Corn Cold Stress

Imbibitional Chilling

That time of year is just around the corner. In many parts of the corn belt, the robins have just started to show up. As the saying goes, “there will be 2 snows on a robin’s back before you can plant.”  Imbibitional chilling is one of the main deterrents from sticking corn in the ground as soon as the wheels can turn. There are some key elements to be aware of so you don’t have to wait until “the buds on the oak trees are the size of a squirrel’s ears” to plant.

Imbibitional chilling injury can occur in both corn and soybeans. The term is derived from when seed first imbibes (takes up) water. Cell membranes stretch and expand as the seed bring water in. The trouble occurs when the water temperature falls in a certain range. Water is at its most dense at 39 degrees Fahrenheit or about 4 degrees Celsius. The density of this water is the leading factor in damaging cell membranes.

Damaged cell membranes can become “leaky” and loose necessary sugars and needed for early vigor and development. Furthermore, damage to cell structures such as the mitochondria will prevent the cell from converting those sugars to energy for crucial early growth.

The key thing to remember with Imbibitional chilling is that the first 48 hours after planting are crucial. Having soil temperatures in the upper 40’s with a decent forecast eliminates much of the chance for damage. If there is cold rain and/or snow in the short-term forecast, it doesn’t take a lot to drop those soil temps back down into the danger zone of the low 40’s.

Today’s hybrids handle early stress much better than they did even 10 years ago. Given a good start, most of todays hybrids can handle stress well, but as the old saying goes, “the first drink is best not be a cold one.”