Seminole Crop E News

Agricultural News for Farmers and Agribusiness in SW Georgia

Corn Update – Dewey Lee

Posted by romeethredge on April 17, 2015

Dewey Lee, UGA Grains Scientist, has this timely corn update for us.

“This year’s corn crop is developing much faster than the corn crop over the last two years.  In 2013 and 2014, we had much cooler weather the first 35 to 40 days of corn growth. Rainfall,though has been somewhat similar.   This year it’s been much warmer.  When I look at the average temperature between this year and the last two years during this time, many areas in the corn growing region of the state are 5 to 7 degrees warmer.  What does this mean?  It means that we need to pay much closer attention to the crop in order to be timely with our inputs, particularly, nitrogen applications.  If the crop enters into a V6 to V7 stage and is showing signs of nutrient stress, some yield potential will lost as the plants begin the process of setting the number of rows that will develop on the ear.  This occurs between V7 and V8/V9.  It takes time for a plant to recover from stress.  This year, it’s not unusual for a corn plant to advance one leaf stage in three days.  This would mean that in 6 to 7 days, the corn plant can go from a V5/V6 stage to a V7/V8 stage.

Notice the bottom leaves that are N deficient. Look at the striping in the new leaves.  These are showing signs of a N/S deficiency.

The plants in the picture have had 70 lbs N  plus 8 lbs of S at planting but it is easy to see a visible sign of nitrogen and/or sulfur deficiency.  As you can see, this corn plant is between the V5 and V6 stage and, in just a few days, will begin setting the number of rows per ear.  It is imperative that this field receive both N & S right away to prevent any further yield loss.  In sandy loam to loamy sand soils, its easy for nitrogen and sulfur to leach quickly through the profile and below the root zone.  In a case like this, nitrogen and sulfur should be sidedressed by the row quickly or 40 to 50 lbs N with a small % of S injected through the pivot on a per acre basis.

A tissue analysis taken at this time and ten days to two weeks later can tell a lot about how much of the applied nutrients are having an impact.  If minor elements or other elements are showing signs of dropping below sufficiency levels, then there is time to apply any needed nutrients either by ground or through the pivot.”

http://georgiagraincrops.com/

 

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