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Ag economist: USDA corn trend yield projection high

An ag economist said the USDA’s 2020 corn yield projection might be too high.

Todd Hubbs at the University of Illinois tells Brownfield the USDA’s corn trend yield model, which draws a trend line from 1988 to the present, has a flaw.

“If you move the starting point into the 80’s, it really starts to increase a lot because we saw numerous crop short falls in the 80’s,” he said.

1988 was a drought year meaning the trend line started from a lower yield than normal, causing a higher yearly increase when drawing a line to today.

Hubbs said his department found that trend yield projections started before and after the 80’s led to lower yield projections for 2020.

“Where you start the sample matters,” he said. And, as a piece of advice, if that’s the way you’re going to do your trend yields, we suggest either using a longer sample or a shorter sample but don’t start in a drought year.”

Hubbs said starting trend yield projections in the 60’s lowers projections by around four bushels an acre, roughly 360 million bushels total.