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(34-01) A method for the Life Cycle Impact Assessment of agricultural management on soil quality. Oberholzer, Hans-Rudolf1, Weisskopf, Peter1, Gaillard, Gérard*,1, 1 Swiss Federal Research Station for Agroecology and Agriculture (FAL), Zürich, Switzerland ABSTRACT- A method is proposed to assess the effects of agricultural management on soil quality in the context of life cycle assessment (LCA). The impact assessment is carried out by means of direct indicators, i.e. measurable physical, chemical and biological soil properties. The indicators were selected based on the following criteria: They ought to (a) have a direct reference to a soil function, (b) be influenced by management practices, (c) be interpretable according to a broadly accepted definition of soil fertility (d) be measurable by a reliable and recognised method and (e) be not reversible in the short term. Additionally, the use of several indicators with similar information content should be avoided. In a LCA on farm level, the actual state of soil quality could be determined with the suggested set of direct indicators including rooting depth of soil, macropore volume, aggregate stability, organic carbon content, content of copper, zinc, cadmium and of organic pollutants, biomass of earth worms, microbial biomass and activity of soil microorganisms. Since this expensive measurement of soil properties is in the most cases unattainable, the method was complemented to enable the impact assessment on soil quality on the basis of management practices such as crop rotation, amount and type of fertilizers, soil tillage and wheeling, used as indirect indicators and to be described at the inventory stage. The influence of indirect indicators on the direct indicators is estimated using expert knowledge and bibliographical references. The method describes the impact on soil quality as the result of medium-term influences of management practices, including slowly changeable soil properties as well as the consequences of regenerating processes. The feasibility and reliability of the method was tested for several farms. Key words: impact assessment, life-cycle assessment, soil quality, indicators |
