Sustainable Balance of Human Activities and Environmental Conservation in Urban Ecosystems

In recent years, emission control, reuse, and recycling of wastes generated in large quantities have been important issues, especially in urban areas. High-quality plant production and thus quality food supplies will play an increasingly important role in human health and welfare. Developing low-cost technologies for efficiently controlling plant growth and food production is an important issue under consideration for environmental protection. To achieve these technologies, material cycling is necessary for sustainable food production. Therefore, the development of efficient plant production systems with less environmental loads must be promoted. I consider that ecosystems, including human activities in urban areas, are semi-closed and discuss the construction of plant production systems based on material circulation as well as the nutritional food supply within semi-closed ecosystems with plant production facilities such as plant factories. First, I introduce the concept of the circulation of materials in urban ecosystems as semi-closed systems. Next, as an application of resource recycling and energy conversion technology in agricultural production, I suggest a combined system with plant production and methane fermentation using organic waste from urban and agricultural areas. I also propose some items as examples of possibilities and perspectives of facility-based material circulation plant production systems with other organisms for a material-cycling-oriented society.