By Andi Anderson
Frost heave is a common issue in alfalfa fields during winter freeze-thaw cycles. It occurs when soil and plant crowns are lifted due to expanding frozen water, often damaging plant roots and affecting spring growth. This issue is particularly concerning in regions experiencing colder-than-usual winters.
When frost heaving occurs, alfalfa crowns may rise above the soil surface, making them vulnerable to winter injury. In severe cases, taproots can break as they remain deep in the soil while the crown moves upward. Plants with broken taproots may initially show spring growth but die as the season progresses due to a lack of deep moisture access.
Frost heave is more likely in soils that undergo frequent freezing and thawing, especially when only a light snow cover is present. Similar to how potholes form on roads, frost heaving happens when liquid water seeps into soil gaps and expands upon freezing.
To prevent frost heave, farmers should focus on maintaining well-drained fields and leaving adequate fall stubble to help retain snow cover.
Selecting well-adapted alfalfa varieties and ensuring proper soil fertility also contribute to root system resilience. Interseeding with grasses can reduce the risk, though it may not eliminate frost heave entirely.
Spring assessments are essential for managing frost heave. Farmers should check for broken roots and evaluate stand density before deciding whether to replant. If damage affects more than 10-20% of plants, replanting may be necessary. For milder cases, delaying the first cut and raising the cutting height can help plants recover. Using rollers or cultipackers to push plants back into the soil can cause further damage and should be avoided.
By recognizing and managing frost heave, farmers can protect their alfalfa fields and ensure healthy spring growth.
Photo Credit: gettyimages-gabrielabertolini
Categories: Ohio, Sustainable Agriculture