Comparing global warming potential, energy use and land use of organic, conventional and integrated winter wheat production
Tuomisto HL., Hodge ID., Riordan P., MacDonald DW.
To ensure a sustainable food supply for the growing population, the challenge is to find agricultural systems that can meet production requirements within environmental constraints and demands. This study compares the impacts of winter wheat production on energy use, land use and 100 years Global Warming Potential (GWP 100) under different arable farming systems and farming practices. Life cycle assessment was used to simulate the impacts of organic, conventional and integrated farming (IF) systems along the production chain from input production up to the farm gate. The IF system models were designed to combine the best practices from organic and conventional systems to reduce negative environmental impacts without significant yield reductions. An integrated system that used food waste digestate as a fertiliser, and utilised pesticides and no-tillage had the lowest energy use and GWP per functional unit of 1000 kg wheat output. When the impacts of some specific practices for reducing energy use and GWP were compared, the highest energy use reductions were achieved by replacing synthetic nitrogen fertilisers with anaerobically treated food waste or nitrogen fixing crops, increasing yields through crop breeding and using no-tillage instead of ploughing. The highest GWP reductions were achieved by using nitrification inhibitors, replacing synthetic nitrogen fertilisers and increasing yields. The major contributors to the uncertainty range of energy use were associated with machinery fuel use and the assumed crop yields. For GWP results, the main source of uncertainty related to the N 2O emissions. In conclusion, farming systems that combine the best practices from organic and conventional systems have potential to reduce negative environmental impacts while maintaining yield levels. © 2012 The Authors. Annals of Applied Biology © 2012 Association of Applied Biologists.