Early season, The Bean Report

The Bean Report – May 26, 2021

May 26, 2021

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Crop Update

  • Soybean seeding really took off for most farms over the last two weeks, with most acres seeded ahead of the May long weekend (70-95% complete across the province). The seeding window is still open for the remaining soybean acres and maximum yield potential can be achieved by planting before the end of May. Soybeans that were planted during the first half of May have emerged and are currently at the VE (emergence) to early VC (unifoliate) stages. Soybean seed depth is variable in many fields. Most seed was driven deep to access soil moisture. In some cases, soil moisture dropped even lower without timely rains following seeding, leaving partially germinated seeds to desiccate.
  • Dry bean seeding ramped up last week (55-65% complete) and is continuing into this week. Seeding is on pause in some fields due to wet soil conditions following the long weekend rain. Seeds have germinated and plants will soon emerge. With this week’s frost risk, it is good news that most bean seedlings are still safely underground.
  • Field pea seeding is complete in the province, with crops ranging from V1 (1st true node) to V4 (4th true node) in western Manitoba and V2 to V6 in central and eastern Manitoba. Keep an eye on true node stages of pea crops as you apply post-emergent herbicides. The cut-off for most products is V6 and plants with short stature may be surprisingly advanced due to dry conditions during early development.
  • Faba bean crops have been slow to emerge with the lack of moisture. Emerged crops are currently at the V1 (first leaf) stage.
Emerged faba beans near Oakburn on May 20.
Field peas at V3 near Plumas on May 19.
Faba beans near Oakburn on May 20.
Germinating soybeans near Gladstone on May 20.
Oak leaves near Neepawa on May 19 – an indicator that it is a good time to plant dry beans (when the oak leaves are the size of a mouse’s ear).
Peas emerging from a 1-inch depth near Dauphin on May 14.
Peas emerging near Dauphin in between no-till cereal stubble on May 14.
Seeding soybeans into no-till canola stubble near Dauphin on May 14, 2021.
Germinating faba bean seed from the regional variety trial at Dauphin on May 14.
Peas at V2-V3 near Plumas on May 19.
Field pea seedling at the 2nd true node stage (excluding the two scale nodes at the base) near Roland on May 18.
Field peas sending out tendrils that will eventually clasp with their neighbours’ on May 18.
Pea seedling that emerged from a 1/2″ depth.
Soybean at the hypocotyl arch stage about to break through the soil surface on May 19.
Yellow soybean cotyledons as a sign of stress from deep seeding.
Emerged soybean seedlings at the VE stage near Winkler on May 19.
Soybeans that emerged from 1 1/2-inch to 1 3/4-inch depths (the maximum depth at which soybeans should be planted).
Germinating soybean seeds in-furrow on May 19.
Pinto bean seeds planted at a 1-inch depth into soil moisture on May 17.
Twisted soybean seedling from cold stress that coincided with May 3-7 seeding dates.
Emerged soybeans near Roland on May 17. Seeded May 1.
Soybean seedling showing stress symptoms from deeper seeding.
Soybean seeded at a 1-inch depth.

Seeding Progress of All Crops in Manitoba

Weather Update

Frost in the Forecast

Frost is in the forecast tonight, with expected lows of -1°C to -5°C around the province. Peas and faba beans have good frost tolerance, as their growing points are located below ground. If damaged, pea and faba bean plants can regrow from the seed below ground, or from the scale nodes if the main stem has been damaged. For crops with more advanced development, this can negatively influence crop uniformity.

On the other hand, soybeans and dry beans are susceptible to frost damage because their growing points are located above ground. At this time, most dry bean crops have not emerged yet and are safe from frost, but emerged soybean seedlings are at risk of damage. The level of damage incurred will depend on the severity and duration of freezing temperatures. Temperatures lower than -2°C are considered to be a hard or killing frost, and there is a risk of severe damage if these temperatures persist for more than 2 hours.

Scout your soybean fields 3-5 days after the frost event to assess the growing points and plant stand. Count the number of healthy plants and those that have green tissue and show signs of regrowth. If plant populations are very low (<80,000 plants/ac), re-seeding options should be considered.

Factors that influence frost severity:

  • Duration of cool temperatures – longer duration of freezing temperatures can cause more damage.
  • Soil moisture – moisture in the soil will retain heat.
  • Wind speed – stronger wind can reduce the severity of frost.
  • Cloud cover – more nighttime cloud cover can reduce plant damage.

Precipitation

Most areas of Manitoba finally received rainfall amounts worth calling home about (20-30+ mm) over the May long weekend. Areas along the western edge and in the central and eastern regions of the province received the most rain (>40 mm). However, there were pockets that received less than 20 mm along the U.S. border in the western and central areas of the province and northern areas located to the west and east of Lake Manitoba.

