This book highlights the significance of urban agricultural production, the technologies and methods for supplying organic materials to the farmland, recovering plant nutrients and energy in cities, and systems for sustaining farmlands in order to produce agricultural crops and supply safe food to citizens. Focusing on the effective recycling of biomass waste generated in cities for use in organic farming, it discusses alternatives to traditional composting, such as carbonizing organic waste, which not only produces recyclable materials but also converts organic waste into energy. Recycling discarded organic matter appropriately and reusing it as both material and energy is the basis of new urban organic farming, and represents a major challenge for the next generation of urban agriculture. As such, the book presents advanced research findings to facilitate the implementation of safe, organic agricultural production with only a small environmental load.