Perspective on a week of quick corn planting
The USDA's weekly Crop Progress report indicated that 43% of the U.S. corn acreage was planted during the week ended May 19, 2013. In terms of percentage of acreage planted, that equaled the record progress for the week ended May 10, 1992. In 1992, 79.3 million acres of corn in the U.S. were planted, implying that 34.1 million acres were planted during the peak week that year. U.S. corn planting intentions for 2013 were reported at 97.3 million acres, implying that 41.8 million acres were planted last week. Conventional wisdom explains the rapid rate of planting progress this year as a function of larger and more technologically sophisticated planters.
We begin our analysis by noting that total planting progress does not necessarily reveal the pace (speed) of corn planting during the week because the pace of planting depends on the number of days during the week that were suitable for planting. Based on an earlier analysis of Illinois planting data, we concluded that the pace of corn planting in terms of acres planted per suitable field day during the peak week of planting had increased about 28% from 1970 to 2011. Since corn acreage in Illinois increased by about 20% during that time period, the percentage of acreage planted per suitable field day during the peak week of planting had increased only marginally over time.
Here, we repeat that earlier analysis of peak week corn planting with the addition of 2012 and 2013 planting data. The analysis is limited to Illinois due to the lack of data relative to the number of suitable field days available per week in other states over a long time period. There is not an obvious reason that the results for Illinois would differ for other major corn producing states.
As indicated in Figure 1, a record 57% of Illinois corn acreage was reported to be planted in the week ended May 19, 2013. That exceeds the previous total peak-week planting progress record of 50% in 1973, 1987, and 1999. Based on planting intentions of 12.2 million acres, the weekly progress implies that a record 7 million acres of corn were planted in the state last week. That is well above the previous record of 5.5 million acres in 1982. As noted above, many observers were quick to credit larger equipment and technological developments for the record planting progress this year. However, planting progress during any week is also influenced by weather conditions, so that rapid progress could also be partially attributed to unusually favorable weather. We measure the effect of weather on planting progress by calculating planting progress per suitable field day as reported by Illinois NASS.
Figure 2 portrays the percentage of the corn acreage planted in Illinois per suitable field day in the peak week of planting from 1970 through 2013. The calculations confirm our previous findings of a very modest increase in the planting rate per suitable day over time. With 5.8 suitable days reported for the week ended May 19, 2013, an average of 9.8% of the acreage was planted per suitable field day during the week. That is above the long-term trend of 7.6%, but well below the previous highs of 11.1% in 1975 and 13.2% in 1999 and equal to the rate in 1994.