This book highlights the multifaceted role of diatoms in revolutionizing agricultural practices toward sustainability. The introductory chapter of Diatoms and Sustainable Agriculture examines the fundamental role of diatoms in fostering a circular economy within the agricultural sector, discussing the challenges and prospects associated with integrating diatoms into sustainable agricultural practices. Additionally, it reviews the potential of diatoms as natural plant growth promoters, elucidating the mechanisms through which these microorganisms enhance crop productivity while reducing reliance on synthetic fertilizers and pesticides. The chapter also covers the pivotal role of diatoms in agricultural watersheds, serving as indicators of ecosystem health and guiding strategies for maintaining river integrity. Furthermore, the book introduces the potential of diatoms for agricultural wastewater bioremediation and applications of diatom frustules as biosensors for the early detection of plant pathogens. The subsequent chapters explore the current status and future prospects of diatoms as insect control agents, highlighting their potential as environmentally friendly alternatives to conventional pesticides. Toward the end, the text delves into the intersection of artificial intelligence and diatom microalgae-based agriculture. This book serves as an important source for researchers and academicians in phycology, biotechnology, and agricultural sciences.