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5 tips for growing soybeans in a cool climate

Western Canadian farmers have always had a keen interest in growing new crops. Pulses and oilseeds were few and far between 30 years ago where I farm in southeast Saskatchewan. Since then farmers have actively participated as new crops have been tested and refined to meet our environment and slowly worked into our mainstream rotations. Today pulses and oilseeds are the main drivers of wealth on most Prairie farms. This could be why soybeans are catching the eye of so many farmers. An oilseed crop that grows like a pulse should be very intriguing in its own right. Add to this the fact that soybeans are relatively simple to grow, harbour few diseases, drop-dead bulletproof for shattering and rarely have grading issues, and their allure grows.

“Where in the world you can grow soybeans, you grow soybeans!” I’m not sure where I first read this quote, maybe 20 years ago, but it intrigued me immensely. Of course the perception has always been that north of the 49th parallel is not a place in the world to grow this crop — that we don’t produce enough heat to nurture a tropical plant to maturity. So why have soybeans become more popular through southern Manitoba over the past decade, and why are they now pushing boundaries into Saskatchewan, Alberta and northern Manitoba? Varieties? Partially! Just as important are the agronomic practices behind these varieties — practices which will enhance success in areas with fewer heat units, or into zero till soils, which tend to be cooler.

It’s been said to me that “If you want to fail at growing soybeans in Saskatchewan, just head down to Iowa and learn how to grow them.” This is not a slight against anyone involved in the production and agronomy of soybeans in Iowa. It simply alludes to the fact that there is lots of time and heat to mature the crop in that region, luxuries we don’t have here. We have to tweak the process to mature our crop in the allotted time.

Presently, the earliest-maturing Roundup Ready soybean varieties fall into a range of 2350 to 2450 Crop Heat Units (CHUs). For many of us, this range of CHU accumulation is outside our normal window. However, these early varieties all have a varying degree of photo or daylight sensitivity. Finding the varieties with the most heightened photo sensitivities is very important. These varieties will still mature when less than ideal CHUs are provided from the environment. Frankly, trial and error has been the method of choice to establish this trait. This trait is an important factor behind the respectable yields and maturity we’re seeing from certain varieties of soybeans in years when their needs for CHUs are not fully achieved.

Once the selection of the cultivar is established, several other practices will enhance maturity and ultimately yields.

Our experience

We began growing soybeans three seasons ago in 2009 under the guidance of Ron Gendzelevich and Shawn Rempel of Quarry Seed and have been supplying seed and agronomic advice to other producers over the past two seasons. To date, every acre we’ve fostered has been grown with a complete and uncompromised input package. We’ve had what we consider admirable success as well as some disappointment. The beauty in this has been being able to diagnose what went wrong with the disappointing yields, knowing they received the same inputs as the higher yielding fields. This has provided me with confidence in the recommendations I offer.

1. Plant into warm soil

The number one absolute wrong thing to do is to plant a soybean seed into cold soil. Period. Everything else I will relate will enhance yield and maturity, but cold soils are a game stopper before you’re out of the gate.

Soybeans like warmth. In soils below 8 C these seeds will do little more than take in moisture and rot. The plants that do make it through the cold shock will be slow growing off the start. They will also have a tendency to set their bottom pods closer to the ground. When placed in soils 10 C and warming, soybeans are the strongest plants out of the ground I have ever witnessed. Our zero- till stubbles are generally cooler, longer in the spring. Avoid heavy trash-covered stubbles or consider a heavy harrow to partially blacken the field. Deep seeding will also tend to put the seed into cooler temps. An inch at most should be enough depth. Watch the weather. If you have the proper soil temperature but there’s a cold front on the way, wait! You will be better off. Later-seeded soybeans have a propensity for catching up on maturity. Every week later they are seeded will generally only add two to three days to their maturity.

2. Use an inoculant

Inoculation is the next most important production factor for soybeans. Soybean rhizobia are a unique strain of bacteria and are not in any way native to our soil. Combine this with the fact that soybeans need to produce vast amounts of nitrogen in their life cycle and it becomes imperative we supply them with the necessary tools to get their work accomplished. A soybean plant will consume in the neighbourhood of six pounds of actual nitrogen per bushel of yield. The best way to enable this is through high rates of granular inoculants on virgin soils. I also recommend liquid on the seed to start the process early in the plant’s life. My personal trials have shown a seven- to 10-bushel yield bump from the use of a granular and liquid in combination versus using liquid alone.

3. Plant on soybean stubble

Generally, your best crop will come from this practice. This will give you a dark, warm stubble to seed into. However, the greatest benefit is the carryover of rhizobia from the previous season. Benefits from applying generous amounts of inoculant are still profoundly beneficial, however not nearly so distinct as on the virgin ground, proving that some bacteria will overwinter in our frozen soils.

One caution when considering cutting inoculant rates when expecting carryover bacteria in the soil is that any flooding may cause the bacteria in these areas to die off, leaving the area similar to virgin soil. The only disease which jumps to mind as a threat would be sclerotinia. My understanding is that soybeans, while being carriers of the disease, generally do not see huge yield reductions. My concern would be more for another broadleaf crop (such as canola) later in the rotation. Over time other disease issues may emerge, for now we seem to have a hall pass.

4. Use high seeding rates

Seeding rates are also a factor to consider. In general, it is felt that any plant seeded at a higher intensity will be hastened in maturity. Soybeans are no different. Along with speeding maturity you will also coax the plant to extend the distance between nodes, which will bring the bottom pods a greater distance from the soil. Wider row spacing will also tend to have this effect. My jury is still out, however, on row spacing, as generally in my area we are trying to conserve moisture. Closing the canopy quicker may outweigh the perceived benefit of wider rows. Every agronomic decision we make regarding soybeans has to be viewed from the perspective of how will this affect maturity. Soybeans are a very elastic plant, meaning they can stack plant mass and yield on to compensate for low seeding rates or emergence issues. Unfortunately for us, some years we will not have the luxury of time to allow the plant to perform this task. Higher targeted plant populations are maturity insurance.

5. Use a fungicide

Another critical ingredient, especially on cool years, is the use of Cruiser Maxx Beans. I hesitate to mention products by name, however, the vigour enhancement in this product is very real and very important when trying to shave days off the back end. Data from the Valley Soybean Expo in Manitoba, consolidated over the past seven years, clearly shows a reduction in days to maturity on a consistent basis and enhanced in cooler years when soybeans are treated with Cruiser. Of course as a minor side benefit, the complete protection of a duel fungicide/insecticide seed treatment is along for the ride.

The future of soybeans

The future of soybean varieties will be the Roundup Ready 2 (R2Y) gene and the varieties carrying this trait. The promise from Monsanto has been that the R2Y gene will enhance the varieties it’s inserted into with certain traits. Namely, a more robust and aggressive plant, pods which have better clearance from the soil and more beans per pod. All leading, of course, to better and more consistent yields. Some producers and industry participants have voiced scepticism as to the whether the genetic improvements are sound, or (more cynically) a way for Monsanto to keep patent rights in place.

From what I have seen this past season, what has been promised from Monsanto is being realized in the final product. The R2Y varieties in general stand out in plots when grown beside the RR1 varieties, from larger, more vigorous looking plants to definitely adding more seeds per pod on average. The proof is in the pudding and the Manitoba Crop Variety Evaluation Trials (MCVET) definitely prove that there are some improved genetics in the offing.

I am personally very excited to see the interest in soybean production displayed throughout Western Canada. I’m sure the breeders, and Monsanto, will hear the message that the market is ripe for more earlier-maturing varieties to enhance the area in which we can be successful growing this crop. We are looking forward. †

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