Dry conditions last week continued to take a toll on Iowa’s corn and soybean crops. The U.S. Drought Monitor on Aug. 1 showed the area of severe drought expanded to include 16 counties in south-central and southeast Iowa. And USDA’s latest weekly statewide crop progress survey, as of Aug. 6, showed a slight decline in Iowa crop conditions again, as Iowa had cooler-than-normal temperatures but below-normal rainfall.

“The cooler temperatures we saw last week were welcome, but the lack of significant rain means drought conditions remain in place for many parts of Iowa, with severe drought in much of south-central and southeast Iowa,” notes Iowa Secretary of Agriculture Bill Northey.

Iowa’s corn condition as of Aug.6 declined to 2% very poor, 8% poor, 26% fair, 53% good and 11% excellent. Soybean condition rated 3% very poor, 9% poor, 29% fair, 50% good and 9% excellent.

Dry conditions expanding, hurting crops
Iowa farmers in the state’s driest areas want a super-soaker to help their crops. “We are in a severe drought in this part of southeast Iowa,” says Pat Swanson, farming near Ottumwa. “We had the third-driest June and July on record here. The corn has begun to fire, and I filed my first silage appraisal for crop insurance. We need rain now in August, which is the critical time for the soybean crop.”

In Greene County in central Iowa, Sheila Hebenstreit says, “We are under an umbrella in a rain-free zone. Generally, we get a sprinkle to a maximum of three-tenths of an inch. Many cornfields look good from the road. But walk out into the field, check the ears and you see things look pretty tough in places.”

Farther north, in Humboldt County, Dean Coleman says: “Crops still look good for as dry as it’s been, although crops on the lighter soils continue to shrink in terms of yield prospects. The bottom leaves of corn plants are firing as you get out into fields.”

Dryness taxing crops in northwest Iowa too
In northwest Iowa, ISU Extension agronomist Joel DeJong says the nine counties he covers have mixed conditions as of Aug. 6, but most have received only 25% to 50% of normal rainfall during the 2017 growing season. “There’s hardly anyone who has average rainfall in the northwest corner of Iowa right now,” he says.

The complete weekly crop and weather report for the week ended Aug. 6 is available on the Iowa Department of Ag and Land Stewardship website IowaAgriculture.gov or on USDA’s site nass.usda.gov/ia. The report summary follows here.

Summary of Iowa crop conditions
All of Iowa had cooler-than-normal temperatures and most of the state received below normal precipitation during the week ending Aug. 6, according to USDA’s National Ag Statistics Service. Statewide there were 5.9 days suitable for fieldwork. Activities included applying fungicides and insecticides, hauling grain, and haying.

Topsoil moisture levels for Iowa declined to 24% very short, 32% short, 44% adequate and zero percent surplus as of Aug. 6. Subsoil moisture statewide averaged 19% very short, 32% short, 48% adequate and 1% surplus.

Corn condition declined slightly last week
USDA’s weekly survey shows 95% of Iowa’s 2017 corn crop has reached silking stage, five days ahead of the five-year average. And 42% of the corn crop has reached dough stage, four days behind last year. Corn condition declined to 2% very poor, 8% poor, 26% fair, 53% good and 11% excellent.

Soybeans blooming as of Aug. 6 reached 89%, one week behind last year and three days behind average. Two-thirds of Iowa’s soybeans were setting pods, five days behind last year but equal to average. Soybean condition is rated 3% very poor, 9% poor, 29% fair, 50% good and 9% excellent. Iowa’s oat crop is 88% harvested, one day ahead of average.

Second cutting of alfalfa hay was nearly complete as of Aug. 6. Third cutting of alfalfa was 38% complete, three days ahead of average. Hay condition dropped to 51% good-to-excellent. Pasture condition also dropped to 34% good-to-excellent. Cooler temperatures improved livestock conditions, but supplemental feeding has been required in some areas.

Weather summary for Iowa
Harry Hillaker, state climatologist with the Iowa Department of Agriculture and Land Stewardship, provides the following summary for the week ended Aug. 6.

It was an unseasonably cool week across Iowa but with less than normal rainfall over most of the state. Temperatures were near normal on Aug. 1-2 and well below normal for the remainder of the reporting week. Highs reached into the low 90-degree range over far southeast Iowa on the first and second of August, but failed to climb out of the 60s over far northwest Iowa on Aug. 3 and over much of the western one-third of the state on Aug. 5.

Temperature 4.6 degrees below normal
Temperature extremes for the week varied from an afternoon high on Aug. 2 of 93 degrees at Donnellson in southeast Iowa to morning lows of 46 degrees at several northwest Iowa locations the morning of Aug. 4, and scattered locations over the southeast one-half of the state the morning of Aug. 5. Temperatures for the week as a whole averaged 4.6 degrees below normal.

Most of last week’s rain fell on Aug. 3 when thunderstorms dampened all but extreme southeast Iowa. There were some scattered showers on Aug. 1 over central and northwest Iowa, and some isolated thunderstorms over east-central Iowa on Aug. 2. Finally, light rain fell across about the southwest one-half of the state on Aug. 5.

Average rainfall less than half of normal
Only a few locations received more than an inch of rain last week, mostly in west-central and northeast Iowa. Guthrie Center reported the most rain with 1.76 inches while Burlington, Donnellson and Davenport had no rain. Statewide average rainfall was 0.41 inch, or less than one-half of the weekly normal of 0.96 inch.