For decades, chemical fertilizers have been used to boost agricultural crop yield. However, due to high procurement costs, environmental contamination, and the potential for land degradation from improper application, there is a current trend towards finding alternative solutions. The global demand for food that is both high-quality and produced sustainably, while preserving soil biodiversity, has led to a demand for premium organic ingredients. This can be achieved through utilizing organic waste in rural and urban areas by applying composting technology to produce organic fertilizers, thus reducing the use of harmful chemicals and protecting the environment. Bio-organic agriculture uses advanced biotechnologies, primarily relying on organic amendments such as nitrogen-fixing bacteria and humic substances, to produce crops. Therefore, utilizing bio-organic farming methods is a crucial step towards achieving agricultural sustainability. In this chapter, the authors highlight the benefits of four organic and biological amendments, including spent grain, vermicompost, PGPR, and humic substances, for enhancing soil fertility and health in different environmental conditions, ultimately promoting agricultural
sustainability.