How-To Guide for Growing Soybeans

The Prairie Giants Crop Report

Field observations at your fingertips

April 22, 2025

Taylor Kurtenbach

How-To Guide for Growing Soybeans

Soybeans continue to gain popularity in our area, especially after the success of the crop in the 2024 growing season. Whether it is your first time growing them, or you are a seasoned pro, here are some things to consider.

Soil salinity – soybeans and corn are more sensitive than other commonly grown crops.
Residual nitrogen – avoid fields with high residual nitrogen. Do not plant soybeans on fields with greater than 70 lbs N. High residual nitrogen can lead to iron deficiency chlorosis (IDC)[3].
Herbicide carryover – soybeans are generally safe to seed after most herbicides applied in the previous season. Clopyralid (Lontrel) may carryover in years with low rainfall.
Weed concerns – this will determine what herbicide system is best to use and will therefore dictate choice of variety. Conventional soybeans should be planted on clean fields with low weed pressure, especially perennials. Enlist E3 soybeans should be avoided on fields with kochia pressure, as dicamba is much stronger on the weed. RR2X soybeans can be used to clean up fields with other problematic weed issues, such as wild oats, using multiple passes of glyphosate.

There are three herbicide systems commonly grown in the area.

Roundup Ready 2 Xtend (RR2X) – these are glyphosate + dicamba tolerant. Popular varieties include S001-D8X (2300 Corn Heat Units), NSC Dauphin (2250 CHU) and Gecko (2225 CHU).
Enlist E3 – glyphosate, glufosinate + 2,4-D choline tolerant. Popular varieties include B0024EE (2325 CHU).
Conventional – not an herbicide tolerant system, weed control methods are similar to peas. Popular varieties include Siberia (2375 CHU). Compared to other varieties, conventional soybeans are on the high end of heat units for our area.

Soybeans are generally not competitive, therefore weed control and keeping your field clean is very important. As a best practice, a pre-burn application should be done prior to seeding, but it is especially important in front of conventional beans. Some options include Authority, Authority Supreme, dicamba (in front of RR2X beans ONLY), Edge MicroActiv, Fierce, Focus, ½ rate imazethapyr (Pursuit/Phantom), Voraxor and Voraxor Complete. All offer extended weed control, but specific product choice is dependent on the weeds present in your field. A Prairie Giants agronomist can help determine this!

In-crop herbicides depend on the herbicide system.

Roundup Ready 2 Xtend

The following products can be applied in-crop in Roundup Ready 2 Xtend soybeans. This does not mean that every product listed should be applied, as it is dependent on weed pressure and staging.

Glyphosate: Soybeans are very glyphosate tolerant. The following are the registered rates and can be applied from 1st trifoliate – flowering. Only one of the following combinations can be made in a season: 360 gr ae (1 REL) x 2 OR 720 gr ae (2 REL) x 1
Dicamba (Xtendimax 2, Engenia): Dicamba can be applied pre-seed/pre-emergence, or in-crop. It is ideally sprayed pre-burn or with first pass if you are targeting kochia. It can be weak on volunteer canola but is strong on kochia. Rates vary, call a Prairie Giants agronomist to discuss.
Imazethapyr (Pursuit, Phantom): A ½ rate can be applied pre-burn or with first pass tank-mixed with glyphosate (registered up to and including 3rd trifoliate) but is limited to only one application per season. It is typically used for residual control of volunteer Roundup Ready canola. Re-cropping restrictions apply – NO canola may be seeded the following year except Clearfield.
Viper ADV: Can be applied up to and including 3rd trifoliate, for non-residual control of volunteer Roundup Ready canola. Unlike imazethapyr, no recropping restrictions exist for the following year. Typically, an application of imazethapyr OR Viper ADV, not both, will be applied IF volunteer canola is potentially Roundup Ready. If a residual pre-burn product was applied before hand, an application may not be necessary.

Enlist E3
As mentioned above, Enlist E3 soybeans are tolerant to glyphosate, glufosinate and 2,4-D choline. The order of applications is dependent on weeds present.

Glyphosate: Can be applied by itself, or tank mixed with Enlist 1.
Glufosinate: Up to two applications may be made up to the start of flowering. Both formulations (glufosinate, glufosinate 200 SN) have products that are registered in soybeans, but not every canola formulation (glufosinate) product is registered. Rates are different depending on the formulation used. Discuss what products are registered in soybeans and rates with a Prairie Giants agronomist prior to applying if you are unsure. Can be applied by itself, or tank mixed with Enlist 1. If using glufosinate 200 SN, AMS should be added.
Enlist 1: Enlist 1 is a special formulation of 2,4-D (2,4-D choline) specifically made for Enlist soybeans and corn. Up to two applications of 0.73 L / acre may be applied and can be tank mixed with glyphosate or glufosinate.

Conventional Soybeans
Conventional soybeans are essentially the same as field peas in terms of what you can spray. A single application of Viper ADV OR Odyssey Ultra Q can be made up to 3rd trifoliate.

Viper ADV: This product offers non-residual control of volunteer canola but has no re-cropping restrictions the following year.
Odyssey Ultra Q: If you want residual control of volunteer canola, this is the product to use, but re-cropping restrictions apply. No canola can be grown the following year, except Clearfield.

In this area, disease and insects are usually not a big concern. Like peas, beans are susceptible to early season seedling diseases and root rots like Fusarium spp., Pythium spp., and Rhizoctonia solani[1]. Phytopthora sojae is a soybean specific disease and can occur anytime throughout the season[1][2]. These diseases can be controlled, or suppressed, by using a registered seed treatment. Cutworms and wireworms can also affect the crop in early stages[2] and can be alleviated using an insecticide seed treatment.

Grasshoppers, soybean aphid and green cloverworm can all affect soybeans in Manitoba[2]. There are multiple diseases that can infect the crop, but a fungicide is often not warranted due to the low disease pressure in this area.

Iron deficiency chlorosis is common in soybeans. It is a nutrient deficiency and causes interveinal yellowing in new leaf tissue. It is commonly caused by high carbonates, especially in wet years, but can be impacted by anything that causes the plant stress[3] (cool soil temperatures, water logging, herbicide stress, soil compaction, high soil nitrate, etc.) The plant can typically grow out of it. Foliar sprays are not effective[3].

Beans typically will dry down naturally, but if there are green spots or weed control is warranted, a pre-harvest application can be made. The following are registered.

Reglone Ion – a true desiccant. This will quickly dry down green spots, including weeds, but does not offer long term weed control (they will grow back).
Heat LQ + Glyphosate – offers both weed control and quicker dry down.
Glyphosate – can not be used alone in RR2X or Enlist E3 beans, as they are both glyphosate tolerant. Can be used for weed control and dry down in conventional soybeans only.

As with any pre-harvest application, consult your grain buyer prior to applying. Read more about pre-harvest applications here.

Prairie Giants agronomists are here to help with any questions you may have and are available for in-season scouting!

Sources:

1. Manitoba Pulse & Soybean Growers. 2019. Scouting for Early Season Diseases. [Online] Available: https://manitobapulse.ca/2019/04/scouting-for-early-season-diseases/

2. Manitoba Pulse & Soybean Growers. 2016. Soybean Insect and Disease Scouting Calendar. [Online] Available: https://manitobapulse.ca/2016/04/soybean-insect-and-disease-scouting-calendar/

3. Riekman, Marla. 2024. Keating Seed Co Soybean Summit (Soil Considerations for Growing Soybeans session)