Cassandra Tkachuk, MSc, PAg, CCA, Production Specialist, MPSG
ACRES AND VARIETIES
In 2019, 1.39 million acres were seeded to soybeans in Manitoba. That marks a decline by approximately 504,000 acres from 2018. This is also the second drop in acres since soybeans peaked at 2.26 million in 2017 (Figure 1). However, soybeans are holding strong, still ranking as the third-largest crop in Manitoba.
Field peas and dry beans were a different story. Pea acres increased to 112,700 acres, up by 28,500, and dry beans rose to 155,700 acres, up by 34,000. The most dramatic increase occurred for navy beans, by about 23,000 acres. But we also saw a rise in pinto, kidney and other (e.g., pink, yellow, Great Northern) bean acres.
We generally see one or two dominant varieties for each market class of dry beans, according to the MASC variety market share report. In 2019, Vibrant (50.7%) unseated Windbreaker (34.7%) as the top pinto bean variety, T9905 (79.9%) remained the top navy bean variety and Eclipse (76.4%) remained the top black bean variety. For smaller-acre beans, Red Hawk (44.7%) and Pink Panther (28.9%) were the top kidney bean varieties, Crimson (36.5%) and Chianti (27.7%) were the top cranberry bean varieties and Merlot (97.3%) was dominant for small red beans.
There have been four popular pea varieties over the past two years. CDC Amarillo (21.2%) held its top spot in 2019, followed closely by AAC Carver (19.3%), CDC Meadow (14.2%) and Abarth (13.4%).
Soybean variety market share cannot be summed up so concisely. The top variety grown in 2019, S007-Y4, held 14.2% of the market share. From there, we see the remainder distributed among a long list of soybean varieties. In a nutshell, the market is flooded, but a wide range of choices and competition in the marketplace are good things.
A COOL, DRY SPRING
The 2019 growing season may be remembered by most as the third dry year in a row in Manitoba. This is nothing new for pulse crops like peas that prefer drier conditions, or edible beans that have a longer history in Manitoba. But this did present a relatively new challenge for our long-season, water-loving soybean crops.
What drove plant development was not just the amount of rainfall but the timing. Most of Manitoba faced dry conditions until an extreme rainfall event on July 9–10 that dropped as much as 6–10 inches of rain at certain locations. Some areas within the northwest, central and Interlake regions seemed to be hit especially hard by dry conditions, where this substantial rainfall event was the only precipitation fields received.
Spring started with slow seedling emergence due to both cool and dry conditions. Scouting in May consisted mainly of seeding depth assessments as we patiently waited for pulses and soybeans to emerge. Dry soil at seeding again tempted farmers to push the boundaries on seed depth to access precious moisture. Yellow cotyledons and swollen hypocotyls (Figure 2), the stress symptoms of deep seeding, were a common sight this past spring as in the previous two years. Delayed and non-uniform emergence was also common, where seeds that were either placed very shallow or placed very deep, emerged later.
Growing degree-days (GDD), the measure of heat accumulation relevant to pulses and soybeans, remained low throughout May and June. So, lack of heat also played a role in slowing plant development. By June 24, 2019, GDD across agro-Manitoba ranged from 66–91% of normal (283–468 GDD) compared to 108–143% of normal (469–699 GDD) by June 24, 2018. GDD accumulation somewhat caught up in July but was still below normal.
At the time of flowering in 2019, soybean crops were about two to three trifoliate stages behind those grown in 2018. In other words, we saw less vegetative growth prior to flowering from these cool, dry conditions. That may be one contributing factor to yield loss.
A significant wind event occurred on June 7, which I fondly refer to as “dust bowl Friday.” It was the type of weather that filled your vehicle with soil if you opened the window to snap a photo. Damage occurred in some fields as abrasion to seedlings or a pinched hypocotyl where wind spun the plant around. Plants grew past it or branched out to compensate for lost stand and it was eventually unnoticeable.
THE YEAR OF THE INSECT
Another thing we will remember about 2019 was the insect pressure. For pulse and soybean crops, the main culprits were cutworms and grasshoppers. It seems that we saw more cutworm and grasshopper pressure than ever in these crops. Several crops were sprayed more than once, some were reseeded and crops like peas and faba beans showed their ability to regrow following cutworm damage (Figure 3).
