Nitrous oxide production from soils in the future: Processes, controls and responses to climate change

Authors: ZHU-BARKER, XIA - University Of California; Steenwerth, Kerri

Submitted to: Recent Research Developments in Soil Science
Publication Type: Book / Chapter
Publication Acceptance Date: 10/1/2017
Publication Date: 1/31/2018
Citation: Zhu-Barker, X., Steenwerth, K.L. 2018. Nitrous oxide production from soils in the future: Processes, controls and responses to climate change. Recent Research Developments in Soil Science. 35:131-183. doi: 10.1016/B978-0-444-63865-6.00006-5.
DOI: https://doi.org/10.1016/B978-0-444-63865-6.00006-5

Interpretive Summary: This chapter summarizes known pathways that contribute to soil N2O emissions, describes the factors that control these pathways, highlights how land management practices influence soil N2O emissions by inducing changes in these factors, and emphasizes the response of soil N2O emission to climate change and potential mitigation practices. With a focus on soil N2O production pathways and their controls, this chapter has outlined the role of commonly used practices on soil N2O emissions, such as fertilization, irrigation, tillage, cover cropping, and organic amendments. Future climate change is expected to affect soil N2O emissions, and the development of land management practices to reduce emissions is necessary to abate further climate change. Important insights with respect to previously unanticipated pathways and mechanisms of soil N2O production have expanded the horizons of researchers and stimulated recent efforts to develop new methods for quantifying these pathways, but critical challenges remain. For example, N2O production processes such as nitrifier denitrification and DNRA remain difficult to quantify, and the mechanisms behind these pathways are still unknown. The variability and heterogeneity of N2O production pathways and their complex relationship with soil conditions also limits the extent to which well-constrained estimates can be made relevant to climate change issues.

Technical Abstract: The increasing abundance of the greenhouse gas nitrous oxide (N2O) in the atmosphere is a global concern. Although it is well known that soils are a major source of atmospheric N2O, elucidation of the complexity of the underlying microbial and chemical production processes and the roles of biotic and abiotic factors is still needed. Land management practices, especially nitrogen (N) fertilization in agroecosystems, are important determinants of soil N2O production and its consequent contribution to climate change. Here, we summarize the known N2O production pathways that contribute to soil N2O production and the factors that control these pathways, highlight the importance of land management practices in controlling soil N2O production, and discuss management strategies to reduce soil N2O emissions. We also address the roles of climate change itself and adopted strategies to mitigate climate change on soil N2O emissions. Although management practices have been identified to reduce soil N2O emissions, understanding of how these management practices act in combination and whether they lead to additive or multiplicative reductions in N2O remains limited. Examination of the underlying mechanisms of soil N cycling and N2O production and collection of empirical data across multiple management practices and soil landscapes under conditions that reflect a changing climate will facilitate model development and identification of effective N2O mitigation strategies.