Response of Corn Products to Soil Preparation, Seeding Rate, and Planting Depth

TRIAL OBJECTIVE

 

  • Late harvest and wet soils in the fall of 2018 prevented raised beds from being implemented in many fields. Fields that were muddy during harvest were rutted and had little or no opportunity for subsequent tillage to repair and prepare fields for spring 2019 planting. Spring rains further limited the opportunity for field preparation prior to planting and resulted in deteriorated seedbed conditions for fields that were prepared in the fall. For these reasons, many fields were planted into less than ideal field conditions.

  • Adequate drainage is necessary for maximum yield potential in the coastal Mid-South. Poor drainage can hamper stand establishment due to soil saturation.

  • The objective of this study was to evaluate stand establishment and yield of corn products to different soil preparation scenarios, planting depths, and seeding rates.

 

RESEARCH SITE DETAILS

Location Scott, MS Planting Date 4/2/19
Soil Type Silt Loam Harvest Date 8/26/19
Previous Crop Cotton  Potential Yield
(bu/acre)
200
Tillage Type Varied Seeding Rate
(seeds/acre)
32K, 37K

  • Two DEKALB® corn products (DKC67-44 brand and DKC70-27 brand) were chosen for this demonstration. There were no differences in yields or stand counts between treatments for either corn product; therefore, the data was combined.
  • 240 lb nitrogen was applied as 32% liquid UAN.
  • The trial included 16 treatments and was planted in strip plots: 12 rows x 600 feet long.
  • Treatments included:
    • Two seeding rates:
      • 32,000 seeds/acre
      • 37,000 seeds/acre
    • Two planting depths:
      • 1.25 inches
      • 2.5 inches
    • Four tillage operations:
      • No-till – Corn planted into standing, mown-off cotton stalks (Figure 1). 
      • Reduced tillage - Stale seedbed rehipped in the spring with minimal tillage (Figure 2).
      • Spring disk flat and plant flat – Conventional tillage without bedding but all done in the spring (Figure 3).
      • Spring disk flat and rehip – Harrow plowed flat and rebedded in spring (Figure 4).
  • All weed control, insect control, and irrigation inputs were applied per local standards on all treatments.
  • Stand counts were taken from 10 row feet per plot at full emergence.
  • Yields were harvested with a commercial combine and adjusted for 15.5% moisture.
  • All data was collected with 20/20 SeedSense® using the Climate FieldView™ platform app and complied from there

 

UNDERSTANDING THE RESULTS

  • Notable effects were observed in the impact of field preparation on corn grain yield.
  • The primary influential factor in this study was drainage as influenced by tillage and row structure.
  • Drainage has long been acknowledged as a major limiting factor in the coastal U.S.  2019 was a year that clearly demonstrated these principals.
  • As much as a 30% difference in stand establishment was observed across land preparation treatments (Figure 7).  Stands were reduced in treatments with poor drainage, water logging, and the associated reduction in temperature (either planted flat or without much row structure as in the no-till treatment).
  • Yield in corn is highly corelated to final stands and that is evident in these results (Figure 6).  The highest yields in this trial were from the treatments with the best stand establishment, typically the stale seedbed, rehipped treatments (Figure 5 and 7).  Planting depth also played a part in establishing optimal stands.  Deeper planting depths typically yielded more across the trial (Figure 6).

 

KEY LEARNINGS

 

  • Every attempt to optimize drainage should be made to help in establishing the best yield potential in southern corn crops.
  • Investments in seed and technology are optimally used when the factors in this study are carefully considered and incorporated into management systems.
  • Flat planting is not a viable option in the southern delta due to the topography, i.e. flat with little/no internal soil drainage.
  • Planting into standing cotton stalks should be weighed carefully and could require adjustments in seeding rates to optimize corn population establishment (ex: slight increases in seeding rates due to reduced establishment).
  • Beds, whether stale or newly formed, offered the best options for corn production at Scott, MS during 2019 and likely will offer a superior option into the future.
  • Corn yields are typically optimal with higher stands and establishing those stands requires consideration for tillage, row formation, and the associated drainage.

     

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