Since their first appearance, nanoscience and nanotechnology have focused on diverse materials science applications and more recently on agriculture as an emerging research area. New nanomaterials synthesis methods have been explored to reduce toxicological and chemical impact on the environment, such as through biosynthesis methods - using diverse bio sources of extracts as reductive and stabilizing agents, generating a sustainable synthesis. Although nanotechnology seems to be an approach for advanced agriculture, it is essential to know all nanomaterial action mechanisms, as these materials can be beneficial to specific organisms and detrimental to others. This book provides a comprehensive and scientifically robust exploration of the synthesis, characterization, and application of green synthesized nanomaterials in agriculture, framed within the principles of the circular economy. This book bridges the gap between nanotechnology and sustainable agricultural practices, offering insights into how green nanomaterials can enhance agricultural productivity while minimizing environmental impact. This book will serve as a key reference for researchers, practitioners, policymakers, and students in the fields of nanotechnology, agriculture, and environmental science. By providing a detailed and scientifically grounded examination of green synthesized nanomaterials, the book promotes sustainable agricultural practices that align with the principles of the circular economy.