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RPM Soils, LLC

Thursday, December 2, 2010

N Rate calculator.

The N Rate calculator has been on line for 4 or 5 years now, but I am not sure how many farmers use it.  I guess you could say this is a followup to Yesterday's blog about regulation. 

Many farmers have been using a yield based N rate for 30 to 40 years.  That approach says that you should apply N at the rate the crop will need to make a given yield.  Yield potential should be based on a five year average on that farm or field.  We have many farmers approaching a 200 bu per acre potential.  A corn crop uses about 1.2 lb of N per bushel of yield.  that makes for easy math.  200 bushel corn should have 240 lb of N applied. 

Researchers in the Midwest have been looking for other ways to make the nitrogen decision for about 10 years.  Research data was collected from hundreds of sites to develop the data needed to determine the ideal N Rate.  That data was plugged into the model that runs the price based N rate calculator.  N Rate Calculator .  Using $820 per ton anhydrous and $5 per bushel corn, the N Rate that will maximize profit in central Illinois is 168 pounds per acre.

Where does the extra nitrogen needed to make 200 bushel corn come from?  It comes from soil organic matter.  Before Nitrogen fertilizers became commonplace, everyone could see the value of the high organic matter soils in central Illinois and northern Illinois .  We have overlooked that value with a one size fits all approach for many years.  Using the N rate Calculator will set you on a track that is both economical and environmentally sensitive.  Iowa, Illinois, Michigan, Ohio, Minnesota and Wisconsin all have their data included in site.  Missouri participated in the studies, but is still wrestling with the data.  I say, at least take a look at it.

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