An examination of LCA method in evaluating measures to reduce environmental loads discharged in the process of agricultural nutrient input: An approach to application of life cycle assessment(LCA) for sustainable agriculture

This paper estimates energy consumption (LC-energy) and C02 (LC-C02) emissions produced throughout the life cycle for each scenario of alternative to reduce environmental loads discharged from rural area (2397ha) in the process of agricultural nutrient input.Four scenarios are formulated for the examination as possible environmental measures regarding the agricultural nutrient input, i.e.Alternation of Cultivation Period for Leveling the Amount of Fertilizer Input (Senario-1), Reduction of ilization (Senario-2), Application of Controlled Release Fertilizer (Senario-3) and Utilization of Agro-by-product Compost (Senario-4).Nitrogen discharge from the area of each scenario is simulated using Nitrogen Flow and Runoff Model. Lowest nitrogen discharge, which is around 85% (239t/yr**-1) of that at present situation, is estimated under the conditions of enario-3. Other hand, LC-energy figures on 1960ha of farm lands are 37.5TJ/yr**-1 (19.2GJ/ha**-1/yr**-1) under present farm practice, 32.3TJ/yr**-1 (16.5 GJ/ha**-1/yr**-1) of lowest estimation for Senario-2 and 38.7TJ/yr**-1 (19.8G.J/ha**-1/yr**-1) of highest figure for Senario-3. LC-CO2 figures which take an amount of carbon in agro-by-products into account ar**-13705t-C02/yr**-1 (7.0t-C02/ha**-1/yr**-1) under present farm practice, 7910t-CO2/yr**-1 (4.0t-C02/ha**-1/yr**-1)of lowest figure for Senario-4 and 13824 t-CO2/yr**-1 (7.1t-C02/ha**-1/yr**-1) of highest figure for Senario-3.Thus, Scenario-3 are considered to be worst environmental measure among the scenarios from the LC-energy and LC-CO2 points of view, although Scenario-3 is more effective to reduce the nitrogen harge from the area. These results indicate that multilateral evaluation should be considered to select more suitable environmental measures in the process of agricultural nutrient input and an approach of LCA-thinking might be useful to evaluate the eco-efficiency of the agricultural activities.