Extension Agronomy

1. Use the best quality glufosinate formulation. Not all glufosinate formulations are created equal!
2. Apply as many of the most effective preemergence herbicide sites of action at maximum rates for a crop as possible based upon soil texture, organic matter, and pH and cost of the herbicides.
   ...A. For maximum waterhemp and kochia control in a glufosinate-resistant soybean, the best preemergence herbicides are sulfentrazone, metribuzin, and pyroxasulfone.
   ...B. For maximum weed control in glufosinate-resistant canola, apply trifluralin and/or ethalfluralin.
3. Environmental conditions at time of glufosinate application is important. Apply glufosinate during high humidity and sunny conditions, followed by high temperatures and low wind speeds.
   ...A. Consult page 133 in the 2026 ND Weed Control Guide regarding Delta T. Apply glufosinate at a Delta T below 16 degrees Fahrenheit and please stop spraying when the Delta T value is greater than 18 degrees Fahrenheit with wind speeds greater than 8 miles per hour. During low wind speeds and slow sprayer travel speeds Delta T values may be a little higher.
4. Apply glufosinate to pigweed (including waterhemp) species LESS THAN 3 INCHES in height, kochia should be same height earlier in season, but can taller (< 6”) when soybean is planted in late-May.
5. Apply glufosinate at 20 gallons per acre spray volume!
6. Almost always include spray grade ammonium sulfate (3 pounds per acre) with glufosinate, however a few new adjuvant products may be as effective as 3 pounds per acre of spray grade ammonium sulfate.
7. Apply glufosinate using medium to coarse spray droplets, especially when the weed and/or crop density is so dense the soil is not visible. A droplet size on the higher end of a coarse droplet size may be desired when the Delta T value is above 16 degrees Fahrenheit.
8. Apply the maximum single application rate for all glufosinate products to maximize weed control. Always add Enlist One to glufosinate in E3 soybean to maximize pigweed (including waterhemp) species control.
9. Apply glufosinate at a travel speed less than 9 miles per hour, especially when weed plants are so tall and dense the soil is not visible. This is especially true for field borders.
10. If a second postemergence herbicide application is necessary, apply 14 days after the first application.
11. Dust/soil particles on weed leaves can create an impenetrable layer for glufosinate to enter plant leaves.
12. Maintain a properly calibrated sprayer and adjust boom height (no more than 20 to 25 inches) above the target maintaining a consistent boom height across the spray boom including the field margin.
13. Do not apply glufosinate at night. Only apply between sunrise and two hours before sunset.

14. If a plant survives a glufosinate application, please pull the plant and remove it from the field to stop glufosinate resistance.

    Prepared by Jeff Stachler, NDSU Extension Cropping Systems Specialist at CREC. Contact information: jeff.stachler@ndsu.edu 3-6-26.

Shareable link: https://youtu.be/jFtL2EVQSSM

Resources shared during the call:

• SF1863 Alfalfa Soil Fertility Requirements in North Dakota Soils https://www.ndsu.edu/agriculture/extension/publications/alfalfa-soil-fertility-requirements-north-dakota-soils
• SF1087 Managing Saline Soils in North Dakota https://www.ndsu.edu/agriculture/extension/publications/managing-saline-soils-north-dakota
• SF1941 Sodicity and Remediation of Sodic Soils in North Dakota https://www.ndsu.edu/agriculture/extension/publications/sodicity-and-remediation-sodic-soils-north-dakota
• SF1809 Soil Testing Unproductive Areas https://www.ndsu.edu/agriculture/extension/publications/soil-testing-unproductive-areas
• https://ndawn.ndsu.nodak.edu/current.html (Change the context to RH at the bottom of the screen)
• Rob Proulx's Delta T page https://raproulx.github.io/nddeltat/

Quick recap

This was the third monthly of the CREC Agronomy Q&A Zoom meeting, where participants discussed several key agronomic topics including alfalfa fertilization, drought adaptation, soil salinity management, and glufosinate efficacy. Jeff presented detailed information on alfalfa nutrient requirements, recommending annual applications of 40-50 pounds of P₂O₅ and potassium based on soil test values and crop removal rates. The group discussed ongoing drought conditions across the region, with participants noting recent rainfalls were helpful but insufficient to break persistent drought patterns, particularly in the southwest areas. We spent some time on soil salinity issues, where Jeff explained salinity and sodicity require different management approaches and emphasized tile drainage is ineffective for sodic soils. The discussion included details about a new publication on perennial salt-tolerant plant species for non-productive cropland, which recommended rotational planting of salt tolerant grass species, strawberry clover, and alfalfa requiring 6-8 years of management before returning to crop production for maybe 2 to 4 years. Jeff also presented comprehensive information on maximizing glufosinate efficacy (activity), covering formulation differences, environmental conditions (particularly humidity and delta T), application timing, and technical considerations including droplet size, spray volume, and adjuvant use.

