Part One – Top 15 Tips after 15 Years of Growing Soybeans

Top Soybean TipsBrian Hellegards, Farm Manager at Kelburn Farm, has been growing soybeans for over 15 years in the Red River Valley. Here are some of his tips to help you with your soybean crop this year.

1. Field Preparation

Planning the crop you’d like to plant on a particular field next year begins with preparation the previous year. Factors you should consider include:

  • Previous crop
  • Herbicide used and risk of carryover into next year
  • Weed control
  • Residue management

Soybeans typically follow a cereal crop, such as spring wheat, in Manitoba. Drought conditions in the previous crop year before you plan on planting soybeans should be considered as herbicides have less moisture to break down.

This can cause a carryover into the following year from clopyralid-based products, such as Curtail™ M and Lontrel™. Pre-seed injury can result from the use of 2,4-D. Keeping good farm records is a key to being prepared and aware of any concerns that could arise.

Soybeans are not good weed competitors. Addressing fields that have perennial weed problems and tilling the soil in the fall as well as managing volunteers in the previous year will help to reduce volunteers the following year. This will also help prepare the soil for spring planting.

A tilled field tends to warm up more quickly in the spring, however, based on our experience this winter at Kelburn Farm, we might consider throttling back a bit as we are experiencing some soil erosion.

2. Soil Testing

Soil testing will help indicate if there is a salt problem in your field. Fields with salts below one mmho/cm are preferred. Carbonate (CCE) levels are preferred below three per cent and pH levels should be between 5.6 and eight.

Factors to consider when reviewing your soil sample are residual nitrate, phosphate and potassium levels. Residual nitrogen levels may vary depending on cropping history. First time growers should have some residual nitrogen available, while fields with a history of soybeans can be lower.

Phosphate levels should be above eight ppm, not only for the soybean crop, but for future crops. Potassium levels should be in the 200 ppm level or greater on sandy soils, and 400 ppm or greater on clay soils. If soil nitrogen levels are above 50 lbs in the top six inches, an alternative crop such as canola should be considered to take advantage of the residual nitrogen.

3. Variety Selection

The first thing to consider in variety selection is your farm location and your area’s heat units. Soybeans have a maturity rating and are listed in CHUs or relative maturity. For example, a 000.9 soybean is an early maturing soybean and is suited for more northern areas or areas with a shorter growing season. A 00.9 maturity soybean is later maturing than a 000.9, and is also later maturing than a 00.5.

Plant a variety that is suited for your area. Fortunately, there are a host of choices for the lower heat unit areas in both RoundUp Ready 2 Yield® and Xtend.

Plant height and structure along with iron deficiency chlorosis (IDC) should also be taken into consideration for each farm or field. Select a variety with a low IDC rating if there is a risk on your field.

4. Planting and Population

Soybeans are planted according to seeds per acre. This is indicated on the bag by seed size. Soybeans are sold by the unit, which is 140,000 seeds. If your target population is 200,000 seeds per acre, a quick calculation of planting population divided by seeds per pound will indicate the seeding rate in pounds per acre.

Factoring in germination, emergence rate and mortality can help to ensure that you reach your targeted plant population. A good rule is to assume X germination, X emergence rate and X mortality. You can calculate what you need to seed working back from those three factors.

5. Planting Date and Depth

Date and soil temperature have always been major discussion points. Should soybeans be planted according to soil temperature, or should you wait for a certain calendar date? Each year, this can be different.

Soybeans should not be planted into cold soil, such as below five degrees Celsius. A preferable temperature is when soil has reached nine or 10 degrees Celsius. Some years, however, this may not take place until the end of May. My preference is to plant on the upside of the weather forecast. If the next three to four days are calling for warm daytime temperatures and soil temperature is rising, then planting can begin, depending again on where your farm is located.

If early spring frost is a concern, then waiting until mid-May to start is reasonable. Do not plant before a rain since spring rains can cause the soil to cool down. This can result in very slow emergence for the soybeans.

Planting depth should be into moisture and not on top of moisture. This depth should be in the one to 1.5” range. Shallow planting can run the risk of the soil drying out and the seed germinating. This causes the seed to run out of moisture, resulting in death of the seed. Planting too deep means colder soil, further distance and more energy needed to emerge and a shorter first pod height as that first pod’s height is somewhat genetically fixed.

6. Row Spacing

Narrow rows of 10” or less are beneficial for first-time growers because the soybeans will cover the ground more quickly, which will help with later season weed competition. Short-season varieties, in some research trials, have shown better results on narrow rows as opposed to wider 30” rows. Narrow rows also take advantage of daylight. Soybeans are daylight sensitive and the more light they receive, the better they grow and mature.

7. Seed Treatments

Depending on the farm’s history and soybeans in rotation, seed treatments can help the soybeans emerge and fight off any early-season soil-borne disease and insect pressure. Seed treatments can also help soybeans in early-season planting with cooler soils to emerge quicker and healthier.

Check back next week for the second half of my tips for successfully growing soybeans. Subscribe below to receive updates when new reports and articles are posted on the Richardson Results website.