I believe pictures like those shown below cause no end of confusion with respect to the analysis of grain markets. The first picture is my Dad, Jim Irwin, planting corn with his 8-row planter in 1971. The second picture is my nephew, Reilly Vaughan, planting corn with his 24-row planter last year. Reilly can plant one of our fields at least 3X faster than my Dad could back in the early 1970s because each trip through the field he plants 24 rows instead of 8 rows. Plus, I am pretty sure he can drive at a faster speed than my Dad did, which means he can the plant the same field maybe 4X faster.
So, it is obvious that today’s much bigger planters can plant the same size field much faster than in the past. That has to be true. But this does not necessarily mean that US farmers can plant the entire corn crop any faster today than in the past. Huh? The trick is that there were a lot more of those 8-row planters around in 1971 than the number of 24-row planters today. Think of it this way. Three 8-row planters working in the same field in 1971 could plant just as fast as a single 24-row planter today (not accounting for faster planting speeds now).
We know that there are a lot fewer commercial-size (full-time) grain farms in the Corn Belt today than in 1971, and those surviving farms are much larger. This means that a 24-row planter today has to cover a lot more acres than my Dad did with his 8-row planter back in 1971. The question then becomes an empirical one. Can the smaller number of bigger planters today cover more acres per day in aggregate than the larger number of smaller planters in the past? It’s really that simple.
I have examined the long historical record of corn planting progress data available from the USDA in a series of farmdoc daily articles (see the list here Collected Publications for Scott Irwin – farmdoc daily (illinois.edu)). The answer I get over and over is that we do not plant the Corn Belt any faster today than we did back in 1971. In other words, its a wash between the larger number of smaller planters in the past versus the smaller number of larger planters today in terms of the speed with which the Corn Belt can be planted. This logic seems to be something that lots of people have a really hard time accepting. I know the pictures don’t help. But it is actually a very satisfying result to an economist. Why would farmers invest in more planting capacity as a sector than what is required to get the corn crop planted in a reasonable amount of time?
Here is the link to my most recent farmdoc daily article on corn planting speed: What Do We Know About the Impact of Late Planting on the U.S. Average Corn Yield? – farmdoc daily (illinois.edu)
Laurence J. Norton Chair of Agricultural Marketing
University of Illinois at Urbana-Champaign