UMN Field Notes Shares Tips After Heavy June Rains

By Scout Nelson

University of Minnesota Extension experts shared critical updates during a recent Strategic Farming: Field Notes podcast. The session focused on post-rainfall decisions related to nitrogen application, disease risks, and equipment use.

Rain in June has made the timing of nitrogen application very important. Experts recommend applying nitrogen early, noting, “There is no such thing as spoon feeding corn with nitrogen.” The crop needs nitrogen available in the soil by growth stage V12 to avoid yield loss.

Producers are increasingly using their own equipment for in-season nitrogen applications, such as Y-drop systems. Although urea may cause leaf burn when spread over the crop, experts say, “There is no evidence of yield reduction.”

On nitrogen stabilizers, urease inhibitors are now cost-effective and useful in dry or variable conditions. They reduce the risk of nitrogen loss from urea by slowing down the conversion process. This is especially helpful when light rainfall fails to incorporate nitrogen into the soil.

Rainfall also affects nitrogen loss processes. “The loss processes of nitrogen are water driven,” experts explained. Wet soil, especially when fully saturated for long periods, increases the risk of denitrification. Yellowing corn in low-lying areas indicates potential nitrogen loss.

Early-season diseases like Pythium root rot are nearly past concern. However, experts warn about Rhizoctonia and Phytophthora root rot in soybeans, which thrive in wet, warm conditions. Resistance management is vital as some disease strains overcome genetic protection.

Later in the season, experts advise monitoring for Sudden Death Syndrome (SDS), white mold, and corn tar spot. These diseases develop based on moisture and temperature. “The risk is greater… because the pathogen is probably there,” they noted.

The podcast also addressed audience questions on timing nitrogen applications, effects of heavy rain, and whether dry winter weather reduces disease risks. For more disease tracking, growers can use the IPM Pipe Tar Spot webpage.

Photo Credit:university-of-minnesota