When is the Best Stage to Roll Soybeans After They Have Emerged?

Submitted by Dennis Lange, MAFRD Farm Production Advisor (Altona).  Updated from Manitoba Cooperator article by Allan Dawson, published on June 27, 2013 “Trifoliate stage best for rolling soybeans after emergence”

Don’t roll soybeans until they reach the first trifoliate stage, or you risk breaking too many young plants.

  • You don’t want any beans at the hook stage
  • Only roll if you have some stones or dirt that will cause you some harvest issues
  • Wait until later in the day when it’s warmer and plants are more plastic and should have less breakage (check to see if plants are breaking) 

Why Roll Your Soybean Field?

Rolling pushes down stones and levels the field allowing the combine cutter bar to be set lower and pick-up low-handing pods.  It can make soybean harvesting faster, more efficient and will reduce the risk of stones damaging the combine.

Soybean plant at firth trifoliate. Picture by Dennis Lange, MAFRD

Soybean plant at first trifoliate. photo: Dennis Lange, MAFRD

These emerging soybeans are at the hook stage. Rolling plants at this stage will cause a lot of plant damage. photo: Dennis Lange, MAFRD


This soybean plant is at the unifoliate stage with two true leaves and the cotyledons below. photo: Dennis Lange, MAFRD


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Seeding Date Relationship to Crop Yield

One of our most used extension messages is seed early!

In a year that is later, this may cause some concern that seeding into the second half of May is not going to have good crop yields. Typically seeding earlier does normally translate into higher yields, but good yield potential remains when seeding throughout the month of May, provided you don’t compromise the seeding operation.

Things Other than Seeding Date That Influence Yield:

  • Using clean seed with high %germination
  • Applying the appropriate fertilizer nutrients and rates to support yield goals
  • Seeding for a good plant stand – taking in account TKW, %germination and seed mortality!
  • Seeding into a firm seedbed
  • Seeding into soil warm enough to result in quick germination and emergence
  • Timely weed control
  • Timely fungicide application if needed
  • Appropriate harvest operation timing

2005-13 Seeding Date x Yield

Table 1: Crop Yield Response to Seeding Date (2005-2013)

Source: MASC – Harvested Acreage Report (2005-2013)

For more information see MAFRD website post “Crop Choice Considerations in a Delayed Year”  http://www.gov.mb.ca/agriculture/crops/production/crop-choice-in-delayed-year.html


 Contributed byAnastasia Kubinec, MAFRD Oilseed Crop Specialist



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What are minimum germination temperatures?

Soil temperature is a useful gauge for timing when crops are seeded.  Table 1 shows the minimum germination temperatures for various crops.  These values should be regarded as approximate since germination depends on several factors.  If the soil is too cool, germination can be delayed which can result in uneven or inadequate seedling emergence.

How do I measure soil temperature?

Determine how deep you will be seeding. Then place your soil thermometer at that targetted depth. Take two measurements throughout the day: one in the morning (8am) and one in the early evening (8pm) . Average the two readings to determine the average soil temperature.

MAFRD recommends that you take readings for two to three days to establish a multiple day average, and reminds you to measure temperature in a number of locations in the field, to account for field variability.  Still not sure, see soil temperature data for various locations across Manitoba is available from MAFRI’s Ag-Weather Program:  http://tgs.gov.mb.ca/climate/SoilTemp.aspx.  This can be used as a guideline for an area, but in-field measurements are going to tell you what is actually going on in your field!

Table 1: Minimum Germination Temperatures for Various Crops

Crop Temperature (°C)
Wheat 4
Barley 3
Oats 5
Corn 10
Canola 5
Flax 9
Sunflower 6
Edible Beans 10
Peas 4
Soybeans 10

Sources: North Dakota StateUniversity Extension Service, Alberta Agriculture & Rural Development and Canola Council of Canada

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Updated Treated Seed Best Management Practices

The Updated Treated Seed Best Management Practices document is now posted to the Health Canada website:  http://www.hc-sc.gc.ca/cps-spc/pubs/pest/_fact-fiche/pollinator-protection-pollinisateurs/treated_seed-semences_traitees-eng.php

The PDF of the updated document is also available:  Pollinator Protection and Responsible Use of Insecticide Treated Seed_January 8, 2014 (Health Canada)


Best Management Practices

Insect pollinators are vital to agricultural production and the environment. Many farmers, including those who grow corn and soybeans, use insecticide treated seed to protect their crop from insect pests. Some insecticides, such as neonicotinoids, are toxic to pollinators. Planting of treated seed can spread dust that contains insecticide into the air, placing pollinators at significant risk of exposure to toxic insecticides. Factors that impact the risk of exposure include the use of treated seed, type of planting equipment, planting conditions, flowering resources and bee yard locations.

