Early season, The Bean Report

The Bean Report – May 22, 2024

MAY 22, 2024

Listen to the Bean Report:

Crop & Seeding Update

  • Seeding is progressing around various rains and recent hailstorms. Rain showers have been fairly consistent across the province to start off the spring. Geomagnetic storms from May 10-13 brought stunning auroras to the sky and also caused interruptions to gps signals, halting seeding progress in some fields.
  • Soybean seeding is ongoing, with an expected increase in acres this year.
  • Field peas are emerging to VS stages across the province, with some seeding ongoing this week.
  • Dry bean seeding has begun with good soil moisture and temperature conditions. Acres are expected to increase this year, above the 5-year average of 155,000 acres.
  • Faba bean seeding is nearing completion.
  • The majority of On-Farm Network seeding timing trials in soybeans and peas have been established, with dry bean nitrogen trials going in this week.
    • Soybean trials are investigating seeding rates, row spacings, inoculation strategies and iron deficiency chlorosis. Pea trials this year are evaluating seeding rates, seed treatments and inoculation strategies.

Dry Bean Seeding Snapshot

  • Plant dry beans from late May to early June, once soils have warmed to 15°C.
  • Plant at a depth of 1 – 1.5”, placing seeds into moisture.
  • 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 to planting these bean types in narrow rows.
  • Target plant populations vary with market class, seed size and, in some cases, row width.
  • Weed management can be a challenge since dry beans are poor competitors with limited in-crop herbicide options. Start by choosing to plant into clean fields with low weed pressure and limited perennial weeds. Aim to keep the crop weed-free until V6, roughly six weeks after planting. Use a pre-plant incorporated herbicide and scout the field early after emergence.
  • Seed treatments are available to minimize the impact of early-season root rots and seedling diseases. Seed Treatment Options for Dry Beans in 2024 →

Research Highlights: Row Spacings and Seeding Rates

Seeding recommendations were revisited for dry beans by Dr. Rob Gulden, with the U of M at Carman and Portage from 2015-2018. Navy and pinto beans were seeded at four row widths (7.5”-30”) and five target plant populations ranging 40-200,000 plants/ac for pinto beans and 80-240,000 plants/ac for navy beans.

Yield

Planting at narrow row widths of 7.5” targeting moderate plant populations of 80-120,000 plants/ac resulted in the greatest, most stable yields for navy and pinto beans.

  • Planting at 7.5” row widths improved dry bean yield over 30” rows by 80% in wet years (2015/16) and 100% in dry years (2017/18), on average.
  • Planting at 15” row widths improved dry bean yield over 30” rows by 26% in wet years (2015/16) and 42% in dry years (2017/18), on average.
  • Plant populations below 80,000 plants/ac reduced the crop’s ability to compete with weeds, and weed control became an issue.
  • Plant populations above 120,000 plants/ac resulted in more severe white mould infections in wet years (2015/16) and caused stand loss.

How does this compare with North Dakota research?

White Mould

White mould was prevalent in 2015 and 2016 due to greater in-season precipitation.

  • Increasing plant population consistently increased white mould severity in 2015/16.
    • For navies, 80-120,000 plants/ac minimized white mould pressure while maintaining yield.
    • For pintos, 80,000 plants/ac minimized white mold pressure while maintaining yield.
  • Where row spacing impacted white mould severity (at 2/3 site-years for navies and 3/4 site-years for pintos), white mould was generally worse at intermediate row widths (15-22.5”).

How does this compare to North Dakota research?

Michael Wunsch, NDSU-Carrington has evaluated the impact of row spacing and plant population on white mould severity in low, medium and high disease pressure environments for pinto beans.

  • Under low disease pressure environments, pinto bean yield was maximized with 7.5” and 15” rows. As disease pressure increased (>20% of plants infected), yield differences among row widths did not occur.
  • Under medium to high pressure disease environments (more than 20% of plants infected), 15” and 22.5” rows had more severe white mould infections than both 7.5” and 30” rows. When less than 40% of plants were infected, 30” rows had the lowest severity.
  • 5” rows only had greater disease severity under low disease pressure environments, which was also where yield was maximized with narrow rows (increased by roughly 400 lbs/ac)
  • Increasing seeding rates from 70,000 seeds/ac increased white mould severity with little to no yield gains in pinto beans when white mould was present.
  • Improving Management of White Mold in Dry Beans →

Lowest Pod Height

Investigating the factors contributing to lowest pod height in these trials indicated that environment plays the biggest role in determining the height of the first node, followed by variety. Row spacing and plant populations by comparison, were responsible for a very small part of the variation in lowest pod height.

  • Narrower rows (<15”) increased pod height by 0.5-0.8 cm in pinto beans,
  • Increasing plant population increased pod heights for T9905 navy beans, but not for other varieties tested (Envoy, Windbreaker, Monterrey).

Dry Bean Inoculant Research in Manitoba

Although dry beans are N-fixers, they are not as efficient as other pulse crops, with the ability to produce 45% of their N requirements on average. Dry beans require the bacteria Rhizobium leguminosarum biovar phaseoli for nitrogen fixation to occur. This is a different rhizobium than for soybeans or field peas.

Inoculants for dry beans have been limited in their availability so they have traditionally been fertilized like a non-legume crop. However, we often see active nodules in the field, indicating that N-fixation is occurring. As a result, research is revisiting the contribution of biological N fixation to dry bean yield.

Successful dry bean inoculant products have the potential to improve dry bean N-fixation, reduce fertilizer use and improve dry bean economics.

Small Plot Research – Evaluating Available Inoculant Products

From 2017-2019, Kristen MacMillan, UM-MPSG Agronomist-in-Residence evaluated two dry bean inoculant products, BOS self-adhering peat inoculant and Primo GX2 granular inoculant (later re-formulated and named N Charge) at Carman and Melita in pinto, navy and black beans. The Primo GX2/N Charge inoculant resulted in better nodulation and a yield advantage in 2020/2021 when compared to untreated and the BOS peat inoculant. In Carman, nodulation was lower overall, and nodulation and yield were the same for the inoculants tested and untreated. Report →

In 2022, four inoculant products were tested and had no effect on yield in Carman, Melita and Portage.

Stay tuned → these research trials are continuing, testing inoculant products in combination with different nitrogen rates.

Developing an Effective Inoculant for Dry Beans

In 2023, Dr. Ivan Oresnik, University of Manitoba, and Dr. George DiCenzo, Queen’s University initiated a research project to isolate strains of native rhizobia from soils with dry bean history. This research aims to identify which of those strains that are forming nodules with dry beans in the field are the most effective at fixing nitrogen. The ultimate goal is to develop an inoculant for dry beans that is readily adaptable for Manitoba conditions. More than 200 strains of rhizobia have been isolated from those soils to-date and This research is on-going.

On-Farm Network: Dry Bean Inoculant Trials

MPSG’s On-Farm Network has hosted five on-farm trials testing dry bean inoculants. So far, there has been no significant effect on nodule number or dry bean yield. Full Report →

Late Spring Frosts

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.

Soybeans and dry beans are susceptible to frost damage because their growing points are located above ground. At this time, 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 or topping up plant stands 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.

Assessing Early-Season Frost Damage →

Meet Our Field Team

Have pulse or soybean agronomy questions this growing season? We’re here to help! Contact Laura (204.751.0538, laura@manitobapulse.ca) or Jennifer (204.751.0737, jennifer@manitobapulse.ca).

Interested in an on-farm trial or results from the On-Farm Network? Contact Chris (204.751.0439, chris@manitobapulse.ca).