Life cycle assessment of energy consumption and CO_2 emission in nitrogen input for crop production: a study on resources consumption and environmental loading of organic waste recycling in agriculture

摘要

Resources consumption and environmental loading (eco-efficiency) of both High input type and Recycling type agriculture scenarios were preliminary examined, using Life Cycle Assessment (LCA) technique. The data collection and examination of life cycle energy and CO_2 emission at each stage, from the fertilizer production up to its use, were carried out to obtain the consumption and emission per unit nitrogen input for crop production. Based on the results of the case study, it was found that the CO_2 emission rate of the Recycling type is 3,373-4,183kg centre dot y~(-1)/ha lower than that of the High input type. On the other hand, quite different life cycle energy consumption levels for the Recycling type are found depending on the composting treatment methods employed. The life cycle energy varied from around 1.3CJ centre dot y~(-1)/ha to around 12.8GJ centre dot y~(-1)/ha, while the life cycle energy of the High input type which was estimated at around 2.TGJ centre dot y~(-1)/ha. Thus, the study results suggest that careful examination should be conducted before the introduction of the Recycling type agriculture to increase the eco-efficiency as a objectives for the regional planning.