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Life cycle assessment of Swiss farming systems: I. Integrated and organic farming

Thomas Nemecek David Dubois Olivier Huguenin-Elie Gérard Gaillard

Part II here

Abstract
Organic farming (OF) is considered a promising solution for reducing environmental burdens related to intensive agricultural management practices. The question arises whether OF really reduces the environmental impacts once lower yields and all the changes in farming methods are taken into consideration. This question is addressed in a comprehensive study of Swiss arable cropping and forage production systems comparing OF to integrated production (IP) systems by means of the life cycle assessment (LCA) method.

The LCA study investigated the environmental impacts of two long-term farming system experiments: the DOC experiment comparing bio-dynamic, bio-organic and conventional/integrated farming and the “Burgrain” experiment encompassing integrated intensive, integrated extensive and organic production. All treatments received similar amounts of farmyard manure. The system boundary encompasses the plant production system; storage and application of farmyard manure is included in the system boundary, the animal husbandry is not included. The Swiss Agricultural Life Cycle Assessment method (SALCA) was used to analyse the environmental impacts.

In the overall assessment OF was revealed to be either superior or similar to IP in environmental terms. OF has its main strengths in better resource conservation, since the farming system relies mainly on farm-internal resources and limits the input of external auxiliary materials. This results in less fossil and mineral resources being consumed. Moreover the greatly restricted use of pesticides makes it possible to markedly reduce ecotoxicity potentials on the one hand, and to achieve a higher biodiversity potential on the other. This overall positive assessment is not valid for all organic products: some products such as potatoes had higher environmental burdens than their counterparts from IP.

The main drawbacks identified for Swiss OF systems are lower yields. As a consequence some production factors are used less efficiently, thus partly negating the advantages of OF. Furthermore, the different manure management strategy leads to relatively high nutrient losses in relation to yield. These two points were shown to be the main priorities for the environmental optimisation of OF systems. The differences between the bio-organic and the bio-dynamic farming systems consisted in a slightly higher input of organic matter, a few applications of mineral fertilisers and copper applications in the former.

The eco-efficiency analysis led to the conclusion that the optimisation of OF is mainly output-driven, i.e. that higher yields of good quality should be achieved with the available (limited) resources. On the contrary, optimisation of IP was found to be input-driven; the inputs should be used in a quantity and manner which minimise the environmental burdens per unit produced. The study showed that despite the efforts of recent years, there is still considerable room for the environmental optimisation of Swiss farming systems.

Research highlights
► Organic farming had similar or lower environmental impacts than integrated production. ► Organic farming used less resources, except land. ► Organic farming had higher biodiversity potential and lower ecotoxicity. ► Weak points of organic farming: lower yields and nutrient losses.

Keywords
Integrated productionOrganic farmingLife cycle assessmentFarming systemsEnvironmental impacts

Life cycle assessment of Swiss farming systems: II. Extensive and intensive production

Abstract
Extensive or low-input farming is considered a way of remedying many problems associated with intensive farming practices. But do extensive farming systems really result in a clear reduction in environmental impacts, especially if their lower productivity is taken into account? This question is studied for Swiss arable cropping and forage production systems in a comprehensive life cycle assessment (LCA) study.

Three long-term experiments (DOC experiment comparing bio-dynamic, bio-organic and conventional farming, the “Burgrain” experiment including integrated intensive, integrated extensive and organic systems and the “Oberacker” experiment with conventional ploughing and no-till soil cultivation, are considered in the LCA study. Furthermore, model systems for arable crops and forage production for feeding livestock are investigated by using the Swiss Agricultural Life Cycle Assessment method (SALCA).

The analysis covers an overall extensification of cropping systems and forage production on the one hand and a partial extensification of fertiliser use, plant protection and soil cultivation on the other. The overall extensification of an intensively managed system reduced environmental impacts in general, both per area unit and per product unit. In arable cropping systems medium production intensity gave the best results for the environment, and the intensity should not fall below the environmental optimum in order to avoid a deterioration of eco-efficiency. In grassland systems, on the contrary, a combination of both intensively and extensively managed plots was preferable to medium intensity practices on the whole area. The differences in yield, production intensity and environmental impact were much more pronounced in grassland than in arable cropping systems.

Partial extensification of a farming system should be conceived in the context of the whole system in order to be successful. For example, the extensification solely of fertiliser use and soil cultivation resulted in a general improvement in the environmental performance of the farming system, whereas a reduction in plant protection intensity by banning certain pesticide categories reduced negative impacts on ecotoxicity and biodiversity only, while increasing other burdens such as global warming, ozone formation, eutrophication and acidification per product unit. The replacement of mineral fertilisers by farmyard manure as a special form of extensification reduced resource use and improved soil quality, while slightly increasing nutrient losses.

These results show that a considerable environmental improvement potential exists in Swiss farming systems and that a detailed eco-efficiency analysis could help to target a further reduction in their environmental impacts.

Research highlights
► Overall extensification of intensive farming systems reduced environmental impacts.
► In arable crops a medium intensity was optimal.
► A combination of intensively and extensively managed forage plots was preferable.
► Environmental impacts were reduced in the no-till system and by lower fertilisation.