The following Best Management Practices (BMPs) are provided to reduce the risk to bees and other insect pollinators from exposure to dust from treated seed. The BMPs provide a toolbox of options that should be used in combination wherever possible.

  1. Read and adhere to the pesticide label and seed tag directions
  2. Practice Integrated Pest Management when choosing seed treatments
  3. Develop and maintain shared communication with beekeepers to help protect honeybees
  4. Recognize pollinator habitat and take special care to reduce dust exposure
  5. Avoid generating dust when handling and loading treated seed
  6. Managing planting equipment to decrease dust drift
  7. Use appropriate seed flow lubricant
  8. Ensure proper clean-up and disposal

Submitted by:  Pam de Rocquigny, MAFRD Cereal Crops Specialist & John Gavloski, MAFRD Extension Entomologist

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Guidelines for Responsible Use of Neonicotinoid Seed Treatments

Prepared by Dr. John Gavloski, Field Crop Entomologist, MAFRD Crops Knowledge Centre

 Potential Risks (costs):     

  1. Increase in selection pressure to develop resistant insect populations if technology is overused.
  2. Potential increase in secondary pest populations
  3. Potential non-target impacts of the insecticide
  4. Increased cost to producer

 Potential Benefits:

  1. Reduced injury to crop from economic populations of insects that may be managed by insecticide
  2. Potential increase in early-season vigour of the crop under some growing conditions.        

When all components of the equation are considered, and the science to support all the components, a neonicotinoid-based seed treatment is most likely to be beneficial when there is a high risk of flea beetles (in canola), wireworms, or seedcorn maggots causing economic damage to the crop. Using neonicotinoids as “insurance” if the risk of damage by these insects is low, is not likely to be the most economical choice in most years.  

Regarding the potential increase of secondary pests, this is probably of greatest concern in corn and soybeans in drier years, where neonicotinoid seed treatments can potentially increase the risk of spider mites (Henry and Szczepaniec. 2013. Ent. Soc. America Ann. Mtg).

Regarding potential vigour-effects of neonicotinoid seed treatments, there are studies that do show some increased early season-vigour, regardless of whether insects are present, and other studies where this vigour effect did not occur. So a potential increase in crop vigour may occur, but may be dependent on growing conditions.   Using a neonicotinoid-based seed treatment for the primary purpose of increasing seedling vigour may not be the best use of the technology either economically or sustainably. In a risk/benefit analysis,  the 4 potential costs mentioned above need to be weighed against a potential increase in early-season vigour when deciding on a seed treatment. The other factor, and possibly the most important in the equation, is what is the risk of insects that the seed treatment may control (in Manitoba this would be flea beetles (on canola) or wireworms or seedcorn maggots).

In Canola: There are currently no seed-treatment alternatives to neonicotinoid insecticides (Lumiderm is currently applied with a neonicotinoid seed treatment). Flea beetles are a chronic and potentially serious pest of canola. Thus neonicotinoid-based seed treatments will likely remain an important management tool until alternative seed-treatments are available.

In soybeans and corn: Reduction in damage by wireworms and seedcorn maggots may occur if populations are high. Reduction in risk from soybean aphids would also be a consideration in some parts of North America, but not likely in Manitoba because the residual effect capable of providing control reaches levels that would be ineffective at killing aphids between 35 and 49 days after planting (McCormack and Ragsdale, 2006: Crop Management; Johnson et al., 2008. J. Econ Entomol. 101: 801-809; Tomizawa and Casida, 2003. Ann. Rev. Entomol. 48: 339-364).  So decisions on seed treatments in these crops in Manitoba, as well as other pulse crops, would most appropriately be based on the risk of wireworms or seedcorn maggot.

In Small grain cereals:   Decisions on whether a neonicotinoid-based seed treatment should be considered in these crops in Manitoba would most appropriately be based on the risk of wireworms.

In Potatoes: Wireworms can be a big concern and some control of other insects such as Colorado potato beetles is possible. Neonicotinoids will likely continue to be used quite extensively until other seed treatment or in-furrow options are available. A cautionary note, however, that Colorado potato beetle resistance to neonicotinoids has been documented in some parts of North America (Szendrei et al. 2012. Pest management Science. 68: 941-94).

