By Nicolás Cafaro La Menza
Key Takeaways
Planting early during soil-warming windows maximizes yield potential and return on investment in crop inputs.
Minimum soil temperature thresholds for germination: corn and soybean are safe to plant at 50°F or greater soil temperature, while sorghum requires 55–60°F or greater.
Soil temperature above the thresholds during the first 24 hours after planting is critical for adequate water uptake (imbibition phase) to ensure good germination. After this imbibition phase, corn and soybean seeds can tolerate temperatures below 50°F without affecting germination as long as the seed is in proper soil moisture.
Start planting corn and soybean when soil temperatures at 2 inches are above 50°F and the weather forecast shows 24 to 48 hours of rising temperatures or similar weather as of planting day.
Adequate soil moisture is essential for rapid seed imbibition, making it even more important to time planting with both temperature and moisture conditions to support strong emergence.
Why do we want to plant early? The planting date management is not about when you plant your first field, but when you plant your last field. Planting early is a key factor in achieving high yields, especially in irrigated fields. Early planting is more critical for soybean than for corn. An eight-day advance in the Nebraska irrigated soybean 50% planting progress date was associated with a Delays in the Nebraska irrigated corn 50% planting progress date did not have much impact on corn yields. Indeed, there is a planting window between mid-April and mid-May in which corn yield does not seem to change much.
Source : unl.edu