The September USDA Crop Production report on Friday delivered another cut to the government’s corn yield estimate, as we expected. We knew USDA was unlikely to cut yield to a level near our Pro Farmer estimate of 173.2 bu. per acre, but the 2.2 bushel drop to 178.5 bu. per acre was a step in the right direction — and there’s good reason to argue the gap is likely to narrow further in coming months.
The September report marked the first time that USDA incorporated objective yield data, which includes field-measured plant counts and ear data, in its corn and soybean estimates this year (the August report relied on satellite data, farmer surveys and crop condition ratings). It comes after our Pro Farmer Crop Tour, which ran from Aug. 17 to 20, sampled thousands of corn and soybean fields across seven major producing states.
We took a close look at USDA’s objective yield data in the report to see how it compares to our Crop Tour findings. USDA found ear counts across the top ten production states (Illinois, Indiana, Iowa, Kansas, Minnesota, Missouri, Nebraska, Ohio, South Dakota and Wisconsin) were down from what was found last September but were actually above (0.04%) final figures for a year ago. That was a surprise considering that counts across the seven Crop Tour states were down 1.84%. That said, the norm the past few years has been for ear counts to move lower through the next few USDA reports. If that trend continues, which we expect, ear counts are likely to end up below a year ago, which will help push estimated yield lower.
Another interesting anecdote found in the objective yield data — ear counts have typically been above planted populations the past several years in Crop Tour states. That is not the case this year. Ear counts are below planted populations for the first time since 2022, indicating USDA found blank stalks as it surveyed the crop, as did our Crop Tour scouts.
So if USDA found a rise in ear counts but still cut yield, what gives? That leaves just one culprit — ear weights. USDA uses implied ear weights in its September report due to a lack of mature crops being available for testing. So, USDA is penciling in sharply lower ear weights from a year ago. Average ear weights for the 10 objective yield states are estimated at an implied .365 lbs. per ear, down sharply from the record .381 lbs. per ear in 2025, but still the third highest ever (behind 2024 and 2025).
Crop Tour found ear length down 4.3% from a year ago. If actual weights were to fall by the same amount, that would imply test weights of .364 lbs. per ear, roughly in line with USDA’s figure. To give some historical perspective, the ten-year average ear weight is .357 lbs. per ear. If you take out 2025, which is an outlier, that average falls to .352 lbs. per ear. The difference does not seem like much but makes a big difference.
Using USDA’s ear counts, we can see what changes to ear weights could mean for a national average yield. If ear weights fall to the 10-year average, USDA’s national yield would fall to 175.6 bu. per acre. Using .352 lbs. per ear, the 10-year average before last year’s outlier, the national average yield sinks to 173.0 bu. per acre. Given the high amount of tip-back found on Tour, smaller ears found in general and pollination problems in the eastern Corn Belt, weights falling beyond what USDA is penciling in is a reasonable expectation.
Bottom line: With ear weights likely to trend lower in coming reports, producers should be prepared for further yield cuts through harvest.