What Do Iowa Agronomists Say About 2025 Corn Yields?

Corn harvest continues to progress across Iowa as October slips by, with nearly a month having passed without a USDA Crop Progress Report. Looking back at the 2024 season, 68% of the corn crop had been harvested in Iowa at this time last year.

Logan Dinkla, agronomic service representative for Syngenta Crop Protection in central, south-central, and southwest Iowa, said harvest has been moving at a fast pace so far.

“Corn yields have been all over the board,” said Dinkla. “There is a major difference in yields based on fungicide applications and hybrids.”

Rainfall was also sporadic throughout his territory this growing season.

“The majority of yield reports I have heard are floating between 180 and 220 bushels per acre, which is off from previous years,” said Dinkla.

Supporting southern and northeastern Iowa, Wyffels agronomy manager Eric Wilson also confirmed that corn yields remain variable throughout October.

“Corn harvest in the southeast is almost finished for most,” said Wilson. “Northeast and southwest Iowa are not as far along but near the 50% mark.”

Fertility Needs

As harvest begins to wrap up in parts of the state, Iowa State University Extension field agronomist Angie Rieck-Hinz and nitrogen science and soil fertility specialist Richard Roth want farmers to start thinking about soil fertility practices.

In a recent Integrated Crop Management News article, Rieck-Hinz and Roth noted that low crop prices and increased fertilizer costs will result in farmers evaluating how to best allocate fertilizer dollars.

“First on your priority list is to take good soil samples so you can adequately assess soil test levels to make decisions on fertilizer inputs,” said Rieck-Hinz and Roth. “Soil tests should be taken every 2-4 years. One note of caution this fall, consider how dry soils may impact fall soil sample results.”

Next, farmers should consider their soil pH. Soil pH affects both biological and chemical reactions in the soil and affects the availability of the essential crop production nutrients and their forms.

After checking soil pH, the next step is to ensure that phosphorus (P) and potassium (K) soil test levels are adequate to sustain crop production.

“Soils with ‘high’ soil test levels for P and K only have a 5% chance to see a positive ROI with additional fertilizer application and a ‘very high’ soil test level has less than a 1% chance of positive ROI,” explained Rieck-Hinz and Roth.

Finally, Rieck-Hinz and Roth recommend that farmers replace for crop removal and consider secondary and micronutrients, such as sulfur.