This story is the first of two parts, and will cover some of the basic requirements of soybean production. Part 2 will delve further into more specialized production issues such as row spacing, weed control and the use of inoculants, seed treatments and starter fertilizers.
The popularity of soybeans in Western Canada is set to increase after a decent performance in 2010, despite excess rainfall in most areas. Soybeans are proving themselves to be solid performers under a variety of field conditions. Traditionally thought of as a high heat-unit crop confined to the Red River Valley in Manitoba, production is now spreading to other parts of southern Manitoba, as well as Saskatchewan and Alberta. Saskatchewan Crop Insurance Corporation recently introduced yield loss coverage for soybeans in designated areas this past year.
In 2010, there were 450,000 to 500,000 acres of soybeans grown in Manitoba. With newcrop contract bids (at the time of writing) in the range of $9 to $10 per bushel for November 2011 delivery, there is talk of 750,000-plus soybean acres in the upcoming year. Statistics Canada has pegged 2010 soybean production in Manitoba alone at 435,000 tonnes, a big jump over 2009’s 321,000 tonnes.
Soybean yields across Western Canada typically vary between 25 and 50 bushels per acre. In southern Manitoba this past season, yields were similar to canola but input costs were significantly less due, in part, to the crop’s ability to fix nitrogen. If corn prices stay strong, an increase in fertilizer demand will likely cause prices to appreciate which in turn will make soybeans even more attractive.
CHECK YOUR HEAT UNITS
Soybeans love heat and moisture and these are key limiting factors to soybean production in our northern climate. Soybean plants are daylight sensitive, with day length initiating the start and end of flowering. Therefore the more heat and moisture (within reason) during the flowering period, the higher the yield potential. Most soybean varieties grown near Morris, Man., for example, have a rating of 2400 heat units or less, and require about 120 days to reach maturity. Although daytime temperatures may be similar across vast regions, cooler night time temperatures in some areas will have a negative impact on yield. It should also be noted that drought stress can be an issue on coarse-textured soils where an equivalent of at least a half an inch of rain per day is required during pod fill.
CHOOSE YOUR MARKET
Should you go conventional or grow a genetically modified variety? More than 90 per cent of soybeans grown in Western Canada are glyphosate-tolerant. Although IP or food-grade beans can return a premium, weed control options tend to be limited. Soybeans are slow to cover the ground and a glyphosate-tolerant system allows for cost-effective weed control throughout most of the season.
ROW CROP OR SOLID SEEDED?
There is growing interest in planting soybeans in rows versus solid seeded. Currently solid seeding is most popular because it does not require any specialized seeding equipment and the beans tend to cover the ground more quickly. Traditionally, it was thought that solid-seeded beans would pod higher because of competition and higher seeding rates, however experience is proving that beans in wide rows are podding the highest due to the plants being closer together in the row. The higher the beans pod, the easier they are to harvest, so this is an important consideration. This topic will be discussed in further detail in Part 2.
Target plant stands for soybeans are normally in the 180,000 to 200,000 plants per acre. For solid seeded beans, targets are closer to 220,000. Seed size will vary by variety and year, so make sure to check your thousand kernel weights. Most farmers factor in a 10 per cent loss between seeding rates and actual emergence.
Waiting for a soil temperature above 10 C before seeding is very important. Research has shown that soil temperature in the first 24 hours is crucial to emergence and establishment of soybeans. If the water absorbed by the seed is too cold, germination and emergence will suffer.
Once out of the ground, soybeans in the cotyledon growth stage can handle temps as low as -3 C but soybeans in the unifoliate and trifoliate stages are more sensitive. It should be noted, however, that cooler weather leading into a frost will help acclimatize the plants and increase tolerance levels.
INOCULANT AND FERTILITY REQUIREMENTS
Nitrogen requirements are critical to soybean production. Inoculant levels must be high enough to ensure proper nodulation and take advantage of the soybean’s ability to fix its own nitrogen. There are many forms of inoculants available in peat, granular and liquid. Seed-applied inoculants encourage nodulation on the main stem while granular inoculants tend to populate lateral roots. On first year fields, it is a good practice to use two different forms of inoculants to ensure proper nodulation.
It is possible for rhizobia populations to build in the soil over time, however new research suggests that rhizobia populations have trouble surviving our cold soils and anaerobic conditions due to excess moisture. Given the northern climate we are in, inoculating every year is cheap insurance and a must in my opinion.
Aside from nitrogen, soybeans also have high phosphate and potassium requirements. A 30-bushel soybean crop will require 40 pounds of P205 and 133 pounds of K respectively. It is important to consider fertilizer application and placements of K or P on deficient soils as the seed and inoculants are very sensitive to the salt levels in many of today’s fertilizers. Very little fertilizer, if any, can be placed in or near the seed row.
As mentioned earlier, weed control is a challenge because soybeans are very slow to cover the ground and offer competition to emerging weeds. Weed control in non-GM beans is mostly restricted to Group 2 products which mean early removal when the weeds are small is crucial.
The biggest difficulty in growing glyphosate-tolerant beans is other tolerant crop volunteers. There are control options available that will be discussed in Part 2. Glyphosatetolerant canola has a bad habit of showing up even if the field has not seen such canola for five or more years.
The main insect pests so far have been soybean aphids. Most of our aphid pressures have appeared later in the season where economic thresholds are as high as 250 aphids per plant. Don’t go out and spray at the first sign of aphids. This past season, green clover worms were an issue in some areas of southern Manitoba but again, they arrived later in the season and threshold
levels warranting control were rarely met. Other potential soybean pests include wireworms, grasshoppers, armyworms and cutworms.
Soybeans are susceptible to soil-borne diseases such as root rot and should be treated before seeding. With heavy growth and wet weather this past season we did see sclerotinia appear in some fields. Disease pressure was highest in fields with a history of susceptible crops such as canola and sunflowers. There are currently no products registered for in-crop control of white mould in soybeans. Spray coverage and penetration into the canopy makes it a challenge to effectively control white mould. Seeding in wide rows
and allowing more air movement through the canopy remains one of the best options in controlling white mould.
HARVEST AND STORAGE
Harvest methods can greatly affect the quality of soybeans. Straight cutting with a flex-style header is the preferred method of harvesting soybeans to minimize dirt tagging. Heavy weed pressures at harvest can also lead to bean staining and dry-down issues. Generally, beans have to be cut very close to the ground to minimize losses, so the smoother and drier the field the better. Many farmers elect to roll their fields especially if stones are present. It is also important to avoid rutting a field too badly with spraying equipment to minimize dirt tagging and keep the flex header running efficiently.
Soybeans must be below 14 per cent moisture when stored to avoid heating. Harvesting the beans below 12 per cent moisture can cause cracking.
In summary, including soybeans in a rotation can help spread out harvest (as they’re a late crop), offer good weed control and help minimize risk because of their lower fertility costs and consistent performance under most weather environments. Make sure to look for Part 2 in an upcoming issue where we will discuss row spacing, fertility, inoculants, seed treatments and weed control in further detail.
BrunelSabourinisalocationagronomist withCargillAgHorizonsandbasedoutof Morris,Man.Contacthim204-746-4743or [email protected]
Target plant stands for soybeans are normally in the 180,000 to 200,000 plants per acre. For solid seeded beans, targets are closer to 220,000.