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

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Response of Corn Products to Soil Preparation, Seeding Rate, and Planting Depth -  2020

 

TRIAL OBJECTIVE

  • Rainy fall and spring weather patterns can result in wet soils that prevent raised beds from being prepared. Heavy spring rains can lead to deteriorated seedbed conditions for fields that were prepared in the fall. For these reasons, it is not uncommon for fields to be 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. For this reason, preparing raised beds for planting are a common practice in the Mid-South. However, when time is tight due to weather conditions, bedding can be a step that growers are tempted to skip.
  • The objective of this study was to evaluate the yield potential of corn products to different soil preparation scenarios, planting depths, and seeding rates. 
    • Previous work at the Bayer Learning Center at Scott, Mississippi has shown a positive yield response to proper field preparation and deeper planting depths. Past data has shown a greater yield response to deeper planting depths for earlier, cooler planting dates.

 

RESEARCH SITE DETAILS

Location Scott, MS     
Soil Type  Clay silt loam   

Previous
Crop
Cotton    
Tillage
Type
 
Various

 
Planting Date 05/04/20    
Harvest Date 09/11/20  

Potential Yield
 (bu/acre)
200    
Seeding Rate
(seeds/acre)
32K, 37K

 

 

  • Two DEKALB® brand VT Double PRO® corn products (DKC66-75 brand and DKC68-69 brand) were selected for this demonstration.
  • Treatments included: 
    • Two seeding rates: 
      • 32,000 seeds/acre
      •  37,000 seeds/acre 
    • Two planting depths: 
      • 1.25 inches
      • 2.5 inches 
    • Four soil preparation methods: 
      • Spring disk flat and rehipped: Harrow plowed flat and rebedded in the spring (Figure 1, left). 
      • Spring disk flat and plant flat: Conventional tillage without bedding performed in the spring (Figure 1, right). 
      • No-till: Corn planted into standing, mown-off cotton stalks (Figure 2).  
      • Reduced tillage: Stale seedbed rehipped in the spring with minimal tillage (Figure 3, left).
  • All weed control, insect control, and irrigation inputs were applied per local standards on all treatments.
 

 

image Figure 1. Spring disk flat and rehipped (left) and spring disk flat and plant flat (right) soil preparation treatments.
image Figure 2. No-till soil preparation treatment.
image Figure 3. Reduced-till treatment of stale seedbed rehipped (left) and no-till treatment of mowed cotton stalks (right) soil preparation treatments. 

UNDERSTANDING THE RESULTS

Seeding rate: Due to spring rains in 2020, most southern corn was planted late which limited yield potential. Therefore, the typical response to seeding rate was not observed in this study. In addition, both corn products are well adapted to the seeding rates used in this study and were able to optimize yield potential across the parameters tested. Because no differences were noted due to seeding rate, data was combined for the purposes of this report. 

 
image Figure 4. Average corn yield response to soil preparation and seeding depth in 2020.

Planting depth: There were no substantial average yield differences due to planting depth in 2020 (Figure 4). In previous demonstrations, we typically observed more of an impact from planting depth than we observed in this demonstration, which showed basically zero impact. This is likely due to not planting into cold, wet soils and not having a large predation of seed by birds. These are the two primary reasons that we typically plant corn deeper. 

 

image Figure 5. DEKALB® brand VT Double PRO® corn product average yield response to soil preparation in 2020.

Corn product: The corn products in this demonstration responded differently to soil preparation method. These results highlight the importance of corn product selection and positioning them to maximize their genetic potential. The field for this study was a stressful production system and DKC66-75 Brand is not well suited for this environment. 

 

image Figure 6. Average corn yield response to soil preparation in 2020.
  • Soil Preparation: In this demonstration, the reduced tillage and spring disked/rehipped systems showed average yield increases of 20 bu/acre compared to flat planted or no-till treatments. This is likely due to improvements in drainage. Raised beds can help relieve seedlings from saturated soils. Observations were similar in 2019 where the no-till and flat planted system did not yield as those with beds.

  • The results from 2019 and 2020 indicate an ability to reduce tillage as long as good drainage is established with the system chosen. 

 

KEY LEARNINGS

  • Corn product selection remains a very important component in maximizing corn yield potential.

  • In this demonstration, planting depth did not appear to have an impact when considering tillage system, corn product or seeding rate. However, growers should remain focused on planting at recommended depths to mitigate risk of bird damage and uneven emergence.

  • Seeding rate did not greatly increase yields in 2020 but yield potential may have been limited by the delayed planting date. Growers should consider corn product, planting date, soil types and maximum yield potential when selecting a seeding rate.  

  • The tillage system used impacted yield potential in this study. Abundant rainfall and excessive soil moisture is the most prominent factor challenging southern corn growers during the planting season. Management options like soil preparation can help improve outcomes. Growers should establish/reestablish drainage (regardless of tillage system) as needed to help optimize yield potential. 

 
 
 
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January 10, 2020

Response of Corn Products to Soil Preparation, Seeding Rate, and Planting Depth  - 2019

 

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    
Soil Type  Silt loam  

Previous
Crop
Cotton    
Tillage
Type

Varied  


 
Planting Date 4/02/19    
Harvest Date 8/26/19  

Potential Yield
 (bu/acre)
200    
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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