La Nina Drought Threat Still There

Recent rains have recharged soil moisture across much of the Corn Belt heading into spring planting season and more moisture is on the way this week, but that hasn’t stopped talk of a possible La Nina-related drought this summer.

By April 1, the Southern Oscillation Index, a key measure of El Nino/La Nina conditions, had reached +0.85, the threshold level of for La Nina conditions, raising the potential for a Corn Belt drought, according to Iowa State Extension climatologist Elwynn Taylor.

“Although the magic threshold of 0.8 for La Nina does not absolutely indicate a La Nina, it is highly likely. A La Nina does not absolutely indicate drought in the Corn Belt, but one becomes much more likely,” Taylor says in comments on the Iowa State Extension Website Saturday.

According to Taylor, the risk of a below-trend U.S. corn yield (assuming a trend yield of 146 bu./acre) is much greater at 70%, compared to a 100-year average risk of 46%, while the chance of a record high yield is only 8%, he says.

The risk of a widespread drought (Corn Belt overall yield of 131 bu./acre or less) is 35% during a La Nina year, compared to the 100-year average risk of 17%, he says.

Taylor puts the most likely corn yield for 2006 in the U .S. at 138 bu./acre based on current information.

The most likely U.S. soybean yield has not yet changed from a trend-line level of 42 bu./acre, Taylor says.

In the near-term, Corn Belt soil moisture is likely to get a further recharge with a major storm expected to move over the northern half of the region Thursday and Friday, bringing widespread rainfall of 1 inch or more.

Some areas of the Corn Belt are actually now too wet and could use a prolonged period of dry weather.

Editors note: Richard Brock, The Corn and Soybean Digest's Marketing Editor, is president of Brock Associates, a farm market advisory firm, and publisher of The Brock Report.

To see more market perspectives, visit Brock's Web site at www.brockreport.com.