| 1. |
- Darnhofer, Ika, et al.
(författare)
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Adaptiveness to enhance the sustainability of farming systems : A review
- 2010
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Ingår i: Agronomy for Sustainable Development. - : Springer. - 1774-0746 .- 1773-0155. ; 30, s. 545-555
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Tidskriftsartikel (refereegranskat)abstract
- During the last decade the context in which farmers must manage their farm has changed rapidly, and often with little warning. Dramatic price swings for agricultural commodities, more stringent quality requirements, new environmental regulations, the debates surrounding genetically modified crops, extreme climatic events, the demand for energy crops, the revision of the Common Agricultural Policy and the consequences of the financial crisis all create uncertainty regarding future threats and potentials. During such turbulent times, a one-sided focus on efficient production is no longer enough. Farmers also need to be able to cope with unexpected events and to adapt to new developments. Based on a literature review, we identify three strategies that strengthen the adaptive capacity of a farm: learning through experimenting and monitoring its outcomes, ensuring a flexible farm organisation to increase the options for new activities by the farm family, and diversifying to spread risks and create buffers. Implementing these strategies enlarges the farmer's room to manoeuvre and allows identifying transition options. These options do not depend only on the farm itself, but also on the farmer's ability to mobilise external resources and to engage in collective action. Change is then no longer seen as a disturbance, but as a trigger for the reorganisation of resources, and for the renewal of the farm organisation and activities. Implementing these strategies comes at a cost, so that farmers need to tackle the inevitable trade-offs between efficiency and adaptability. However, unless farmers master this challenge they cannot ensure the sustainability of their farms.
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| 2. |
- Engström, Lena, et al.
(författare)
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Reducing nitrate leaching after winter oilseed rape and peas in mild and cold winters
- 2011
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Ingår i: Agronomy for Sustainable Development. - : Springer Science and Business Media LLC. - 1774-0746 .- 1773-0155. ; 31, s. 337-347
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Tidskriftsartikel (refereegranskat)abstract
- Nitrate leaching after winter oilseed rape and peas has not been studied at the most northern limits of oilseed rape cultivation where winters vary between being mild, with continuous drainage, and cold, with periods of frozen soil. Here, we studied the effect of N fertilisation to oilseed rape, catch crops after oilseed rape and peas and dired drilling of winter wheat after oilseed rape on N leaching in south-west Sweden. Nitrate leaching was determined in two field experiments, dated 2004-2006 and 2005-2007, respectively, on a sandy loam. Our results show that under oilseed rape nitrate leaching was low, at 16-23 kg N ha(-1), in a mild winter with drainage from October to March. In the subsequent mild winter nitrate leaching under wheat was higher, amounting to 35-94 kg N ha(-1). Nitrate leaching levels were similar, 32-58 kg N ha(-1), for all crops in a cold winter with a long-lasting snow cover and main drainage occurring after snowmelt in March and April. Application of fertiliser N to oilseed rape at the optimum N rate, rather than 50 kg N ha(-1) above optimum, reduced leaching in a following winter wheat crop by 25 and 27 kg N ha(-1) in a cold and a mild winter, respectively. Spring undersowing of perennial ryegrass as a catch crop reduced leaching by 12 kg N ha(-1) after optimally fertilised oilseed rape in a mild winter, despite only growing until mid-September when winter wheat was sown. An undersown catch crop of peas, then grown until November, reduced leaching by 15 kg N ha(-1). Direct drilling of winter wheat after oilseed rape had no effect. These findings show that there are risks of enhanced leaching in early spring after a cold winter with a snow cover and superficially frozen soil. Optimising the spring N rate for oilseed rape was the most effective measure to decrease leaching in both mild and cold winters, and this effect was improved by an undersown catch crop in a mild winter.
