best possible yield this year, here are five top tips to keep in mind.


As with any crop, your success with soybeans begins with seed selection. Don McClure, soybean development scientist at NK Brand, Syngenta Seeds, says soybeans yield best when they are grown in their adapted Heat Unit (HU) Zone and when they are full season within that zone. “Because of their indeterminate nature, late soybeans will almost always mature. However, the best yields still come from varieties that are full season but not too late for the area,” McClure says. To avoid disappointment, he recommends that Manitoba growers make sure the varieties they select are appropriate to their growing region. For example, growers in a 2,500 HU region should grow varieties adapted to that maturity, and not make the mistake of assuming that 2,600 HU or 2,400 HU varieties will be “close enough.”


Your soybean crop will need to stand up against seed and soil borne diseases as well as insects pests and weeds. Doug Lindberg, seed care specialist for Syngenta, says “Seed and soil borne diseases can reduce germination, cut plant stand, result in slower canopy closure and ultimately reduce yield. In addition, over the last seven years Manitoba has seen an increase in soybean aphid infestations, and this past summer we saw populations high enough to warrant an overspray.”

Fortunately, soybeans respond well to seed treatment. “A seed treatment with the active ingredient thiamethoxam can provide seed and soil borne disease control and offer protection from late season soybean aphids. The seed treatment can also provide your soybean crop with increased vigour and help promote early emergence.”


Soybean seeds require gentler handling than small grains typically do. Any fall greater than three feet could impact germination. You’ll want to re-think tossing bags of seed into the back of your truck. Also, if you are using bulk soybean seed, avoid augering too roughly. Run your auger at a reduced speed and lower angle to reduce drop level, and run it at full capacity. This will help protect your seed from damage before it’s been planted.


As with any crop, how and when you seed will make a big difference to your end results. For starters, test your soil to determine nutrient levels so you know what fertilizer may need to be added. When it comes time to seed, soil temperature is an important factor to consider. If the soil temperature is below 10C, then avoid planting. In spring, keep in mind that there is normally a two-hour delay between air temperature and tilled soil seeding depth temperature. Calendar timing is also a factor to consider: research has shown that a three-day delay in seeding can lead to a one day delay in the soybean reaching its physiological maturity.

If you are using treated seed, a slight reduction in seeding rates is recommended because more seeds will germinate, more will emerge and there will be a thicker, more vigorous plant stand. Treating your seed will also increase the speed of emergence, which will help to avoid any possible concerns of soil crusting from a hard rain.


Research from the University of Guelph and Agriculture and Agri-Food Canada (2005) has shown that if soybean plants compete with weeds at a crucial point in their development — generally around three weeks after emergence — there will be irreversible yield loss. This has become known as the “switchpoint effect.” The switchpoint effect is known more for its relation to corn given that, according to the research, corn plants can sense weeds even prior to emergence, and the effect can be an even greater acreage reduction. However, because soybeans produce fewer bushels per acre, every bushel counts. That means a reduction in yield could mean a greater percentage of lost dollars.

It’s crucial to get your fields clean as early as possible and do everything you can to prevent weeds before they start. If your soybeans experience the switchpoint effect, you could be facing dramatic, irreversible yield losses of up to a bushel each day.

Keeping these tips in mind as you approach the soybean seeding season will help put you well on your way to a successful soybean crop.

Nathan Klages is the crop manager for horticulture, corn and beans with Syngenta Crop Protection Canada.

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