Agronomy Notebook

By Dave Nanda, 
Director of Genetics & Technology 
Seed Consultants, Inc.

It has been proven by many tests conducted by the universities and seed companies over the years that earlier planted corn typically yields more than the later plantings. It has been demonstrated that in the central Corn Belt, you can lose about one bushel per acre per day if you plant corn after May 10th. However, they seldom explain why. The reasons are as follows:

North of the equator, June 21st is the longest day of the year. Plants can trap most sun light during May 21st to July 20th period. Earlier planted corn has more time to capture solar radiation. That’s the main reason for higher yield potential.

Is heat more important than light for yield and maturity? You can’t grow crops without either heat or light. Fortunately, both come from the sun. Heat provides the energy and light is required for photosynthesis, a process that converts carbon dioxide into organic compounds, especially sugars, starches and proteins.… Continue reading

Recent research add strength to the long held belief that corn grown in rotation with soybeans requires less nitrogen fertilizer and produces better yields than continuous corn.

“Our research shows that corn residue acts like a ‘sponge’ immobilizing the fertilizer, making it temporarily unavailable to the corn plant,” said John Shanahan, Pioneer agronomy research manager. “Growers working with continuous corn need to be mindful of crop residue from the previous year and adjust (and likely increase) their nitrogen fertilizer rates accordingly.”

These findings are part of a long-term, multi-location study by Pioneer that began in 2006 to examine the response of corn in limited nitrogen environments. Evaluations have been conducted yearly at Pioneer research stations in Johnston, Iowa; Champaign, Ill.; Windfall, Ind.; and York, Neb.

“While many studies have tested corn response to nitrogen fertilizer, there has been limited information on corn hybrid performance in nitrogen-deficient environments,” Shanahan says.

The nitrogen treatments in the study were standardized to five rates as a percentage of university economic optimum recommendations (from 0 to 130%), applied to corn in continuous production as well as corn in rotation with soybeans, and positioned on the same plots from year to year.… Continue reading