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| 3. |
- Friberg, Hanna
(författare)
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Survival of Fusarium graminearum, the causal agent of Fusarium head blight. A review
- 2013
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Ingår i: Agronomy for Sustainable Development. - : Springer Science and Business Media LLC. - 1774-0746 .- 1773-0155. ; 33, s. 97-111
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Tidskriftsartikel (refereegranskat)abstract
- Wheat is one of the most cultivated crops worldwide. In 2010, 20 % of wheat and durum wheat were cultivated in Europe, 17 % in China and 9 % in Russia and in North America. Wheat yield can be highly decreased by several factors. In particular Fusarium graminearum Schwabe is a worldwide fungal pest impacting wheat production. F. graminearum is the causal agent of Fusarium head blight, root and stem-base rot of cereals. Losses caused by Fusarium head blight in Northern and Central America from 1998 to 2002 reached $2.7 billion. Moreover, F. graminearum produces mycotoxins which affect human and animal health. The threshold of these mycotoxins in foodstuffs is regulated in Europe since 2007. F. graminearum survives for several years saprotrophically in the soil, on dead organic matter, particularly on crop residues. F. graminearum adapts to a wide range of environmental variations, and produces extracellular enzymes allowing feeding on different crop residues. However, F. graminearum competes with other decomposers such as other Fusarium spp. belonging to the same complex of species. Actually, it is not known whether F. graminearum mycotoxins give F. graminearum a competitive advantage during the saprotrophic period. Anthropogenic factors including preceding crops, tillage system and weed management can alter the development of the soil biota, which in turn can change the saprotrophic development of F. graminearum and disease risk. We review the ecological requirements of F. graminearum saprotrophic persistence. The major conclusions are: (1) temperature, water, light and O-2 are key conditions for F. graminearum growth and the development of its sexual reproduction structures on crop residues, although the fungus can resist for a long time under extreme conditions. (2) F. graminearum survival is enhanced by high quantities of available crop residues and by rich residues, while sexual reproduction structures occur on poor residues. (3) F. graminearum is a poor competitor over time for residues decomposition. F. graminearum survival can be controlled by the enhancement of the decomposition processes by other organisms. In addition, the development of F. graminearum on crop residues can be limited by antagonistic fungi and soil animals growing at the expense of F. graminearum-infested residues. (4) Agricultural practices are key factors for the control of F. graminearum survival. A suitable crop rotation and an inversive tillage can limit the risk of Fusarium head blight development.
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| 4. |
- Jensen, Erik Steen
(författare)
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Legumes for mitigation of climate change and the provision of feedstock for biofuels and biorefineries. A review
- 2012
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Ingår i: Agronomy for Sustainable Development. - : Springer Science and Business Media LLC. - 1774-0746 .- 1773-0155. ; 32, s. 329-364
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Forskningsöversikt (refereegranskat)abstract
- Elevated rates of N2O losses can occur following the termination of legume-based pastures, or where legumes had been green- or brown-manured and there was a rapid build-up of high concentrations of nitrate in soil. Legume crops and legume-based pastures use 35% to 60% less fossil energy than N-fertilized cereals or grasslands, and the inclusion of legumes in cropping sequences reduced the average annual energy usage over a rotation by 12% to 34%. The reduced energy use was primarily due to the removal of the need to apply N fertilizer and the subsequently lower N fertilizer requirements for crops grown following legumes. Life cycle energy balances of legume-based rotations were also assisted by a lower use of agrichemicals for crop protection as diversification of cropping sequences reduce the incidence of cereal pathogens and pests and assisted weed control, although it was noted that differences in fossil energy use between legumes and N-fertilized systems were greatly diminished if energy use was expressed per unit of biomass or grain produced. For a change in land use to result in a net increase C sequestration in soil, the inputs of C remaining in plant residues need to exceed the CO2 respired by soil microbes during the decomposition of plant residues or soil organic C, and the C lost through wind or water erosion. The net N-balance of the system was a key driver of changes in soil C stocks in many environments, and data collected