Moisture levels across Iowa are tiptoeing a fine line after a recent spree of rainfalls brought some welcome relief from the ongoing drought. With crop conditions hanging in the balance, all eyes are on the state's famous corn fields, which are now entering a crucial stage of development.
Recent rainfalls have been a much-needed blessing and even an answer to prayer. Conditions at the end of June saw southeast Iowa experiencing drought levels ranging from abnormal to extreme just as corn plants entered the most critical and moisture-reliant stage of the growing season, pollination.
Even with the gift of rain showers, the U.S. Drought Monitor continues to report similar conditions to the end of June. Experts say some areas have been experiencing drought relief while others continue to suffer.
“Moisture levels as always — sounds like a broken record anymore — but it’s been spotty,” says Alex Fynaardt, an agronomist at Key Co-op in New Sharon. “Some areas got good rain, and it seems like the areas that have gotten the heavy rains have continued to get the heavy rains. So the places that are good are really good. The places that are drier are just barely getting by, I guess, in my opinion.
"The crops really look good when you go out and look at them or drive around, but some of them are a lot closer to being drought stressed than others," he adds.
Counties close to the Missouri line have borne the brunt of the drought. Davis and Wapello counties got hit hardest with a county-wide D3, extreme drought, according to data from the monitor’s July 4 update. Data from the U.S. Department of Agriculture shows that 57% of the state’s topsoil and 64% of the subsoil has either a short or very short moisture level. Those numbers show improvement from the department’s June 26 report, when the numbers were 67% and 68% respectively.
The USDA reports that 30% of the state's corn crop is fair, 53% is good and 8% is in excellent condition, while 36% of soybeans are fair, 46% are good and 6% are excellent. Data shows that 9% of corn and 12% of soybeans are poor to very poor.
Clarabell Probasco, an Iowa State Extension Office field agronomist covering an area that includes Appanoose, Davis, Jefferson, Monroe, Van Buren and Wapello counties, says that the rainfall has certainly been helpful. However, a D3 drought like the one affecting the state’s southernmost counties is the product of a deeper, more profound moisture deficiency and can’t be expected to lift after only a little bit of rain.
“Once you get down and enter those D2, D3 obviously further down the ladder drought zones, it takes a lot more rainfall to get back out of them,” Probasco says.
“We have gotten some really good rains. I know most of south-central Iowa is averaging probably three and a half inches plus for rainfall totals over the last two weeks, so it’s definitely helped out a bunch,” she adds. “But like I said, we were already in a pretty big deficit, so it hasn’t climbed us out of the hole at all, but it’s kind of helped us maintain a good crop condition and kind of take some of that stress off those plants.”
The pollination stage is when the plant begins to produce silks out of each of its ears. Each strand of silk reaches back to the ear and attaches to a kernel. Ideally, every silk will get pollinated before the stage is done. Currently, the USDA reports that 22% of Iowa’s corn is silking, meaning that nearly a quarter of the state’s corn has begun to pollinate, a critical stage for setting crop yield and viability of ears.
“Ideally, you want every single silk to get a piece of pollen to fertilize it and fertilize that kernel back on that ear,” Probasco says. “So right now is pretty critical for us to be as stress-free as possible, because if we don’t have good rains, then our plants are stressed, they’re not tasseling as well as they probably can be, and our pollination won’t happen as effectively as it could, and then obviously, that also is telling us how many ears long that plant is going to be at least viable for.”
Fynaardt says that current conditions are very similar to what they were at this time last year, and that lack of rain from July until about the end of August, during the pollination and grain-fill stages, is where crops began to lose some of their yield. He says that cooler temperatures can help to counter the same result this year, but that rainfall is still vital.
“We actually hope for cool nights, cool days … humidity is fine. High humidity is not a problem. But if we stay really hot during pollination, it can have some ill effects on pollination; we won’t get as good as what we would if it was 10, 15 degrees cooler,” he says. “So when we see that nighttime temperatures go down in the 50s, that’s actually really good right now.”
Morning dew can also help to buy time between rain showers, but the current trend toward drought stress has the potential to be tough on this year’s yield.
Source: ottumwacourier.com
Photo Credit: gettyimages-luc-pouliot
Categories: Iowa, Crops, Corn, Soybeans, Weather