Through a responsible use program and careful attention to how seeds are applied, many of the risks of neonicotinoid insecticides can be minimized. What commodity groups, and possibly even the companies that market neonicotinoid seed treatments, need to be concerned with is the overuse of the products when risk of potential threats the seed-treatments can control are low, and that all efforts are made to reduce the drift of dust from seed-treatments when planting corn and soybeans.

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Soybean Harvest Losses Based on Cutting Height

Prepared by : John Heard, MAFRD Field Crop Nutrition Specialist

There is always incentive to minimize harvest losses.  Here is a graph of measured losses due to improper cutting height in a low podding variety in 2013: Soybean Yield Loss Due to Cutting Height

Make sure you visit your farmer clients as they harvest to do some harvest loss measures.  Determine the average loss per square foot and divide the number of seeds by 4 to estimate bu/ac loss.  Cutter bars cutting stems at 2” will minimize stubble harvest loss.  If the combine operator will not slow down to 3 mph to maintain a low cutting height, then your farmer cannot afford to let them leave so much crop in the field.


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What Should My Soybeans Look like when they are Ready to Harvest?

Prepared by Dennis Lange, MAFRI Farm Production Advisor (Altona)

For new growers knowing when soybeans are ready to harvest can be difficult.  Driving by the field, you may think that it is ready to harvest, but on closer inspection you may find plants that still look yellow to green instead of tan to brown. If your entire field has a greenish tinge or a majority of plants in the field once you walk in look green, your beans would not be ready to harvest.  If there is only a few plants that look like this, you may be ok or this might represent only a low spot or less advanced spot in the field. 

Note the green stem in the group of brown stems


This Field is 5 – 7 days away from harvest (credit: D.Lange, MAFRI)

The soybean plants and pods when mature, should be brown or tan in color and the seeds should rattle in the pod.  When the crop is mature and ready for harvest the seeds would be oval shape and firm.

Seeds on left are ripe and ready to harvest, seeds on right are green and not ready to harvest

Once the combine pulls into the field check the moisture which should be below 13%. The Canadian standard for safe storage is 14% moisture, however soybeans going into the USA require 13% moisture and since a large portion of the soybeans do go into the USA  it best to keep below that 13% level.

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Manitoba Sclerotinia Risk Assessment Update

MAFRI currently does not produce sclerotinia risk maps like we do for Fusarium Head Blight, as we do not have a proven and consistent model to forecast sclerotinia risk. 

Since Manitoba producers grow multiple sclerotinia susceptible crop (canola, soybean, sunflower, dry bean, etc.), the inoculum is present in the environment, but risk and disease development is dependent on a combination of inoculum as well as day/night temperature, precipitation, crop canopy and soil moisture, which can vary from field to field.

 Scout and monitor your fields, you may be at greater risk and require a fungicide application if you have the following conditions:


  • Ground is damp to wet and,
  • Canopy is moderately closed to closed (i.e. you cannot see the ground through the leaves), and
  • Canopy is still damp to wet when walking through the field at 10am (i.e. your pants are wet), and
  • Field is at 20 – 50% flowering (you are wanting to cover the petal so when it falls into a humid canopy, it won’t be a viable food source for the sclerotinia to start on).

 Conditions can change throughout flowering.  If the canopy is somewhat open and dry at 20% flower you may not feel that you need to spray, but if there is a rainfall event and the canopy is wet at 30 – 40% flower, you may want spray then.

 Dry Bean:

  • Ground is damp to wet and,
  • Canopy is moderately closed and is continuing to close, and
  • 50 – 80% of the Field has started to flower (at least one open flower per plant)
  • Dry bean may require a second application at full flower, depending on the precipitation, temperature and canopy moisture

 Sunflower (for Sclerotinia Head Rot only) :

  • Ground has been damp to wet for the past week, and
  • Plants are at R5 (sunflower face is open with ray petals out, but pollination has not yet started)

Spraying for sclerotinia in soybean is not being considered at this time as flowering has not yet occurred. Damage and economic loss in soybean has only occured in one growing season on record. Sclerotinia development can occur under extreme wet and cool conditions, or the crop is significantly lodged and further information will be posted if these conditions do occur later on in the 2013 growing season. 

