Iowa Crop Conditions Decline As Heat Takes Toll

Iowa Crop Conditions Decline As Heat Takes Toll

Iowa's 2012 corn crop rates 62% good to excellent as of July 1; a week ago it was 68%, a year ago 82%. Many areas remain short on moisture.

Crop prices continue to climb as Iowa and the rest of the Corn Belt get set for a hot, dry week. Corn prices reached $6.56 per bushel on Monday June 2, a nine-month high. Soybeans for the November new crop contract reached $14.37 per bushel. This year looks like it will be one of the worst in decades for the U.S. corn crop, with a heat wave and dry conditions hitting the Midwest just one year after a huge crop was produced. Hot, dry weather during pollination is threatening to cause significant damage to the 2012 U.S. corn crop. When it's time to pollinate, corn doesn't like it much above 90 degrees.

This corn is saying "THANKS" for a drink of water on the Chip Mathis farm at Elkhart in central Iowa. He irrigates a seed corn production field with a center pivot rig. Hot, dry weather during pollination is threatening to wreak havoc on the 2012 U.S. corn crop. At pollination, corn doesn't like it much above 90 degrees.

In Iowa, the condition of the state's corn crop has worsened since last week, "but corn in Iowa is still in considerably better condition than corn in neighboring Corn Belt states," notes Chip Mathis, who farms near Elkhart in central Iowa. He snapped the photo that accompanies this article showing the center pivot irrigation rig on his farm. There isn't much irrigating done in Iowa—in most years you don't need it for field corn. But some growers with seed corn production, such as Mathis, use irrigation because they grow corn for seed which is a higher value crop than regular commercial corn.

Pumping 1,000 gallons per minute, Mathis is using the rig to apply nine-tenths of an inch of water to the field this week. The corn got six-tenths of an inch from the center pivot rig last week. "You've heard how some farmers claim they can hear their corn grow," notes Mathis. "Well, I think I hear this irrigated corn saying "THANKS!"

Continued dry weather hurting Iowa crops, but Iowa is doing better than neighboring states

USDA's weekly Crops & Weather report issued July 2, based on conditions statewide as of July 1, rates Iowa's 2012 corn crop at 62% "good to excellent." That is well below the 82% rating a year ago at this time. "Agronomists normally consider 70% good to excellent ratings as standard for a good yield," says Greg Thessen, who directs the statewide weekly survey for the Iowa field office of USDA's National Ag Statistics Service in Des Moines.

Looking at corn ratings for other states as of July 1, Thessen points out Illinois corn is currently rated just 26% good to excellent; Indiana, 19%; Missouri, 18% and Ohio, 33%. Nebraska, with a 56% good to excellent rating, and Minnesota, where rains have fallen in ample amounts and which has a 72% good to excellent rating, joins Wisconsin as the only other states besides Iowa where at least half of the corn crop is in good condition.

The situation is similar for soybeans. Iowa's good to excellent rating covers 59% of the crop, which is better than Nebraska, 45%; Illinois, 28%; Indiana 20%; Ohio 29%; Missouri, 18%; and Wisconsin, 19%. Only Minnesota, with a 74% good to excellent rating, has a soybean crop rated better than Iowa's.

This summer the Corn Belt is suffering from worst heat wave in more than a decade

As of July 1, the survey shows 54% of Iowa's topsoil and subsoil is now rated inadequate. A year ago 100% of Iowa's soils had adequate moisture, which enabled the 2011 corn crop to pollinate well and Iowa ended up with a 172 bushel per acre yield average, despite a heat wave in mid-July. Iowa had the highest corn yield average of all states last year.

Hot weather in the mid to upper 90s can interfere with pollination and the Midwest is suffering under the worst heat wave in more than a decade, says Harry Hillaker, state climatologist with the Iowa Department of Agriculture in Des Moines. The situation is serious this summer because of dry soil conditions over most of Iowa and the Corn Belt.

These high temperatures will evaporate about .30 inch of moisture a day from soil

Rain fell over much of the Corn Belt from Nebraska to Ohio beginning Friday June 30, 2012. Most of the precipitation totals ranged from only one-tenth of an inch to a half-inch. In Iowa a line from Sioux City to Cherokee received 1 to 2 inches and heavier rainfall of up to two inches fell in a zone from Des Moines to the southeast toward Burlington. But Iowa's state climatologist Hillaker warns the hot weather at the high temperatures expected this week will evaporate .30 of an inch of moisture a day from soils. No rainfall is expected over most of Iowa this week and temperatures are to reach the upper 90s every day.

