Planting Corn or Applying Nitrogen?

Weather causes farmers to make choices, delaying planting corn impacts yield.

Published on: May 13, 2013

The wettest first quarter of the year since 2008 is causing many farmers to make a choice between planting corn and applying nitrogen fertilizer. However, for Peter Scharf the answer is simple

The University of Missouri Extension agronomist says that once the rains stop, planting corn first is the best option. "Almost all of the time, the right decision is to plant," he says. "Delaying planting is more likely to hurt yields than delaying nitrogen application." Scharf says that actually delaying nitrogen application will actually help in some years.

He cites research from 2008-2010 that were similar to wet springs like the one we are now experiencing. Over those three years, corn receiving nitrogen fertilizer when it was knee-high out-yielded corn receiving all nitrogen fertilizer at planting by an average of 60 bushels per acre each year. "This is because the nitrogen applied at planting was lost due to wet weather and was not there when the crop needed it in June and July."

University of Missouri Extension agronomist Peter Scharf says that once the rains stop, planting corn first is the best option. "Almost all of the time, the right decision is to plant," he says. "Delaying planting is more likely to hurt yields than delaying nitrogen application."
University of Missouri Extension agronomist Peter Scharf says that once the rains stop, planting corn first is the best option. "Almost all of the time, the right decision is to plant," he says. "Delaying planting is more likely to hurt yields than delaying nitrogen application."

A change in machinery may be required
Delayed nitrogen application may mean changing machinery. Some producers may have planned to use nitrogen-application equipment before planting corn. However, applying nitrogen once the corn is in the ground and up will require machinery that works in a standing crop. Scharf encourages producers to be flexible about how they get their nitrogen applied. He notes that a number of fertilizer dealers have recently purchased or leased high-clearance applicators, and many have side-dress units available. "This creates options in addition to equipment that the producer actually owns."

Every decision that you make influences the size and scope for corn yields. From the corn hybrid you select to the seeding rate and row width you choose. Download our FREE report over Maximizing Your Corn Yield.

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Due to drought, much of the nitrogen fertilizer applied to corn last year was not used. Some producers may have hoped to use this nitrogen with another corn crop planted this year. This possibility looked reasonable all through the fall of 2012, but is questionable now. A small number of deep soil samples Scharf and others took this spring have revealed less nitrogen than expected.

Nitrate has moved down
"We found almost zero nitrate in the top foot, but about 20 pounds of nitrogen per acre as nitrate in the second foot and another 20 in the third foot," Scharf said. "In short, the nitrate has moved down, and it seems likely that a good bit has moved below 3 feet deep. I wouldn't take a credit for last year's nitrogen unless it was backed up by a deep soil test."

Soil tests to measure residual nitrogen are available through the MU Soil and Plant Testing Laboratory, through local extension centers or through commercial vendors. Before planting corn, farmers should take the time to get their soil tested.

For information on how to interpret soil test results, MU Extension guide G9177, "Preplant Nitrogen Test for Adjusting Corn Nitrogen Recommendations," is available for free download here.

Information also is available from Scharf here. Precipitation maps are available at the link for "N Watch 2013," a tracking tool begun in 2009 to help producers make assessments about nitrogen loss in certain regions of the state.

Source: University of Missouri Extension

Every decision that you make influences the size and scope for corn yields. From the corn hybrid you select to the seeding rate and row width you choose. Download our FREE report over Maximizing Your Corn Yield.