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College of Food, Agricultural, and Environmental Sciences


Inspect Crops for Ponding or Freezing Damage

May 17, 2010

COLUMBUS, Ohio – Ohio growers have enjoyed early corn and soybean planting this growing season, but now they may be facing some crop damage due to recent heavy rains and some freezing nighttime temperatures.

According to the Ohio Agricultural Statistics Service, 84 percent of the corn has been planted, 47 percent ahead of last year and 12 percent ahead of the five-year average. With soybeans, 45 percent of the crop is in the ground, 29 percent ahead of last year.

But frost damage and saturated soils may impact seedling or plants that have already emerged, said Peter Thomison, an Ohio State University Extension agronomist. Sixty percent of the corn has emerged and over 20 percent of the soybeans have emerged.

"Frost damage alone is unlikely to affect corn that much. The growing point is below or at the soil surface, so it's usually not much of a problem," said Thomison, who also holds an appointment with the Ohio Agricultural Research and Development Center. "With soybeans, it's a different matter. Once the plant emerges, it's vulnerable to frost damage. It's probably a good thing that not more soybeans have been planted."

For corn, Thomison said that the problem arises when the crop has been exposed to both freezing damage and prolonged saturated soils or ponding conditions.

"The combination of freeze damage plus heavy rains is a bad situation right now for some fields. On the one hand it's a major asset to have the corn's growing point below the soil surface when you have frost damage. But on the other hand, when the plant's growing point is below the soil surface and you have saturated soils, it's a major disadvantage because the plant is subject to more injury from lack of oxygen," said Thomison.

Thomison recommends that growers inspect their corn plants for damage to determine whether replanting is necessary. "When it comes to prolonged ponding conditions, the plants may be killed outright."

Thomison recommends that growers dig up corn plants and inspect the growing point. If the growing point is dark-colored, rather than a creamy-white color, the plants may be damaged and dying and would be tagged for replanting.

Soybeans sitting in saturated fields for prolonged periods will also die from oxygen deprivation, much like corn. In addition, soybeans are often more susceptible to root rot organisms that thrive under wet conditions.

"Warm temperatures may facilitate the rotting process rapidly," said Thomison.

But despite the potential injuries to corn and soybeans from freezing temperatures and rains, problems appear to be localized.

"By and large, we are not hearing of major ponding or flooding issues. The only thing the weather is doing right now is delaying farmers from getting the rest of their crop in the ground. If fields dry out, we can still get planting accomplished without major yield sacrifices."

Candace Pollock
Peter Thomison