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Prevented plant: Considerations for corn and soybean

Liz Stahl, Extension educator and Phyllis Bongard, Content development and communications specialist

Farmers across parts of Minnesota are dealing with excessively wet conditions that have delayed crop planting. As wet conditions persist and final planting dates for crop insurance in Minnesota for corn (May 31 across southern Minnesota) and soybean (June 10) approach, farmers are faced with the decision of whether or not to plant some of their crop / take prevent plant, plant their planned crop late, or switch to a different crop. There are many factors to consider when making these decisions and each farmer will need to evaluate what options fit best with their operation and situation.

Farmers should be in contact with their insurance representative for more details on the rules of prevent plant, eligible acres, options and implications during the late planting period, any follow-up management requirements, and impacts on items such as insurance coverage and actual production history (APH).

For more details from USDA’s Risk Management Agency (RMA), see Prevented Planting: Iowa, Minnesota and Wisconsin (2019).
You may also be interested in Prevented planting decision for corn in the Midwest from the University of Illinois.

Here you'll find a discussion of the key considerations for making Prevented Plant decisions.

Whether or not to plant corn late:

  • Yield penalty – Yield potential for corn planted after mid-May begins to decline fairly rapidly according to long-term research conducted at Lamberton (1988 – 2003) and across three locations (Lamberton, Morris, and Waseca) from 2009 – 2011. Although yield impacts in a given year will vary, in these trials, corn yield was reduced by an average of
    • 11 to 18% when planting was delayed until May 30.
    • 16 to 24% when corn was planted on June 4
    • 21 to 31% when corn was planted on June 9.
  • Hybrid maturity and selection - It is recommended to stay the course with adapted hybrids (a hybrid considered full-season for the area) until May 25. If planting delays continue, switching to an earlier relative maturity (RM) is recommended to help ensure the hybrid reaches maturity before a killing freeze. General recommendations include:
    • If planting is between May 25 and May 31, select a hybrid 5 to 7 relative maturity (RM) units earlier that what is considered full season for the area.
    • If planting is between June 1 and June 10, a hybrid 8 to 15 RM earlier is recommended.
    • If planting is between June 11 and 15, a hybrid 15 or more RM earlier is recommended.
    • Note: if switching to an earlier hybrid, keep in mind the agronomic traits (e.g. standability, disease tolerance), technology traits (e.g. Bt traits for above ground or below ground insect pests), herbicide resistance traits, and yield potential of the earlier hybrid.
  • Grain moisture at harvest and risks from an early frost – Switching to an earlier hybrid can help offset the risk of high grain moisture content at harvest. Wet corn at harvest can lead to added expense from drying corn. A general guideline for the cost to dry corn is $0.045 per point per bushel of corn. This will vary by dryer type, fuel prices, if corn is dried on the farm, etc., but provides a rough estimate of potential drying costs when corn has a higher moisture content at harvest.

    Although difficult to predict, the combination of a late planting date and early frost can result in significant yield reductions and high grain moisture content. A summary of planting date trials conducted in north central Iowa demonstrates the dramatic impact an early frost can have on grain yield and moisture when corn is planted late (Benson, Garren O., 1990. A review. J. Prod. Agric. 3:180-184). In this study, very-early (15 RM earlier than adapted) and adapted/full season hybrids were planted between June 1 and June 20. An early fall freeze occurred two weeks earlier than normal, which impacted grain yields and moistures:
    • Very-early hybrids (15 RM earlier)
      • Grain moisture contents ranged from 17 to 29% for corn planted June 1 to June 20, respectively.
      • Grain yields averaged 96 to 58% of maximum for corn planted June 1 to June 20, respectively.
    • Adapted/full-season hybrids
      • Grain moisture contents ranged from 32 to 64% for corn planted June 1 to 20, respectively.
      • Grain yields averaged 74 to 29% of maximum for corn planted June 1 to 20, respectively.
    For more details on this study see this article by Roger Elmore, Iowa State University Extension: Corn Yield Predictions for Replanted and Late-planted Fields

    It is important farmers consider their ability to artificially dry wet grain and dryer and storage capacity when considering to plant corn past the last planting date for crop insurance. Combining high moisture grain can slow down harvest and also result in higher than normal harvest losses.
  • Field conditions at planting – If wet conditions persist, farmers may be faced with the decision to plant corn in less than ideal conditions. “Mudding in” a crop can result in significantly reduced root systems in corn, which can predispose the corn to further stress, reduced ability to take up nutrients and moisture, and ultimately reduced yield potential.
  • Pest pressure – If corn is planted much later than normal, it may be at greater risk from pests that you normally haven’t had to deal with. For example, late planted corn may be more susceptible to injury from black cutworm or even true armyworm.
    For the most recent reports, see the Black cutworm reporting network.
  • Seeding rate – It is recommended to follow best management practices for corn regardless of planting date, targeting a final stand of 32,000 to 34,000 plants per acre

Whether or not to plant soybean late:

For a discussion on important yield and relative maturity considerations, see Delayed (again) soybean planting.

Whether or not to switch from corn to soybean:

  • Impact on rotation - If you typically follow a corn/soybean rotation, switching from corn to soybean will mean that you will now be planting soybeans after soybean. A review of almost 750,000 fields across the Midwest found an average yield penalty of 10.3% for planting continuous soybean (Seifert, Roberts, and Lobell. 2017. Agron. J. 109(2): 541 – 548).
  • Impact on diseases - Multiple years of soybean encourages soil-borne diseases like soybean cyst nematode (SCN) and sudden death syndrome (SDS). Soybean disease issues are likely a key factor the yield penalty observed with continuous soybean. Avoiding soybean on soybean is strongly encouraged to help manage these diseases.
  • Field inputs to date – If N (nitrogen) was applied for corn already, the available N can be utilized by the soybean although it will provide little benefit to soybean (in the process soybean will fix less of its own N via the nodules). Corn will make the most economic use of N applied.
    If corn herbicides were applied to date, this will limit what crops can be planted as any rotational restrictions must be followed.

If you decide to take Prevented Plant:

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