Oct 18, 2012  |  Today's News

Yes, we know that we’re nearing the time for fall applied nitrogen in Illinois. It’s a practice as old as you can remember, right? However, some people would like to see fall applied nitrogen go the way of the cuckoo clock.

If it’s not one thing, it’s another, right? 2012 is a year we’d like to get into the history books sooner rather than later, but let’s be sure that we’re handling nutrient management in the best way possible to protect the environment while maximizing your investment. The other option would be to let fall applied nitrogen be a part of the history books, too.

Illinois Corn keeps an eye on nutrient management issues on your behalf, and advocates for best management practices to be voluntary. It doesn’t take too many bad apples to spoil the bunch, however, and nutrient application could become more regulated in the future.

Crops are leaving the field significantly earlier than in recent years and farmers are all too excited to leave the devastation of 2012 behind and look forward to the promise of an abundant crop in 2013.  Just be sure that you are paying attention to nutrient application guidelines in your rush to prepare for next year.  When should you apply to get the biggest return on investment? 

Any nitrogen application will be tricky this year as low productivity in many areas due to the drought makes it hard to estimate how much nitrogen will be carried over into next year.  The best way to determine your field’s nitrogen needs is to take part in a free soil sampling conducted by the University of Illinois and paid for by the Illinois Council on Best Management Practices.  The actual amount of nitrogen available in the spring will vary depending on the wetness of our winter weather.

In most cases, research has proven that the largest return on investment for nitrogen application occurs when the nitrogen is applied in the spring, closest to when the plant requires the most nitrogen.  This option provides the largest yield benefit from nitrogen application.  However, the window for nitrogen application is often small, infrastructure is not always there, and farmers are taking a risk that they can get nitrogen applied.

If you must apply in the fall, remember that the ground temperature four inches below the surface must be 50 degrees or below.  The temperature impacts the activity of microorganisms that can convert the ammonium into nitrate.

A safe bet is not to apply prior to the third week of October in most of Illinois, the second week of October in northern Illinois.  Check your soil temperatures when in doubt.

Also, anhydrous ammonia is the safest for fall application.  Applying urea in the fall can cause nitrogen loss before the plant has an opportunity to uptake the nitrogen in the spring.