Jennifer McCombe-Théroux, Production Specialist – East, MPSG
Pulse Beat 96, Fall/Winter 2022
Farming and each growing season never fail to amaze me. We plan, prepare and then execute – all while never knowing what Mother Nature will throw at us. This spring was a complete 180° from last year: we went from early seeding and persistent dry and hot conditions to a prolonged wet and cold environment that continued well into late spring. In early May, heavy precipitation and flood waters caused extensive overland flooding across Manitoba, with 26 municipalities declaring flood-related states of emergency.
Seeding operations were delayed overall, and occurred on a field-by-field basis that depended on which field was ready, with the same crop type being sown across a wide range of seeding dates on each farm. For example, one farm that was part of the Manitoba Pulse and Soybean Growers (MPSG) Scouting Network had seeding dates for field peas ranging from May 25 to June 15. This wide range of seeding dates added another level of complexity to each farming operation. Switching crop types involved recalibrating drills and prioritizing field operations between seeding, spraying, rolling, and in some cases cleaning up debris from flood waters. As spring progressed, challenging weather conditions continued. Farmers started prioritizing the crops to sow based on maturity and crop insurance deadlines. By May 31, the provincial seeding progress sat at 40 per cent completion, in comparison to the five-year average of 92 per cent seeded.
Due to wet conditions and calendar dates, some farmers switched crop types out of longer season crops, including soybeans. The Morris soybean variety trial site was discarded due to saturated wet conditions that did not dry up enough to allow proper seeding within a reasonable timeframe.
This spring, Manitoba Agriculture Services Corporation (MASC) permanently extended the soybean seeding deadline (Table.1). More varieties have adapted to Manitoba conditions since soybean seeding deadlines were last determined, and the change reflects an accumulation of new and more up-to-date data. This review was well-time, considering the season’s delayed timed seeding. These changes were made in consultation between MASC, MPSG and Manitoba Agriculture.
Good, vigorous emergence was common this year due to adequate moisture and shallower seeding, along with little to no crusting. Many low spots were not seeded due to standing water and conditions that were unsuitable to pass through with the seeder. Due to wet conditions and time management, many farmers were forced into post-emergent rolling instead of right-after seeding for soybeans and pulses, an option that adds flexibility if conditions are not suitable for the former method. Rolling in saturated fields can cause soil crusting and sealing which inhibits emergence. Soybeans can be rolled post-emergence at the first trifoliate stage (V1), and field peas up until the third true leaf node stage (V3). There were some signs of seedling stress and disease, along with strong winds, sand blasting and hail reported in various areas, which did impact crops, but most grew through it.
July had great growing conditions with warm weather and consistent rainfall, resulting in incredible growth in pulse and soybean crops. It was a late start, about a month behind normal, but pulse crops grew rapidly. The growing season conditions were conducive to disease development in many regions. Thanks to consistent rains, high humidity and thick canopies from established plant populations, canopies stayed wet for prolonged periods. On many fields foliar and stem diseases did not impact peas and soybeans as early as anticipated. For peas, fields with good drainage, first-time fields or fields with extended rotations experienced the least amount of disease pressure. On heavier ground with poorer drainage, pea crops remained stressed, and stunted, and root rots developed. Pockets of root rot also appeared in low laying areas of fields. The importance of field selection and choosing the right fields for peas was magnified this year as they do not like standing water or prolonged wet conditions. Choosing fields with good drainage, and coarser soil types, and evaluating your rotation for disease carryover, proved especially important. In drier seasons prior to this year, farmers decided between one fungicide application versus none, whereas this year, they had to choose between one or two applications.
Fungicide applications for dry beans are purely preventative, meaning you spray before you see signs of white mould. Many farmers applied two passes of fungicide as conditions for disease development were strong, along with excellent yield potential. Some fields were impacted by late season white mould.
The resiliency of soybeans under a wet season shone through this year, and overall incidence of foliar and stem diseases was low. On heavier soils with consistent saturation, yellowing from moisture stress was observed, along with iron deficiency chlorosis (IDC), although most fields grew out of this, especially if a variety semi-tolerant to IDC was grown. Where more severe IDC symptoms occurs, it’s a good idea to test your soil for both carbonates and soluble salts. This information (Table.2) can aid in selecting a variety with the right IDC tolerance. This information is available in MPSG’s Soybean Variety Guide. Some fields were affected by Phytophthora root and stem rot (PRR), which showed up later in the season along with some late infection of white mould.
