| 1. |
- Andersson, Karin, et al.
(author)
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Ammonia emissions from untreated, separated and digested cattle slurry-Effects of slurry type and application strategy on a Swedish clay soil
- 2023
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In: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 226, s. 194-208
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Journal article (peer-reviewed)abstract
- Animal slurry contains plant nutrients such as nitrogen (N) that are essential for crop production. Inorganic slurry N is easily volatilised as ammonia after field application, reducing slurry fertiliser value and causing environmental problems. Ammonia emissions can be reduced by lowering slurry pH, rapid infiltration or incorporation of slurry into soil. This study investigated the effect of different combinations of slurry types and application strategies on ammonia emissions. The slurry types tested were untreated cattle slurry (CS), the liquid fraction from mechanical solid-liquid separation of cattle slurry (LF) and biogas digestate based mainly on cattle slurry (BD). The application strategies tested were trailing hoses, trailing shoes, trailing hose application of acidified slurry and slurry injection. Ammonia emissions after slurry application were measured using wind tunnels, with continuous measurements of ammonia concentrations in outgoing air. Comparisons were also made between measured ammonia emissions and emissions predicted by the ALFAM2 model. Cumulative ammonia emissions after 70 h from LF, CS and BD represented 23%, 29% and 32% of total ammoniacal nitrogen (TAN) applied. Trailing shoes and 50 mm deep injection slots reduced ammonia emissions by on average 17% and 37%, respectively, compared with trailing hoses. Slurry acidification resulted in an average reduction in ammonia emissions of 83%. The ALFAM2 model was reasonably accurate in predicting cumulative emissions (70 h). Accuracy in predicting emission dynamics was low in some cases, likely due to differences between wind tunnel measurements and open-air emis-sions and to model error.(c) 2023 The Authors. Published by Elsevier Ltd on behalf of IAgrE. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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| 2. |
- Andersson, Karin, et al.
(author)
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Effect of exposed surface area on ammonia emissions from untreated, separated, and digested cattle manure
- 2021
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In: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 202, s. 66-78
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Journal article (peer-reviewed)abstract
- Ammonia (NH3) emissions from land-applied liquid manure (slurry) contribute to nitrogen deposition, acidification, and formation of fine particles in the atmosphere. Optimal management and field application techniques can reduce emission. A reduction in contact area between the slurry and the atmosphere is expected to reduce NH3 emission. The objectives of this study were to develop a method for quantifying the exposed surface area (ESA) of field-applied slurry over time, and determine the degree to which ESA explains differences in NH3 emission. Two experiments were conducted in which untreated, separated, and digested slurry was applied in bands on two different soils with spring oats stubble. Emission data were obtained from online wind tunnel measurements and slurry characteristics such as surface pH, viscosity, and particle size distribution were measured. The new ESA method relies on fluorescent dye added to the slurry prior to field application, followed by imaging. The results show that the ESA measurements can give new insight into the soil-slurry interactions after manure application, and this may help explain why some types of slurry and application techniques lead to successful abatement under some circumstances, but not under others. Furthermore, a pH-, TAN-, temperature-, and ESA normalised NH3 emission were estimated, helping idetify the effects of infiltration. (c) 2020 IAgrE. Published by Elsevier Ltd. All rights reserved.
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| 3. |
- Delin, Sofia
(author)
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Effects on nitrate leaching of the timing of cattle slurry application to leys
- 2021
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In: Soil Use and Management. - : Wiley. - 0266-0032 .- 1475-2743. ; 37, s. 436-448
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Journal article (peer-reviewed)abstract
- This study compared the effects on nitrate leaching of slurry application to ley in early Autumn (15 September), late Autumn (1 November) and Spring (April) under Swedish growing conditions. In two separate two-year experiments, started in Autumn 2009 and 2010, on a sandy loam soil in south-west Sweden, these three application times were compared with no slurry application in grass-clover and grass swards. Soil water was sampled with ceramic suction cups, and nitrate leaching was calculated from water nitrate concentrations and drain discharge. Plant measurements indicated that, during Autumn, the grass took up at least 20 kg of the 50 kg nitrogen (N) applied with slurry in September. The mineral nitrogen level in the subsoil (30-90 cm) in December was around 2 kg N ha(-1) higher in this treatment. Nitrate leaching was on average 5 and 6 kg N ha(-1) year(-1) higher after early and late Autumn slurry application, respectively, than after Spring application (p < .001), but the difference varied from 0 to 10 kg N ha(-1) year(-1) between experiments and sward types. Nitrate leaching losses in kg N ha(-1) were lower from the grass sward, but higher if related to nitrogen inputs and dry matter yield. These results indicate that Autumn application can increase the risk of nitrate leaching, but that early/late application within Autumn is less important. It is more important to limit the amount of slurry applied in Autumn and to consider other risks of nitrogen losses associated with time of application, such as ammonia emissions.
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| 4. |
- Karlsson Potter, Hanna, et al.
