Nitrogen Loss Pathways – Which is Yours?

This article is about

  • Right Source
  • Right Rate
  • Right Time
  • Right Place

The well-known poem by Robert Frost, “The Road Not Taken”, kindles our imagination about the richness of life gained by taking the less traveled paths. While it may seem a far reach, this “less traveled path” metaphor also pertains to you and the N nutrition of your plants; whether you are a professional turf or crop manager, or a hobby horticulturalist.

Greater fertilizer N costs and knowledge of the environmental impacts of N losses are driving us all toward better N stewardship. Weather, or the lack of its control, hinders us from perfect N management. But weather variability should not prevent us from striving for lower losses down the “more traveled N loss pathways”.   

The nitrate leaching and drainage N loss pathway is probably the “more traveled” in humid, higher rainfall environments (>25 to 30 in./yr). Nitrate losses under annual crop systems may range between 10 and 40 lbs of N/A/yr in higher rainfall environments. Nitrate losses under deep-rooted perennial crops are often lower. If rainfall, irrigation (>1/2 in. within a few days after application), or tillage do not soil incorporate surface-applied urea or urea-containing N fertilizers within a few days after application, ammonia volatilization (gaseous loss as ammonia) may range from 20 to 40% of the N applied, and rival N losses from leaching and drainage. Recent research has shown that such ammonia volatilization losses can also occur if urea is applied on snowpack or wet soil surfaces in colder environments.N-cycle

Gaseous loss of N from soils as nitrous oxide (a potent greenhouse gas affecting climate change), through nitrification and denitrification processes, is often <2 to 8 lbs of N/A in humid regions and may be <1 to 2 lbs/A in less humid regions (e.g. west of the Mississippi River). While this N loss is globally important, it may have small economic significance to the majority of individual landowners and crop producers.  Loss of N2 during denitrification, especially in wet fine-textured soils with poor internal drainage, is a more prominent N loss compared to nitrous oxide.

From an economic vantage point, the focus for most of us should be on the “more traveled N loss pathway” in our own particular plant and soil system. That means taking management action to reduce the risks of loss via nitrate leaching/drainage or ammonia volatilization. To start, we need to better understand the characteristics, properties and best management practices for the N fertilizers we may choose among.

Consider visiting the Nutrient Source Specifics articles available on-line at and talk with your nutrient supplier, crop adviser, or agricultural professional to learn more about the N fertilizers available for your use. Identify ways to prevent N loss down the “more traveled loss pathways”, and get more in your plants. Your bottom-line will improve and our water and air resources will be better protected. Dare to venture beyond your past boundaries, and choose the “less traveled pathway” toward higher N use efficiency this year!


Dr. Cliff Snyder, "Nitrogen Loss Pathways - Which is Yours"
Plant Nutrition Today - Spring 2012, No. 6;