HARLAN, Iowa — Iowa State University (ISU) Agronomist Clarke McGrath hasn’t experienced a summer this scorching since about the mid- to late-1990s when the state’s highest official temperature in Keosauqua, Iowa topped 107 degrees in July 1999.

“I haven’t seen anything like it since the mid-90s, I think ‘96, when it got so hot for a week or better and we had several guys lose cattle,” McGrath said when Onawa and Mapleton, Iowa recorded 105 degrees last week. “We are anywhere from good looking crops to some areas that are harvesting silage due to early plant death from drought.

“We probably will not (have) a great yield year overall in Southwest Iowa, maybe average,” McGrath added. “Most everyone is dry to extremely dry, with the good crop areas getting just enough rainfall in June and July to get by.”

The July 31 crop report released by the Iowa Department of Agriculture and Land Stewardship (IDALS) said more rain and a break in the heat were needed.

“Iowa crops continued to show stress as temperatures reached the mid-90s with some sporadic rainfall totals varying between 1 and 4 inches,” said last week’s report.

“In general, northeastern counties experienced the most plentiful rains to date, but most areas still remain short on moisture.”

State Climatologist Harry Hillaker said recently the statewide average temperature for June 2006 was 70.2 degrees, nearly three degrees cooler from one year ago (72.9 in 2005), while July was the warmest in 2002 (76.7).

“July ranks the 23rd warmest July among 134 years of state records, thus statistically, one would expect a July this warm (to be) about an average of every five or six years,” he said. “(The years) 1999 and 2002 are Iowa’s only warmest Julys since 1988.”

Currently, heat indices among official National Weather Service locations reached a maximum of 113 degrees at Iowa City in southeast Iowa on July 17, which was much higher than recorded at some other reporting points, Hillaker added.

“As is typically the case, western and southern Iowa have experienced the worst of the heat,” he said. “Omaha-Council Bluffs has recorded 28 days of 90 degrees or higher in June and July 2006. “Normally, they would have 19 such days; however, last June/July, they had 31.”

The current National Weather Service forecast also indicated that temperatures would edge back up above normal by tomorrow and would be near or a little above normal through Aug. 10, Hillaker added. ISU Crops Specialist John Holmes in Clarion, Iowa, said the rains that central Iowa received last week and early this week helped crops in most of his area.

“(Those) rains did not cover all of my area and there are dry areas badly in need of rain in some of my counties,” he said. “Most areas in my counties are not suffering severe stress.”

While farmers in Holmes’ area counties continue to be surprised at how good their crops look, he said they recognize that crops planted in coarse soils would suffer first.

“Many of those areas are showing serious crop injury from dry weather,” he said. “Farmers are concerned about their hay crops – or the lack of hay from fields. I had one dealer tell me that he expects corn yields to be down significantly based on an annual crop tour that’s conducted by a few local folks in his county.”

Brian Lang, ISU crops specialist in upper northeast Iowa, said the heat wasn’t a huge problem for corn and soybeans – as long as sufficient subsoil moisture was present, with the exception of minor acres on sandy soils.

“The heat accelerated maturation of alfalfa, so third crop harvest is well under way,” he said.

As far as diseases this summer, Virgil Schmitt, ISU crops specialist in Muscatine, said soybeans in their respective counties have suffered from White mold, Sudden death syndrome, Brown stem rot, Phytopthora root rot, Rhizoctonia root rot; corn crops in Lang’s area have also had Eyespot, Gray leafspot and rust.

McGrath said today’s hybrids tend to cannibalize the stalk pretty heavily, which compromises standability.

“Harvest ease will depend on fall weather and winds – if we get late, and we get a big wind or some early snow on the corn, it will probably go down,” he said.

Holmes said corn yields in southwest Iowa would likely be down some due to the heat and dry conditions, with soybean yields probably being even less due to the lack of rain.

“If rain is received in August,” he said, “it will definitely help soybean yield prospects.”

Despite crops in southeast Iowa coming through this summer’s excessive heat quite well, Schmitt said “we could use a good, long, slow, soaking rain.”

“We’ve generally had adequate moisture to help the crops deal with the heat, which is often not the case,” he said. “We still have the potential for excellent corn and soybean yields, but we will need some rain and cooler temperatures in August to get them.”

This farm news was published in the August 9, 2006 issue of Farm World, serving Indiana, Ohio, Illinois, Kentucky, Michigan and Tennessee.