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 –

Crop Potential and Nutrient Requirement

How many pounds of nitrogen does it take to grow a decent crop of corn? This is a question we have all contemplated at onetime or another. It’s usually a precursor to a discussion on rates, timing, placement, chemical formulation, etc. but today I want to share some info on the original question; How many lbs of N,P,K,S, etc does it take to produce these big crops of corn.

Whole Plant Uptake and YieldResearch from Tony Vyn shows that if yield increases by 3X (108 to 299 bu/acre) you remove 8X N, 9X K, and 10X S from the ground.

As you can see in the chart above, the nutrients required are dependant on your final yield. Higher yielding crops have a much greater demand for nutrients than lower yielding ones. In the case of nitrogen, you need approximately 65 lbs more N for every 30 bu increase in yield. Fields that used to yield 175 bu and yielded 240 last year use double (130 lbs more) the amount of nitrogen to make that crop.
Crop Potential ChartCrop potential can be established in the mid
vegetative growth stages and we can use this information to nail down our final nitrogen recommendation. Fields that have more lbs of N,P,K/acre out of the ground earlier in the growing season turn into higher yielding crops.
Because of the differences in the requirement for nitrogen we recommend analyzing the crop potential earlier in season to determine your optimum nitrogen rate.

If you are planning a late N application this year, consider using whole plant analysis to know when to chase the big yield or save your money on a crop that may not need much additional N.

The cost of a whole plant analysis is $40.00 and the results will be available 2 days after we receive the sample.

Agronomy Newsletter Dec 15

Staygreen Program 2016

Whole Plant

Based off of the successes of last year’s Staygreen Nitrogen Management Program we will be running this program again next year, with a few changes.

The noteable addition to the 2016 program is the whole plant nitrogen test, (see above) which will tell us how many lbs of nitrogen you have removed from the soil at different growth stages. This number can be used to estimate nitrogen use efficiency (NUE) and provide insight on how much nitrogen you are actually taking up after tasseling.

Are you interested in becoming a Staygreen partner? We are looking for partners (either individuals of companies) in areas that are logistically hard for us to service or with parties that would like to add this program to their field monitoring services. If you are interested email Chris Roelands –

The Staygreen program includes, Soil nitrate, plant tissue (all nutrients), and whole plant analysis through the growing season for an in depth look at the nutrient status of your crops. For full details on the Staygreen 2016 program please visit our website:

Join us at the Southwest Ag Conference

If you are attending the Southwest Ag Conference (January 5th and 6th) Dale Cowan (Agris), Paul Sullivan (PT Sullivan Agro) and Chris Roelands (Honeyland Ag Services) will present their learnings on nitrogen management in the session: Nitrogen Testing: New Zip in an Old Game. Join us to learn more about results from past years and recommendations going forward.


Enhanced Nitrogen Recommendation Tool for 2016

We are taking nitrogen management to the next level in 2016 with the development of a model to evaluate the nitrogen status on your farm. Using data and observations from previous years the model will take in as much information as possible to determine the estimated nitrogen surplus or deficit. Parameters built into the model include: soil nitrate (single or multiple depths), soil ammonium, N mineralization potential, growth stage, yield goal, and more!


Feed and Forage Analysis

Did you know we analyse feed and forages? Are you interested in learning more about animal nutrition? Read our animal nutrition newsletter here:


Have a Merry Christmas and a Happy New Year!