Increased food and feed trade necessitates considering effective management of food by-product and animal waste. Waste resource management is essential to decrease negative environmental impacts of waste products such as animal waste from intensive dairy farms, which depend on imported feed grains and hay, and unutilized by-products of imported agricultural food. It is also important in reducing the negative impacts caused by artificial fertilizer application. In addition, waste resources can be used for making compost that can replace soil disinfectant and the replacement reduces environmental toxicity. Therefore, utilization of multi-functional compost has the potential to be effective resource and disease management. This study investigates the environmental impacts of multi-functional compost made from dairy animal waste and activated bleaching earth used in the manufacture of edible oil.

Comparative life cycle assessment (LCA) was used in this study, which was carried out in an area in Mie Prefecture, Japan. Multi-functional compost made using a vertical airtight compost machine was compared with conventional compost prepared in an open stirrer; it can be effective in preventing plant diseases caused by soil fungi (Fusarium). Furthermore, LCA of greenhouse tomato production was conducted to assess the post-application effects of the compost. The background data for the assessment of compost were accumulated by interviewing the machine manufacturer and the authority in the cooking-oil company. The data available on the JLCA database and ecoinvent 2.0 were also used. The information compiled for agricultural extension services was used for evaluating post-application effect of the compost.

The results indicate that lesser amounts of greenhouse and acidification gases are directly emitted during the production of multi-functional compost than during the production of conventional compost. However, greenhouse gas emissions from the production process of the vertical airtight compost machine were greater than that of the open stirrer. Moreover, distinct differences were observed between the post-application effects of the two types of compost. We believe that the use of multi-functional compost would alleviate the negative environmental impacts of artificial fertilizers and pesticides. The results imply that the development of multi-functional agricultural inputs is a practical method for establishing sustainable agricultural systems.