"Hot, dry weather is indeed a concern as Iowa is now entering the critical pollination period for corn," observes Iowa Secretary of Agriculture Bill Northey. "Iowa continues to receive periodic rains this summer, but many areas of the state still remain short of moisture. They just didn't get the recharge on reserve subsoil moisture as we had a dry fall and dry winter. Hopefully, the heat will break and the state's crop will get timely rainfall as needed this summer."

The latest Crops & Weather report, based on the weekly statewide survey, is on the Iowa Department of Agriculture & Land Stewardship website and on USDA's site Here's a summary of the July 2 report.

More rain needed to relieve stress on crops and improve growing conditions

CROP REPORT: Although Iowa saw precipitation early and again late in the week ending July 1, the bulk of the week was sunny and hot with record high temperatures experienced in many areas of the state. Additional rain is needed to relieve stress on crops and improve conditions.

There were 6.0 days suitable for fieldwork statewide during the past week. As of July 1, topsoil moisture levels for the state declined to 28% very short, 45% short, 27% adequate and zero percent surplus. South Central Iowa is the driest with 91% of the topsoil moisture rated short to very short. Looking at the statewide average for subsoil moisture on July 1, subsoil moisture dropped to 24% very short, 49% short, 27% adequate and zero percent surplus.

About 16% of Iowa's corn crop silking on July 1, two weeks ahead of normal

Crop conditions declined for all crops for the week ending July 1, 2012. Sixteen percent of the Iowa corn crop is silking, which is nearly two weeks ahead of normal. Corn condition is reported at 2% very poor, 8% poor, 28% fair, 49% good and 13% excellent.

Twenty-six percent of Iowa's 2012 soybean crop is now blooming, ahead of last year's 10% and the 5-year average of 15% for this date. Soybean condition is rated 3% very poor, 9% poor, 29% fair, 49% good and 10% excellent. As of July 1, 68% of the state's oat crop has turned color, well ahead of last year's 15% and the 5-year average of 24%. Also, 20% of the oat crop has been harvested, two weeks ahead of normal. Oat condition is rated 2% very poor, 13% poor, 32% fair, 47% good and 6% excellent. The second cutting of alfalfa hay, at 76% complete, is almost three weeks ahead of normal. Hay condition is rated 5% very poor, 13% poor, 39% fair, 38% good and 5% excellent.

Just over one quarter of Iowa's pasture and range land is rated in good to excellent condition, the lowest since the week ending August 13, 2006. Pasture condition now rates 9% very poor, 25% poor, 39% fair, 24% good and 3% excellent. Hot and humid conditions during the week were uncomfortable for livestock.

IOWA PRELIMINARY WEATHER SUMMARY—for week ending July 1, 2012

By Harry Hillaker, State Climatologist, Iowa Department of Agriculture & Land Stewardship

The past week began with dry weather on Monday (June 25), and Tuesday (June 26) but with a welcome break from the heat as daytime highs were mostly in the 80s. Much warmer weather made a rapid return on Wednesday (June 27) and continued through the rest of the period. High temperatures were mostly in the 90s on Wednesday, Thursday and Sunday with 80s north and 90s south on Friday and Saturday. Dry weather continued through Wednesday and Thursday with thunderstorms bringing rainfall to west central, central and east central Iowa on Friday.

Statewide average rainfall for the week was a quarter inch, normal is 1.15 inches

Friday's rain was very welcome but was accompanied by hail and widespread severe winds from about Des Moines east-northeastward to Anamosa. Finally, a few scattered thunderstorms brought locally heavy rain to parts of southeast Iowa on Saturday night into Sunday morning. Rain totals for the week varied from none over most of the northern one-third of the state, as well as portions of far southern Iowa, to 4.17 inches at Oakville in Louisa County. The statewide average rainfall was 0.25 inches for the week ending July 1, 2012--while normal for that week is 1.15 inches.

Temperatures varied from a Tuesday morning low of 43 degrees at Belle Plaine to a Thursday afternoon high of 104 degrees at Keokuk. Triple digit heat was also reported in a few areas on Wednesday (101 at Des Moines, Little Sioux and Sioux Center) and Friday (102 at Keokuk and Keosauqua). Temperatures for the week as a whole averaged from 1 to 2 degrees above normal in the far east to 6 to 7 degrees above normal over the southwest with a statewide average of 4.3 degrees above normal.

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