Parameterisation for National Scale Modelling of Macronutrient Emissions to Water and Air

Globally, increases in emissions to atmosphere and water associated with the biogeochemical cycling of carbon, nitrogen and phosphorous are concerning. While the sources of these emissions are varied, agricultural and other primary production land uses have been identified as both major contributors to some emissions, and potential sinks. Specifically targeted solutions are being sought to reduce emissions and increase storage in these areas. LUCI (the Land Utilisation and Capability Indicator) is a GIS framework developed to consider the impacts of land use on various ecosystem services in a holistic and spatially explicit manner. It is designed to work at a variety of scales, from sub-field to catchment, using readily available national data that can be supplemented with local knowledge. Current tools available with the framework include flood mitigation, habitat connectivity, erosion and sediment delivery, agricultural productivity, carbon sequestration, and water quality. At present LUCI models emissions of N and P to water using an export coefficient approach linked to land use, land management and soils, and models emissions to air of carbon dioxide only; methane and nitrous oxide are not currently considered. This study aims to refine the representation in LUCI of N and P emissions to water and develop preliminary approaches for representing methane and nitrous oxide emissions to air. The ultimate aim is the provision of a set of model representations and associated parameters that can better represent emissions to air and water and suggest spatially explicit solutions that will not undermine, and may benefit, enterprise and/or community economic assets. The physical processes associated with emissions are being investigated and categorised based on land management, soil and climate regimes for two case study countries - Wales and New Zealand. Preliminary parameters, associated modelled results and potential future refinements are presented and discussed.