Purdue University Department of Agronomy

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7 May 2013
URL: http://www.kingcorn.org/news/timeless/PlantingPace.html

The Pace of Corn Planting Progress Over Years: Another Conundrum

R.L. (Bob) Nielsen
Agronomy Dept., Purdue Univ.
West Lafayette, IN 47907-2054
Email address: rnielsen at purdue.edu

In response to this year's delayed planting season, I recently discussed the conundrum of statewide corn yields relative to statewide planting progress (Nielsen, 2013). There is another conundrum related to the fact that today's larger field equipment, including planters, allows for greater planting progress per day or per week than was possible many years ago. This fact encourages optimism that delayed starts to the planting season can be overcome by the ability to plant a greater percent of the state's crop per week when "push comes to shove."

Certainly, the number of 24-, 32-, 36-row, or larger planters across the U.S. Midwest is greater today than, say, twenty years ago. Certainly, an individual farmer can plant more acres of corn per day with this large equipment than 20 years ago. However, historical data suggests that the pace of corn planting in terms of percent of total corn acres planted each week has not changed in 20 years.

Figure 1 depicts the single greatest week of corn planting progress in Indiana for each year since 1992. The record greatest weekly planting pace during those 21 years was 50 percent during the first week of May in 2001. The next two fastest weeks of corn planting progress were in 1992 and 1993 with 46 and 42 percent, respectively. Indiana corn growers have rarely come close to that magnitude of weekly planting progress since.

So, the conundrum is why has the maximum percent of total corn acres planted in single week not increased in 20 years? The answer does not appear to be related to changes in total corn acres planted in Indiana because that number has remained fairly consistent in recent history (Fig. 1).

One could speculate that farmers today are planting soybeans earlier than they did twenty years ago and so fewer resources are available to plant corn during the traditionally important 4-week planting window that begins in late April. One way to address this question is to calculate the ratio of soy to corn planting progress during that 4-week period and then determine whether that ratio has changed over time. Doing so indeed suggests that soybean planting progress during that 4-week period has increased somewhat since 1992, but the historical relationship is statistically very weak (Fig. 2).

Another factor that may contribute to the planting pace conundrum is the fact that the number of corn growers in Indiana has decreased over time and those remaining are farming more acres than they did twenty years ago. Even though farm machinery is larger today and cover more acres per day than twenty years ago, fewer farmers are farming more acres and so total planting progress in terms of percent of total acres per week remains fairly unchanged.

For what it's worth, that's my opinion and you are entitled to it.

Related reading

Nielsen, RL (Bob). 2013. The Planting Date Conundrum for Corn. Corny News Network, Purdue Univ. online at http://www.kingcorn.org/news/timeless/PltDateCornYld.html [URL accessed May 2013].

USDA-NASS. 2013. Quick Stats. USDA Nat'l Ag. Statistics Service. online at http://www.nass.usda.gov/Quick_Stats [URL accessed May 2013].

Max planting progress
Fig. 1. The greatest single week of corn planting progress (percent of corn acres planted) in Indiana each
year since 1992.

Max planting progress
Fig. 2. The annual ratio of [Percent of soy acres planted] versus [Percent of corn acres planted] during
the 4-week period beginning April 23. Indiana soybean and corn planting progress, 1992 - 2012.