With such a small optimum planting window, it’s easy to get anxious to kick off the corn planting season. However, “jumping the gun” and planting too early can damage yield through imbibitional chilling injury. Imbibitional chilling occurs when the soil temperature drops below 50 F during the first 24 to 36 hours after planting. The seeds absorb, or “imbibe” water to begin germination. If the water is too cold, seeds become swollen and less elastic, and may rupture. Rupturing damages the growth point, causing irregularly grown roots or shoots.
FACTORS TO CONSIDER:
- Soil temperature
- Future weather patterns
- Early scouting
- WATCH SOIL AND WEATHER CONDITIONS. Planting timing is crucial to raising a high-yielding crop. Growers need to check the soil temperature and upcoming weather patterns before planting to ensure conditions are right for proper seedling germination. The soil temperature should be 50 F or warmer at the depth of planting – don’t rely on the surface temperature. Weather forecasts are equally important. Ideally, weather should be dry for a week to 10 days following planting. This allows the corn to begin germination. Imbibitional chilling of corn often occurs when there’s a combination of low soil temperatures and cool rains. If cold rain is predicted in the short-term forecast, it’s best to hold off planting.
- SCOUT EARLY IN COOL CONDITIONS. If you’ve experienced a cold snap after planting, scout fields for signs of imbibitional chilling injury. Start digging up plants within two weeks of planting, looking for irregular elongation or “corkscrewing” of the mesocotyl, or “leafing-out” underground with delayed or failed seedling emergence. Additionally, growers will see an uneven stand as the crop emerges. Uneven stands could signal herbicide injury or compaction issues. Digging seedlings and looking for irregular growth are keys to accurate diagnosis.
- CONSIDER REPLANTING. If imbibition chilling injury occurs, replanting as soon as possible is the only way to avoid yield loss. Otherwise, a grower may leave 15 to 20 percent of yield in the field. The earlier a grower replants, the more promising the yield.
Imbibitional chilling of corn typically occurs when cool soil temperatures are paired with a cool rain in the first 24 to 36 hours after planting. To prevent seedling injury, monitor soil temperatures and weather forecasts before planting. If a cold snap hits soon after seed is in the ground, scout early and decide if damage warrants replanting.
For more information, visit our website or contact your local Mycogen Seeds commercial agronomist or trusted agronomic adviser.