Organic production systems : sustainability assessment of rice in Italy

Even though organic practices are getting more and more widespread, there is scant of information on their environmental impacts. A comprehensive approach is needed in order to take into account, on the one hand, the lower amount of inputs normally used (e.g. pesticides) in organic systems and, on the other hand, the lower yield they usually imply. The aim of this study is to assess the environmental profile of organic rice cultivation in a farm located in Pavia district (Lombardy). To this purpose, a Life Cycle Assessment methodology, with a cradle-to-field gate perspective, was applied. Inventory data were collected in a rice farm located in Lomellina where organic rice has been cultivated over about 70ha in the past 15 years. The environmental profile of organic rice was analysed in terms of 11 different impact categories: climate change (CC), ozone depletion (OD), particulate matter (PM), human toxicity (HT), Photochemical ozone formation (POF), terrestrial acidification (TA), terrestrial eutrophication (TE), freshwater eutrophication (FE), marine eutrophication (ME), freshwater ecotoxicity (FEx), and mineral and fossil resource depletion (MFRD). The results suggest that the main environmental hotspots for organic rice are: the emissions of methane from the flooded fields, the production of compost, the nitrogen emissions associated with the application of fertiliser and the mechanisation of the field operations. Finally, different mitigation strategies have been proposed and investigated. Among these strategies, the substitution of organic compost with cattle manure appears to bring the greatest benefits in 9 out of 11 impact categories. Such benefits range from approximately 13% up to 51%, depending on the impact categories considered. The introduction of aerations during the cultivation period can reduce only climate change (about 9%) but increase all the other environmental effects.