Identifying opportunities to reduce greenhouse gas emissions for climate change mitigation in grain production systems in North West NSW using Life Cycle Assessment (LCA) approaches.

Greenhouse gas emission profiles for wheat production in North West NSW were modelled using LCA methodology with development of inventory processes. Calculated emissions for 1 tonne of wheat were 153, 179 and 205 kg CO₂-e for crops grown after chickpea, canola and wheat, respectively. Major contributions to the emissions came from the manufacturing, transport and soil emissions of urea fertiliser at 75, 101 and 119 kg CO₂-e per tonne after chickpea, canola and wheat. Opportunities to reduce emissions primarily involve incorporating legumes into a rotation schedule to reduce use of synthetic N fertilisers. Split application of N-fertiliser may reduce emissions in the longer term where N fertiliser is only applied as in-crop rainfall allows. Economic benefits such as fertiliser cost savings and grain protein gains may occur by undertaking these changes. Greenhouse gas emission profiles will provide grain growers with information about emission sources and potentially increase sustainability and profitability.