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Agronomy Notebook



White mold poses significant threat to soybean and dry bean yields

Soybean and dry bean growers across the Midwest and North Central United States need to prioritize white mold when evaluating their ‘disease watch list’ for 2012.

White mold, also known as Sclerotinia stem rot, was first discovered in the United States in the late 1800s on tomatoes. Since then, the pathogen has been found on hundreds of other crops and by 1992 it had established itself as a wide-spread problem in geographies where climate provided optimum condition for disease proliferation.

When left untreated, white mold can cause yield loss or total crop loss depending on the infected crop, with the added challenge of lingering in the soil for up to 10 years.

The reason behind the rapid increase of white mold has yet to be determined, but it is thought to be related to changes in cultural practices that promote a greater canopy density. The increase in white mold also is believed to be influenced by changes in the genetic base of current soybean and dry bean varieties, or changes in the white mold pathogen.… Continue reading

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Why early planting usually pays

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

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Research confirms benefits of crop rotation

 

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

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