Organic agriculture addresses the public demand to diminish environmental pollution of agricultural production. Untilnow, however, only few studies tried to determine the integrated environmental impact of conventional versus organicproduction using life cycle assessment (LCA). The aim of this article was to review prospects and constraints of LCA as atool to assess the integrated environmental impact of conventional and organic animal production. This aim was illustratedusing results from LCAs in the literature and from a pilot study comparing conventional and organic milk production. Thisreview shows that LCAs of different case studies currently cannot be compared directly. Such a comparison requires furtherinternational standardisation of the LCA method. A within-case-study comparison of LCAs of conventional and organicproduction, however, appeared suitable to gain knowledge and to track down main differences in potential environmentalimpact. Acidification potential of milk production, for example, is for 78–97% due to volatilisation of ammonia, which is notreduced necessarily by changing from conventional to organic milk production. Eutrophication potential per tonne of milk orper ha of farmland was lower for organic than for conventional milk production due to lower fertiliser application rates.Global warming potential of milk production is for 48–65% due to emission of methane. Organic milk production inherentlyincreases methane emission and, therefore, can reduce global warming potential only by reducing emission of carbon dioxideand nitrous oxide considerably. Organic milk production reduces pesticide use, whereas it increases land use per tonne ofmilk. Conclusions regarding potential environmental impact of organic versus conventional milk production, however, arebased largely on comparison of experimental farms. To show differences in potential environmental impact among variousproduction systems, however, LCAs should be performed at a large number of practical farms for each production system ofinterest. Application of LCA on practical farms, however, requires in-depth research to understand underlying processes, andto predict, or measure, variation in emissions realised in practice.
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