The rapid planting progress during the week ended 19 May alleviated some of the corn production concerns. Still, a larger than average per centage 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 30 May 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 per cent 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 per cent of total soybean acreage. The per centage of the acreage planted late has ranged from nine per cent in 2012 to 66 per cent in 1995. There were five years in which late planting exceeded 50 per cent, and all of those years were in the 1990s. Late planted acreage accounted for 48 per cent of the acreage in 1986 and 47 per cent in 2011. Acreage and yield outcomes in those years might influence expectations for this year if it turns out that a large per centage of the acreage is planted late.

In the five years with the most late planted acreage (1990, 1991, 1993, 1995, and 1996), total planted acreage exceeded March intentions in four years. The increase ranged from about 800,000 acres (1.3 per cent) to about 2.1 million acres (3.6 per cent). Planted acreage was 1.6 million acres (2.7 per cent) less than intentions in 1990. In both 1986 and 2011, planted acreage was about 1.6 million acres (2.6 per cent and 2.0 per cent, respectively) less than March intentions. Acreage responses in years of large amounts of late planting have not been consistent in either direction or magnitude relative to intentions reported in March. The difference between actual planted acreage and March intentions in those seven years ranged from 1.3 to 3.6 per cent and averaged 2.4 per cent. Based on planting intentions of 77.126 million acres this year, the previous experience suggests that planted acres will differ from intentions by about 1.8 million acres, in a range of 1.0 to 2.8 million acres, if late plantings are large. History, however, does not offer much insight on the likely direction of the difference.

The US average soybean yield relative to trend value also varied in the previous years of large amounts of late-planted acreage. The US average yield was less than one bushel above trend value in 1986 and 1996, very near trend in 1990 and 1991, and about a bushel below trend in 1995 and 2011. The largest deviation from trend was the nearly three bushel shortfall in 1993. Yields are mostly determined by July and August weather conditions. The history of yields in late-planted years suggests that like most other years, the US average yield this year should be within about one bushel of the trend value of 44 bushels per acre unless summer weather conditions are extreme.

The USDA’s weekly Crop Progress report indicated that 24 per cent of the US soybean acreage had been planted as of 19 May. That compares to the previous 5-year average planting progress of 42 per cent. The slowest progress relative to the previous 5-year average was in Iowa and delays are likely to continue there due to recent and upcoming precipitation. The report to be released on 3 June will allow a calculation of the per centage of the crop planted late by our definition. It appears that per centage will be above the long term average of 32 per cent, but well below the historical extreme of 66 per cent. November 2013 soybean futures have increased about $0.75 from the low on 10 May. Much of that increase is apparently based on production concerns related to prospects of more than the average amount of late planting. History suggests that those concerns, particularly from the yield side, are probably premature. The USDA’s 28 June Acreage report will provide a clearer picture of the magnitude of planted acreage.