Strategies for measuring flows of reactive nitrogen at the landscape scale

Within a rural landscape there are flows of reactive nitrogen (Nr) through and between the soil, vegetation, atmosphere and hydrological systems as well as transfer as a result of agricultural activities. Measurements of these flows and transfers have generally been limited to individual media (e.g., hydrological flows) or the interface between two media (e.g., exchange between the soil and the atmosphere). However, the study of flows of Nr at the landscape scale requires a more integrated approach that combines measurement techniques to quantify the flows from one medium to the next. This paper discusses the design of an experiment carried out in the NitroEurope IP to characterise the Nr flows in six contrasting European rural landscapes during a period of 1-2 years. The focus is on characterisation as it is not possible to measure all Nr Methods/Approach flows at all locations and, therefore, the measurements provide indicators of flows (including high and low flows), which can be used to characterise landscape conditions and serve as a basis for testing of landscape scale nitrogen models.