AgResearch is the host of the NZAGRC and is New Zealand's largest centre for pastoral agriculture research and development.

AgResearch includes teams of researchers with skills relevant to the Centre in rumen function, rumen microbiology, ruminant physiology, soil science, environmental science, agricultural systems management, forage plant growth and development, on-farm practice change, social science, technology uptake, genomics, proteomics and metabolomics of animals, plants and microorganisms.


Life Cycle Assessment - International comparisons

Life Cycle Assessment (LCA) is a tool to account for total greenhouse gas (GHG) emissions, including from energy use and the production of all inputs that go into farm systems, e.g. fertilisers, feeds. It is product focused and can cover a range of stages along a product life cycle including from extraction of raw materials used, through farm and processing stages, to transport, consumer and waste stages. This talk will cover comparison of the carbon footprint (total GHG emissions) of New Zealand milk, lamb and beef products in comparison with those produced overseas. It will focus on studies where valid comparisons are possible using the same methodology. It will also cover current international work on developing internationally-agreed methods through FAO and the European Commission - where New Zealand is playing a key role. Results from recent Product Environmental Footprinting work will be presented, which will include a range of other resource and environmental indicators as well as GHG emissions.

Stewart Ledgard is a Principal Scientist with AgResearch and an adjunct Professor in Life Cycle Management at Massey University. He has worked with agricultural sector and policy groups in the areas of life cycle management and greenhouse gases for over 10 years, and in nutrient management for over 30 years.

Stewart has worked with government and agricultural sector groups in determining and reducing the carbon footprint of agricultural products, and has linked research in use of Life Cycle Assessment (LCA) in agricultural systems in a range of countries internationally. NZ research in this area involved development of methodology for carbon footprinting of dairy, beef, lamb, wool and venison. This methodology was then applied across regional and national farm datasets and used to determine the effectiveness of potential reduction options. International research has included training of researchers and linked research in Australia, Chile, Uruguay, France and the United Kingdom. Stewart is a member of the operations group (representing AgResearch) in the NZ Life Cycle Management Centre, which included co-supervision of a PhD student.

Stewart led a Technical Advisory Group (TAG) of the Livestock Environmental Assessment and Performance (LEAP) partnership associated with the Food and Agriculture Organization (FAO) on developing Guidelines for estimating greenhouse gas emissions from small ruminant supply chains. He is currently co-chairing another LEAP TAG on nutrient accounting and environmental assessment across multiple livestock supply chains.
Stewart has also worked on nutrient management research, covering work on initial development of the OVERSEER® nutrient budget model, nitrogen mitigation on farms, and on developing and evaluating practical nitrogen mitigation options for farmers. He has also worked with NZ policy groups, including several Regional Councils on approaches for landholders to work within limits on nutrient losses from catchments to meet water quality targets.

Stewart has been active in publishing his research. This includes 8 book chapters, 116 scientific journal papers, 108 refereed scientific conference papers and over 350 other general publications and client reports.


Back to News