COMPARISON AND EVALUATION OF RICE (ORYZA SATIVA L.) CROPPING SYSTEMS FOR SUSTAINABLE AGRICULTURE

In recent decades, the global agrifood system has increasingly faced variety of challenges, including climate change, soil degradation, loss of biodiversity, economic instability and the growing demand for food driven by population growth. Traditional agricultural practices adopted in rice (Oryza sativa L.) production, often characterised by intensive monoculture, heavy reliance on chemical inputs, and extensive resource use, have significantly contributed to these problems. The Paris Agreement aims to limit the global temperature increase to below 2°C above preindustrial levels, necessitating rapid decarbonisation across all economic sectors. The global food system alone accounts for nearly one-third of total global greenhouse gas (GHG) emissions and poses a risk to achieving the Paris Agreement’s targets (Crippa et al., 2021). In the European Union (EU), agriculture contributes 12 per cent of the total GHG emissions. It is a major driver of environmental issues such as biodiversity loss and eutrophication (Leip et al., 2015). In reply, the EU has introduced the European Green Deal (European Commission, 2019), a policy initiative that includes the Farm-to-Fork and Biodiversity strategies. Its key targets include achieving net-zero GHG emissions by 2050, reducing fertiliser inputs by 20 per cent, shifting 25 per cent of farmland to organic management, and planting three billion trees by 2030. However, the specific policy measures remain undefined and are left to individual Member States. Achieving these objectives requires a fundamental transformation in the production and consumption of agricultural goods. Agroecology (AE) represents an integrated approach that includes ecological and social principles into the design and management of food and agricultural systems (Barrios et al.,2020). Recognized as a potential practice to meet these goals under the common agricultural policy (CAP), AE is seen by scientists as a promising approach to addressing these challenges (Peeters et al., 2021). Local examples have demonstrated that AE can enhance various ecosystem services (Boeraeveet al., 2020). However, there is a lack of comprehensive evaluation to determine whether the outcomes observed at local levels are scalable. Moreover, research has yet to assess whether scaling AE to the territorial (i.e., EU) level might introduce new challenges, such as those arising from absolute thresholds in land use or nutrient availability from biological source. This thesis aims to apply the concepts of agroecology and sustainability to rice farming at various levels: the bibliographic level to determine what exists in the literature, the field level to test what was found in the bibliography, and finally, the farm level to evaluate the farming system in terms of sustainability and agroecology. For this, different research methods were used to retrieve data, information, and knowledge and to arrive at an integrated assessment of rice farming activities with the tools that the scientific field provides. All the chapters of the thesis are strictly connected. In fact, from the systematic review work, "organic" is the most recurring keyword in CO2 mitigation strategies. Additionally, among the techniques to be adopted for mitigation, "organic fertilisation" is among those that receive the highest scores. These very important results helped decide on the field trials. Specifically, for organic fertilisation, a consortium of nitrogen-fixing biostimulant bacteria was tested for two years as a more sustainable addition to traditional mineral fertilizations. The second field study concerns the world of organic rice, with seed replication and an in-depth review of allelopathic rice varieties, which, due to their potential ability to compete with significant weeds, could be a more sustainable varietal choice in the future. In the final chapter of this thesis, after analysing the sustainability of rice cultivation both in the literature and in the field, the study focuses on the farm level. This involved a multidisciplinary survey of four rice farms (two organic and two conventional), analysed through three different studies: Life Cycle Assessment - LCA (environmental impact study), OASIS (agroecological level study), and Gross Margin (economic study).