Assessing environmental impacts of chemical fertilizers and organic fertilizers in Sri Lankan paddy fields through life cycle analysis

Abstract

The application of fertilizer is a very important activity in paddy cultivation as it is one of the yield-determining factors. But the use of chemical fertilizer is a matter of debate as it is suspected as a cause of many prevailing health problems and comparatively large amounts of environmental pollution. Therefore, the focus of this study was to carry out a proper life cycle analysis on the application of chemical and agricultural waste-based organic fertilizers considering all the important steps such as collection of raw material, manufacturing, transportation, and application fields. The integration application of chemical and organic fertilizers was considered with two different ratios. Characterized results reveal that chemical fertilizer application has the highest impact on all selected categories, while organic fertilizer application has lower impact.The combination of chemical and organic fertilizers shows that reducing the proportion of chemical fertilizers reduces environmental impacts. Additionally, the study identifies the processes that significantly contribute to each impact category, such as urea production for climate change and freshwater ecotoxicity, and composting and field application for human toxicity and terrestrial acidification. Normalized results show that switching to organic fertilizers could reduce up to 82.4% of the current environmental impact. Therefore, an integrated approach will give more benefits in many ways. These findings provide valuable insights for policymakers and farmers in making informed decisions regarding sustainable fertilizer management.