Corn Yield Implications of Late Planting
University of Illinois Extension Agronomist Emerson Nafziger discusses the impact of late corn planting and how farmers should set about nitrogen applications this spring. He was interviewed May 1, 2019, by Todd Gleason.
The following summary is taken from a May 1, 2019, University of Illinois farmdocDaily article written by agricultural economists Scott Irwin and Todd Hubbs.
“The impact of late planting on projections of the U.S. average corn yield is an important question right now due to the very wet conditions so far this spring through much of the Corn Belt. We estimate that the relationship of late planting with corn yield trend deviations is highly non-linear, with a largely flat segment up to 10 percent above average late planting and then a steeply sloped segment for late planting that is 10 percent or more above average. This nicely matches the curvature of planting date effects on corn yield estimated in agronomic field trials (e.g., farmdoc daily, May 20, 2015; Nafziger, 2017). The key then for 2019 is whether late corn planting will be 10 percent or more above average, where the negative impact on corn yield is relatively large. Specifically, when late planting is 10 percent or more above average the chance of corn yield being below trend is 83 percent and the average deviation from trend yield is –6.1 bushels per acre. We analyze topsoil surplus moisture patterns in analog years to 2019 and the analysis suggests late planting this year is likely to be at least 10 percent. The implication is that there is a significantly elevated probability of a below-trend corn yield in 2019 and that present projections of U.S. average corn yield should likely be reduced to 170 bushels per acre or less. It is important to recognize that good summer weather conditions can offset the projected negative impact of late planting on the national average corn yield, but history indicates the probability of this happening is not very high if wet conditions in the Corn Belt persist through mid-May.” - Irwin and Hubbs, University of Illinois