How Long is Too Long for a Crop to be Under Water?

How Long is Too Long for a Crop to be Under Water?

May 28, 2008

A story in the May 20, 2005 CropWatch answers this question. Flooded Fields and Crusted Soils: Determining When Replanting is Your Best Option includes replanting guides for corn and soybean by Lori Abendroth and Roger Elmore, extension agronomists formerly with UNL, and a table of how to estimate plant survival from flood damage at various crop stages. Air temperature is a key factor in survival - cooler is better.

From the table: 

  • For corn prior to the 6th leaf stage that's underwater (6 inches of water on surface) and the air temperature is less than 77°F. will survive for four days. Longer flooding results in lower yields especially at lower nitrogen levels.

     

  • Small soybeans that are completely submerged will survive several days to a week if air temperature is below 90°F.