A scenario analysis of the organic material circulation through gardenization of residential vacant lots

Abstract

Vacant lots are increasing in suburban areas of Japan. Vacant lots, commonly regarded as a nuisance, may become places where urbanites can enjoy harvesting fresh vegetables and organic materials can be utilized as composts, if they are turned into allotment gardens. This study aims to discuss the feasibility of the organic material utilization in three scenarios wit h a different gardenization degree. First, experiments in producing composts were conducted to identify the composition of organic materials for producing usable compost, as well as the amount of compost required for gardenizing vacant lots. Second, the number of households that is needed to cooperate in providing organic materials in each scenario was analyzed. The study identified that the ratio of the weight of kitchen wastes and pruning wastes to produce usable compost was 3:2 and that at least the corporation of 16 families would be necessary to produce the enough amount of compost to gardenize the average size of a housing lot. As a consequence, it was estimated that the scenario which considers only existing gardens on vacant lot s was feasible for the organic material circulation, whilst the other two scenarios, which assumed more gardenization would happen, would need further understandings by urbanites.