GENESEO, Ill. — Corn planting progress was well behind the five-year average through early May and an agronomist urges farmers to wait for ideal conditions.
“We need to have patience and we still have time. We do not want to push the conditions. I’d rather plant into ideal conditions on May 15 than mud-in corn on May 1,” said Brent Tharp, Wyffels Hybrids agronomist and technical product manager.
“We’re better off planting into ideal conditions because if we do push it and you start mudding things in, that’s not going to set us up very well to where if the rest of the year turns out little dry and a little stressful, it’s good to have the nodal roots established and have good root growth.
“If we mud things in, the roots will not do that, and we’ll pay the consequences if we have a stressful end of the season.”
Tharp recommended that farmers stick to their original plans and not start thinking about switching hybrids until the last week of May.
“I know there’s some talk out there and I’ve seen some questions about the need to switch out full-season hybrids. No, we need to stick to our plans. This corn plant has a great ability to adapt to the environment it’s put in and it will adapt to the later planting dates,” he said.
A multitude of university planting date trials have been conducted indicating how planting date influences corn yield potential. Tharp took the data a step further to determine how yields by planting date compare to trend-line yields.
“Planting date trials do show us that even if we get into May 15, we’re still at 95% of the yield potential, and even if we get out to May 20, we’re still at 92% of yield potential,” Tharp said.
U.S. corn trend-line yields from 1961 to 2021 have increased at a rate of about 1.9 bushels per acre per year, according to U.S. Department of Agriculture National Agricultural Statistics Service data.
“The main driver of this is genetic improvement and plant breeding. So, they’re doing a good job in the research departments in the seed industry because we are getting genetic gain,” Tharp said.
“When looking at trend-line yield there are years that are above trend-line and years that are below trend-line. I wanted to see if there is a relationship of planting date to where the yield is above or below trend-line.”
Tharp correlated final corn yields to when planting progress reached 50% from 1997 to 2021 in Illinois and how those yields compared to trend.
“Theoretically if you think an earlier planting date produces more yield, then we would have above trend-line yields with earlier plantings, and later planting dates would result in below trend-yields. This is what it would theoretically look like if planting date was the end-all, be-all driver for final corn yields, but, spoiler alert, this isn’t how the data looked,” Tharp said.
“In looking at the Illinois data at 50% planting date for the past 25 years and plot that out against the Illinois 60-year trend-line yield, there’s not a strong correlation. It’s not that nice stair-step down that we theoretically would have if the corn planting date was the end-all be-all influencer of final yield.
“In fact, there are a lot of things that happen in the middle or the end of the season that ultimately determines our final yield.”
For example, in the drought year of 2012, 50% of the Illinois corn crop was planted by April 20. The crop finished 40% below trend due to the mid- and late-season factors.
Yields were over 10% below trend in 2002 and about 10% below trend in 2005 with both attributed to drought conditions. Fifty percent of Illinois corn was planted by April 20 in 2005 and half planted by May 12 in 2002.
“We need to stick to our plans.”— Brent Tharp, agronomist and technical product manager, Wyffels Hybrids
Planting progress reached 50% by May 15 in 2013 and Illinois yields averaged slightly above trend. Half the corn was planted around May 23, 2009, and ended up surpassing trend. The 50% planted level in Illinois in 2019 wasn’t reached until about June 1 and the crop finished slightly below trend.
“As we look at this in the beginning of May, there’s still a lot of time to where we can get above trend yields and we just want to make sure we can get the crop into the ground in ideal conditions and we don’t want to be pushing it at this point in time,” Tharp said. “The rest of the year makes a big difference.”