Page Banner

United States Department of Agriculture

Agricultural Research Service

Research Project: INCREASING SUSTAINABILITY AND MITIGATING GREENHOUSE GAS EMISSIONS OF FOOD AND BIOFUEL PRODUCTION SYSTEMS OF THE UPPER MIDWEST U.S.

Location: Soil and Water Management Research

Title: Climate, duration, and N placement determine N2O emissions in reduced tillage systems: a meta-analysis

Authors
item Van Kessel, Chris -
item Venterea, Rodney
item Six, Johan -
item Adviento Borde, Arlene -
item Linquist, Bruce -
item Van Groenigen, Kees Jan -

Submitted to: Global Change Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 14, 2012
Publication Date: January 1, 2013
Repository URL: http://handle.nal.usda.gov/10113/57208
Citation: Van Kessel, C., Venterea, R.T., Six, J., Adviento Borde, A., Linquist, B., Van Groenigen, K. 2013. Climate, duration, and N placement determine N2O emissions in reduced tillage systems: a meta-analysis. Global Change Biology. 19(1)33-44.

Interpretive Summary: No-tillage management is being promoted in agro-ecosystems to reduce erosion and store carbon to reduce greenhouse gas emissions. The impact of no tillage on N2O emissions, however, has been variable with increases as well as decreases in emissions. Here we report on the short and long term impact of tillage operations on N2O emissions and grain yield. A meta-analysis was conducted on 239 direct comparisons between conventional tillage (CT) and no-tillage and reduced tillage (NT and RT) on yield and N2O emissions. Across all sites, NT or RT did not alter N2O emissions compared to CT. Across all climates, when NT and RT were implemented for more than 10 years, there was a reduction in N2O emissions. Under dry climatic conditions, the reduction in N2O after more than 10 years became highly significant compared to less than 10 years of NT and RT. No significant correlation was found between soil texture and N2O emissions. When fertilizer-N was placed at greater than 5 cm depth, NT and RT significantly reduced N2O emissions, in particular in a humid climate. Whereas NT and RT showed a significant decline in yield (4.7 %), the steepest decline in yield, 11.3 %, was observed under NT and RT in a dry climate. Compared to CT under dry climatic conditions, yield-scaled N2O increased significantly (57%) when NT and RT was implemented for more than 10 years but decreased significantly (27%) after less than 10 years of NT and RT. In conclusion, there was a significant decrease in N2O emissions, including yield-scaled N2O emissions, in a humid climate when the fertilizer-N was placed at more than 5 cm depth and NT and RT practices had been implemented for more than 10 years. Therefore, in humid climatic regions, placement of fertilizer-N at more than 5 cm depth and prolonged NT and RT practices is recommended as a mitigation strategy for reducing N2O emissions. These recommendations will be of interest to farmers and regulators interested in reducing greenhouse gas emissions.

Technical Abstract: No-tillage management is being promoted in agro-ecosystems to reduce erosion and sequester additional soil C. The impact of no tillage on N2O emissions, however, has been variable with increases as well as decreases in emissions. Here we report on the short and long term impact of tillage operations on N2O emissions and grain yield. A meta-analysis was conducted on 239 direct comparisons between conventional tillage (CT) and no-tillage and reduced tillage (NT and RT) on yield and N2O emissions. Across all sites, NT or RT did not alter N2O emissions compared to CT. Across all climates, when NT and RT were implemented for >10 years, there was a reduction in N2O emissions (P<0.1). Under dry climatic conditions, the reduction in N2O after > 10 years became highly significant compared to < 10 years of NT and RT (P <0.01). No significant correlation was found between soil texture and N2O emissions. When fertilizer-N was placed at =5 cm depth, NT and RT significantly reduced N2O emissions, in particular in a humid climate (P<0.01). Whereas NT and RT showed a significant decline in yield (4.7 %), the steepest decline in yield, 11.3 %, was observed under NT and RT in a dry climate. Compared to CT under dry climatic conditions, yield-scaled N2O increased significantly (57%) when NT and RT was implemented < 10 years but decreased significantly (27%) after >10 years of NT and RT. In conclusion, there was a significant decrease in N2O emissions, including yield-scaled N2O emissions, in a humid climate when the fertilizer-N was placed at = 5 cm depth and NT and RT practices had been implemented for > 10 years. Therefore in humid climatic regions, placement of fertilizer-N at > 5 cm depth and prolonged NT and RT practices is to be recommended as a mitigation strategy for reducing N2O emissions.

Last Modified: 8/29/2014