| 1. |
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| 2. |
- Jönsson, Håkan, et al.
(author)
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Återvinn fler näringsämnen än fosfor i avloppsvatten
- 2012
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In: Dagens nyheter. - 1101-2447. ; ?, s. 6-
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Other publication (pop. science, debate, etc.)abstract
- För att minska utsläppen av växthusgaser bör vi återvinna fler växtnäringsämnen ur avloppsslammet. Regeringens ensidiga fokus på fosfor i detta avseende riskerar att skada det långsiktiga miljöarbetet. Vi vill skärpa miljömålen och inkludera även ämnen som kväve, kalium och svavel, skriver professorer och forskare från SLU.
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| 3. |
- Liu, Jian, et al.
(author)
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Biomass production and phosphorus retention by catch crops on clayey soils in southern and central Sweden
- 2015
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In: Field Crops Research. - : Elsevier BV. - 0378-4290 .- 1872-6852. ; 171, s. 130-137
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Journal article (peer-reviewed)abstract
- Catch crops are a potential option to reduce phosphorus (P) losses, but little is known about their establishment success and capacity to retain P on clayey soils in regions with short autumns, e.g. Sweden. This study screened biomass production and P retention by eight catch crop species: the perennials chicory (Cichorium intybus L), cocksfoot (Dactylis glomerata L), perennial ryegrass (Lolium perenne L.) and red clover (Trifolium pratense L) and the annuals phacelia (Phacelia tanacetifolia L), white mustard (Sinapis alba L), oilseed radish (Raphanus sativus L oleiformis) and white radish (R. longipinnatus). The catch crops were grown at six field sites, where the perennial species were under-sown with barley and the annual species were after-sown following barley harvest. Biomass production, P content in above-ground and below-ground plant parts and content of available P in the soil were determined in autumn and survival rate of the catch crops in the following spring. Biomass production and P retention in autumn both differed significantly between species (p < 0.0001), and were greatly affected by site-specific conditions and time of sowing, which differed between experiments. Growth of catch crops can also be suppressed by low precipitation. Content of P in roots varied substantially between species, a factor which must be considered in species comparisons. The under-sown species produced more or equivalent amounts of biomass, retained more or equivalent amounts of P in autumn and survived better over winter than the after-sown species. Thus under-sown catch crops generally seem more suitable as catch crops for P. (C) 2014 Elsevier B.V. All rights reserved.
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| 4. |
- Liu, Jian, et al.
(author)
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Freezing-thawing effects on phosphorus leaching from catch crops
- 2014
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In: Nutrient cycling in agroecosystems. - : Springer Science and Business Media LLC. - 1385-1314 .- 1573-0867. ; 99, s. 17-30
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Journal article (peer-reviewed)abstract
- It is suggested that catch crops can be grown to reduce phosphorus (P) losses. However, after exposure to freezing-thawing cycles (FTCs), catch crop material can become a source of P losses to waters in moderately cold climates. This study screened potential P leaching from intact plant material of eight catch crop species: chicory (Chichorium intybus L.), cocksfoot (Dactylis glomerata L.), perennial ryegrass (Lolium perenne L.), red clover (Trifolium pratense L.), phacelia (Phacelia tanacetifolia L.), white mustard (Sinapis alba L.), oilseed radish (Raphanus sativus L. oleiformis), and white radish (R. longipinnatus). The catch crops were grown in six field experiments on clay soils, where soil lysimeters (0.25 m deep) with intact crops were extracted in autumn and after used for leaching experiments before and after seven FTCs in the laboratory. The eight catch crops did not reduce P leaching before FTCs. After FTCs, leachate total-P concentration from ryegrass, oilseed radish and red clover lysimeters were significantly (p=0.0022) higher than those from the other species and the control without a catch crop. FTCS significantly (p= 0.0064) altered total-P concentration and the proportions of different forms of P. There was a significant increase in total-P concentration in leachate from ryegrass (p=0.0008) and oilseed radish (p= 0.02). Thus, the potential risk of P leaching from ryegrass and oilseed radish material after FTCs must ne considered, since they are commonly grown as nitrogen catch crops in the Nordic countries. Morever, the roots of the tested catch crops contained 7-86 % total-P, which is important when ealuating O leaching risks.
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| 5. |
- Tidåker, Pernilla, et al.
(author)
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Estimating the environmental footprint of barley with improved nitrogen uptake efficiency—a Swedish scenario study
- 2016
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In: European Journal of Agronomy. - : Elsevier BV. - 1161-0301 .- 1873-7331. ; 80, s. 45-54
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Journal article (peer-reviewed)abstract
- Plant breeding is a powerful tool for improving nitrogen (N) uptake efficiency and thus reducing the environmental impact relating to crop production. This study evaluated the environmental impact of current barley production systems in two Swedish agricultural areas (South and East) compared with scenarios with improved N uptake efficiency at two levels, in which the fraction of mineral N available for daily crop uptake was increased by 50 and 100%. Life cycle assessment (LCA) methodology was used to quantify energy use, global warming potential (GWP) and acidification and eutrophication potentials along the production chain for spring barley with differing N uptake efficiency, but similar N application rate. The functional unit, to which all energy use and emissions were related, was 1 Mg barley grain. Energy use, GWP and acidification proved to be higher for the East production system, mainly due to lower yield, while eutrophication was higher for South. The two impacts most affected by improved N uptake efficiency were eutrophication and GWP, with GWP decreasing due to a combination of higher yield, soil carbon sequestration and lower indirect emissions of N2O due to lower N leaching. Accounting for land savings due to increased yield, reducing the pressure to transform land elsewhere, would further lower the carbon footprint. Potential eutrophication per Mg grain was reduced by 15% in the production system with the highest N uptake efficiency in southern Sweden. Crops with improved N uptake efficiency can thus be an important complementary measure for reducing N losses to water, provided that the N application rate does not increase. However, incentives for farmers to maintain or even lower the N application rate might be required. Using simulation modelling is a promising approach for assessment of expected effects of improved crop varieties when no long-term experimental data are available. However, advanced crop models are required to better reflect the effect of plant breeding on e.g. expected yield. Future model development should involve expertise in plant breeding, plant physiology and dynamic crop and soil modelling.
