The impact of rice cultivation methods on environmental sustainability using life cycle assessment and cumulative exergy demand

Rice or Paddy cultivation has a significant impact on the environment, especially concerning water usage and greenhouse gas emissions. In this study, a life cycle assessment (LCA) and cumulative exergy demand (CExD) analysis were carried out to compare the environmental effects of paddy cultivation under various scenarios. The ReCiPe2016 method was utilized to evaluate three different impact categories. Specifically, for the Hashemi variety, the resource impact category for conventional and mechanized methods was 162.82 and 182.25 USD2013, respectively. For the Khazar variety, the resource impact category for conventional and mechanized methods was 112.49 and 126.19 USD2013, respectively. The ecosystem category showed the lowest environmental emissions. It was found that electricity was the primary contributor, accounting for over 40% of the environmental emissions across all damage categories. The CExD method identified seven types of energy, with non-renewable fossil energy showing significant values in both conventional and mechanized cultivation of the Hashemi variety (21666.32 and 24537.68 MJ ton–1) as well as for the Khazar variety (14938.53 and 16847.06 MJ ton–1). Mechanized cultivation of the Khazar variety exhibited a notable energy output of 1498.68 MJ ton–1 of renewable biomass energy. By conducting a thorough comparison using LCA and CExD, it becomes possible to pinpoint the most sustainable practices for paddy cultivation, considering the full scope of environmental impacts and resource consumption. This valuable information can guide decision-making and facilitate the development of more sustainable agricultural practices.