A New Cover Crop or Just Another Learning Opportunity From 2025?

By Meaghan Anderson and Erin Hodgson et.al

While harvest is slowing down across the state, many have noticed new plant growth in the field: volunteer corn. While volunteer plants aren't unusual, it is rare to see so many fields with substantial unwanted plants this fall. Let’s examine why and what it might mean for 2026.

The crop

Corn and soybean suffered from numerous stressors this year, resulting in a relatively quick maturing crops throughout Iowa. Several issues come to mind when thinking about why crops matured so rapidly in 2025:

1. Early planting. Approximately 1/3 of the corn crop was planted before April 27.
2. Excessive rainfall. Too much water caused nutrient leaching and other stresses in some cornfields, particularly in central and north central Iowa.
3. Hot temperatures. Warm, humid conditions in July hastened reproductive development, and created ideal conditions for southern rust to develop and spread.

Ultimately, the environmental conditions resulted in corn that was more challenging to harvest. Challenges ranged from threshing corn grain from rubbery cobs to variable test weights and seed size.