Iowa Crops Continue to Hold Up, Despite Dryness

Statewide, 77% of corn and 73% of beans rated good to excellent as of July 2. Rod Swoboda

Published on: Jul 5, 2006

Crop conditions across Iowa continue to look pretty good, despite dryness in some areas that threatens to reduce yields of corn, soybeans and hay. Statewide 77% of the corn and 73% of the soybeans currently rate good to excellent, according to the weekly survey by Iowa Ag Statistics Service, released July 3. The government survey is based on crop reporters' observations as of July 2.

Compared to other states, Iowa has the second highest rating in the Corn Belt. Nationally, 68% of corn and 64% of soybeans are rated good to excellent as of July 2.  Iowa, Minnesota and Wisconsin are the only Midwest states with higher combined ratings for both crops than the national averages.

Last week had "hit and miss" thunderstorms with below-normal precipitation, says state climatologist Harry Hillaker, of the Iowa Department of Agriculture. Forest City, Glenwood, Mason City and Sidney, for example, received no rainfall last week, while Conrad received more than 2.5 inches and Fulton got 2 inches.

Where are the driest areas of Iowa?

May and June were the sixth driest for those two months in 134 years, he says.  Statewide, 50% of topsoil moisture and 52% of subsoil moisture were rated adequate to surplus for the week that ended July 2. In both cases, that's 25 percentage points lower than a year ago.

West-central, southwest, central and south-central Iowa are the driest areas of the state. The dryness is occurring just as corn pollination, a key stage of development for that crop, is about to begin.

Parts of the state that were dry received some rain over the July 4th weekend, but it's been very spotty. "Especially here in central Iowa, we're seeing a lot of variability," says Steve Johnson, Iowa State University Extension farm management specialist. "The variability in crop stress is showing up across soil types. Those soils that are lighter and don't have as much moisture holding capacity are where the corn is showing the most stress."

Corn is shooting tassels, beans flowering

"We're also seeing differences in the amount of stress just across the road or across the township - depending on where the rain fell," says Johnson. "So even though you hear certain rainfall amounts for a certain town reported on the radio, that may not be true on your farm even though you are located nearby."

Looking at the forecast this week, it's cooler than last week. There's no rain in the forecast until possibly Sunday, July 9. "At least the crop has most of the corn rows filled in," notes Johnson. "Corn is beginning to tassel and silk. Beans are flowering. This is a very critical time for the crop. Corn and soybean plants are going to increase their uptake of moisture."

Most of the moisture the crops are using to grow is from the subsoil, where it was banked from spring rains. "I think you are likely to see stress on these crops, especially on the sandier and lighter soils," says Johnson.