USDA’s weekly survey released Sept. 4 shows 15% of Iowa’s 2018 corn crop has now reached maturity, eight days ahead of average. It also shows that a few fields have already been harvested for grain.

Widespread rainfall this past week caused flooding conditions in some fields, as a series of storms brought significant rainfall to much of the state.

“Southeast Iowa was fairly dry most of the summer, now we’ve had nearly 10 inches of rain in a week. Time to let things dry out,” says Darin Leach, who writes an article each month for Wallaces Farmer magazine.

Labor Day weekend Leach drove from his home in Des Moines in central Iowa to the family farm operated by his parents in Muscatine County in southeast Iowa. “It was really wet at the farm this past weekend,” he says. “Rain totals were 1.5 inches on Saturday, 4 inches on Sunday and some hard but shorter showers on Monday, Sept. 3.”

This is on top of a 3-inch rain they received on Aug. 28. 

Crop development stays ahead
“Crop development in Iowa here at the end of the growing season is running well ahead of average. We could start to see a lot more harvest activity in the next couple of weeks if weather conditions allow,” says Mike Naig, Iowa ag secretary.

The complete weekly Iowa Crop Progress and Weather Report is available at IDALS.

Widespread rainfall meant Iowa farmers had just 2.7 days suitable for fieldwork during the week ending Sept. 2, according to USDA National Ag Statistics Service. Activities for the week included cutting hay, chopping corn silage and moving grain.

Topsoil moisture is rated 4% very short, 6% short, 69% adequate and 21% surplus. Subsoil moisture is rated 6% very short, 9% short, 71% adequate and 14% surplus. Much of southern Iowa received multiple inches of rain over the past week, easing moisture concerns in some areas although levels are still mostly short to very short.

15% of corn mature
The survey shows 95% of the state’s corn crop has reached dough stage or beyond with 77% dented or beyond, over a week ahead of both last year and the five-year average. Also, as of Sept. 2, 15% of the corn crop was mature, eight days ahead of average. There were a few reports of corn harvested for grain. Corn condition is rated 74% good to excellent. Almost one-third of the soybean crop was coloring with 4% dropping leaves. Soybean condition is 72% good to excellent.

The third cutting of alfalfa hay was 79% complete, now over a week behind the previous year as weather conditions last week allowed for little progress in cutting hay. Pasture conditions improved to 47% good to excellent.

Weather summary
According to Justin Glisan, IDALS climatologist, the final week of August was warmer and wetter than normal. Many locations received rainfall between 2 to 4 inches above normal, including drought-stricken areas in southern Iowa. Average temperatures were up to 4 degrees warmer than normal.

A series of systems moved across Iowa on Aug. 27, bringing moderate rainfall to much of the eastern two-thirds of the state. The northern tier of counties also experienced severe thunderstorms with heavy rain; Cresco (Howard County) received 3.32 inches. There were multiple reports of hail from Sioux County to Palo Alto County, with three-inch diameter hail in Ayrshire.

Aug. 28 was also an active weather day as a strong cold front swept through the state, bringing severe thunderstorms and locally heavy rain to northern and southeast Iowa. Over 30 stations recorded rainfall above one inch, with Keokuk (Lee County) reporting 4.90 inches. High pressure moved into Iowa on Aug. 29 bringing generally clear skies and cooler temperatures. This pattern persisted into Aug. 30 as the high pressure moved across the state.

Temps unseasonably cool
Average high temperatures were unseasonably cool, ranging from the low 70s in the north to mid-70s and low 80s in the south. Aug. 31 to Sept. 2 saw waves of showers and thunderstorms across Iowa, with many locations reporting multiple inches of rain. Traer (Tama County) observed 5.42 inches on Saturday; Montezuma (Poweshiek County) reported 5.16 inches on Sunday.

There were also multiple reports of severe hail and straight-line winds across 11 counties. Two-inch diameter hail fell in Cass County on Friday and in Polk County on Sept. 1. Tree damage from severe high winds was observed in Dubuque (Dubuque County) on Sept. 2. Average highs over the weekend were generally a few degrees warmer than normal, with Lamoni (Decatur County) observing 91 degrees on Sept. 2.