Blog

In this webinar, Jim Isermann and Abigail Peterson will review key spring management considerations for cover crop fields, including termination approaches, tillage options, planting green and IPM. They will also discuss what they've seen across Illinois over the years and what practices are making a difference for planting success.

Presenters: Abigail Peterson, Director of Agronomy for the Illinois Soybean Association, and Jim Isermann, Soil Health Specialist for the Illinois Sustainable Ag Partnership

Download Peterson and Isermann's PowerPoint Presentation.

• Applications and Fall Establishment
  • Application methods
    • Interseeding vs. overseeding
      • Can use other machinery to avoid multiple passes, broadcast method or aerial planting
    • Drills are the most common seeding method; best seed-to-ground contact
      • Can be slow, but can improve speed by using airseeders and planters with special plates
  • Row spacing can vary between 7.5-, 15- or 30-inch rows
    • Depends on the type of cover crop being planted and management level
    • 15-inch spacing is a great option for ground coverage and leads to better cash crop establishment
• Select application method based on where you are at in harvest
• Change seeding rate and population to accommodate cover crop application method and accomplish your goals: biodiversity, ground coverage or to get biomass in the field
• Fall 2022 establishment
  • Strip-tilled fields are a great option for cover crops
  • If using oats as a winterkill, get it planted in late September/early October
  • Want to change management in terms of planting depth and termination to accommodate cover crop system
  • Aerial seeded fields can be hit and miss
    • Knowing when you can get seed in the ground and if it will rain after
    • Soybean vs. corn residue – can be challenging to plant into soybean residue
• Biomass is really important for spring management
  • What you do in fall will impact your spring management decisions
  • Cereal rye will be used as the general example because they are winter-hearty and the most common cover crop
  • Biomass can be considered a benefit and a concern
    • Need biomass to get the most out of cover crops, but need to balance with the potential issues
  • 2 main goals of biomass:
    • Protect the soil
    • Weed control
  • Want to keep soil microbes alive, so you need to feed the soil
    • Microorganisms need carbon to stay alive
      • 24:1 is an ideal C:N ratio
        • Will give good biomass and also breakdown easily over the year
        • Too much and the residue will breakdown more slowly
        • Big differences in C:N depending on the cash crop and the cover crop planted
  • Cereal rye ahead of corn is where most cover crop issues happen
  • Barley and triticale are good overwinter choices
  • Annual ryegrass is a good cover crop but harder to establish and terminate
    • Lower C:N ratio and can work when planted ahead of corn
  • Look at cover crop mixes that are practical and will overwinter
    • Barley, oats, rapeseed and crimson clover
    • Need balance of entire system to keep the biomass manageable
  • Cover crop biomass can be used to help manage weeds, including waterhemp
• Chemical and mechanical termination methods can be used
  • Most growers will use chemical termination of cover crops
  • Key considerations with chemical termination
    • Avoid using nitrogen carriers
    • Leaf burn can prevent glyphosate from entering
    • Broadleaf control
    • Want warm temperatures for active growth
    • Watch your tank mixes
      • Atrazine and metribuzin can antagonize glyphosate
    • Talk with someone who has experience terminating cover crops
    • Don’t rely on contact herbicides in spring for termination
  • When it comes time to terminate cover crops, make sure there is growth
    • 18- to 24-inch height range for cereal rye is good for termination
  • Mechanical termination with a roller-crimper cuts down on chemical use
    • Can let cover crops grow taller for better weed control, but need to roll it down to promote soybean growth
  • Tillage can be used for termination if cover crops are small or if using a legume cover crop
• Nitrogen management is important for both no-till and cover crops
  • There is a difference between nitrogen concerns and allelopathy
    • Main concern is corn planted in cereal rye
    • Cereal rye releases chemical substances into the environment that are good for weed control but can inhibit corn growth if not managed properly
  • Key considerations if planting corn into cereal rye
    • Do not plant within 10 days of termination
    • Planting 2 inches deep
    • Close the seed slot
  • When switching to no-till or strip-till, need to be more timely with nitrogen applications because there isn’t a spike in microbial activity from a spring tillage pass
  • Key considerations with cover crops
    • Supply plenty of nitrogen at planting, ideally
    • 30 units of banded nitrogen with planter
• Spring planting considerations
  • Looking at the biomass and understanding when to terminate are important
    • Can terminate 10 to 14 days before planting if possible, but planting green can also work and help with soil health and weed control
  • Understand nitrogen management within your system
  • Adjust planter properly as soil changes
    • Want good depth control
    • Row cleaners can have issues with wrapping if you have a lot of biomass
      • Early termination can help
    • No-till corn is not advised immediately
      • Want to avoid seed slots