Impact of Uneven Emergence in Corn

Trial Overview

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  • Corn yield potential can be affected negatively by uneven seedling emergence.  Factors that can adversely affect seedling emergence include:
         - Plant residue (trash)
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         - Large soil clods or chunks
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         - Poor soil conditions (cool temperatures and excessively wet/dry soil)
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         - Poor soil-to-seed contact
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         - Uneven planting depth
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Research Objective

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  • Determine the impact on yield potential of late emerging corn plants.
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Monmouth, IL
Silt loam
Soybean
Conventional
05/09/2016
09/28/2016
NA
36,000 seeds/acre
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Marking of seedling emergence
         - Seedlings emerging first were marked with red flags.
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         - Seedlings emerging on day 3 or two days after first emerging seedlings were marked with white flags.
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         - Seedlings emerging on day 5 or two days after second seedling group were marked with blue flags. 
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          - Five randomly selected ears from each seedling group were hand harvested.
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          - Ears were weighed and average kernels/ear calculated.
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Understanding the Results

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Figure 1. Ear samples of A) Seedlings emerging on day 1; B) Seedlings emerging on day 3; C) Seedlings emerging on day 5.
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Figure 2. Average kernel rows and kernels/row when corn seedlings emerge erratically.
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  • Late emerging seedlings suffer from extra competition and struggle to become established.
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  • Late emerging seedlings exhibit reduced growth throughout the growing season and at harvest have smaller ears, reduced kernel count, and reduced yield (Figures 1, 2, and 3).
              - Figure 1A shows ear samples of seedlings emerging on day 1(average of 18 kernel rows, 30.8 kernels/row, and 554 kernels/ear).
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              - Figure 1B shows ear samples of seedlings emerging on day 3 (average of 16.8 kernel rows, 32.2 kernels/row, and 540.96 kernels/ear).
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              - Figure 1C shows ear samples of seedlings emerging on day 5 (average of 17.2 kernel rows, 19.2 kernels/row, and 330.24 kernels/ear).
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  • Seedling emergence on Day 1 represents yield potential of 100%, Day 3 represents 98%, and Day 5 represents 60%, respectively.
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What Does This Mean for Your Farm

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  • Utilization of available tools and techniques can help ensure uniform plant emergence and can help maximize yield potential. Tools and techniques include:
         - Waiting to plant until soil moisture and temperatures are conducive to seed germination.
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         - Tilling appropriately to create a uniform seed bed.
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         - Planter set and adjusted properly to help ensure even planting depths.
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              - Row cleaners properly set to push aside plant residue and soil chunks.
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              - Use of seed firmers to help ensure good seed-to-soil contact.
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