from pasture, cropping, and agroforestry systems all indicated that legumes played a pivotal role in providing the additional organic N required to encourage the accumulation of soil C at rates greater than can be achieved by cereals or grasses even when they were supplied with N fertilizer. Legumes contain a range of compounds, which could be refined to produce raw industrial materials currently manufactured from petroleum-based sources, pharmaceuticals, surfactants, or food additives as valuable by-products if legume biomass was to be used to generate biodiesel, bioethanol, biojet A1 fuel, or biogas. The attraction of using leguminous material feedstock is that they do not need the inputs of N fertilizer that would otherwise be necessary to support the production of high grain yields or large amounts of plant biomass since it is the high fossil energy use in the synthesis, transport, and application of N fertilizers that often negates much of the net C benefits of many other bioenergy sources. The use of legume biomass for biorefineries needs careful thought as there will be significant trade-offs with the current role of legumes in contributing to the organic fertility of soils. Agricultural systems will require novel management and plant breeding solutions to provide the range of options that will be required to mitigate climate change. Given their array of ecosystem services and their ability to reduce greenhouse gas emissions, lower the use of fossil energy, accelerate rates of C sequestration in soil, and provide a valuable source of feedstock for biorefineries, legumes should be considered as important components in the development of future agroecosystems.
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| 5. |
- Komakech, Allan, et al.
(författare)
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Maps of animal urban agriculture in Kampala City
- 2014
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Ingår i: Agronomy for Sustainable Development. - : Springer Science and Business Media LLC. - 1774-0746 .- 1773-0155. ; 34, s. 493-500
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Tidskriftsartikel (refereegranskat)abstract
- Animal urban agriculture has a vital role to feed the ever-growing population of African cities. However, there is a lack of knowledge on animal farming, animal feed and manure recycling in cities. Here, we mapped animal farms in Kampala City. We determined the number and type of animals kept. We identified animal feeds and the manure management practices. The results show that animal farms are predominantly located on the periphery of the city. Poultry are the dominant animal species in the city, followed by pigs, cattle, goats and sheep. The most common feedstuffs are fruit and vegetable peel and pasture. Sixty percent of the animal manure is discarded, whereas 32 % is recycled as fertiliser. Therefore, the fertiliser potential of manure is underutilised.
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| 6. |
- Åkerfeldt, Magdalena, et al.
(författare)
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Low nutritive quality of own-mixed chicken rations in Kampala City, Uganda
- 2014
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Ingår i: Agronomy for Sustainable Development. - : Springer Science and Business Media LLC. - 1774-0746 .- 1773-0155. ; 34, s. 921-926
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Tidskriftsartikel (refereegranskat)abstract
- Chicken production is popular in Kampala City, Uganda. Indeed about 70 % of all poultry products consumed in Kampala are produced locally. However, the high cost of feed is a major limiting factor. As a consequence, chicken farmers are formulating and mixing their own feeds. However, these own-mixed feeds may not meet recommended nutrient levels. We therefore studied five classes of own-mixed chicken feeds: broiler starter, broiler finisher, chick mash, grower mash, and layer mash. Samples of the chicken feeds were collected from farmers in and around Kampala City. We analyzed crude protein, ether extract, crude fiber, total starch, ash, calcium, phosphorus, and gross energy contents of the feeds. The apparent metabolizable energy content was calculated. We compared data with dietary requirements recommended for chickens in the tropics. Results show that own-mixed rations contained 21.9-36.3 % less protein than minimum recommendations. Broiler rations contained 16.2-20 % less metabolizable energy than minimum recommendations, and their crude fiber content was 37.5-50 % higher than the maximum recommendation. Layer mash contained 66.7 % less calcium and 17.5 % less metabolizable energy than minimum recommendations. All the five classes of own-mixed chicken rations were very high in ash content, ranging from 17.0 to 21.2 %. We conclude that own-mixed chicken rations do not conform to the dietary recommendations. There is therefore a need to give chicken farmers training on feed formulation and mixing.
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