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 ESN is more efficient, can I reduce the amount of Nitrogen I apply?

ESN has been proven to increase N-use efficiency in many crops and environments.  Growers often ask if this means they can reduce overall N rates when using ESN.  University studies indicate when ESN is applied as recommended, a lower rate of ESN can indeed maintain crop yields similar to the normal recommended rate of conventional N sources.  However, profitability is usually greatest and risk lowest if ESN is used at the same rates as the grower’s conventional program.  The typical yield increase observed with recommended ESN applications is usually worth more than the savings achieved by reducing the N rate.  Each user should perform comparison profit calculations using their own costs and estimated ESN performance in their environment.  Contact your ESN representative for assistance in estimating these profit comparisons.  In some crops that may be sensitive to excess N supply, it may be beneficial to reduce the N rates somewhat with ESN to prevent loss of crop quality or yield from excess N.

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.

Is ESN recommended for use on all acres?

ESN is designed for soil and environments that are at risk for N-loss and where nitrogen is a limiting factor for growth. The added value of ESN may not be realized in soils that have other limiting factors such as compaction, drought, flooding, imbalance of other nutrients and excessively high or low pH. ESN does not correct existing problems in the soil other than the loss of N from traditional sources.  ESN may have some benefits not related to N loss that results from continuous feeding and controlled-release nitrogen supply.

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.

Must ESN be blended with other nitrogen fertilizers to work effectively?

In many situations, ESN need not be blended with other N sources.  ESN was designed to release N in approximate synchronization with the N demand of many crops.  It was designed to serve as a “stand-alone” N source in many situations.  Hundreds of studies on corn, potatoes, cotton and other summer crops or fall applications on winter cereals have proven excellent results using ESN to supply all the N needed in one application.  There are situations where ESN may be or should be blended with an immediately available N source, such as urea or ammonium sulfate, to meet immediate needs of a growing crop.  For example, if ESN is used for spring top-dress of winter wheat after wheat has broken dormancy, some immediately available N is recommended.  Or if top-dressing corn with ESN after about V6 growth stage, ESN should be blended with an immediately available N source to meet immediate N needs of the crop.  The greatest benefit of ESN usually occurs when using ESN for a majority of the N fertilizer needs.

See Use Recommendations for more information.

What happens if ESN freezes?

Freezing temperatures virtually stop release from ESN.  Diffusion of water into the ESN granule is stopped and, if some urea has already begun to dissolve, the release of urea solution through the coating also ceases.  If ESN has not yet hydrated – the urea has not yet begun to dissolve – the urea inside the coating will remain in the solid state until temperatures warm sufficiently for diffusion to begin again.  ESN granules do not rupture, burst, or disintegrate upon freezing and will persist for long periods intact in frozen conditions.  These properties make ESN a great alternative for fall applications in areas where soils are frozen during winter.

What is ESN?

ESN is a controlled release nitrogen fertilizer. It consists of a quality urea granule contained within a unique polymer coating. The analysis of ESN is 44-0-0.

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.

Will ESN work in no-till corn?

Yes. ESN performs very well in no-till corn. ESN granules come to rest under crop residue. The granules then begin to hydrate and in response to increasing temperature, will begin releasing N to the soil for crop uptake.