Summary

Alfalfa Fertilization Best Practices

Jeff led the third monthly CREC Agronomy Q&A session, focusing on alfalfa fertilization and other agricultural challenges. He discussed key nutrients for alfalfa, including phosphorus, potassium, boron, and sulfur, and provided recommendations for application based on soil tests and tonnage removed. Jeff emphasized the importance of pre-plant application of P and K and annual post-first cutting fertilization, particularly for phosphorus and potassium, and highlighted the need to consider soil clay chemistry in determining the quantity of K to apply. No specific questions were asked during this segment. The group discussed soil testing reliability for boron, with Jeff confirming that the hot water extraction method is sufficient for accurate testing.

Drought Conditions

They addressed ongoing drought conditions, with Jeff explaining while recent rains have provided some relief in the northwest, the southwest region remains affected as well as an area at a diagonal starting in Stutsman County and going through Griggs, Steele, Nelson, and into Grand Forks Counties. Craig shared despite recent rainfall, Daryl indicated drought conditions still remain and Craig clarified water quality issues persist regardless of short-term rain events. Victor noted that while crops look better than last year, they lack moisture reserves and remain dependent on continued rainfall, with cooler weather forecasted for the next ten days some relief may be observed.

Soil Salinity Management Discussion

Jeff discussed soil salinity and sodicity issues, emphasizing the importance of distinguishing between the two types and understanding which solutions are effective. He highlighted key publications on managing saline soils and mentioned a new publication on perennial salt-tolerant plant species for non-productive cropland, which includes recommendations for winter seeding of salt-tolerant species. Jeff also explained the role of cutting salt-tolerant species to add in reducing salinity and improving soil structure, and he expressed skepticism about untested products claiming to reduce soil salinity. The group discussed soil salinity management. Craig shared that salinity remediation requires a long-term commitment of 10-15 years, citing a successful trial in Mercer County that showed gradual improvement over several years.

Ways to Maximize Glufosinate Efficacy (activity)

Jeff presented research on maximizing glufosinate effectiveness, emphasizing glufosinate formulations matter significantly, with some products being less effective than others. The discussion included environmental conditions for optimal herbicide application, particularly the importance of humidity (focusing on Delta T), sunshine, and temperature, with recommendations to stop spraying at Delta T levels above 25 degrees Fahrenheit. Jeff reported on the impact of droplet size and sprayer travel speed on glufosinate efficacy with best droplet size being medium to coarse droplets, depending upon the nozzle type and manufacturer. Weed size and the need for AMS to be added as an adjuvant and that no AMS replacement adjuvants should be used with glufosinate formulations.

Carrington REC Agronomy Q&A

Wednesday, May 13, 2026

Shareable link: https://youtu.be/BJ7OXfze51Y

Resources shared during the call:

• A934 Replanting or Late Planting Crops
• W253-26 North Dakota Weed Control Guide
• Cover Crops | NDSU Agriculture
• W1947 North Dakota Herbicide Chart
• Crop and Pest Report
• Alfalfa | NDSU Agriculture
• NDSU Langdon REC has published many reports authored by Naeem Kalwar on the subject of soil health/sodicity/salinity Soil Health | NDSU Agriculture
• https://www.ndascd.com/governors-legacy

Registration is OPEN for this year’s Crop Management Field School, Wednesday, June 24, 2026! Read the details at www.ndsu.ag/CMFS26 or register direct at www.tinyurl.com/payCREC .

Summary of the Meeting Transcript

1. Weather Outlook & Field Conditions

Jeff opens with an extended weather forecast for North Dakota. Key points include:

• Warm temperatures through Saturday, then a sharp cool-down with highs 48–60°F from May 17–23.
• Frost risk around May 17–19. Depending upon the lowest temperature and the duration of the lowest temperature will depend upon whether frost or freeze damage could occur to emerged corn and soybean. It will not get cold enough to damage emerged small cereal crops, field pea, or likely flax.
• Rain forecasts keep shifting, but most areas may receive 0.3–0.42 inches early next week.
• More rain chances around May 21, 26–27, and early June.
• Rain is “much needed… for pre-emergence herbicides, but also for those that have planted seeds into dry soil”.
• High winds are causing soil movement and damaging emerged crops.

2. Herbicide Options for Cover Crops

Jeff reviews pages 105–106 of the Weed Control Guide:

• Brassicas are the most sensitive to many herbicides.
• Lentils and flax show sensitivity to several wheat herbicides.
• Soybean pre-emergence programs relying on sulfentrazone essentially eliminate the option of brassica cover crops.
• Brassica cover crops can only be planted after a small grain cereal crop to allow for enough growth. Brassica cover crops seeded with soybean leaf drop or earlier or in corn between the V5 to V8 stage may allow enough time for successful brassica species cover crop establishment. Planting cover crops in a standing corn or soybean crop is tricky due to the herbicides applied in those crops and the injury they can or will cause to the cover crop species planted.

