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- Fogelfors, Håkan, et al.
(författare)
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Selective pressure on Cirsium arvense (L.) Scop. and Sonchus arvensis L. growth characteristics on different types of farmland in Sweden
- 2009
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Ingår i: Acta Agriculturae Scandinavica, Section B - Soil and Plant Science. - : Informa UK Limited. - 0906-4710 .- 1651-1913. ; 59, s. 42-49
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Tidskriftsartikel (refereegranskat)abstract
- Changes in cropping systems during the past century have led to selective pressure on weed flora. Species and ecotypes with characteristics enabling them to survive in high-input farmland have increased in numbers, at the cost of plants lacking these characters. Since the 1950s, the perennial weed species Cirsium arvense (L.) Scop. and Sonchus arvensis L. have mainly been controlled by the herbicide group synthetic auxins like MCPA. During recent decades, C. arvense seems to have become less susceptible to MCPA in both Europe and North America but the reasons are unclear.To study the importance of selective pressure on weed ecotypes, both short- and long-term studies were carried out in Uppsala, Sweden. The first consisted of two growth-characteristic greenhouse experiments. The hypothesis was that ecotypes of C. arvense and S. arvensis from high-input farmland were different and displayed a more competitive growth pattern than did ecotypes from low-input farmland.The second study was a field experiment with four ecotypes of C. arvense from low-input farmland to study if selective pressure was in force, over a period of six years. The four ecotypes had different growth characteristics and herbicide sensitivity and they were exposed to crop competition and MCPA treatments during the experimental period. The hypothesis was that ecotypes with a more competitive growth pattern and MCPA tolerance would survive to a greater extent than would other ecotypes. For C. arvense, the results from the growth-characteristic experiment showed that the growth pattern of ecotypes from high-input farmland differed, showing a more directly elongated growth pattern with fewer spines on the leaves compared with ecotypes from low-input farmland, which usually were of rosette-type. Results from the field experiment with C. arvense showed that after six years MCPA-sensitive and/or rosette-type ecotypes had almost disappeared while ecotypes with a more directly elongated growth pattern and less sensitive to MCPA survived to a much greater extent. The conclusion was therefore that when exposed to selective pressure like crop competition and herbicide treatments, ecotypes of C. arvense with a more directly elongated growth pattern and less sensitive to herbicide treatment survived to a greater extent compared with ecotypes missing these traits. Ecotypes from high-input farmland had generally fewer leaf spines than did ecotypes from low-input farmland. This may suggest a trade-off between spine formation and rapid competitive growth. In the growth-characteristic experiment with S. arvensis, no differences between ecotypes from high- and low- input farmland regarding growth characteristics or leaf spines could be detected. This might partly be due to a lower exposure of S. arvensis to selective pressure compared with C. arvense, since S. arvensis generally is less sensitive to MCPA.
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| 2. |
- Fogelfors, Håkan, et al.
