What Controls Emergence?
- Seed Quality
Why Corn is Sensitive to Early Season Stress
- Corn is a warm-season crop – optimal temperature for emergence is 85-90 F – so it is almost always under some degree of cold stress.
- Prolonged exposure to soil temperatures below 50 F promotes seed deterioration and seedling disease.
Modes of Damage in Cold, Wet Soils
- Cold imbibition causes physical damage.
- Extended cold delays emergence and further damages seeds.
- Damaged seeds are likely to be attacked by insects and disease.
- Surviving seedlings are likely to produce runts.
Imbibitional Chilling Injury
- Cell membranes are brittle in the cold
- Force of hydration causes membrane rupture
- Leaked cell contents invite pathogens
Water temperature during initial contact is critical.
Most damage occurs during imbibition at less than 50 F.
|Imbibitional chilling and cold injury (photo above and below). Note club and corkscrew shapes, and underground emergence in these 2 photos.
- Frost damage can lead to runts and uneven stands.
- Multiple events are more damaging than a single frost.
- A healthy growing point does not guarantee a healthy stand.
- Growth may be blocked by dead tissue.
- Growing point needs a healthy coleoptile to push through soil.
|Flooding damage – note necrotic area of each root above root tip.
Stress Emergence Scores
- Genetic potential of hybrids to emerge under stressful environmental conditions (cold, wet soils or short periods of severe low temperatures).
- Avoid planting ahead of a cold event
- Plant into moisture
- Plant well-drained, low-residue fields first
- Use a residue manager
- Use the right seed treatment
- Choose the right hybrids
- Stress Emergence
- High Residue Suitability