3. Discussion: Planting Barley or Rye With Soybeans to Reduce Wind Damage

One participant asked about planting barley or rye with soybeans to protect seedlings from wind.

Jeff’s response:

• Carrington REC has tested rye and barley as protective cover.
• Rye works well but requires careful termination timing to avoid drying out soils.
• Barley planted in the spring has been used successfully with dry beans and could help with soybeans.
• Oats should be planted in IDC-prone areas because they take up the most excess nitrogen, reducing iron deficiency chlorosis risk.

Quote: “Rye is a great cover crop… The more biomass and root growth, the more coverage of the soil, therefore the greater the weed control”.

4. Preemergence Herbicides in Dry Conditions

Major concerns discussed:

• Applying preemergence herbicides to dry soil causes them to bind to soil particles rather than move into the weed germination zone.
• Wind erosion can physically remove herbicide-treated soil, reducing efficacy and potentially harming downwind crops.
• Most modern herbicides can remain on the soil surface 10–20 days without degrading, but activation requires moisture.
• Incorporation (PPI) of herbicides is an option but requires proper equipment (field cultivator is the best, not vertical tillage). Vertical tillage tools do not uniformly distribute PPI herbicides to obtain uniform and effective weed control.

Quote: “If we apply herbicides to these dry surfaces, it's gonna be attached to the soil particles right now… instead of being mixed with the water”.

5. Seed Treatments in Cold, Dry Soils

One participant asked whether seed treatments remain effective in cold and dry soils.

Key points:

• Cold, dry soils do not degrade seed treatments; they remain on the seed coat until moisture arrives.
• Cold, wet soils are more problematic because chemicals can leach away before uptake and plants grow slowly allowing for a longer time period for infection.
• Typical seed treatment efficacy window is 14–21 days, possibly up to a month depending on product.
• Wheat may still benefit from seed treatments if:
  • Seed is scabby
  • Loose smut is present
  • Wheat is grown too frequently in rotation
  • Root rots (especially Rhizoctonia) are a concern

6. Insect Activity in Cold Weather

Anitha explains:

• Insects are cold‑blooded; cold temperatures slow or stop their activity.
• Seed treatments remain inactive until the seed imbibes water.
• Cold, slow-growing crops remain vulnerable longer, but insects also feed less.

Quote: “When it is cold, they don't even try to eat. They just lay inactive”.

7. Preemergence Herbicides vs. Emerging Weeds

I was mentioned from out west weeds (pigweed, wild oats, quackgrass) are emerging ahead of crops.

Jeff’s guidance:

• Even a tenth of an inch of rain can help activate preemergence (PRE) herbicides.
• If weeds emerge from the soil before herbicide activation, PRE’s will not control them.
• For kochia and waterhemp, preemergence herbicides are essential due to widespread resistance.
• Zidua offers the best residual kochia and waterhemp control, but requires significant rainfall and is costly.

8. Alfalfa Planting Timing

• Historically, mid-May is the cutoff.
• This year, planting may be feasible until Memorial Day, depending on rainfall.
• Late planting increases risk due to poor establishment moisture.

9. Soil Salinity Issues

A major discussion topic:

• High salinity is more visible than usual due to:
  • The wet 2025 growing season and into the fall
  • Deep frost
  • Lack of significant spring rains
• Capillary action with water is pulling salts from 5–6 feet deep to the surface.
• Tillage worsens salinity by drying soil and increasing upward salt movement.
• Many farmers still till and plant through saline areas, losing $183–$676 per acre in these non-productive areas of the field.

Quote: “We’re increasing the salt concentration farther away from the main spots… I’ve never seen salts higher in elevation outside these low spots than this spring”.

A new NDSU publication on salt‑tolerant species is forthcoming.

10. Governor’s Program for Saline Acres

• Provides funding to seed salt‑tolerant plant species.
• Current rules limit haying/grazing, which reduces effectiveness.
• Advocates hope to expand the program in the next legislative session.

11. Closing

Jeff encourages feedback and notes:

• Sessions are recorded.
• An AI summary (like this one) will be posted online.
• Follow-up information will be shared with participants.

• Video recording with bookmarks

• Publications referenced
  • NDSU AE1690 Frequently Asked Questions About Subsurface (Tile) Drainage
  • NDSU SF1617 Evaluation of Soils for Suitability for Tile Drainage Performance
  • NDSU SF990 Soil Sampling as a Basis for Fertilizer Application