4 Ways N Can Be Lost to Weather

Written by Dr. Tracy Blackmer
August 15, 2016

One of the reasons nitrogen (N) has been historically difficult to manage is because it’s easily lost to unpredictable weather conditions.


Here are 4 ways that nitrogen can be lost, and the role that weather conditions play in each scenario:

Nitrificationfinal-nitrification.png

A biological process where soil microorganisms convert N from the ammonium form to the nitrate form. This is important because most of the nitrogen the plant will take up will come in nitrate form with water uptake. Nitrification doesn’t mean yield loss, but it can lead to it; because N is extremely water-mobile, it can easily be lost to leaching and denitrification.

The role that weather plays:

Because nitrification is a biological process, it is influenced by soil temperatures. Generally speaking, soil temperatures above 50 degrees will have much faster nitrification conversions than cooler soil conditions.

 

LeachingLeaching1.png

Occurs after nitrogen has converted to nitrate; water carries the nitrate away from the root zone or below the roots.

The role that weather plays:

With above average rain, you should expect above average leaching in a field with good drainage. Leaching can not only move nitrates below the root zone but also away from the field through streams and tile lines.

 

DenitrificationDenitrification2.png

The biological process where soil microorganisms convert nitrate to a nitrogen gas which can easily be lost to the atmosphere. This occurs in anaerobic conditions and the microorganisms are using the oxygen from the NO3.

The role that weather plays:

Denitrification is more likely to occur in soils that are wetter, in soils that are not well drained, and when the soil temperature is above 50 degrees. Because denitrification happens on a microscopic scale, it does not take large areas of standing water for denitrification to occur, but only microscopic areas with anaerobic conditions.

 

VolatilizationVolatilization2.png

Occurs when N, most commonly in the form of animal manure or urea fertilizers, converts to ammonia gas and is lost to the atmosphere when applied to the soil surface.

The role that weather plays:

Volatilization can be triggered by warm, wet weather.

 

Unexpected rain could mean unexpected N loss.

Dr. Tracy Blackmer

Author

Dr. Tracy Blackmer Dr. Tracy Blackmer is an expert agronomist with over 20 years of experience incorporating precision agriculture technologies in agronomic management for growers. His work has included organizing a network of over 1,000 growers from 12 different states to conduct Nitrogen adaptive management using imagery, yield response, and other feedback assessments. Tracy also focuses on implementing large-scale, on-farm trials that are easy for growers to implement and result in improved agronomic recommendations. His work as the Vice President of Science at FarmLogs includes developing tools that improve local management for growers through better and simplified recommendations and monitoring.