Originally published in Purdue Pest Management & Crop Production Newsletter (3 May 1996)

Toad Stranglers, Goose Drownders, and Corn Survival

R.L. (Bob) Nielsen , Agronomy Department , Purdue University, West Lafayette, IN 47907-1150

The recent spate of toad-strangling rains has divided Indiana corn growers into basically two camps. There are those with a fair amount of corn already planted before the rainy weather set in and those who elected to wait until the soils warmed up and now have nothing in the ground. Neither group is entirely sure whether they should feel cocky about their decision or sheepish. What can one expect from corn fields that are under water or simply saturated?

Corn, like most crops, requires high levels of soil oxygen to successfully germinate. Flooded or ponded soils, or soils that are simply saturated contain very little available soil oxygen. Germination won't occur until soils dry out sufficiently. Soil oxygen is also essential for the metabolic processes of a developing seedling, including the active absorption and transport of nutrients from the soil.

Anyway you look at it, flooded or saturated soils are not conducive to good germination or early seedling growth of corn. How long can corn withstand the oxygen-depleting effects of saturated soils?

No one knows for sure, but experience suggests from four to seven days before death of the seed or young seedling occurs. The cooler it is, the slower the death because of reduced oxygen demands by the seed or seedling. The larger the plants, the longer they can tolerate the stress. Compounding the outright effects of depleted soil oxygen reserves is the risk of soil-borne diseases on seeds or seedlings that are already stressed.

What to Look For? Obviously, only time will tell whether a corn field that has been under water or saturated for long periods of time will require replanting. As you walk your fields and dig around (don't trying wading out!), look for obvious discoloration of the seeds or seedlings that indicates disease or death of the plant tissue.

Think Ahead. If your field walking or gut tells you that replanting may be warranted, you might want to be talking with your seed dealer soon. Seed supplies for the 1996 season were somewhat tight to begin with, so you should get your foot in the door as soon as you begin considering the need for replant.

As you consider a replant decision, I encourage you to stop in at your local Cooperative Extension Service office and pick up a copy of my Extension publication, AY-264, Estimating Yield and Dollar Returns from Corn Replanting. This worksheet-oriented publication helps walk you through the steps of not only estimating potential yield losses from damaged stands of corn, but also through the steps of calculating the economic returns (or losses) of replanting the damaged field.

Return to the the Chat 'n Chew Cafe.

The Corn Growers Guidebook , a WWW resource for corn management systems in Indiana and the eastern CornBelt.

Purdue University Agronomy Extension WWW Home Page.

Purdue Agronomy On-Line! , Purdue's Agronomy Department WWW Home Page.

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