Methods and metrics for the assessment of nutrient use efficiency of livestock supply chains

PhD project by Aimable Uwizeye. The intensive use of nutrients, such as nitrogen (N) and phosphorus (P), in agriculture has contributed to an increase of crop and animal production around the world. At present, the management of nutrient use in farming systems is an important issue to ensure agricultural sustainability. This requires defining nutrient use efficiency from a chain perspective.

Most of the gains in global food and feed production have been achieved through the increased use of the major nutrients nitrogen (N) and phosphorus (P). The N and P losses to air and water bodies could lead to environmental impacts such as eutrophication, global warming and acidification. So far no study has assessed the nutrient use efficiency (NUE) along the global livestock supply chain (LSC) using a life cycle approach. This research project will address this gap through the development of methods and metrics to assess NUE of regional and global livestock supply chains; the outputs will support the identification of management options to minimize nutrient losses along the chains. The project includes a definition of NUE from a life-cycle perspective, an identification of which data is needed for a representative assessment, the evaluation of NUE in contrasting livestock production systems (e.g. species and production intensities) and geo-climatic environments, and finally the evaluation of environmental risks associated with nutrient pressures, pathways and responses in different regions.
Results of this project will feed into the Livestock Environmental Assessment and Performance (LEAP) Partnership, with the aim of supporting the development of common NUE metrics. LEAP aims to develop harmonized indicators and methods for the assessment of the environmental performance of livestock supply systems. It promotes an exchange of information and technical expertise between the private sectors, governmental and non-governmental organizations towards improving and harmonizing the way in which livestock food chains are assessed and monitored.