Rain continued to fall in many parts of Iowa, interrupting planting progress. Unfortunately, severe weather rocked some parts of western Iowa and did extensive damage.

“Our hearts go out to the Iowans and communities that suffered damage caused by the severe weather over the weekend [of April 27-28],” said Mike Naig, Iowa secretary of agriculture, in a news release. “As they begin a long process of recovering and rebuilding, the outpouring of support from fellow Iowans is a reminder of how truly special our state and its people are.”

Welcome rainfall

In areas not rocked by storm damage, the rainfall was welcome. The most recent figures available from the week ended April 28 showed topsoil moisture across Iowa ranked 5% very short and 17% short. Meanwhile, 68% of areas had adequate topsoil moisture, with 10% surplus.

This was even before last week’s rains, which brought more moisture to Iowa soils that had been parched going into the growing season. One farmer in southwestern Iowa — an area particularly short on moisture earlier this spring — reported to me that corn planting was 25% complete on his farm, with none of his soybean acres planted.

The most recent planting figures available showed corn planting as 39% complete, four days ahead of 2023 and three days ahead of the five-year average. Two percent of the expected corn crop emerged.

Twenty-five percent of the expected soybean crop has been planted, four days ahead of last year and five days ahead of the average. Ninety percent of the expected oat crop has been planted, five days ahead of last year and nine days ahead of the five-year average. Fifty-three percent of the oat crop has emerged, eight days ahead of last year.

Pastures and hay ground continued to green up, but warmer temperatures would aid in growth. Reports were received of cattle being turned out onto pasture.

Don’t sweat it … yet

Even if rainfall has delayed corn and soybean planting, it’s still a long way from concern that yield potential could be adversely clipped. Farmers who can complete corn and soybean planting by May 20 will sacrifice some yield potential, as opposed to finishing up a few weeks earlier, says Mark Licht, Iowa State University Extension agronomist. However, differences are minimal, he says.

In the case of soybeans, yield benefits may be gleaned by planting in mid-April, but that’s not a given. Early planting benefits can be snapped if a May frost zaps emerged soybeans.

What is a given is that yields start crashing after May 20. ISU and other Midwest land-grant universities show that soybean yields decline 0.62 bushel per day after May 20, with higher yield loss potential for corn.

“If you can’t get done planting by May 20, your yield loss for late planting is greater with corn,” Licht says. In these cases, farmers would want to opt to plant corn first and then soybeans, he says.