(författare)
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Strategic analysis of Swedish agriculture : production systems and agricultural landscapes in a time of change
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This strategic analysis of Swedish agriculture – production systems and agricultural landscapes in a time of change – focuses on climate change, future availability of natural resources and economic regulation in a global food market. The background to the project was that the Faculty of Natural Resources and Agriculture of the Swedish University of Agricultural Sciences identified an urgent need to explore the implications and opportunities of coming changes for agricultural production systems, arable land use and farm landscape functions in Sweden. Another objective was to determine the research needed to ensure that we are equipped to adapt to the coming changes. The analysis was carried out in the form of three literature reviews (Climate Change and Agricultural Land Use in Sweden: A Literature Review, (Eckersten et al., 2008a); Changes in the Global Natural Resource Base Relevant for Future Agriculture in Sweden – A Literature Review, (Johansson, 2008); and Economic Globalisation and Swedish Agriculture – Future Changes Affecting Swedish Agriculture from an Economic Perspective with Special Emphasis on Globalisation, (Holstein, 2008). It also comprised workshops and seminars and finally production of this synthesis report, which summarises the work done and suggests six research themes. Different IPCC emission scenarios describe pathways for those factors that are regarded as important for emissions of greenhouse gases (GHG), such as demography and social, economic and technological development. The projected global temperature increase varies from a little less than 2 °C up to 3.5-4.0 °C by the end of this century. Shrinking glaciers and rising sea levels are some of the consequences of the temperature increase. This climate change will have considerable consequences for agriculture, ecosystem function and human health on a global scale. The conditions for food production in Sweden are projected to become more favourable in terms of potential productivity as a result of future climate change. However, despite more favourable average cropping conditions, there could be drawbacks in the form of more frequent extreme weather events and, for example, more severe crop pathogen attacks and increased risks of nutrient leaching. The temperature increase is predicted to be greater during winter than during summer. Furthermore, precipitation will probably increase and the precipitation pattern will change. The temperature increase may lead to an extension of the growing season by several months in southern Sweden. Swedish agriculture is currently dependent on high inputs of external resources. The situation at present is that agricultural demands are increasing with regard to the natural resource base, e.g. ecosystem services and fossil fuels. The use of fossil fuels to sustain food production cannot continue indefinitely; agriculture world-wide must adopt mitigation strategies. One way is to search for self-sustaining, diversified, low-input, energy-efficient agricultural systems, using local renewable resources and ecosystem services. Another way to meet the challenges of future food supply and at the same time sustain life-support systems might be through intensive high-input agriculture on the 'best' land in order to save other areas for nature conservation. Swedish agriculture and food production are closely linked to the global food and feed market. Increased globalisation means that the profitability of Swedish farms is influenced to an increasing extent by actors on the global market. Conditions for Swedish agriculture in the past have been largely determined by political regulations, national and subsequently by CAP (Common Agricultural Policy in EU), but are gradually becoming more dependent on world market forces. Sweden has a comparative disadvantage in primary production compared with many other countries but the competitiveness of the Swedish food sector as a whole has increased during recent years due to increased exports of processed products. Another opportunity is to increase production of products with added value, e.g. organic products. However, the effects of globalisation on Swedish agriculture are hard to predict. Increased liberalisation will lead to increased competition, which will most probably lead to decreased production in Sweden. However, future changes in land productivity could potentially affect land use more than does the degree of liberalisation in trade. The conclusion that Swedish agriculture will decrease, at least in terms of land use, may very well turn out to be incorrect. This should be clear, not only from scenarios where climate change makes Swedish production more competitive but also from the latest developments on the world market where large increases in demand for agricultural products have been noted. This increase may have the consequence that land in less competitive countries will become sufficiently productive. Twelve climate scenarios for different regions in Sweden were developed within the FANAN project, from south-west Skåne in the south to Övertorneå in the north. Projections of future cropping systems under the new climatic conditions are described for three regions, south-west Skåne, Mälardalen district and the coast region of Västerbotten. There are diametrically opposed scenarios for future land use and appropriate design of agricultural production systems in the literature, which implies a need for a great variety of research. Research in adaptation as well as mitigation strategies will be important. Problems are interlinked and interdisciplinary research will probably be necessary to solve the complex problems concerning agriculture and the food supply of future populations. Six different strategic research themes are presented as a result of the FANAN project: 1.Future analyses of long-term sustainable land use, p.54. 2.Sustainable production systems — crop and animal sciences, p. 55. Cooling crops — crop-soil interactions Crop breeding — perennial cereals Domestic animal production Cultivation techniques 3.Ecosystem services in production systems of the agricultural landscape, p. 59. 4.From words to action, p. 60. 5.Monitoring of agricultural production, p. 62. 6.Multidisciplinary research network, p. 62. Large research programmes rather than small disciplinary projects will promote the solution of future complex problems. It will be necessary to combine empirical research with modelling and synthesis work in order to generate good science that is relevant to the challenges in sustainable agricultural management. FANAN concludes that SLU has a central role to play in developing these sustainable strategies
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