Fundamentally Speaking

The September crop production report earlier this month reported that the 2025 U.S. corn yield came in at 186.7 bushels per acre (bpa), down 2.1 bpa from the August estimate.

Still, it is a record yield and well above the prior peak set a year ago at 179.3 bpa.

As opposed to the August report, for the September estimates the USDA did use actual field measurements including the plant and ear populations of ten objective states.

Looking at the 10-state objective corn ear population data, the USDA is using the same 28,700 ears per acre figure as they used for the final estimates last year, so the reason for the record yield this season is they are projecting the heaviest corn ear weights in history, offsetting a similar corn ear population from the year prior.

Corn yields are based on the number of ears per acre and the weight of each ear with rising figures for both resulting in higher yields and vice versa.

This chart shows the 10-state objective corn ear population in ears per acre on the left-hand axis while reported on the right-hand axis is the implied corn ear weight in pounds per ear.

We also show in the yellow boxes the 10-state weighed yield using the data from the ten objective states.

An interesting side note is that the long-term growth in corn plant and ear populations appears to be slowing as from 2005 to 2014 ear populations increased by an annual average of 376 per season but from 2015 to 2025 that has slowed to a yearly increase of just 46 ears per acre.

The other part of the equation is the weight of each year and that is tied more into growing conditions, specifically temperature and precipitation during the key developmental months especially in July.

This year, in many of the key corn growing states, growing conditions in July were quite favorable with regard to both temperatures and precipitation and this results in the September 2025 10-state implied ear weight of 0.3804 pounds per ear.

This is the highest weight ever surpassing what was seen in 2024 where the 0.3659 pounds per ear figure had been the highest ever.

This results in the ten-state objective yield coming in at 195.6 bpa, again topping the prior peak set a year ago at 187.6 bpa.

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