Options to model the effects of tillage on N2O emissions at the global scale

Strategies on agricultural management can help to reduce global greenhouse gas (GHG) emissions. However, the potential of agricultural management to reduce GHG emissions at the global scale is unclear. Global ecosystem models often lack sufficient detail in their representation of management, such as tillage. This paper explores whether and how tillage can be incorporated in global ecosystem models for the analysis of nitrous oxide (N2O) emissions. We identify the most important nitrogen processes in soils and their response to tillage. We review how these processes and tillage effects are described in field-scale models and evaluate whether they can be incorporated in the global-scale models while considering the data requirements for a global application. The most important processes are described in field-scale models and the basic data requirements can be met at the global scale. We therefore conclude that there is potential to incorporate tillage in global ecosystem models for the analysis of N2O emissions. There are several options for how the relevant processes can be incorporated into global ecosystem models, so that generally there is potential to study the effects of tillage on N2O emissions globally. Given the many interactions with other processes, modelers need to identify the modelling approaches that are consistent with their modelling framework and test these.