Adjusting Nitrogen Rates for Crop Potential

Adjusting N Rates for Crop Potential

The Right Rate of Nitrogen: A Simple Way to Adjust N Rates for Corn Crop Potential

After compiling research from the past two years we know the amount of N that a crop needs is just as variable as the nitrogen in the ground. A field with high yield potential (230+ bu) will need 300+ lbs of N to meet it’s potential. A 200 bushel crop of corn requires about 220 lbs. The key to not running out of “gas” is to know how much you need to get to your destination!

A good rule of thumb is that corn will have 50% of its N out of the ground by V10. If you have 100 lbs removed at V10 your crop will remove approximately 200 lbs.  Last year the best performing field we measured removed 170 lbs by V10!

How do we measure crop potential?
By measuring the amount of N removed from the ground.

When should you measure crop potential?
We can assess how much N your crop will need starting at knee high corn through to tassel and you can use this information to adjust your late N application.

For more information please visit our website –

The Plant Tissue Tracker

The Plant Tissue Tracker

The Hefty Brothers, Randy Dowdy, and Kip Cullers all use tissue testing to monitor nutrient levels through the growing season. You should too!

We have added a few features to our tissue tracker (pictured above) to make your life easier:
* Nutrients from multiple tissue tests are tracked on an easy to read report.
* Compare more than one zone/field on the same report.
* All data is tracked by GDU to provide a fair comparison between fields planted at different times.
* Average, High, and Low Ranges by GDU are provided for corn.
* Tracking nutrients through the growing season is also available for whole plant analysis. Not sure what whole plant analysis is? Read This:

For more information on the Plant Tissue Tracker visit:

Nitrates in Corn Silage

With dry conditions the risk of nitrate accumulation in corn silage is increased.  Here are a few things you should know:

  • Having high nitrates is a “perfect storm” where plants take up large quantities of nitrate and cannot convert it into other forms of N.
  • Soil nitrate levels are high this year. When soil nitrate levels are high, the risk of high nitrate levels in the plant are greater. We have been monitoring nitrate levels in corn fields for grain farmers and we know that the levels of nitrate in corn fields are much higher than usual this year.
  • Take caution after a rain. After a long drought a rain can cause a rapid increase in nitrate in the plant.
  • Fermentation will decrease nitrate levels. Typically, levels can be reduced by approximately 40% by waiting a couple of weeks.
  • Nitrates accumulate in the lower portion of the stalk. Cutting the corn silage higher may help reduce the levels.
  • Ideal levels of nitrate are under 1000 ppm and over 4000 ppm is considered unsafe to feed.
  • We report potential for high nitrate by NIR to give you a quick check. If nitrate probability is medium or high, we recommend a chemistry nitrate test to measure the actual level.

Nitrate Probablity

  • High nitrates lead to higher silo gas levels. Take caution when working with corn silage with high levels.


*Nitrate Information from OMAFRA Fact Sheet, “Potential Nitrate Poisoning and Silo Gas When Using Corn Damaged by Dry Weather for Silage, Green Chop or Grazing”