Canola Council of Canada July 3, 2013 New Release – Moisture Raises Sclerotinia Stem Rot Risk  http://canolacouncil.org/news/moisture-raises-sclerotinia-stem-rot-risk/                                                    

NSDU Sclerotinia Risk Map http://www.ag.ndsu.edu/sclerotinia/.  Please note this is based on temperature and precipitation only and is not based on individual field conditions


Prepared by:  Anastasia Kubinec – MAFRI Oilseed Crop Specialist  and  Holly Derksen – MAFRI Field Crop Pathologist

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Banded nitrogen with wide spaced seed rows

Question from a Subscriber of Crop Chatter:  I’m setting up a triple shoot air drill with wide (12.6 inch) spaced seed shanks. Each seed shank has a 3.5 inch paired row seed opener with a granular fertilizer placement tube to put granular fertilizer in the center of each paired row. Additionally, the drill has mid row banding shanks on 25.2″ spacing to apply NH3. I have a 3 compartment air tank.

For cereals, I will place the seed and phosphorus together through the paired row openers, with starter urea placed in the middle of each seed row through the granular fertilizer tubes. For canola, the seed and phosphorus will be placed together with ammonium sulphate (and possibly some urea if a fertilizer blend is used) in the center of each seed row. For soybeans, the seed and granular innoculant will be placed together and phosphorus will be placed in the seed row centers. NH3 will be applied for cereals and canola through the mid row shanks with 1″ openers. The NH3 will therefore be up to about 7″ away from the furthest placed seed.

I’m trying to determine how to best split the total nitrogen rate between urea and NH3. Since NH3 is cheaper and less handling than urea, my preference is to maximize NH3 use. Given that I have heavy clay soil:

1) How long it will take the furthest away plants to be able to access the NH3?
2) How much urea should be applied to keep the crop well suppied with nitrogen until all plants can access the NH3 band?

Answer (provided by John Heard, MAFRI Soil Nutrition Specialist)

Crop roots access nitrogen in mid-row bands in 2 ways:  roots growing  laterally can intercept the band and mid-row placed  ammonia converts to nitrate-N which then migrates as roots consume soil moisture.  Usually mid-row banded nitrogen is available for crop growth by the time it is needed.  Your seed-placed phosphorus fertilizer usually contains nitrogen to keep the seedling nourished.  But we hear on occasion that early season crop yellowing (MN deficiency?) is observed in the situations here – cool, heavy clay soil with wide spaced mid-row bands.  In years with warm, moist or dry soils, root access to bands will likely be quicker than this year.  Fortunately you have an option to place some urea in a band close to, but safely away from the seed.  I should think no more than 10-20% of the nitrogen requirement needs to be supplied there.

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Should I Be Cancelling My Soybean Seed?

Answer (provided by Dennis Lange, MAFRI Farm Production Advisor at Altona):

 Before you considering cancelling you soybean seed, here are a few things to consider:

  1. Variety Choice:  Is the variety suited for your growing region? If you chose a variety based on maturity ( found in Seed Manitoba 2013) and you are planting in May, you should reach  maturity  before reaching a killing frost, based on a normal growing season.
  2. Soil temperature: Soybeans like warm soils to germinate and grow. The warmer the soil, the quicker the beans come out of the ground.  For example, with soil temperatures at 10°C soybeans  take 14-17 days to emerge  vs. 7-10 days when soil temperatures are at 15°C.
  3. Seeding Date: Know the seeding deadlines in your growing region. If in Soybean Area 1, full coverage deadline is June 6. If in Soybean Areas 2, 3 or new crop insurance test area, your deadline is May 30. For further information contact MASC to determine which area you are in. Table 1: Soybean Yields by Seeding Date (2008-2012)

Using MASC seeding information from 2008-2012, yield potential differs depending on seeding date by Risk area.  

  • Risk Area 12 (includes Red River Valley) – highest yield potential was seeded during the 2nd week of May. 
  • In Western Manitoba:
  • Risk Area 1 – best yields when seeded in the 4th week of May, followed by week 3
  • Risk Area 2 – best yields in the 2nd week of May, with weeks 3 and 4 equal
  • Risk Area 3 – best yields in the 3rd week of May, followed by the 4th and 2nd weeks
  • Risk Area 4 – best yields in the 2nd week of May, with yields dropping in 4th week
  • Risk area 15 – similar to Risk Area 4 trends with best week the 2nd and yields dropping in the 4th week of May 

 In conclusion, if you are planting a variety that is suited for your growing region and planting in May, you should be confident that growing soybeans this year is still the right decision. Beans like warm soil so typically, planting in the 2nd or 3rd week of May when soil temperatures are warmer, allows the beans to get out of the ground quicker. But, waiting until June to plant, increases the risk of fall frost damage and yield reductions.

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