WEBINAR: Understanding Biologicals For Improved Soybean Management

The biological product market available to corn and soybean growers has exploded in recent years with new technologies and management tools designed to enhance fertilizer use, reduce crop stress, stimulate soil microbial activity, manage crop residues and improve soil health. This webinar will highlight how biological products are categorized based on active ingredients and modes of action, as well as summarize research on which product types work, where and why they work and, most importantly, what other management practices help achieve the full economic benefit of biologicals.

Presenter: Connor Sible, University of Illinois at Urbana-Champaign Ph.D. Research Assistant

Connor Sible is a Ph.D. Research Assistant in the Department of Crop Sciences at the University of Illinois studying under the advisement of Dr. Frederick E. Below. He is currently in the third year of his Ph.D. program in the Crop Physiology Laboratory at the University of Illinois, where he previously received his bachelor’s and master’s degrees in crop sciences. His research focuses on categorizing biological products and understanding where, how and why they work to improve fertilizer use efficiency and increase crop yields. He also uses agronomic inputs and various methods of crop residue management to enhance nutrient release and improve soil health. Connor has regularly presented his research findings at local and regional field days, and at American Society of Agronomy Annual meetings, where he has been a consistent winner in the graduate student poster and speaker competitions. 


Download Sible's PowerPoint Presentation.

  • Current yield gap between the record and average yield is 138 bushels per acre 
    • A lot of potential to get more yield out of our acres
  • Increasing pods to the top or bottom of the plant will drive yields
    • 1 additional pod = 2 bushels per acre
  • Traditional approach to soybean management
    • Select a variety and maturity group appropriate for the region
    • Plant populations between 80,000 and 160,000
      • Later the planting goes, the higher the population
    • Earlier planting dates being pushed earlier and earlier
      • You lose half a bushel per day after April 20 planting date
    • Fertility – Leftovers from previous corn crop
    • Fungicide/insecticide at R3
  • Current biological uses:
    • Seed treatments 
    • In-furrow with starter fertilizer
    • Foliar – Vegetative stages with post herbicide
    • Foliar – Reproductive stages with fungicide/insecticide
    • On dry fertilizers 
    • On crop residues
  • Biologicals are plant growth regulators (PGRs), beneficial microbes and biostimulants
    • Beneficial microbes, such as:
      • Nitrogen-fixing bacteria
      • P-solubilizing bacteria
      • Mycorrhizal fungi
    • Biostimulants, such as:
      • Enzymes (Phosphatases)
      • Humic/fulvic acids
      • Marine extracts
      • Sugars
  • Nitrogen-fixing bacteria – Increase plant available N
    • Nitrogen-fixing bacteria increase plant available N through legume-rhizobium relationship
      • Soybeans need to accumulate 4 to 5 pounds of N per bushel of grain
      • About 50% of a soybean’s N comes from the nodules
    • Alternative N sources for soybeans
      • Non-rhizobia microbe root and/or leaf colonization to provide supplemental N
    • Key takeaways 
      • Can increase soybean grain yields
      • New and innovative biologicals can provide alternative approaches to N-fixation in soybeans, opening space for seed treatment
  • P-Solubilizing Bacteria (PSBs)– Increase availability of mineral P
    • P isn’t plant useable in soil; PSBs secrete acids to make it available to the plant
    • Key takeaways
      • Need adequate soil contact near the growing root to supply P for immediate uptake to optimize yield
      • PSBs are living microbes that can increase P availability all season, essential to optimize grain fill
  • Mycorrhizal Fungi – Extend root system 
    • Microorganisms that increase root surface area and soil contact through a symbiotic relationship
    • Key takeaways
      • Greatest potential of success is by planting the product as close to the seedling as possible
      • The source of inoculum impacts efficacy, and the environment/crop it is used in may determine which source is optimal
  • Enzymes (Phosphatases) – Increase availability of organic P
    • Release P from organic matter to make it available to the plant
    • Not all phosphatases are the same and soil environment will impact which enzyme works the best
  • Biological synergy between PSBs and Phosphatases
    • Two biologicals increasing availability of different P pools; provides soil P for a crop that isn’t typically fertilized with synthetic P
  • Humic/Fulvic Acids – Chelate soil cations and feed microbes
    • Functional groups help chelate cations
    • Chelation of cations keeps P available; supplies Zn
    • High carbon content feeds soil microbes, stimulates roots
    • Key takeaways
      • Can benefit soybean grain yield by interacting with soil nutrients and microbial communities to promote greater crop growth
  • Marine Extracts and Sugars – Improve plant health
    • Marine extracts are sourced from algae, seaweed and kelp, which all contain multiple biomolecules (amino acids, carbs, plant hormones)
      • Mechanism
        • Multiple compounds means multiple modes of actions
        • Impossible to know which is having primary influence
        • Stimulate root microbial activity
      • Foliar applications mitigate drought stress by regulating water use
      • Soil applications promote root growth and soil microbial activity
    • Sugars
      • Direct energy source for soil microbes, or signaling molecule in plants
  • Biologicals summary
    • Biologicals can be effective at increasing grain yields
    • Efficacy depends on the type of product used, placement and timing
    • Need to understand how the products work and where to add into your system
    • The market is full of unique products with the potential to improve crop management and soil health and increase yields


Illinois Soybean Association
The Illinois Soybean Association (ISA) checkoff and membership programs represent more than 43,000 soybean farmers in Illinois. The checkoff funds market development and utilization efforts while the membership program supports the government relations interests of Illinois soybean farmers at the local, state, and national level through the Illinois Soybean Growers (ISG). ISA upholds the interests of Illinois soybean producers through promotion, advocacy, and education with the vision of becoming a market leader in sustainable soybean production and profitability. For more information, visit the website and



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