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Microsource Minute

Volatilization: Part 2

 

Ammonia (NH3) volatilization is influenced by many factors including soil moisture, temperature, pH, buffering capacity, urease activity, residue cover, precipitation, and wind. It can be time and cost prohibitive to manage these effects. However, reducing the risk can be less complicated with an understanding of how quickly volatilization occurs.

Two Sides of the Story

The first story that we have been taught is cumulative volatilization loss (blue curve) from surface applied nitrogen can reach as high as 50% over time. That risk has been proven by universities and independent research alike.  The other side of this issue is generally not discussed.  That is, most of the ammonia volatilization loss occurs in the first 10 days (red curve) after application.  The graphic below illustrates two different curves, cumulative and daily loss, derived from the same trial data.  

Ammonia Volatilization Loss

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Nitrogen Rate: 120 lbs N/ac equivalent surface applied

Key Points    

  • Urea (daily):  Untreated urea experienced 95% of  loss by Day 10

  • Urea + NBPT (daily):  Urea treated with NBPT significantly reduced ammonia loss

  • Urea (cumulative):  The curve flattens beyond 10 days. The cumulative loss from Day 10-27 is less than 1%.

Evaluating the daily loss story provides another angle to mitigate volatilization losses.  The best return on your surface applied nitrogen investment will be earned if protected for the first 10 days.

Reducing the Risk

The 4R framework is always a great concept to properly manage fertilizer applications.  Placing your nitrogen below the soil surface (Right Place), is one way to eliminate volatilization losses.  Urease inhibitors (NBPT) are a great tool to protect your nitrogen investment and increase flexibility for timing of application.  NBPT works by inhibiting the activity of the urease enzyme, slowing hydrolysis thus minimizing the risk of ammonia volatilization. The effectiveness of NBPT is well known in the industry, but there are mixed marketing messages on how long the nitrogen needs protected.  It’s clear from our studies that beyond 10 days, volatilization losses are minimal.

Start With the Right Source

  • Work with a reputable supplier who looks after your best interests

  • Be wary of new products and technologies that want to extend your volatility protection

  • Why pay a premium for a timeframe when risk is minimal?

  • MicroSource is dedicated to offering the right product, at the right rate, to protect against the period of greatest risk

Author: Ethan Enochs

 
 
Ethan Enochs