Green cloverworm, a noted insect pest of soybeans and dry beans, and thistle caterpillar were also present in 2019. Last seen in great quantities in 2017, thistle caterpillar can often appear to be more of a pest than it really is due to its ugly presence in the upper canopy. A few fields in 2019 had damaging populations, but most bean crops did not experience significant defoliation and yield loss from these two pests.
For a full review of insect pressure in pulse and soybean crops, refer to Manitoba Agriculture Entomologist John Gavloski’s article.
FIELDS TURNING YELLOW
In some regions of Manitoba, we saw curious mid-season yellowing of soybean crops. There were a few potential causes that could not be diagnosed from the road.
The most common cause was a late flush of iron deficiency chlorosis (IDC) in soybean crops. Soluble salts and carbonates are the main drivers of IDC. Since there is a naturally high carbonate concentration across much of Manitoba, this IDC was likely brought on by the rise of salts to the upper soil profile via mid-season rainfall. Depending on its persistence in a field, IDC could be another source of yield loss in 2019.
It is important to note that pulse and soybean crops have a lower tolerance to salinity than other crops. That means excessive salt concentrations will injure these plants by disrupting water and nutrient uptake into the roots. An increase in salinity over the past couple of years has been noticed in some areas. We recommend keeping an eye on soluble salt concentrations each year to gauge your risk.
Other (less common) causes of yellowing would have been nitrogen deficiency due to inoculant failure or the presence of root rot. However, we saw less infection in 2019 from soil-borne pathogens such as Fusarium spp. or Phytophthora root rot, which prefer wetter soil conditions. That is one good news story from 2019.
NEW PESTS – A WEED, A DISEASE AND AN INSECT
In 2019, we identified three new economically important pests. But these findings don’t come as much of a surprise. We have been actively monitoring for these pests and expecting their arrival.
Tall waterhemp was reported by farmers who noticed large, surviving weeds in their fields. A few tall waterhemp plants had been found previously in Manitoba, but more significant populations were found in 2019. This weed is worrisome because it is a prolific seed producer with documented resistance in the U.S. to at least seven herbicide classes. It is also a Tier 1 noxious weed that has to be destroyed.
To date, tall waterhemp has been identified in four different municipalities — Dufferin, Rhineland, Ste. Anne, Reynolds and Whitemouth. Manitoba Agriculture and Resource Development Weeds Specialist, Tammy Jones, has been working with farmers to prevent the spread of tall waterhemp and communicate our concerns about this pest. For everything you need to know about tall waterhemp, check out Tammy’s article.
Soybean cyst nematode (SCN)
The presence of SCN was confirmed in Manitoba in 2019 due to monitoring led by Dr. Mario Tenuta at the University of Manitoba. It was detected in four out of 106 fields and four out of 18 rural municipalities (Emerson-Franklin, Montcalm, Rhineland and Norfolk- Treherne) in total throughout the entire survey’s history. Thankfully, SCN populations are extremely low and consistent with the recent establishment of the pest. Unfortunately, once present, this pest cannot be eradicated from a field and can spread rapidly
Preventing soil movement is the best way to keep this pest out of your field. SCN populations can also be managed by rotating to non-host crops (soybeans, dry beans and peas are all hosts), growing resistant varieties, controlling host weed species and reducing tillage. To learn more about this pest and the findings in Manitoba, refer to the SCN article on page 37 and visit scncoalition.com.
Pea leaf weevil
Pea leaf weevil, a pest of peas and faba beans that we have been tracking across Western Canada, was officially detected in Manitoba for the first time in 2019. This detection was made by an agronomist in the Swan River area. Active monitoring also took place in the highest-risk pea growing areas along the Saskatchewan border, led by John Gavloski.
Pea and faba bean growers, especially those in the western areas of the province, are advised to scout for this pest throughout the coming growing season and assess the impact in individual fields before adjusting management practices. Plans are in place to continue monitoring for pea leaf weevil in 2020. For more information, visit John Gavloski’s article.
When we thought our crops had been through enough, the rains finally came at harvest. This left some dry bean crops sitting in windrows or standing in the fields, and most soybean crops still standing. Some quality loss was noted at the time, including sprouting. But most crops were still looking good.