Frequently Asked Questions

The following 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 of 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.

If nitrogen in ESN releases as urea, does it volatilize in the same way as urea when left on the surface?

No.  ESN protects against volatilization even more effectively than urease inhibitors and for a longer time.  Urea released from ESN is less susceptible to volatilization because only a small amount is released at a time, which maintains a lower urea concentration and prevents the temporary rise in pH around the fertilizer granule that is responsible for causing ammonia volatilization. 

How deeply do I need to incorporate ESN?

In many areas where intermittent precipitation or dew is present at somewhat regular intervals, no incorporation may be necessary.   In areas of limited rainfall, such as dryland cropping systems in arid and semi-arid areas, some light incorporation is highly recommended.  ESN need not be deeply incorporated as with a moldboard plow, but typically a harrow or sometimes even broadcast ahead of the seeder provides sufficient incorporation into the soil surface to provide good contact with the soil. 

Does ESN need to be soil incorporated to work effectively?

No. Research and grower experience show that ESN works very well when surface applied in many geographies where intermittent moisture or even heavy dew is present.  Many users have had great results top-dressing winter wheat and no-till corn.  To maintain a more predictable N release rate, it is advisable to incorporate ESN where possible.  Surface application without incorporation is generally not recommended in semi-arid and arid areas without irrigation.  When surface applied to very dry soil, ESN granules have difficulty absorbing water and may be slow to release nitrogen. Some moisture is required to initiate and maintain that process. In arid and semi-arid areas without irrigation, incorporation is recommended.

Is ESN release controlled by soil moisture?

ESN release is controlled by soil temperature.  Some moisture is needed to initiate the diffusion process and continue dissolving the urea inside the coating, but temperature controls the rate of the process.

Will ESN work if the soil is very dry?

ESN will continue to release in very dry soil.  Laboratory studies have demonstrated that soil moisture does not slow the ESN diffusion process and N release until soil moisture dries to about 20-30% of field capacity (near the permanent wilting point). At this point, the release can slow or, at even lower soil moisture content, even cease.  Very dry conditions for an extended time may inhibit the release of N from ESN if it is left on the dry soil surface, but the process will recommence when moisture is present again.   But even in very dry soils, ESN can continue to release N if it is in good contact with the soil.  Some studies have shown there may be benefits to using ESN to control vegetative growth in very dry conditions and thereby reduce moisture stress.

See the canola moisture stress fact sheet for more information.

How does ESN’s coating control nitrogen release?

ESN’s coating encapsulates a soluble nitrogen fertilizer.  The coating forms a protective barrier that acts as a semi-permeable membrane surrounding the fertilizer granule.  Tiny, molecular-size pores in the polymer coating allow water to enter the granule slowly.  The water dissolves the soluble fertilizer which then diffuses, or oozes, out thru the coating into the soil.  The rate of the process is controlled by soil temperature.  ESN’s coating remains intact through the release process maintaining the protective barrier and controlling N supply to the crop.  ESN does not release N by swelling, rupture, or “breakdown” of the coating. 

Does ESN release N thru coating failures or fractures?

ESN’s primary release mechanism is by diffusion thru tiny, molecular-size pores in the polymer coating.  A few granules may contain tiny flaws from the coating process, or may be damaged by normal handling processes.  These granules release N quickly on contact with water.  While a small portion of the N in ESN may be released quickly thru these imperfections, the primary release mechanism is by diffusion thru intact coatings.   Sulfur-coated urea, an older technology, does release N through fractures or degradation of the sulfur coating. 

Does the ESN coating “breakdown” or come off in water or soil?

No.  ESN’s coating remains intact during the process of N release.  It does not dissolve in contact with water or breakdown or come off over the course of the growing season.  Once N has released from ESN, the coating will eventually decompose by soil organisms in about 18-24 months. 

How long does it take for ESN to “breakdown”? How long do ESN coatings persist in the soil?

ESN’s coating is a biodegradable polymer that decomposes in about 18-24 months in soils.  The end products of ESN decomposition are carbon dioxide, ammonia, and water. However, this “breakdown” is not the mechanism of N release.  The term “breakdown” is an incorrect description of the ESN release process.  ESN’s primary release mechanism is by diffusion thru tiny, molecular-size pores in the polymer coating.