Flooding Has Hurt Iowa's 2010 Corn, Soybean Crop Prospects
USDA has reduced the rating of Iowa's corn crop in the good-to-excellent category from 72% to 66%, largely due to extremely wet conditions this past week.
Rod Swoboda
Published: Jul 8, 2010
Iowa's 2010 corn crop has fallen from 72% in the good-to-excellent category to 66% due mainly to flooding and excessive rainfall this past week. Similarly, the state's soybean crop has dropped from 66% in the good-to-excellent category to 64%, according to the government's weekly weather and crop conditions report released July 6.
The statewide survey, conducted and released by the Iowa office of USDA's National Ag Statistics Service, says the heaviest flooding damage in fields was in southeast Iowa and west central Iowa. In low-lying fields where ponding has occurred, corn and soybeans have been stunted or completely drowned out. Many places where crops were killed have already been replanted. But sections of fields that are still too wet likely won't be replanted.
Aside from the excessively wet and ponded areas, corn and soybeans are mostly in good condition in Iowa as a whole, as corn is beginning to tassel and soybeans are blooming during the first week of July. Oats are also rated in mostly good condition and continuing to turn color as they approach maturity.
About 8% of Iowa corn crop has tasseled and is now silking
About 8% of this year's corn crop in Iowa is tasseled and had begun to silk by July 6. The survey shows 27% of the state's soybean crop had bloomed by that date. Regarding the state's hay crop, the report shows 93% of the first crop alfalfa had been harvested and 34% of the second crop by July 6.
The entire weekly report is available on the Iowa Department of Agriculture website at www.IowaAgriculture.gov or on USDA's site at www.nass.usda.gov/ia.
"The warm and dry weather a week ago was very welcome as it allowed fields to start drying out and some fieldwork to take place. But unfortunately that dry stretch of five or six days was too late for some farmers who have had crops drowned out during the very wet month of June," says Harry Hillaker, state climatologist with the Iowa Department of Agriculture. "Then the additional rain that came over this past weekend—the Fourth of July weekend—made additional flooding a real problem, especially in southern Iowa, which has been hardest hit by the extremely wet weather that much of Iowa had during the month of June."
Northeast and north central Iowa areas drenched this week
While Southeast Iowa has been deluged with rain after rain after rain in recent weeks, areas of north central and northeast Iowa were doing fairly well until they received very heavy rains this week. For example, the Waterloo area had 7 inches of rain over the two-day period of July 6 and 7. "The ground in north central and northeast Iowa was already wet, so there are even more drowned-out areas in fields there now after this week's rains," notes Hillaker.
Earlier in the 2010 growing season planting went well and north central Iowa was considered a garden spot. John Holmes is an Extension field agronomist for Iowa State University and he covers counties in central, north central and into northeast Iowa—key corn and soybean producing areas in the state.
"We are seeing some areas of central and north central Iowa that as of today, July 7, look good—Story County from what I've seen looks pretty good. Corn is tasseling there," says Holmes. "But you get up in northern Hamilton and into Webster County, and Humboldt, Wright, Hancock and Franklin counties, they really were deluged in the past couple weeks which caused flooded areas in many fields. Those soils were saturated already, even before the latest rains."
There's a lot of yellow, nitrogen-deficient corn in Iowa fields
Wet soils kept farmers from getting into fields to get spraying done. "We have a number of fields that weren't sprayed for weeds," says Holmes. "Also, a significant number of farmers weren't able to get into fields to replant the drowned-out spots. There are ponds throughout north central, central and into northeast Iowa and a lot of yellow corn in streaks and areas of fields this year."
In northern Iowa, Holmes says "we have anything from really nice looking corn that is now tasseling and silking to corn that is probably just over knee-high and is pale yellow and really looks marginal. Not very pretty at all."
He adds, "In Worth, Mitchell, Floyd and Cerro Gordo Counties, they too have had excessive water. There is some corn that looks really good this year and some that looks very poor."
Yield potential not good for fields that lost N this year
Corn yield prospects aren't very bright in fields that have lost so much nitrogen, says Holmes. "As for the yellow corn that has lost nitrogen, some of the fields will struggle to make 100 to 120 bushels per acre. Some of the short corn won't make that. In fact, it's questionable whether those plants will even produce corn."
Also, the damaged, late, short corn is going to produce wet grain at harvest this fall. "I think corn that is tasseling now will make decent corn," he observes. "But the corn that is so short and late won't. There are areas so saturated that those plants will be late maturing and if they do produce grain it will be quite wet." Also, with so much rain falling in June, this year's Iowa corn and bean crops in general have developed a shallower root system than normal.
Holmes has a farmer friend who was finishing planting soybeans on July 7. The ponds that had sprung up earlier in the fields had finally gone down and dried up so the farmer went in and re-planted beans in those spots.
Some fields in Iowa will produce tremendous yields, too
"We had a hailstorm go through northern Wright County and through Franklin County and over into Humboldt, Hancock and Cerro Gordo counties. The ground finally dried out enough that some of those farmers have replanted those hailed out fields and areas of fields," says Holmes. "I saw soybeans that were just coming up yesterday, July 6, near Meservey. A friend of mine said he was going to finish planting the dried-up ponds in his fields on July 6 and then go to the County Fair. He said, "I don't think I've ever done that before."
It's easy to drive down the road and see the problem fields—and get a distorted picture of the whole county. "Keep in mind we do have areas in Iowa, even here in the soggy parts of north central and central Iowa, that are going to produce some tremendous amounts of corn this fall," says Holmes. "Some of these fields this summer are indeed looking very nice. However, in other areas of the state—such as in southeast and south central Iowa—they've have had one problem after another this year, mainly due to the very heavy amounts of rainfall they received throughout June and into July."
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