He says that might be 220 bushels per acre; or it could be 150 bushels per acre. A 10 day delay beyond the first of May would have an impact of 10 multiplied by 0.3 percent per day decrease in yield. Applied to the 220 bushel yield would be 213 bushels per acre. Applied to the 150 bushel yield would be 146 bushels per acre.
It is quite possible that the 146 bushel yield could occur when corn was planted in a given year on May 10, and the 214 bushel per acre yield could occur when the corn was planted the following year, on May 15.
In this case, a larger yield was generated at a later planting date.
Nielsen says, “A delayed planting of corn in an otherwise high yielding year may still be higher yielding than a crop planted on the optimum planting date in an otherwise lower yielding year. Farmers know this to be true because some have had June-planted crops in recent years that ultimately yielded better than any crop they have ever had.............. because the remainder of the growing season following the delayed planting was exceptional.”
He says look at 2009 and 2012. 2012 corn was planted early and yielded much less than the 2009 corn which was planted late, all because of the yield influencing factors other than the planting date.
Since planting date is only one of several yield-influencing factors, the date for planting corn has a much more minor impact than believed by many corn growers. Planting corn after May 1 may lead to lower corn yields; however that is only 23 percent of the determinant. It is quite possible for later planted corn to out-yield earlier planted corn.
Source: FarmGate blog