Despite its wet, late start, Iowa's corn crop looks good as harvest begins, and a damaging early frost failed to materialize.
"The crop is actually maturing a little early. We're within five days of the whole crop in central Iowa maturing,” says Roger Elmore, Iowa Extension corn specialist.
He expects the state average yield to be slightly below the September forecast of 168 bushels per acre.
"We're not going to have that really great yield because there's so much variability in those canopies and so much plant-to-plant variability,” he says.
Cool September weather helped the crop, says Kendall Lamkey, chair of the Iowa State University agronomy department.
"We've only had five days over 90 degrees in Ames, and had a couple of weeks in early September that were exceptionally cool for that time of the year. That actually saved the corn. We had cool nights and perfect daytime temperatures. We've had perfect corn-growing weather since the floods. If we'd had normal daytime highs, the crop would be in trouble,” Lamkey says.
"Temperatures that got into the low 50's improved the low end of the yield. Cooler weather and the longer growing season really helped,” Elmore says.
"We have had some frost in low-lying areas. But, right now, even here in central Iowa, we could take a frost and not be hurt too much. Most people now aren't worried about frost in field corn,” Elmore says.
"We needed cool weather and lots of sun, and got it. We needed late frost and got it. Given what we were handed, the crop has done well. The replants in wet holes that were flooded are still a couple of weeks off from maturing.”
Wet conditions put pressure on corn following corn, however.
"It's a year when we'll see a big differentiation between corn in rotation and corn on corn. Cooler, wetter soils at the start hurt corn on corn. So there were huge differentials right from the start on things like plant height and emergence rates. With corn on corn, it's possible get anywhere from zero to 30% yield loss. This year we'll be on the high end of that scale,” Elmore says.