A perennial topic in the grain markets during the spring is the timeliness of planting corn. I reviewed data from agronomic field trials on the impact of planting date on corn yields in a farmdoc daily article from a couple of weeks ago (What Do We Know About Planting Dates and Corn and Soybean Yield from Agronomic Field Trials? – farmdoc daily (illinois.edu)). This work clearly shows that planting date matters and planting after mid-May results in potentially substantial hits to corn yield. So, we want to avoid planting as much of the corn crop after mid-May as possible to avoid that yield hit.
So this brings us to the question of how fast US farmers can plant the corn crop. You would think this would not be a controversial topic. But, trust me it is! I describe conventional wisdom this way: the increase in average planter size over time means that we can now plant the Corn Belt in as little as 5 days. Whether 5 days is the right number or not, surely we can plant the crop much faster than in the past with all those 24 and 36-row planters you see out in the fields. As in so many cases, Darrel Good was the first person I knew who expressed skepticism about this conventional wisdom. He said there were a lot of 4-row planters back in the day. So we set out to determine how many days it really takes to plant the US corn crop. That was over 10 years ago and I am still writing about it.
My latest FDD article updates the analysis I first did with Darrel and then continued with Todd Hubbs. You can find it here: What Do We Know About How Long It Takes to Plant the U.S. Corn Crop? – farmdoc daily (illinois.edu). We show, again, that the minimum number of suitable field days to plant the US corn crop has not changed (on average) in over 40 years. 14 days is the minimum. Huh? What’s behind this? Basically, we have fewer large planters that in aggregate have the same capacity as a greater number of smaller planters in the past. That is what the data imply. People seem to have a really hard time believing that because some farmers with a lot of acreage can plant it all in 5 days. But that does not mean the same thing holds in aggregate.
So take a look. I think you will enjoy reading this “contrarian” article on corn planting speed.
Laurence J. Norton Chair of Agricultural Marketing
University of Illinois at Urbana-Champaign
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