Do you know the nutrient needs of your soybeans or when it is best to apply fertilizer? In this ILSoyAdvisor webinar, Connor Sible provides the answers to those questions as well as how weather, genetics, row spacing and biologicals influence soybean yield.

Presenter: Connor Sible, postdoctoral research associate at the University of Illinois

Download Sible’s PowerPoint Presentation.

• Are we achieving full soybean yield potential?
• The soybean yield gap is the World Record Yield (190 bushels) minus the Average U.S. Record Yield (53 bushels) = 137 bushels
  • How can we get here?
• The six secrets of soybean success, ranked by biggest impact in 2022
  • Weather – 35+ bushels per acre
  • Genetics/Variety – 25 bushels per acre
  • Row Spacing – 9 bushels per acre
  • Foliar Protection – 5 bushels per acre
  • Fertility – 4 bushels per acre
  • Seed Treatment – 2 bushels per acre
• Weather dominates everything and drives soybean yields
  • Planting date is determined by weather
    • Yields decrease by almost half a bushel per acre each day planted after April 23
  • Emergence date, not planting date, actually sets up yield projections
  • Soybean yield algorithm
    • Yield = Pod number per acre x Seeds per pod x Weight per seed
    • Most yield comes from the middle of the plant
    • 1 additional pod = 2 bushels per acre
  • Planting date gives you more opportunities to add nodes, which translates to greater yields
• Genetics/Variety
  • All soybean varieties are not created equal – can see a 27.6 bushel yield range in variety
  • The higher the maturity group for the region, the higher the yield
    • Longer maturity will typically translate to higher yields
• Row Spacing
  • Faster you close the row, the more sunlight you can capture and get the plant off to a faster start
  • 20-inch rows help close the row and suppress weeds more compared to 30-inch rows
  • Narrowing rows helps retains pods and seeds per acre, which improves yields
• Foliar Protection
  • Once rows are closed, you want leaves to be as full as possible
    • As soon as insects start feeding, you remove leaf area and opportunity to fill pods and increase seed weight
  • Fungicide applications at R3 growth stage help keep plants green longer, which translates to healthier plants and greater yields
  • Foliar protection increases yield by increasing seed weight
    • Keeps the plant greener longer and increases seed weight
• Fertility
  • It takes a lot of nitrogen and potassium to produce an 80-bushel soybean crop
    • Corn stover has a lot of potassium in it
    • Two nutrients required in high amounts
  • However, 81% of phosphorus goes to the grain
    • Need to provide enough nutrition to fill the seed
    • Not a large total amount needed to produce, but most goes to the grain to fill the seed
  • Benefits to providing nutrients the soybean needs that we don’t typically think about
  • Every point increase in maturity group, the response to fertility increases by 7.3 bushels
  • Key takeaways
    • Soybean needs fertility and foliar protection to obtain higher yields
    • Fuller maturity soybean variety for a given location tends to be more responsive to the addition of preplant P and K applications
• Seed treatment
  • Protect that soybean from the start and get it off to a good start
  • Seed treatment value will be higher with an April plant date versus May
• Can we achieve greater than 80 bushels per acre?
  • Start to add success factors together
  • 2021 Soybean Yield Study
    • Does early planting need narrow rows? – This is being looked at
    • When planting in narrow rows, management is needed for higher yields
      • Consider the synergies when factors are used together
• Biologicals are another option for managing soybean
  • Beneficial microbes:
    • Nitrogen-fixing bacteria – Increase Plant Available N
    • P-Solubilizing Bacteria – Increase Availability of Mineral P
    • Mycorrhizal Fungi – Extension of the Root System
  • Biostimulants:
    • Enzymes (Phosphatases) – Increase Availability of Organic P
    • Humic/Fulvic Acids – Chelate Soil Cations and Feed Microbes
    • Marine extracts – Soil Applied Stimulates Microbes and Roots
    • Sugars – Foliar Applied Mitigates Stresses (Drought)
  • Can learn more about biologicals from this ILSoyAdvisor webinar
• Strategy for producing high soybean yields
  • Early and rapid leaf area development
  • Prolonged leaf area duration, pod set and seed growth
  • Prevent crop stress