Ask The Agronomist – Top 3 Questions & Answers

If you have questions about nitrogen application, chances are someone else does too. Check out the top three Ask the Agronomist questions and answers submitted to ESN this year.

I haven’t been able to find any information on fall-applied nitrogen, for corn or sugar beets. We usually have four frozen months where the ESN cannot continue to release N. Do you have research that either supports or disproves this theory?

We have done several studies looking at fall-applied ESN:

-We have had success with fall-applied ESN for spring-planted corn in Minnesota, Iowa, and Missouri as long as ESN is placed in the soil and not left on the surface. We have very limited research on this application for sugar beets.

-In Western Canada, ESN is commonly applied in the fall for both winter and spring wheat and canola.

-One area in which we did not have good results with fall-applied ESN was in Ontario, presumably because the soil did not stay frozen and there was too much release over winter.

-As long as ESN is applied when soil temperatures are cold and expected to continue to cool and ESN is incorporated into the soil where it will stay frozen, you should have good results. We recommend following guidelines similar to those for fall-applied ammonia.

-We do not recommend fall-applied ESN where there is high potential for winter and early spring N losses, such as on sandy soils or in high rainfall regions with periodic thawing during the winter. If fall-applied ammonia is not an acceptable practice in your area, fall-applied ESN would be considered similarly risky.

To learn more about the fall application of ESN, click here.

What is the minimum blend percentage to gain value of using ESN in a spring, pre-plant incorporated northern corn area plan? I see on the ROI calculator that 55-60% ESN is breakeven on cost, but the calculator shows better returns at lower percentages of ESN, give the 5 bushel of corn does not change.

-Typical yield increases with ESN over a similar application of a conventional N source in the northern Corn Belt would be in the range of about 8-15 bu/acre. The greater the potential for N loss, the greater the benefit. Under conditions of greater loss, yield increases of more than 20-25 bu/acre are common.

-Generally, our studies show that for pre-plant applications, using ESN for 75-100% of your N produces a greater yield increase than 50%.

-In some studies, 75% ESN produced yields similar to 100%, but in other studies, 100% was best. The yield benefit of using 50% is often about half that of using 75-100%. Many growers want some immediately available N blended with the ESN to give a little bit of an early boost. That said, we have conducted hundreds of university studies with 100% ESN with great results.

-In the example you used, if the assumption is a 5 bu/acre increase with 50% ESN, you would likely see a yield increase more like 10-15 bu/acre with 75-100% ESN. Depending on your fertilizer and corn prices, you should show a greater net return with the greater yield benefit, even though the cost for ESN is proportionately greater.

-A good estimation of the optimum pre-plant ESN percentage for many situations is about 75-80%. This should maximize your yield benefit and your profit.

To learn more about recommended ESN blends to maximize your profits, click here.

What advice can be given on application timing and placement of ESN in the Northern Corn Belt?

There are several ESN timing and placement options that work well on corn. There are many different combinations and applications that some growers use, however, the below suggestions represent the most common applications that have been widely tested in university studies.

-Apply ESN pre-plant for your entire N needs. In most situations, ESN can supply 100% of your nitrogen needs and need not be blended with other N sources, but many users are more comfortable blending ESN with a small amount of a soluble N source such as urea or ammonium sulfate. Since many growers are finding they need some sulfur, ammonium sulfate makes a great option. Recommended blend percentages are 70-90% of the total N as ESN for pre-plant Incorporation with a final tillage pass is preferred where possible but is not necessary for no-till plantings.

-Apply a small amount of N pre-plant – such as starter, N that comes from the P source, weed-and-feed, etc. Then top-dress the bulk of the N as a blend of ESN and urea or ammonium sulfate. Recommended blend percentage for this application is 50-80% of the N as ESN. The earlier this top-dress application occurs, the higher the percentage of ESN you should use. For very sandy soils where early season leaching potential is high, this application often performs better than all pre-plant.

To learn more about ESN application on corn, click here.

To learn more about ESN application on spring wheat, click here.

Have a question that you didn’t find here? Submit your questions here, or give us a shout on Twitter, @smartnitrogen. We look forward to hearing from you and answering your questions about ESN Smart Nitrogen.

Disclaimer: This information is not intended to be complete or detailed use recommendations for all geographies, crops, or applications. User assumes all responsibility for proper use and handling for specific geographies, crops, and applications. Please consult ESN recommendations and/or your Nutrien ESN representative for complete recommendations for use. Consult ESN recommendations for more information.

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