Vast majority of Iowa corn is planted with drought conditions improving

An estimated 86% of the state’s corn crop has been seeded this year within the prime planting window, and widespread rainfall is helping to alleviate drought conditions that have persisted for more than a year.

The seeding slowed somewhat last week with the weather allowing for an average less than four days of field work, but corn and soybean planting is about a week ahead of the five-year average, according to the U.S. Department of Agriculture.

Iowa State University research has determined that the most productive corn is planted before mid-May. Yields have tended to dissipate rapidly when planting happens after June 1.

“Farmers should have a window of opportunity in the coming week to make more planting progress, as forecasts indicate drier conditions and more seasonal temperatures,” said Mike Naig, the state’s agriculture secretary.

Statewide temperatures averaged nearly 8 degrees above normal last week, and parts of the state had more than 5 inches of rainfall, according to State Climatologist Justin Glisan.

The heaviest rainfall was in northern Iowa, including in areas that had been suffering from severe drought. A U.S. Drought Monitor report last week said about 31% of Iowa is in some measure of drought. A new report that will take into account all of last week’s rainfall is expected Thursday.

About 83% of the state’s topsoil has adequate or surplus moisture for crops, the USDA said on Monday. That’s a significant increase from the 67% it reported a week before.

About a third of the corn crop has germinated and emerged from the ground, which is two days ahead of the five-year average.

Soybean fields are about 69% planted, with about 19% emerged, the USDA said.