Northwest Iowa Crop Conditions

The weather has been very active this season, with thunderstorms occurring nearly every week in July. On Monday night, parts of northwest Iowa experienced winds exceeding 90 MPH, while gusts over 60 MPH were common across the entire region. Although there was significant damage to trees and property, crop damage was seemingly limited.  However, it will take more time to evaluate the extent of damage from wind and excessive rain.

Rainfall totals over the past two weeks have ranged from 3 to 8 inches, with some locations now reporting over 12 inches for the month. This is well above the average July rainfall of about 3.4 inches. Interestingly, July has been consistently drier than normal over the past decade, the trend has shifted toward wetter conditions in August and September.

Corn pollination is wrapping up across the area. Many fields are currently being treated with fungicides to protect against leaf diseases. The combination of wet weather, hail, and wind damage has created ideal conditions for high disease pressure. Despite these challenges, most corn looks excellent, and yield potential remains very strong. Some farms could still see record-breaking yields if they have a strong finish. The next few weeks are critical as corn starts the grain fill stage.  Late season stress will reduce kernel size and weight. Hot weather accelerates maturity, and cooler temps will slow it down. A slightly cooler-than-normal August would be ideal to maximize yields by extending the grain fill time.

Soybeans are now beginning to set pods. In areas with excessive rainfall and poor drainage, some fields are showing yellowing and signs of stress. However, overall soybean conditions are good. August is the most crucial month for determining soybean yields. Soil moisture is currently adequate or excess, but timely rain later in August will still be needed to finish strong.