NASS corrects September corn yields: Kansas down 3, Nebraska up 5

The USDA's National Agricultural Statistics Service has cut its corrected September corn yield forecast for Kansas to 119 bushels per acre, down 3 bushels, and raised Nebraska's to 182 bushels per acre, up 5 bushels, after admitting a processing error in how it combined irrigated and non-irrigated objective yield observations.

The corrected national figure is 178.8 bushels per acre, an upward revision of 0.3 bushels. NASS has amended the affected September data and forecasts in its Crop Production reports and in the Quick Stats database.

The correction, confirmed October 26, follows concerns raised about the October 9 Crop Production report. NASS responded by reviewing its September and October corn estimation procedures in full.

What went wrong?

Bryan Combs, director of the Office of the Agricultural Statistics Board, said the review identified a September processing error involving incorrect acreage weights used to combine irrigated and non-irrigated objective yield observations for Kansas and Nebraska.

The fault ran wider than two states. It affected September corn plant populations and ear counts for both Kansas and Nebraska and the 10-state averages, plus yield forecasts for both states and for the United States as a whole.

NASS also re-examined the October data and estimation procedures. It confirmed the October yield and production forecasts remain unchanged.

What changes now?

"Moving forward, we will implement additional pre-publication checks to verify acreage weights and validate objective yield calculations," Combs said. "We are evaluating further improvements to strengthen our quality-control procedures."

He credited external scrutiny for the catch. "We thank the farmers and data users who brought the concerns to our attention. NASS remains committed to providing timely, accurate, and reliable agricultural statistics and to promptly communicating and correcting any errors identified in our published data."

What did growers lose?

The National Corn Growers Association put a number on the damage. Matt Frostic, a Michigan farmer and NCGA president, said recent NASS reports have cost corn growers billions of dollars in market value.

"Corn prices dropped in conjunction with the release of recent reports and have only continued to drop," Frostic said. "An error of this magnitude is unacceptable, and only further erodes farmer confidence in the agency's ability to produce statistically sound and accurate reports."

His statement framed the timing as the cruelest part. Growers absorbed the losses, he said, at a point when profit margins were already marginal at best, and when the cost of fuel and other inputs stood at all-time highs.

What happens next?

Frostic demanded structural change rather than an apology. "NASS needs to seriously examine the processes and procedures that led to this mistake and take immediate action to prevent it from occurring again," he said.

The NCGA wants a meeting with the service to review its improvement plans and how it intends to rebuild farmer confidence in the reports. No date for that meeting has been announced.

For market watchers, the practical takeaway is narrow but firm: October's yield and production forecasts stand as published, and September's revisions are already reflected in Quick Stats. The new pre-publication checks on acreage weights will be tested with the next round of reports, and traders should watch whether NASS discloses further quality-control changes before the January final estimates.

All NASS reports are available at www.nass.usda.gov/Publications.