Source: Agvise Laboratories
As soybean acres continue to rise and become more common in rotations, PRR is a soybean disease that may become more challenging for Manitoba farmers. Once PRR is present in fields, the spores can persist in the soil for up to 10 years. PRR is unique in that it can infect soybeans throughout the whole season. Rotation and variety resistance are the best strategies to manage PRR but additional tools to address this disease are important to support the sustainable growth of soybean production. MPSG is collaborating with AYOS Technologies and seed companies to independently rate variety field tolerance or partial resistance to PRR, and trialing a soil test to identify which PRR pathotypes are present in fields infected by the disease. This information will help farmers select varieties with major gene resistance to those pathotypes. Read more about this research on page 33.
Thanks to heavy rains, strong winds and some hail, bacterial blight was observed in soybeans, peas and dry beans.
Generally, this is not yield limiting. It is important to differentiate Bacterial blight from other diseases as the blight is not managed with a fungicide. Bacterial blight generally impacts the top of the plant canopy as the damage is caused by environmental factors.
Distinctive pest issues of 2022:
1. Springtails were found feeding on soybean seeds in some fields. Springtails are tiny, wingless, white insects that live below ground. They are most harmful to seedlings.
2. Pea leaf weevil surveys across western Manitoba found low to moderate population densities in 2022.
3. Pea and soybean aphids were widespread and some at spraying thresholds across Manitoba (more on this here).
4. Grasshoppers were widespread in soybeans, field peas and dry beans but in many fields were mainly found along the edges.
5. Pea rust was observed in some fields in western Manitoba (more on page 24).
6. Root rots were present in low-lying areas and saturated pea and dry bean fields.
7. Late-season white mould infection was observed in both soybeans and dry beans.
8. Over 90 suspected samples of water- hemp were submitted to the Pest Surveillance Initiative Lab, and the majority were confirmed. Water-hemp is a Tier 1 noxious weed, meaning all plants must be destroyed if found. Do not put water-hemp through the combine, or you risk spreading the seed. Water- hemp is a prolific seed producer (with an average of 250,000 seeds per plant), so we recommend that you physically remove it from your field by pulling it up, digging up the roots, and bagging it for removal.
Soybeans, peas and dry beans each demonstrated a fantastic number of pods per plant and seed per pods. The yield potential of each looked strong.
Pea harvest started in mid-August this year and varied across the province based on seeding date. Large biomass, high moisture conditions, and heavy winds and rains meant many pea crops had lodged in-season, which made harvest slow going. Based on field characteristics and moisture, there was a wide spread of yields for field peas, most averaging between 50 and 80 bu/acre.
Dry bean harvest started in early September on earlier sown fields and reported fantastic yields reaching 2,000 – 3,000 lbs/acre in a wide range of bean classes. 2017 holds the record average for dry bean yields at 2,100 lbs/acre. Signs are promising that the average may exceed this in 2022.
This year the concern in soybeans was if maturity would be far enough along to withstand a frost. As soybeans reach R7 staging (early maturity,) the risk of yield loss from frost declines. While Manitoba soybean fields experienced a a range of staging based on seeding dates and maturities, some earlier soybeans
started reaching R7 by the second week of September. A killing frost arrived in much of the western side of the province on September 22 with the rest of the province following on September 27. Thankfully, most soybean crops were then past the risk of frost damage.
August rains are critical for seed fill and yield. Throughout the season, rains were consistent, especially in August, which contributed to a strong yield potential with a high number of pods per plant and seeds per pod. In soybeans, many fields saw four or five beans per pod. Soybean harvest slowly started mid- September in central Manitoba in earlier maturing varieties and earlier sown fields. The resiliency of soybeans throughout this challenging season shone through, with yields averaging between 40 and 65 bu/acre.
Although it was an unusually late start to a season that confronted farmers with countless challenges, Mother Nature provided some balance and offered an extended fall without an early frost, along with some fantastic yields to make us all optimistic for next year.
For more specifics on the past growing season, visit the catalogue of Bean Reports at manitobapulse.ca/the-bean-report.
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