Economic Tidbits

14 Days to Plant Corn

Tweets and other anecdotal reports indicated a few planters were rolling in Nebraska last week. Time will tell whether the wet winter and spring will cause significant delays in getting this year’s crop in the ground. Conventional wisdom suggests today’s farmers can cover more ground, in less time, due to larger planters and equipment. Meaning farmers today can plant more acres in fewer days compared to the past.

However, analysis by agricultural economists at the University of Illinois suggests the conventional wisdom may be fallacy. Scott Irwin and Todd Hubbs examined corn planting progress in Illinois, Indiana, and Iowa using historical data. They found the maximum planting rates per suitable field day have increased very little over time. The minimum number of days it takes to plant corn in all three states is 14 days, a slight decrease from the 15 days it took in the early 1980s in Indiana and Illinois, and roughly the same number of days in Iowa. Irwin and Hubbs conclude, “This demonstrates that weather is the key determinant of timely planting of aggregate corn acreage in the U.S. not planting rate per day, which is surprisingly stable through time.”  Irwin, S. and T. Hubbs. “Here We Go Again: How Many Days Does It Take to Plant the U.S. Corn Crop? Farmdoc daily (9):69, Department of Agricultural and Consumer Economics, University of Illinois at Urban-Champaign, April 17, 2019.

The University of Illinois findings lead to another question: are the number days available for planting changing over time? Here again, research can provide an answer. Michelle Mensing, with Decision Innovation Solutions, examined historical weather trends in Iowa, Kansas and Missouri with an eye on trends in the number of days suitable for fieldwork while a graduate student at Kansas State University. Using data over a 42-year period, Mensing found the median number of days suitable for planting was 15 days. In other words, in half the years analyzed, 15 days or less were suitable for planting. She also found that in two years, there were 10 days or less suitable for planting. One of Mensing’s more intriguing findings is that the days suitable for planting in Iowa are declining over time. Her findings suggest Iowa is losing 0.12 days suitable for planting each year, or a little more than a day over a 10-year period.

Taken together, Mensing’s and the University of Illinois’ research results could mean farmers will face increasing difficulties planting a crop in future years. Unfortunately, neither study included Nebraska. Nebraska’s climate variations are greater than that experienced in the states examined, so the number of days suitable for fieldwork in Nebraska probably varies more. At the same time, given eastern Nebraska’s similarity to Iowa, there may be portions of eastern Nebraska that are slowly losing days available for planting. It’s probably a research question which deserves a closer look.  

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