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Sunflower Production: Know Before You Grow

Feb 5, 2020

Agronomy, Crop Management, Grain, Market Update, Soybean, Technology

With a large portion of corn and soybean acres still in the field heading into #plant2020, we wanted to use this blog post to discuss options to utilize acres once those 2019 crops are removed.

Sunflowers may be one of the best choices available this growing season for a host of reasons – the crop is a great late-plant option, performs well under average fertility conditions, and requires fewer inputs.

But keep in mind, sunflower production isn’t without challenges; weed control, insect pressure, and diseases can all reduce the yield and profitability of the crop.

Sunflower Field

Stay on top of yield threats:

Weed Control:

  • It is critical to achieve good pre-emergence weed kill.
  • There are very few foliar options that will not kill both broadleaf weeds and sunflowers.
  • Sunflowers provide little to no crop canopy, making weed control more difficult throughout the season.
  • Use a group 15 and a PPO in pre-emergence applications. Authority Supreme and BroadAxe are our favorites with rates that are soil specific. #AskArthur for more info.

It’s easy to remove grasses from a broadleaf crop – the challenge is removing broadleaf weeds from a broadleaf crop and still having a crop to harvest! Pre-emergence application and coverage is the most important tool in the fight against weeds in a sunflower crop.

Conventional tillage operations will need to consider carryover implications on the next crop in the planned rotation and review the herbicide labels of weed control options used on the previous crop.

Again, no matter which tillage practice, good pre-emergent weed control is critical to season-long weed control.

Diseases:

  • White mold is the most destructive disease of a sunflower crop.
  • There are no white mold resistant hybrids currently available.

Keep all of these factors in mind when considering the decision to grow sunflowers in 2020.

Controlling White Mold:

Don’t rotate broadleaf crops.

Rotating broadleaf crops such as soybeans, canola, and sunflowers will allow the disease to become established. White mold is difficult to manage once it is established, making effective control more difficult in future broadleaf crops and likely changing your crop rotation plans.

If you planted soybeans in 2019, be cautious and aware of the threat white mold carries; consider planting a non-susceptible crop – corn, sorghum, or wheat.

Management practices can also help control the establishment rate of white mold.

Weed populations: Actively growing, dormant, or dead can act as a host for white mold mycelium that will infect sunflowers. Crop debris can also harbor the fungus and should be buried each year. Excess nitrogen has also been proven to facilitate the onset of white mold issues due to the nutrient’s creation of a dense plant canopy. Thus, moderate fertility programs are most successful in the management of white mold.

Fungicide applications should be early (before V1) at a half rate and again at a full-rate mid-season.

Agronomist Inspecting Sunflower Plant

Fertility:

  • Sunflowers efficiently utilize nitrogen.
  • Excess nitrogen will create a dense crop canopy and increase the likelihood of white mold infection.
  • Nitrogen application will increase plant height, but will not increase plant yield.
  • Increased nitrogen rates will decrease seed oil content (if Oilseed Sunflowers are grown) but will increase protein.

Soil tests should be pulled to assess nitrate levels and manure, and previous crop credits should be calculated into the estimated yield formula, although research shows no yield increase from additional pounds of applied nitrogen.

For new fields, NDSU recommends soil samples be pulled to at least a 4-foot depth for consideration of deeper nitrogen in nitrogen fertility recommendations. Approximately 30 pounds of nitrogen should be credited between 2- to 4-feet in depth but not subtracted; anything over 30 pounds of nitrogen per acre should be subtracted from the total nitrogen recommendation.

Because the removal of phosphorus by the sunflower grain is low, no added phosphorus is recommended; 150 ppm of potassium is also sufficient and typical of ND soils.

Sunflower crops will likely experience early-season sulfur deficiency due to above average snowfall this winter. Plan to preplant or postemergence apply 10 pounds of sulfur as a sulfate or thiosulfate. (1)

Insects:

  • There are 6 to 10 destructive insects seen regularly in ND
  • There are Economic Injury Levels established for several of them
  • Scouting is critical at R-3 and R-5.1
  • Pheromone traps can be used as indicators as well

Insects love sunflowers and are plentiful in fields especially during full bloom. Most of the insects are beneficial or don’t cause economical damage. However, a handful can cause problems that need to be remedied on occasion. Talk to your ACI agronomist about lining up scouting to protect your crop.

Agronomist Showing Sunflower Field

Additional considerations: If sunflowers are in your rotation for 2020, the final planting date for crop insurance is June 15. Think about planting sunflowers on some of your poorer soils to protect your actual production history (APH), and remember that if there is no established APH, the county T-yield will be used.

As always, the Arthur team is just a phone call away to answer any agronomic or marketing questions you may have. We appreciate the opportunity to be your service provider and look forward to hearing from you in 2020.