click image to zoom For the current year, the USDA reported four percent of the crop had been planted as of April 21. That leaves 29 days to plant the crop before late planting begins (May 20). For late plantings this year to equal the long term average of 15 percent, 81 percent of the crop needs to be planted in that 29 day period. Reaching 85 percent planted by May 20 depends on how many days are suitable for planting and how much of the crop can be planted in each suitable day. The likely number of suitable days for planting through May 20 can be projected based on the average number of suitable days during that period in the past. We have not assembled that data for the U.S., but the data have been calculated for Illinois for the period 1967 through 2012. Based on estimates of days suitable for fieldwork reported in the Illinois Weather and Crops report and shown in Figure 2, about 50 percent of the days from the last 10 days of April through the first three weeks of May were suitable for fieldwork. Assuming those estimates are also reasonable for other corn producing states, history suggests there will be about 14.5 days suitable for field work from April 22 through May 20, 2013.
How much of the corn crop can be planted per day suitable for fieldwork? There is a general perception that modern planting equipment has resulted in a much faster planting pace over time and now allows for a very large percentage of the crop to be planted per day. That perception, however, is somewhat misleading. More acres can certainly be planted per day with a 36 row planter and modern seed handling equipment and guidance technology than with an 8 row planter of several years ago. The question is whether fewer, but larger planters can plant more acres per day in total than smaller, but more numerous planters of 20, 30, and 40 years ago. We examined that question in a post on June 3, 2011 by calculating both the number of acres and percentage of the corn acres planted per day suitable for field work from 1970 through 2011 in Illinois. The conclusion was that Illinois farmers are now planting 15 to 20 percent more acres per day than in the 1970s. However, in terms of percentage of the crop planted per suitable field day, we found only a very small trend increase over time.
click image to zoom Our previous analysis was based on planting progress only for the peak week of planting each year. Here, we focus on the average planting progress per suitable field day up to the point where approximately 90 percent of the Illinois corn crop is planted, as this variable is the most relevant for assessing prospects for what is almost the entire 2013 planting season. That variable is plotted in Figure 3 for 1970-2012. Similar to our earlier analysis of progress in peak planting weeks, the average percentage planting progress per suitable field day shows remarkably little trend over time. The average was 4.2 percent in the 1970s, while it was an average of 4.8 percent for 2003-2012. There may be a slight increase in our ability to plant the corn crop now, but it is by no means a large difference.