, Volume 114, Issue 1, pp 41-70

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Nitrogen–climate interactions in US agriculture

  • G. Philip RobertsonAffiliated withDepartment of Plant, Soil and Microbial Sciences, WK Kellogg Biological Station, and Great Lakes Bioenergy Research Center, Michigan State University Email author 
  • , Tom W. BruulsemaAffiliated withInternational Plant Nutrition Institute
  • , Ron J. GehlAffiliated withDepartment of Soil Science, NC State University
  • , David KanterAffiliated withWoodrow Wilson School of Public and International Affairs, Princeton University
  • , Denise L. MauzerallAffiliated withWoodrow Wilson School of Public and International Affairs, Princeton UniversityDepartment of Civil and Environmental Engineering, Princeton University
  • , C. Alan RotzAffiliated withPasture Systems and Watershed Management Research Unit, USDA-ARS
  • , Candiss O. WilliamsAffiliated withCharles E. Kellogg National Soil Survey Laboratory, USDA-NRCS


Agriculture in the United States (US) cycles large quantities of nitrogen (N) to produce food, fuel, and fiber and is a major source of excess reactive nitrogen (Nr) in the environment. Nitrogen lost from cropping systems and animal operations moves to waterways, groundwater, and the atmosphere. Changes in climate and climate variability may further affect the ability of agricultural systems to conserve N. The N that escapes affects climate directly through the emissions of nitrous oxide (N2O), and indirectly through the loss of nitrate (NO3 ), nitrogen oxides (NO x ) and ammonia to downstream and downwind ecosystems that then emit some of the N received as N2O and NO x . Emissions of NO x lead to the formation of tropospheric ozone, a greenhouse gas that can also harm crops directly. There are many opportunities to mitigate the impact of agricultural N on climate and the impact of climate on agricultural N. Some are available today; many need further research; and all await effective incentives to become adopted. Research needs can be grouped into four major categories: (1) an improved understanding of agricultural N cycle responses to changing climate; (2) a systems-level understanding of important crop and animal systems sufficient to identify key interactions and feedbacks; (3) the further development and testing of quantitative models capable of predicting N-climate interactions with confidence across a wide variety of crop-soil-climate combinations; and (4) socioecological research to better understand the incentives necessary to achieve meaningful deployment of realistic solutions.


Nitrate Nitrous oxide Ozone Greenhouse gases Mitigation Methane Fertilizer