Find more detailed weather stats, including rainfall amounts from the past 8 days and rainfall since May 1 in the Manitoba Agriculture and Resource Development Crop Weather Report.

Dry Bean Seeding Recommendations

  • Plant dry beans from late May to early June, once soils have warmed to 15°C. MASC seeding deadlines are June 10 for risk area 1 and June 6 for risk areas 2, 3 and the insurance test area.
  • Plant at a depth of 0.75 – 1.5”, placing seeds into moisture.
  • Dry bean inoculants and nitrogen fertility recommendations are currently being researched at the University of Manitoba (U of M). So far, the inoculants available to farmers had little success, so nitrogen fertilization to an average rate of 70 lbs of N per acre continues to be standard practice. This means 70 lbs as a combination of residual soil N and applied N.
Dry bean yield response (% of non-fertilized control) to N rate (lbs/ac) at five site-years in MB from 2017-2019. Means followed by different letters are statistically different at p<0.05.
  • Research on row widths and plant populations for pinto and navy beans has recently wrapped up at the U of M. Dry beans can successfully be planted in narrow (<15”) or wide rows (>15”), with black, navy and pinto bean types typically being better suited to narrow-row production. Research has indicated a yield advantage (90% yield increase) to planting these bean types in narrow rows (7.5”), targeting plant stands of 80-120,000 plants/ac.

  • Target plant populations vary with market class, seed size and, in some cases, row width (see table below). Dry bean seed is susceptible to damage from handling, whether you’re cleaning seed, treating seed, or running it through equipment. Soak tests reveal if seed coats have been cracked or damaged and are a useful tool to help you adjust your seeding rates before planting.
  • Rolling in dry bean fields is more common if you’re planning for direct harvest. When rolling post-emergence, target the V1 to V2 stages and roll during the afternoon of a warm (25°C+) day. Check for breakage as you go.

Pre- and Post-Emergent Dry Bean Herbicide Options

Pre- and Post-Emergent Soybean Herbicide Options

Soybean Seed Depth Assessment

The optimum seed depth for soybeans in Manitoba is 0.75 to 1.75 inches. Ensuring seed depth is within the optimum range will strongly influence soybean yield.

  • Dig for seed carefully using a good digging tool (one that is small, sturdy and has a ruler). Scrape away soil within the furrow to uncover seed or underground seedlings. Measure the distance from the seed to the top of the true soil surface. This does not always equate to the top of the furrow. Check different furrows along the seeder, noting whether you are in a wheel track or not.
  • Post-emergent seed depth assessment can be done by measuring the length of white space along the hypocotyl from the root hairs to the green tissue.
  • Does your equipment influence seed depth? If your seeder has openers that dig a deep furrow and create bigger hills, and/or if you have wide packing wheels that push more soil over the furrow, your seed may end up deeper than intended. Rolling afterward may add even more soil to the furrow. Try to anticipate how much additional soil will be pushed onto the furrow after rolling. Check seed depth after rolling to accurately estimate this and achieve the seed depth you want in future years.
  • Symptoms of deep seeding may include a swollen hypocotyl, elongated hypocotyl arch, yellow cotyledons above or below ground and/or loss of cotyledons. Deep seeding is considered to be >1.75 inches, according to the most recent research from the Soybean and Pulse Agronomy Lab in Manitoba.
  • Symptoms of shallow seeding include seed stranding, where seeds did not make it into the furrow, desiccated seeds within the furrow that partially germinated then ran out of moisture or reduced plant stand after emergence.

Update from the On-Farm Network

Most of the On-Farm Network trials are in the ground, with just a few more soybean and dry bean trials to plant. We have quite a diverse program lined up this season, with more trial types in peas and dry beans than ever before. Whether you have questions about soybean row spacing, dry bean fertility, pea seeding rates, faba bean fungicide or lots of things in between, the 2021 OFN program has something for you! Stay tuned to The Bean Report, OFN in the Field and follow along on Twitter (@OFNagronomist) to keep up with the OFN team this season!

Scouting Sessions: Scouting and Trapping for the Pea Leaf Weevil

Resources to Stay Connected

While we operate in a virtual space again in 2021, there are several resources available to stay connected and learn from experts in the industry. This year, the agronomy team at MPSG is bringing you Scouting Sessions – a series of short videos on timely and interesting pulse and soybean topics. These videos will be available on our social media, website and in The Bean Report throughout the season!

Educational resources to sign up for:

New Fact Sheet! Guide to Conducting On-Farm Trials

Quick Links to Production Resources

Soybeans

Field Peas

Dry Beans

Faba Beans