Effects of Flooding on Corn Emergence and Seedlings

Overview

• Flooding in corn fields can negatively affect yield potential and cause other problems.
• Growth stage of the corn plants when flooding occurs, the frequency and duration of the flooding, and air temperatures during that time can affect the extent of damage the corn receives from flooding.
• Plant survival, potential nitrogen loss, and soil crusting should be considered when deciding on management options.
• Farmers may re-seed poor stands with corn or soybeans if doing so is timely, soils are fit, and herbicide labels have allowable re-cropping intervals.

Early Season Corn Plant Survival in Flooded Fields

Different corn products have different responses to flooding, but the general effects of flooding on yield potential depend on the growth stage of the corn plant, the duration of submersion, and air temperature, with temperature being one of the most critical components of plant survival. Flooding reduces plant respiration which can result in a very negative impact on young corn plants. Corn plants need oxygen to survive, and oxygen is depleted after about 48 hours due to the reduced gas exchange between the atmosphere and the saturated soil.^1,2

Generally, germinating seeds will survive for four days. Corn seedlings at or below the soil surface are at the highest risk of dying when the field is flooded, as submerged seedlings can survive for only two to four days.² Emerged corn plants have a better chance of surviving, especially if the growing point is above water. However, if air temperatures are above 77 °F, the plants may not survive more than 24 hours of submersion.¹ If temperatures are cooler (<77 °F), corn plants with fewer than six leaves can survive approximately four days of flooding.¹ Table 1 summarizes some potential survival scenarios for corn seedlings based on the air temperature.

Table 1. Potential survival of flooded corn seedlings in various scenarios.

Potential Impact on Corn Yield from Flooding

Research in Iowa looked at the impact of flood duration on final grain yield in corn. Seedlings that were six inches tall were flooded for 72, 48, or 24 hours at a low nitrogen (N) fertilizer level of 50 lb/acre. The researchers observed yield reductions of 32, 22, and 18%, respectively. At high N levels (350 lb/acre) yield reductions ranged from 19 to 14%. The following year, yield losses were less than five percent.²

Potential Flooding Problems Affecting Early Season Corn

Considerable loss of nitrogen (N) through leaching or denitrification can occur in corn fields submerged for more than two days. Leaching is more prevalent in sandy soils. Denitrification, which is more prevalent in heavier-textured soils, occurs when saturation leads to anaerobic, or low oxygen, conditions. Research conducted by the University of Nebraska indicated an approximately 10 to 25% nitrate loss when soils were saturated for 5 or 10 days, respectively.³ This was reported while soil temperatures were between 55 and 60 °F. Sidedressing more N is a possible solution if considerable N was lost in the field.

As wet soils dry out, the soil surface can form a crust, potentially inhibiting seedling emergence. Fields may be at greater risk for soil crusting if they have:

• Fine textured soils
• Low organic matter
• Little surface residue
• Excessive tillage.⁴
  

A rotary hoe can help break up the crust and aid seedling emergence. Timing is essential and breaking the crust as soon as possible is most beneficial. Assuming no seedling disease infection occurs, cooler soils can allow seedlings to survive longer as they break through the crust.

Scouting and Corn Replanting Options

It is important to look for signs of new leaf growth by scouting corn fields three to five days after the water has receded.^1,2 Dig up seedlings, slice through the root crown, and look at the growing point. A white or cream-colored growing point that is firm indicates the plant is recovering (Figure 3). Growing points that are darkening and soft are beginning to die.² Stand counts need to be taken to determine the remaining plant population.

If replanting with corn, minimizing soil disturbance by using minimum or no tillage is recommended to maintain the efficacy of any herbicides and/or soil insecticides already applied to the field. Switching to alternative crops when replanting corn fields must be carefully considered. Before replanting with soybean, check your herbicide label and consult local experts to determine if the previously applied corn herbicides could damage the replanted crop. It is important to scout fields entirely before making the decision to replant.

Sources

¹Brhel, J., Specht, J., Nygren, A. and Meuller, N. 2024. Corn and soybean survival in saturated and flooded soils. University of Nebraska-Lincoln, CropWatch. https://cropwatch.unl.edu/corn-and-soybean-survival-saturated-and-flooded-soils/
²Thomison, P. and Geyer, A. 2017. Effects of flooding and ponding on corn. Ohio State University Extension, Ohioline. https://ohioline.osu.edu/factsheet/agf-118
³Ferguson, R.B. 2008. Assessing nitrogen loss due to saturated soils. University of Nebraska-Lincoln, CropWatch. https://cropwatch.unl.edu/assessing-nitrogen-loss-due-saturated-soils/
⁴Al-Kaisi, M. and Pedersen, P. 2007. Wet conditions: Challenges and opportunities. Iowa State University Extension and Outreach, Integrated Crop Management. https://crops.extension.iastate.edu/encyclopedia/wet-conditions-challenges-and-opportunities
Web sources verified 05/11/2026. 1222_124643