KANSAS CITY, Mo. — Widespread rainfall over the weekend brought corn and soybean planting to a soggy halt across much of the Midwest, and forecast for more rain most of this week will continue to limit fieldwork in many areas.

Corn and soybean futures traded higher overnight after the three-day holiday weekend. Corn planting already is past the mid-May optimal planting time after which yields begin to decline. But with fieldwork likely halted for another week, ideas were many producers will opt not to plant after the “prevent plant” date of May 31 in several Midwest states. In some cases the delays may even delay soybean planting.

Early forecasts for the US Department of Agriculture’s Crop Progress planting numbers, which will be released at 3:00 p.m. Eastern Time May 28, were for 85 percent to 90 percent of the corn crop planted in the 18 major states compared with about 90 percent as the average for the date, and 45 percent to 50 percent of the soybeans planted in the 18 major states compared with about 65 percent as the average.

Soil moisture maps from Weather Derivatives, a Belton, Mo.-based energy and agricultural weather service, showed topsoil moisture as “excessive” across most of Iowa with all of the state at least “surplus,” along with eastern Nebraska, northwestern Illinois and southern Minnesota as “surplus.” There were flooding advisories issued over the weekend for much of Iowa, the nation’s largest corn and soybean growing state.

“If you were in Iowa over the weekend, there were several dark and stormy nights,” said David Salmon, president of Weather Derivatives. “Looks like that estate may expand and persist for the rest of this week at least.”