Potential freezing temperatures
Some of you may be watching the weather forecast and worried about the potential for freeze damage to soybean. Many of us have been through this before. Most often things work out just fine for the soybeans. I expect Minnesota Extension agronomists will provide more information if things take a turn for the worse. In the meantime, here are some points to consider.
- Unlike soybeans, the growing point of emerged corn is still below the soil surface and protected from frost.
- Soybeans that have not emerged (including hypocotyl crook) will be OK.
- Soybean injury or death from freezing temperatures is more likely in low areas
- Soybeans in the cotyledon stage are more freeze tolerant than later stages.
- Temperatures will likely need to drop below 32 F for soybean seedlings to be killed. In an NDSU study, 50% of seedlings were able to tolerate temperatures as low as 24 F for a short time. In this same study, peas were similar to soybean, edible beans were less tolerant and alfalfa were more tolerant to frost.
- Soil moisture, soil type and previous crop residue can influence freeze tolerance.
- Plants with a live growing point remaining can survive
- Plants frozen below the cotyledons will be dead.
- Yield loss will be related to stand loss and soybean compensate well for reduced stands.
- You will need to wait several days to adequately assess stand loss.
Badaruddin, M. and Meyer, D.W. (2001), Factors Modifying Frost Tolerance of Legume Species. Crop Sci., 41: 1911-1916. doi:10.2135/cropsci2001.1911
Meyer, D.W. and Badaruddin, M. (2001), Frost Tolerance of Ten Seedling Legume Species at Four Growth Stages. Crop Sci., 41: 1838-1842. doi:10.2135/cropsci2001.1838
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