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| 6. |
- Tidåker, Pernilla, et al.
(author)
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Rotational grass/clover as energy crop in a cereal cropping system – a life cycle perspective
- 2014
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In: Agricultural Systems. - : Elsevier BV. - 0308-521X .- 1873-2267. ; 129, s. 133-141
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Journal article (peer-reviewed)abstract
- Rotational perennial grass/clover has multiple effects in cropping systems dominated by cereals. This study evaluated the environmental impact of rotational grass/clover ley for anaerobic digestion in a cereal-dominated grain production system in Sweden. Life cycle assessment (LCA) methodology was used to compare two scenarios: (i) a cropping system including only spring barley and winter wheat; and (ii) a cropping system including 2-year grass/clover ley in combination with spring barley and winter wheat. The functional unit was one tonne of grain. The two main functions of the grass/clover crop were to provide feedstock for biogas production and to act as an organic fertiliser for allocation among the cereal crops in the rotation. Special consideration was given to nitrogen (N) management and the rotational effects of the grass/clover ley. In total, 73% of the N requirement of cereals in the ley scenario was met through symbiotic N fixation. Replacing diesel with biogas and mineral fertiliser with digested grass/clover biomass (digestate) reduced the use of fossil fuels substantially, from 1480 MJ per tonne in the reference scenario to -2900 MJ per tonne in the ley scenario. Potential eutrophication per tonne grain increased in the ley scenario, mainly owing to significantly higher ammonia emissions from spreading digestate and the larger area required for producing the same amount of grain. Potential acidification also increased when N mineral fertiliser was replaced by digestate. Crops relying on symbiotic N fixation are a promising feedstock for reducing the use of non-renewable energy in the production chain of farm-based bioenergy, but careful handling of the N-rich digestate is required. Replacing cereals intended for feed or food with bioenergy crops leads to indirect land use changes (iLUC) when the displaced crops must be produced elsewhere and the benefits obtained when biofuels replace fossil fuels may thereby be outweighed. In this study, the iLUC factor assumed had a critical effect on global warming potential in the ley scenario. However, carbon sequestration and the higher yield potential of subsequent cereal crops can mitigate greenhouse gas emissions from iLUC to a varying extent. We recommend that crop sequences rather than single crops be considered when evaluating the environmental impact of production systems that include perennial legumes for food, feed and bioenergy. (C) 2014 Elsevier Ltd. All rights reserved.
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| 7. |
- Bergkvist, Göran, et al.
(author)
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Odlingsmaterialet
- 2014
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In: Rapporter från Jordbearbetningsavdelningen, Sveriges lantbruksuniversitet. ; , s. 26-42
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Book chapter (other academic/artistic)
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| 8. |
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| 9. |
- Andersson, Annica, et al.
(author)
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Stråsäd
- 2015
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In: Vår Mat : odling av åker- och trädgårdsgrödor : biologi förutsättningar och historia. ; , s. 266-298
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Book chapter (other academic/artistic)
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| 10. |
- Aronsson, Helena, et al.
(author)
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Combining mechanical control of couch grass (Elymus repens L.) with reduced tillage in early autumn and cover crops to decrease nitrogen and phosphorus leaching
- 2015
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In: Nutrient Cycling in Agroecosystems. - : Kluwer Academic Publishers. - 1385-1314 .- 1573-0867. ; 102:3, s. 383-396
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Journal article (peer-reviewed)abstract
- Methods for control of couch grass (Elymus repens L.) with reduced tillage and cover crops to achieve low risk of nitrogen (N) and phosphorus (P) leaching were investigated. Treatments with reduced post-harvest tillage (one or two passes with duckfoot cultivator), hoeing between rows in combination with a cover crop, and a cover crop mown twice during autumn were compared with treatments with conventional disc cultivation and the control without tillage or cover crop. The study was conducted on a sandy soil in Sweden with measurements of N and P leaching. A 2-year experimental protocol was used, repeated twice. Treatments were implemented in the first year, and effects on couch grass (shoot density, shoot and rhizome biomass) were measured during autumn and in the second year. Significant effects of a single duckfoot cultivation and cover crop strategies were observed on couch grass shoot density in autumn but persistent effects were not verified. In conclusion, a single cultivation after harvest instead of repeated reduced the risk of N leaching and a cover crop in combination with hoeing or mowing effectively reduced it. Repeated cultivations resulted in mean annual N leaching of 26 kg N ha−1 compared with 20 kg in the treatment with one cultivation, 17 kg in the control, 16 and 12 kg in cover crop treatments with mowing and hoeing, respectively. The P leaching was small (0.04–0.09 P ha−1 year−1), but there were indications of increased P drainage water concentrations in the treatment with a cover crop which was mown. © 2015, The Author(s).
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