WEBINAR: Explaining the 100-Bushel Yield Gap

A few growers have broken 100-bushel soybean yields and the world record is 171 bushels. Yet for many growers, field yields remain in the 50 to 75-bushel range. So, what are the limiting factors why U.S. and Illinois yields are often below contest winners? Todd Steinacher, CCA, will explore why this gap exists and what factors in the life of a soybean plant determine final yield. 


  • Importance of Soybean Production
    • Food ingredients
    • Industrial products
  • Sustainability and Profitability
    • Gap is only important if it is profitable to grow 100 bushels per acre
    • Build a budget to track and validate results
  • Developing and Preserving Yield
    • Pods/plant: Genetics, plant health – genetics are correlated to how bean will react
    • Beans/pod: Sunlight/energy (planting date), insect feeding
    • Plant health will have direct impact later
      • As we start to build foundation think of these items as building blocks
      • The mortar between the blocks is good agronomy
      • Too much focus on one block (i.e. seed selection or plant health) weakens the foundation and makes it unstable
  • Building Yield
    • 70 to 90 bushels per acre is average – half of field is well above average and half of field is well below
    • Focus on area below average
  • SWOT Analysis
    • Analyze bean genetic lines
      • Better understanding of genetics helps manage the variety the way that variety wants to be managed
      • In-law analogy
    • Balance internal and external factors in genetic selection
      • Internal factors: Genetic strengths to express, weakness that were passed down
      • External factors: Environment
  • The Power of Data
    • Replication: Want genetics to perform more than one time by more than one person
    • Environments: Soil types, basic agronomics, planting dates
    • Year: Want to see genetics do well over multiple years
    • Percent wins: If genetics are winning 70 to 80 percent of time it is a stellar product
      • Just because a variety did well in a local trial don’t know that it will fit into your operation.
  • Seed Selection
    • Import to start foundation with seed selection
    • If it’s in lower one-third of yielding across environments it’s not a good variety
      • Every bean will be different in how it interacts with environment
      • Early planting is always subject to geographic location and can affect fungicide application and yield percentage based on potential
  • Early Season Management
    • Seed treatments: Allowing for early planting dates, while ensuring adequate stands
    • Root zone development (tillage): Improving seed-to-soil contact and reducing early season root restriction
    • Starter fertilizers: Provide plant available nutrients close to root zone
    • Residual herbicides: Reducing early season pressures
  • Mid-Season Management
    • Genetic selection: Proper GxE, offensive or defensive
    • Weed suppression: Providing more to the plant
    • K and P uptake and partitioning for 60-bushel soybean crop
      • Did the corn crop leave enough nutrients for soybeans?
      • Nutritional supply and demand – reduced root growth
        • Minimal nutrient uptake during the first month of growth
        • Nutrient uptake increases during months two and three
        • Is nitrogen a limiting factor?
  • Plant Health
    • If in 50-bushel yield range, top end of performance isn’t there
    • If have higher yields, more disease pressure will occur on top end and will see more benefit from plant health management plan.
  • Late Season Management
    • Rapid and steady dry matter accumulation R3-R4
      • Seeds and pods are most vulnerable to abortions
      • Seed count is reduced and weight per seed reduced
      • Stress can impact how many blooms successfully produce pods
      • Planting date can have a direct impact
    • Rapid remobilization R5-R6
      • Root growth has stopped, nitrogen fixation has capped
      • Maximum height, nodes, total leaf area, pod set, total beans per plant, weight per seed
    • Management of R4.5
      • Fungicide and Insecticide at R3-R4 – how long will it last
      • Seed treatment: Reduce sudden death syndrome (SDS) pressure/impact
    • Soybean plant is always in flux so do some Crop Soy Investigation (CSI)
      • Look backwards in a soybean crop’s life to determine when, what and why something happened
      • How many nodes developed, how many pods developed, how many blooms created, what is the weight of the beans?

Illinois Soybean Association
The Illinois Soybean Association (ISA) is a statewide organization that strives to enable Illinois soybean producers to be the most knowledgeable and profitable soybean producers around the world. ISA represents more than 43,000 soybean farmers in Illinois through two primary roles; the state soybean checkoff and legislative and regulatory advocacy efforts.



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