Expectations from Delayed Planting

By Mark Licht and Sotirios Archontoulis

The planting is slow in 2022 – according to last Monday’s USDA Crop Progress Report corn planting was at 14% and soybean planting was at 7% comlete. This is nearly two weeks behind normal. This week’s warm temperatures have driven up soil termperatures but wet soil conditions are still the limiting factor for much of Iowa.

Historical USDA National Agriculture Statistics Service data suggests when 50% of state-level corn is planted by May 10, there is still a chance for up to 20% higher than trendline yields (Figure 1). When this is delayed to May 16, the chance of above trendline yield drop to only 2%. The 2022 Iowa trendline corn yield is 201.4 bushels/acre. And it should be noted that super early planting progres does not necessarily result in the yields. For example in 2010 and 2012, 50% corn planting occurred by April 23 and May 2 yet both years resulted in yield below trendline.

As it is well known, the weather during the growing season is very important. Weather conditions exploit the yield potential available for a given planting date. Recently research indicates 70% of corn yield variability is explained by planting date. Generally speaking, if Iowa corn is planted before May 18 yield potential remains greater than 95%.

Similarly, greater than 95% soybean yield potential is maintained with planting dates prior to May 20. However, soybean is less sensitive to planting delays than corn and greater variation in yield potential occurs with delayed planting situations (i.e., soybean yield potential does not drop off as fast as corn yield potential, Figure 1). If the 50% soybean planting is reached before May 20 there are very good changes for yields to be above trendline. The Iowa trendline yield for 2022 soybean yield is 57.5 bushels/acre.

The combination of date of planting by genetics sets the yield potential. However, uniformity in seed emergence is also a key for high yield potential. Regardless of planting date, planting conditions and planter setup are key to ensuring adequate stand establishment and uniformity.

Figure 1: USDA National Agriculture Statistics Servie corn and soybean yield data expresessed as percent change from trendline as affected by date 50% planting is reached.