The late start to the 2013 corn planting season has created concerns about the likely magnitude of planted acreage and likely yield potential. 

The rapid planting progress during the week ended May 19 alleviated some of the corn production concerns.

Still, a larger than average percentage of the crop will be planted later than is considered optimal for maximum yield potential.  

Recent and upcoming heavy precipitation, particularly in Iowa and parts of Illinois and Missouri, suggest that some corn acreage will be planted extremely late, switched to soybeans, or not planted at all so that production uncertainty persists.

Until recently, there was little concern about the timeliness of soybean planting. However, the same weather that will delay the completion of corn planting may also result in more than the average amount of late planting for soybeans. 

As with corn, there is not agreement on what constitutes late planting for soybeans. We have defined late planting as occurring after June 10 in years prior to 1986 and after May 30 since 1986. The difference in late planting dates reflects the shift to early planting dates, similar to that which occurred for corn. 

By this definition, an average of 32 percent of the acreage was planted late in the 33 years from 1980 through 2012. The average is relatively high since the planting of double-cropped soybeans generally occurs “late”. Those acres typically account for six to nine percent of total soybean acreage. 

The percentage of the acreage planted late has ranged from nine percent in 2012 to 66 percent in 1995. There were five years in which late planting exceeded 50 percent, and all of those years were in the 1990s.