Energy and greenhouse gas emissions of Australian cotton: from field to fabric

Abstract

Australian cotton production has seen vast changes in the past two decades, in both its on-farm and off-farm activities. The resource inputs include both the direct and indirect inputs. A Life Cycle Assessment (LCA) has been carried out in this project to evaluate the energy usage and greenhouse gas emissions of cotton production from field to fabric, which is from the real beginning i.e. tillage up to export shipping. It is found that on-farm indirect cotton-farming is the most energy consuming component (63%), consuming some 32.36 GJ/ha of energy. It is also found to be the most greenhouse gas emitting component (57%), emitting some 1.64 tonne of CO2/ha. This research also shows that on-farm direct stage uses 14.07 GJ/ha of energy and emits 0.78 tonne of CO2/ha. Energy use and the emissions by the off-farm direct section are calculated as 5.09 GJ/ha and 0.14 tonne CO2/ha respectively. Energy consumed by the off-farm indirect farming section is found to be 0.036 GJ/ha or 0.002 tonne CO2/ha. The total energy usage and greenhouse gas emissions in the Australian cotton farming system are estimated to be 46.43 GJ/ha and 2.42 tonnes CO2/ha for on-farm, 5.13 GJ/ha and 0.145 tonne CO2/ha for the off-farm sections. In total (after including the 300 kgCO2/ha soil emission caused by nitrogen based fertilisers), 51.57 GJ/ha of energy is used and 2.86 tonnes CO2/ha is emitted by a typical Australian cotton farming system from field to fabric.