USDA corrects September corn data due to 'processing error'

By Tom Polansek

CHICAGO, Oct 23 (Reuters) - The US Department of Agriculture has corrected corn data it issued in September after a "processing error" affected US yield and production forecasts, the agency said on Friday.

The USDA has faced scrutiny from grain traders, analysts and economists over the reliability ​of its crop estimates because of a string of data missteps. The agency, long viewed as the gold standard of global agricultural market information, previously said it was seeking to improve crop estimates.

The USDA's National Agricultural Statistics Service discovered the error after concerns arose about a crop report this month that projected US farmers would harvest more bushels of corn than previously expected, according to the agency statement. The bigger-than-expected crop forecast tanked US corn futures.

"NASS found a processing error that affected September corn plant populations, ear counts, yields, and production for Kansas and Nebraska," the statement said.

"The error also affected the September 10-state averages for plant populations and ear counts, along with US corn yield and production forecasts."

A corrected report that the USDA posted on its website showed a September corn yield of 178.8 bushels per acre. Last month, the USDA said its September yield estimate was 178.5 bushels per acre.

The USDA revised its September production estimate to 15.828 billion bushels, from the original September estimate of 15.800 billion.

October crop forecasts were reviewed, validated and have not changed, the USDA said.