Sustainability within agriculture is a very complex issue with numerous interconnections within the production system. Besides the sustainability aspects generally discussed; ecological, social end economic, agriculture also involves ethical issues related to animal husbandry. Sustainability is also a matter of values, what can be considered most important in a sustainable system is value based. Scenarios call be of several different types. The main feature with scenario analyses is that they encompass future systems, but there are several approaches on how these futures should be designed. In this study we have worked with a forecasting scenario technique. Thereafter the systems needed to fulfil these states are described. The aim was to develop a method that would incorporate scientific knowledge and practical experiences in the scenarios. This should be done in a way that enabled traceability through the process. This paper presents a methodology for working with scenarios for future agricultural production systems. It starts with identifying all relevant sustainability goals for the system (within all four fields of sustainability, ecological, economic, social and animal welfare) and describing them in a measurable way. Thereafter one scenario is designed for every single sustainability parameter (e.g. energy use, nitrogen losses). The next step is to group the sustainability goal according to some common idea of values. The scenarios based on every goal belonging to the same group are then combined into one scenario, generating one scenario for each group. The scenarios call then be evaluated economically, environmental and from an animal welfare point of view. The method has been used oil pig production and dairy production. It offers a structured way of synthesising large amount of research into something comprehensible and practically understandable that call be used as a platform for further discussions about sustainable agriculture.

Today there is a strong trend in Sweden for industrially processed meals to replace homemade meals. In the public debate this is often claimed to increase the environmental impact from foods. In the study presented in this article, we used life-cycle assessment to quantify the environmental impact of three meals: homemade, semiprepared, and ready-to-eat. The differences in environmental impact between the meals were small; the ready-to-eat meal used the most energy, whereas the homemade meal had higher emissions causing eutrophication and global warming. The dominating contributor to the environmental impact was agriculture, accounting for 30%, of the impact related to energy and 95% of that related to eutrophication. Industry, packaging, and consumer home transport and food preparation also contributed significantly. Important factors were raw material use, energy efficiency in industry and households, packaging, and residue treatment. To decrease the overall environmental impact of food consumption, improvements in agriculture are very important, together with raw-material use within industry and households.

Abstract To study future, sustainable production systems, a step-wise method was used to create three future scenarios for pig production based on different sustainability goals. The first scenario focused on animal welfare and the natural behavior of the animals. The second targeted low impacts on the environment and the efficient use of natural resources. The third scenario aimed at product quality and safety. Each scenario fulfilled different aspects of sustainability, but there were goal conflicts because no scenario fulfilled all sustainability goals. The scenarios were then parameterized. The environmental impact was calculated using the life-cycle assessment (LCA) methodology, and the economic cost was calculated from the same data set. The cost per kilo of pork was highest for the animal welfare scenario and similar for the other two scenarios. The environmental scenario had the lowest environmental impact, and the product-quality scenario the highest. The results are discussed based on different future priorities.

Abstract In order to assess the ecological sustainability of agricultural production systems, there is a need for effective tools. We describe an environmental systems analysis tool called SALSA (Systems Analysis for Sustainable Agriculture). It consists of substance/material flow models in which the simulation results are interpreted with life-cycle assessment methodology. The application of SALSA is demonstrated in a case study in which three different ways of producing pigs are compared with respect to energy input and the environmental impacts of global warming, eutrophication, and acidification. The scenario that combined a low-protein diet without soy meal with an improved manure-management technique with low nitrogen losses was the best for all impact categories studied. The strength of the SALSA models was their capacity to capture consequences of management options that had an influence on several processes on a farm, which enabled the type of complex studies we describe.

A simulation model, ORWARE (ORganic WAste REsearch), for the handling of organic waste in urban areas has been constructed. The model provides a comprehensive view of the environmental effects, plant nutrient utilisation and energy turnover for this large and complex system. The ORWARE model consists of several sub-models; sewage plant, incineration, landfill, compost, anaerobic digestion, truck transport, transport by sewers, residue transport and spreading of residues on arable land. The model is intended for simulating different scenarios, and the results are: emissions to air and water, energy turnover and the amount of residues returned to arable land. All results are presented, both as the gross figure for the entire system and figures for each process. Throughout the model all physical flows are described by the same variable vector, consisting of 43 substances. This extensive vector facilitates a thorough analysis of the results, but involves some difficulties in acquiring relevant data. In this paper, the model is described. Results from a hypothetical case study are presented in a companion paper.

A leader cable guidance system for a 9 m span experimental gantry running on crawler tracks has been designed and evaluated, both theoretically and practically. The system is described and the theory behind the control of this machine explained. Field trials have shown that the path of the experimental gantry is consistent over repeated passes under automatic control to ±60 mm. These results confirm the predictions of a computer model which shows that further improvements could be made at modest cost. The use of straight line automatic guidance and control of a commercial field gantry is discussed and economic aspects considered. It is concluded that such a system can be economically viable for intensive field vegetable production.