The rains that fell over much of the central U.S. have dried out enough to allow farmers to get back into the field and resume what so far has been a jump-start to the crop season.

It's been quite an anomalous year so far in corn and soybean country. There's corn already out of the ground in parts of Iowa and Illinois, and those who haven't planted yet are getting a lot of fieldwork knocked out early. So what, if any, effect will the early progress have on your corn yield potential once the combine rolls this fall?

Though there have been a lot of warnings about the potential drawbacks of planting corn well ahead of schedule even when the weather permits, the sooner the seed's in the ground, the lower your chances for a yield hit compared to late-planted corn, says University of Illinois Extension agronomist Emerson Nafziger.

"The yield response indicates a slight yield advantage for corn planted in mid-April, but a generally very flat yield response for corn planted between early April and early May," he says. "In contrast, there is a yield penalty associated with corn planted later than early May, with increasingly large penalties as planting occurs after mid-May."

What's most notable from the research behind this conclusion, Nafziger adds, is it disproves a common misconception about yield potential and early planting. Instead, it's more of a preventative measure to avoid losses from having to wait beyond the optimal planting window.

"Contrary to popular opinion, this research indicates that there is not a substantial yield premium for early planting, but confirms that there is a notable yield penalty for late planting," he says. "The potentially beneficial impact of planting a large portion of the crop early, then, is in the avoidance of the yield penalty of late planting."