Manitoba soybean acreage has more than doubled in the last 10 years, and this year even more farmers are expected to give the crop a try.
Manitoba Agriculture, Food and Rural Development (MAFRD) pulse specialist Dennis Lange offered some tips at the Dauphin Agriculture Society’s Farm Outlook 2015 conference.
Lange reviewed the importance of selecting the right variety for your area, noting that days to maturity is the most important factor.
The length of time between planting and maturity varies between 113 days in short-season varieties up to 121 days in mid- to long-season lines.
“Pick the varieties that are suited for the growing region. Go with something you know and are comfortable with and then when you want to expand into other lines make sure you do your research on the available varieties — days to maturity, soil type, yield potential.”
Lange said soybeans typically grow best in soil with 50 pounds or less of nitrogen. In soil with 80 to 100 pounds of nitrogen you may run into some problems as the plants will take the closest nitrogen source.
Soybeans also remove 0.84 pound of phosphate per bushel and attention must be paid to ensure a proper fertilization strategy to ensure application rates are meeting removal rates through the entire crop rotation.
“Soybeans are very good scavengers for phosphate but what is interesting is that they respond very well to soil with high phosphate levels, much better than low phosphate levels,” said Lange.
He recommends building up the phosphate over a number of years through crop rotations, and MAFRD recently created a spreadsheet calculator to assist producers in determining nutrient removal and balance through rotations. It’s available on the Manitoba Pulse and Soybean Growers (MPSG) website at www.manitobapulse.ca/production-resources/.
When seeding, Lange recommends seeding depths of three-quarters inch to 1-1/4 inch deep and to aim to be in the 130,000- to 170,000-established-plants-per-acre range for the best yield potential. To determine stands, he recommends a new tool on the MPSG website. “With this app you use the hula-hoop diameter or a square foot and then conduct a few counts. When you hit the calculate button you are going to get some information and it will tell you whether the quality population is high, good, adequate or low.”
The calculator is available at www.manitobapulse.ca/mpga-bean-app/.
“For seeding date in western Manitoba I tend to use May 15 to May 25 as a guideline. You want to try to get them into warm soil but you don’t want to get them in too early because there is that risk of a spring frost,” said Lange.
It is recommended to plant soybeans in soil at a minimum of 10 C. At this temperature, seeds will take two to three weeks to germinate. If planted in cooler soil, the seed will sit in the ground and when it emerges, it will not be as vigorous as those planted in warmer soil.
“It is also really important that you are using inoculants and if you are a new grower, I would recommend using a liquid and granular combination. The liquid goes on the seed and the granular goes beside the seed,” said Lange.
“Using the two different forms, when you have that option, does give you more insurance and will give you better yield potential, especially in years where there is a very wet spring.”
MPSG and MAFRD have developed a document to help you assess pest risks on your operation and aid you in deciding whether a seed treatment is necessary and what type of seed treatment would be most appropriate. It’s available on the MPGA website at www.manitobapulse.ca/production-resources/.
“You have to look at your own farm and determine whether the level of pest warrants the use of an insecticide,” said Lange. “Overuse of some of the products can have some negative effects, including residue in surface water, persistence in soil and in some conditions be harmful to pollinators. However, not using a seed treatment can be risky, especially in cool soils if you have some early planting.”
Soybean seedlings are not competitive with weeds and control is primarily handled with herbicides.
“Weed control is very important with soybeans. You need to know your weeds and you have to scout you weeds to make sure you are in there and controlling them early,” said Lange. “Scout your fields before you spray and after you spray and watch for the weeds that aren’t controlled.”
Lange noted that Manitoba currently has two confirmed cases of glyphosate-tolerant kochia, both found in the Red River Valley.