Today, Governor Kim Reynolds signed an extension of the proclamation relating to the weight limits and transportation of grain, fertilizer, and manure.  

The proclamation is effective immediately and continues through January 20, 2023. The proclamation allows vehicles transporting corn, soybeans, hay, straw, silage, stover, fertilizer (dry, liquid, and gas), and manure (dry and liquid) to be overweight (not exceeding 90,000 pounds gross weight) without a permit for the duration of this proclamation. 

This proclamation applies to loads transported on all highways within Iowa (excluding the interstate system) and those which do not exceed a maximum of 90,000 pounds gross weight, do not exceed the maximum axle weight limit determined under the non-primary highway maximum gross weight table in Iowa Code ยง 321.463 (6) (b), by more than 12.5 percent, do not exceed the legal maximum axle weight limit of 20,000 pounds, and comply with posted limits on roads and bridges. 

See the proclamation here