COMPARATIVE ENVIRONMENTAL LIFE CYCLE ASSESSMENT (LCA) OF ORGANIC AND CONVENTIONAL SUGARCANE GROWING IN QUEENSLAND

A COMPARISON of the environmental impacts of organic and conventional sugarcane growing in Queensland has been undertaken using environmental life cycle assessment (LCA). The aim of the assessment was to provide initial insight into the comparative environmental performance of organic and conventional cane growing as currently practised in Queensland. The assessment used primary data from cane farms in the Rocky Point and Mackay canegrowng areas that participated in a recent RIRDC-funded project to investigate the fledgling organic cane industry, data from cane production models, as well as simulated agronomic data from the APSIM crop modelling tool. This paper reports results for energy input, greenhouse gas emissions, acidification potential and eutrophication potential. The results show that, for the impact categories of energy input and greenhouse gas emissions, there is no significant difference between the two systems. The energy avoided by not using synthetic fertilisers and chemicals is offset by the more intensive use of machinery and the transport of low-density nutrient sources in organic systems. However, growing organic cane may provide greenhouse gas benefits if the expected lower levels of denitrification are taken into consideration. Organic growing can provide benefits in relation to water quality and eco-toxicity due to the elimination of inorganic fertilisers, herbicides, and pesticides. The lower yields currently being achieved from organic cane, due to conversion of the system, have a significant influence on the overall environmental burden per tonne of cane. However, if yields were to increase to levels comparable with conventional cane due to improvements in soil health and nutrient levels, this would improve the environmental performance of organic systems relative to conventional systems.