FieldTalk

1. Planting Population – target 28,000-34,000 seeds/ac (rate influenced on numerous factors – climate, soil type & productivity, resources available, planting date, hybrid characteristics, chu region, end use, economics)

        1 bag = 80,000 kernels/bag > 32,000 seeds/ac = 2.5 bags/acre; 34,000 ac/bag = 2.35 ac/bag

2. Plant corn using a planter > consistent seed placement & consistent seed depth

3. Depth – target planting depth is 1.5 – 2.5”; plant into 0.5” of moisture 

  1. Target this depth to achieve good seed-to-soil contact and good development on the nodal root system (critical for structural support and nutrient and water uptake)
  2. Goal: even planting depth > even emergence
  3. Too shallow is worse than too deep
Too Shallow: < 1.5" Too Deep: > 2.5”
  • Poor development of nodal root system
  • Early season lodging
  • Poor plant health mid-late season
  • Delayed/ no emergence Leafing out underground 

4. Soil Temperature – 10 ℃ at planting depth with a 48 hr warming trend

  1. Corn does not germinate below 10 ℃; corn seed is very temperature sensitive
  2. Wait for warm soils to avoid imbibitional chilling (within 24 hrs of planting) & cold injury
    1. Imbibitional chilling occurs when there is a drastic change in the water temperature during imbibition. The critical time for this to occur is within 24 hours of planting.
    2. Cold Injury is when there is a change in the soil temperature after the seed has imbibed water. Cold injury is typically less severe than imbibitional chilling.
  3. Cool soils + cool weather > better to leave the seed in the bag

5. Seed Bed Preparation – plant into a firm seed bed with residue well managed

  1. Poor residue management/ no-till fields can result in hair-pinning of the emerging seedling
  2. Want seedbed to be firm because seed-to-soil contact is increased and for good nodal root development
  3. Excess tillage can result in crusting & compaction
  4. Avoid planting and tilling wet soils

6. Planter Speed – most planters run at 4-5 mph at the fastest

  1. As speed increases, spacing within the row and depth uniformity is reduced
  2. Speed is dictated by planters metering abilities

7. Emergence – Optimal emergence conditions: 10 - 16 days; Unfavorable emergence conditions: up to 21 days.

  1. Even emergence is critical; yield loss from uneven emergence can range from 5-10%

CORN FERTILITY TIPS

Nitrogen (N)

  • Critical to profitability > corn has a very high response to N
  • Application
    • Pre-plant – broadcast & incorporate
      • Side band – 4 inches from seed row High salt index products – ammonium nitrate, urea, potash
    • Fertigation (through the irrigation pivot)
  • Grazing – consider the N left from manure and urine
  • General Recommendation Rates
    • 1 lb actual N/ target bu of grain
      • 150 bu = 150 lbs actual N
    • 8-10 lbs of N/ target ton
      • 21 ton = 189 lbs actual N
  • 63% of plant N is taken up by pollination; 37% of N is taken up during grain fill
    • 50% of N supply used between V8 and VT

Phosphorus (P)

  • Early season development & growth of root system
    • Cold soils have a very slow release of plant available P > Include P in starter fertilizer
  • Important after tasseling – continually taken up during grain fill > long season supply is critical
  • Starter P response can vary year-to-year based on:
    • soil moisture, temperature, crop vigour, hybrid
  • Include in the seed row or close to the seed – immobile nutrient
  • Depending on soil levels: 10 – 40 lbs P2O5
  • Band phosphorus
    • Side banded
    • Spring, fall or at planting
  • Rotation – not recommended to plant corn after canola

Potassium (K)

  • Associated with movement of water, nutrients, and carbohydrates within the plant and stalk strength
  • Rapid K uptake between V6 and VT/R1 timing
  • Application: banding is more efficient than broadcast
  • Watch the salinity of the fertilizer

Sulfur (S)

  • Available S vs elemental S
  • N:S ratio – 10-12:1
  • Know what the crop needs and apply for that season