U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Main content area

Anhydrous Ammonia Injection Depth Does Not Affect Nitrous Oxide Emissions in a Silt Loam over Two Growing Seasons

Bijesh Maharjan, Rodney T. Venterea
Journal of environmental quality 2014 v.43 no.5 pp. 1527-1535
Zea mays, anhydrous ammonia, clay, clay soils, climatic factors, conventional tillage, crop yield, emissions, equipment, field experimentation, growing season, long term experiments, nitrogen fertilizers, nitrous oxide, no-tillage, reduced tillage, silt, silt loam soils, soil water content, Minnesota
Anhydrous ammonia (AA) is a major fertilizer source in North America that can promote greater emissions of nitrous oxide (NO) than other nitrogen (N) fertilizers. Previous studies found that injection of AA at a shallow depth (0.1 m) decreased NO in a rainfed clay loam but increased NO in an irrigated loamy sand compared with the standard injection depth of 0.2 m. The objective of this study was to evaluate the effects of AA injection depth in a silt loam soil used for corn (L.) production and managed under two contrasting tillage regimes over two consecutive growing seasons (2010 and 2011) in Minnesota. In contrast with previous studies, AA placement depth did not affect NO emissions in either tillage system or in either growing season. Tillage by itself affected NO emissions only in the drier of two seasons, during which NO emissions under no tillage (NT) exceeded those under conventional tillage (CT) by 55%. Soil moisture content under NT was also greater than under CT only in the drier of the two seasons. Effects of AA placement depth and long-term tillage regime on NO emissions exhibit intersite as well as interannual variation, which should be considered when developing NO mitigation strategies. Further study is needed to identify specific soil, climate, or other factors that mediate the contrasting responses to management practices across sites.