Flood impact - should you replant corn?

By Scout Nelson

Recent flooding has impacted corn fields across parts of Nebraska, leading farmers to consider the necessity of replanting. Historically, replant decisions should be guided by a thorough assessment of the surviving plant stands and potential recovery, with a focus on both economic and agricultural factors.

After the floodwaters go down, farmers should wait five to seven days for the corn to emerge before checking the plants. During this time, they should count plants in different parts of the field, including both good and bad areas, to get an accurate idea of the plant population. For precise counting, use row length measurements to calculate the number of plants per acre.

When assessing plant survival, it's crucial to examine the growing point of the plants. If the growing point is firm with new growth, the plant is likely to survive. Discolored and soft growing points indicate a non-viable plant.

Factors like the timing of emergence and the uniformity of the stand also play a significant role in determining whether replanting is beneficial. For example, if a significant portion of the stand emerges three weeks later than the first plants, replanting might increase yields by about 10%.

Economic considerations are also important. The decision to replant should consider the cost, which includes tillage, seed, fuel, additional pesticides, and labor. It's important to consult with seed dealers about available hybrid seeds and any possible rebates for replant situations.

Farmers should also consider the potential yield from the existing stand using yield potential tables based on planting date and plant population. For example, if a field initially planted on April 25 retains 25,000 plants per acre, the expected yield might be 95% of the maximum.

Replanting on May 30 might only yield about 69% of the maximum, suggesting it might be better to stick with the original stand under certain circumstances.

The decision to replant corn should be based on a combination of agronomic data, plant health assessment, and economic analysis, with a recognition of the increased risks of late-season pests and diseases in replanted fields.

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