(author)
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Precision nitrogen application – potential to lower the climate impact of crop production
- 2022
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Reports (other academic/artistic)abstract
- The agriculture sector is a significant contributor to global greenhouse gas emissions, especially methane (CH4) and nitrous oxides (N2O). Nitrous oxide emissions originate primarily from nitrogen fertiliser production and use. A nitrogen fertilisation rate close to crop demand is desirable for several reasons, e.g. it limits fertiliser use per unit of crop produced and reduces the risk of N2O emissions and nitrogen leaching.This study estimated the impact of two different measures for more accurate nitrogen fertilisation, field-specific nitrogen fertilisation (accounting for between-field variation) and variable-rate nitrogen application (accounting for within-field variation), compared with a uniform fertilisation application. Effects on nitrogen leaching, N2O emissions, grain yield and nitrogen balance were analysed. Calculations of leaching and N2O emissions were based on different examples of within- and between-field variation on two soil types, represented by two experimental fields in south-west Sweden from which measured data on grain yield and N2O emissions were obtained. Climate impact in a life cycle perspective, including fertiliser production and use, was calculated. The results for N2O emissions were compared with the results of simulations using the IPCC model for N2O emissions and a nitrogen balance-based model.According to the results, the climate impact from field N2O emissions was reduced by around 5% when using field-specific nitrogen fertilisation. An additional reduction of 1-10% (depending on in-field variations in nitrogen demand) was achieved when using variable-rate nitrogen application. The amount of fertiliser used was very important for the overall climate impact of crop production, indicating that measures which increase nitrogen use efficiency and keep nitrogen fertiliser doses below the optimum rate are preferable in a climate impact perspective. The commonly used IPCC model for predicting field N2O emissions failed to predict reductions in N2O from better nitrogen use efficiency. The nitrogen balance-based model performed better in predicting field N2O emissions in relation to what could be expected based on measured N2O emissions, but the estimated reduction was not as high as that predicted from field measurements.
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| 5. |
- Wallman, Magdalena, 1976, et al.
(author)
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Nitrous oxide emissions from five fertilizer treatments during one year-High-frequency measurements on a Swedish Cambisol
- 2022
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In: Agriculture, Ecosystems & Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 337
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Journal article (peer-reviewed)abstract
- Nitrous oxide (N2O) is a strong greenhouse gas, and the emissions from managed soils are increasing. Emissions of N2O are highly variable in time and space, and there are potential triggers for emission peaks both in crop season and no-crop season. The aim of this study was to compare how fertilizer treatments, differing in rate and source of nitrogen (N), influence direct N2O emissions from soil, in crop season as well as in no-crop season, with the use of automated, high-frequency chamber measurements. Emissions were measured from cereal production on a Swedish clay-rich soil fertilized with biogas digestate, pig slurry and two levels of mineral N, as well as from control plots receiving no fertilizer N. The results showed that N2O emissions per unit area were low in all treatments, compared to other studies. Emissions from the treatment with mineral fertilizers at recommended rates were similar to the emissions from the control (0.65 and 0.48 kg N2O-N ha(-1) yr(-1), respectively). One-year cumulative emissions from a mineral N input rate 50 % higher than recommended were about three times higher than the control. Emissions of N2O from the pig slurry and biogas digestate treatments per unit area were of the same magnitude as from the high mineral N treatment. While the emissions from the high mineral N treatment were associated with elevated concentrations of nitrate in the drainage water, the high emissions from the organic fertilizer treatments were probably a result of large input of ammonium and degradable organic matter both in the year studied and in the preceding year. Most (approximately 75 %) of the N2O emissions occurred between harvest in autumn and sowing in spring, mainly in periods of freeze-thaw cycles. The relative differences between treatments were roughly the same during crop season and no-crop season. This study concludes that it is possible to combine high yields with very low N2O emissions -even on a clay soil in a semi-humid climate -when using mineral fertilizers at recommended rates.
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| 6. |
- Wallmann, Magdalena, 1976, et al.
(author)
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Nitrogen leaching from tile-drained fields and lysimeters receiving contrasting rates and sources of nitrogen
- 2022
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In: Soil Use and Management. - : Wiley. - 0266-0032 .- 1475-2743. ; 38:1, s. 596-610
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Journal article (peer-reviewed)abstract
- Leaching of nitrogen from arable land can lead to pollution of groundwater and surface water. Various measures have been implemented in agriculture to reduce leaching, but there is still potential to do more. To find the best agricultural management regime to limit the problem, leaching from soils under different management must be measured. Different methods to estimate leaching are available, but they have not been thoroughly evaluated. This study compared (a) leaching of nitrogen from five different fertilizer treatments differing in amount and source (mineral and organic) of nitrogen and (b) two different methods for measuring leaching (tile-drained field plots and lysimeters). Nitrogen leaching from five different fertilizer treatments was studied for three years in a tile-drained field facility and for three of the treatments also for 16 months in a lysimeter facility. Leaching from organic and mineral nitrogen sources was similar in the three-year field study. Mineral nitrogen input above the economic optimum tended to give greater leaching (by 24%-43%) than nitrogen input at the expected optimum. Measurements in lysimeters and tile-drained field plots gave similar results, although leaching values tended to be slightly higher (by 18%-25%) in the tile-drained field. Overall, both facilities give reliable estimates of nitrogen leaching and are suitable for leaching studies.
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