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| 2. |
- Björck, Lennart, et al.
(författare)
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Tveksam vinst med ekolantbruk
- 2009
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Ingår i: Svenska dagbladet. - 1101-2412. ; -
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 3. |
- Eklind, Ylva, et al.
(författare)
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Carbon Turnover and Ammonia Emissions during Composting of Biowaste at Different Temperatures
- 2007
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Ingår i: Journal of Environmental Quality. - : Wiley. - 0047-2425 .- 1537-2537. ; 36:5, s. 1512-1520
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Tidskriftsartikel (refereegranskat)abstract
- The effects of different process temperatures (40, 55, and 67°C) during composting of source-separated household waste were studied in a 200 L compost reactor at an oxygen concentration of 16%. The overall decomposition measured as carbon mineralization, decomposition of different carbon constituents, and the dynamics of nitrogen mineralization and the microbial community, are reported. Ammonia emissions at 67°C were more than double those at lower temperatures, and they were lowest at 40°C. The decomposition rate, measured as CO2 emission, was highest at 55°C. Decomposition of crude fat was slower at 40°C than at 55 and 67°C. The peak in microbial biomass was largest in the run at 40°C, where substantial differences were seen in the microbial community structure and succession compared to thermophilic temperatures. Biowaste composting can be optimized to obtain both a high decomposition rate and low ammonia emissions by controlling the process at about 55°C in the initial, high-rate stage. To reduce ammonia emissions it seems worthwhile to reduce the temperature after an initial high-temperature stage.
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| 4. |
- Kirchmann, Holger, et al.
(författare)
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Trace element concentration in wheat grain: results from the Swedish long-term soil fertility experiments and national monitoring program
- 2009
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Ingår i: Environmental Geochemistry and Health. - : Springer Science and Business Media LLC. - 0269-4042 .- 1573-2983. ; 31, s. 561-571
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Tidskriftsartikel (refereegranskat)abstract
- Concentrations of trace elements in wheat grain sampled between 1967 and 2003 from the Swedish long-term soil fertility experiments were analyzed using ICP-MS. The long-term effect of inorganic and organic fertilization on trace metal concentrations was investigated including the impact of atmospheric deposition and myccorhiza, whereas other factors such as soil conditions, crop cultivar, etc. are not discussed in this paper. Mean values derived from 10 experimental sites were reported. Significantly declining Pb and Cd concentrations in wheat grain could be explained by lower atmospheric deposition. Mean Se contents in all samples were 0.031 mg kg(-1) grain dry weight. No samples had sufficiently high Se concentrations for human (0.05 mg Se kg(-1)) or animal demand (0.1 mg Se kg(-1)). Concentrations of Co in wheat grain were extremely low, 0.002-0.005 mg Co kg(-1) grain dry weight, and far below the minimum levels required by animals, which applied to all fertilizer treatments. A doubling of Mo concentrations in grain since 1975 resulted in Cu/Mo ratios often below one, which may cause molybdenosis in ruminants. The increase in Mo concentrations in crops correlated with the decline in sulfur deposition. Concentrations of Cu and Fe declined in NPK-fertilized wheat as compared to unfertilized or manure-treated wheat. Very low concentrations of Se and Co and low concentrations of Fe and Cu require attention to counteract risks for deficiencies. The main characteristic of the study is that there are few significant changes over time between different fertilizer treatments, but throughout there are low concentrations of most trace elements in all treatments. In general, good agreement between concentrations in wheat from the long-term fertility experiments and the national monitoring program indicate that values are representative.
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