Wednesday, July 28, 2010

Weather Influences on Corn Development and Yield

Three weather trends in August will determine whether corn yields bust bins, or just turn out to be a bust this year, according to meteorologist Elwynn Taylor of Iowa State University.

Taylor spoke July 20 to the annual Top Farmer Crop Workshop at Purdue University.

After a warm start to the season that accelerated plant development, more hot weather in August could have plants racing to maturity. That happened in 1995, says Taylor, and it left less time for corn kernels to fill, reducing yields to levels typically seen in drought years. By contrasts, record yields followed the cooler temperatures of 1992 and 1994, when an extended period for filling added weight to the crop.

Click here to play
The direction of temperatures could hinge on the second trend to watch: development of La Nina cooling of the equatorial Pacific. The sooner a La Nina develops in August, the more likely warm, dry weather will be seen that could cut yields.
The final factor are weekly crop ratings put out by USDA. These don’t mean much early in the growing season, says Taylor. But if 50% or more of the crop is rated good to excellent in the third week of August, odds increase for above average yields.
Check out a video of his presentation on this page.