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| Registros recuperados: 27 | |
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| Carter, Mette S.; Sørensen, Peter; Petersen, Søren O.; Ambus, Per. |
| Organic arable farming faces challenges with low crop yields, partly due to inefficient use of green manure-derived nitrogen (N). Under current farming practices, green manure leys are often cut and mulched during the growing season with the associated risk of environmental N losses, leading to eutrophication and global warming. In this 3-month incubation experiment, we tested a new green manure management strategy as part of the ICROFS project HighCrop. With the new strategy, green manure leys are instead harvested and preserved until the following spring either as compost mixed with straw (grass-clover:straw, 4:1, w:w) or as silage of harvested ley biomass. In spring, these two green manure materials can then be used for targeted fertilization of spring... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Nutrient turnover; Air and water emissions. |
| Ano: 2013 |
URL: http://orgprints.org/25941/19/25941a.pdf |
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| Petersen, Søren O.. |
| Within organic farming there is a continued effort to close nutrient cycles in order to improve nutrient use efficiency for crop production while also minimizing environmental impacts. In Denmark a long-term crop rotation experiment on three soil types, i.e., Jyndevad (4.5% clay, 2.0% C), Foulum (8.8% clay, 3.8% C) and Flakkebjerg (15.5% clay, 1.7% C), provides a platform for studies of agronomic and environmental aspects of organic farming. Selected results from investigations at these sites are presented. In 2007 and 2008 one study determined soil microbial biomass N and mineralizable N on all three locations during the growing season in four selected rotations, three organic and one conventional; the objective was to evaluate the role of soil... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Farming Systems; Air and water emissions; Denmark. |
| Ano: 2009 |
URL: http://orgprints.org/19468/4/19468.pdf |
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| Carter, Mette S.; Sørensen, Peter; Petersen, Søren O.; Ma, Xiuzhi; Ambus, Per. |
| More efficient use of green manure-derived nitrogen (N) may improve crop yields and reduce environmental impacts in stockless organic arable farming. In this 3-month incubation study, we tested a new strategy where green manure leys are harvested and preserved until the following spring either as compost mixed with straw (grass-clover:straw, 4:1, w:w) or as silage of harvested ley biomass. Grass-clover compost or silage was soil-incorporated by either simulated ploughing (green manure placed at 15 cm depth) or harrowing (green manure mixed into the upper 5-cm soil horizon) in order to assess treatment effects on net release of plant-available N, nitrous oxide (N2O) fluxes, and soil respiration. Grass-clover silage provided the highest net N release with... |
| Tipo: Journal paper |
Palavras-chave: Nutrient turnover; Air and water emissions. |
| Ano: 2013 |
URL: http://orgprints.org/24960/7/24960.pdf |
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| Duan, Yun-Feng; Hallin, Sara; Jones, Christopher M.; Priemé, Anders; Labouriau, Rodrigo; Petersen, Søren O.. |
| Organic agriculture depends on recycling of N to sustain crop production, and the use of catch crops to prevent leaching losses during winter is part of this strategy. The finding in this study, that catch crop residues were a more consistent source of nitrous oxide emissions in spring than synthetic fertiliser, indicates catch crop residue decomposition may contribute negatively to the climate impact of the farming system. Management practices are needed that reduce the potential for denitrification, which is the main source of nitrous oxide. Possible strategies include cultivation to promote aerobic rather than anaerobic degradation, and timing of manure application to avoid that mineral N from manure accumulates during residue decomposition.... |
| Tipo: Journal paper |
Palavras-chave: Crop combinations and interactions; Soil biology; Nutrient turnover; Air and water emissions. |
| Ano: 2018 |
URL: http://orgprints.org/36654/1/fmicb_09_02629.pdf |
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| Petersen, Søren O.; Bol, Roland; Dittert, Klaus; Christofides, Calliopi; Roslev, Peter; Hansen, Martin N.. |
| Managed grasslands can accumulate soil organic carbon and thereby remove CO2 from the atmosphere. When grazed, however, the interaction between N inputs (fertilization, feeding, N fixation) and excretal returns can lead to sward deterioration and elevated emissions of N2O in urine patches. Both effects may reduce the positive effect of carbon storage on the greenhouse gas balance. A field plot study was carried out between 19 September and 4 October 2001, in which cattle urine amended with 13C- and 15N-labelled urea was added to a sandy loam pasture. Two levels of urea, corresponding to 23.3 and 39.8 g urea-N m-2, were compared with an unamended control. Ammonia losses corresponded to 14 and 12% of the urea-N applied in the low (UL) and high (UH) urea... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Air and water emissions. |
| Ano: 2004 |
URL: http://orgprints.org/2906/1/Ghent_presentation_020604.ppt |
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| Li, Xiaoxi; Sørensen, Peter; Olesen, Jørgen E.; Petersen, Søren O.. |
| Catch crops, especially leguminous catch crops, may increase crop nitrogen (N) supply and decrease environmental impacts in cropping systems, but they may also stimulate nitrous oxide (N2O) emissions following spring incorporation. In this 28-day laboratory incubation study, we examined the carbon (C) and N dynamics and N2O evolution after simulated incorporation of residues from three catch crop species into a loamy sand soil, with variable soil moisture (40, 50 or 60% water-filled pore space (WFPS)). The catch crops include two leguminous (red clover and winter vetch) and one non-leguminous species (ryegrass). Plant material was placed in a discrete layer surrounded by soil in which the nitrate (NO3-) pool was enriched with 15N to distinguish N2O derived... |
| Tipo: Journal paper |
Palavras-chave: Pasture and forage crops; Crop combinations and interactions; Nutrient turnover; Air and water emissions; Farm nutrient management. |
| Ano: 2015 |
URL: http://orgprints.org/30111/1/LXX3-2016%20SBB%20vol%2092%20p153-160.pdf |
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| Petersen, Søren O.; Roslev, Peter; Bol, Roland. |
| Within grazed pastures, urine patches are hot-spots of nitrogen turnover since dietary N surpluses are excreted mainly as urea in the urine. This short-term experiment investigated 13C uptake in microbial lipids after simulated deposition of cattle urine at 10.0 and 17.1 g urea-C m-2. Confined field plots without or with cattle urine amendment were sampled after 4 and 14 days, and soil from 0-5 and 10-20 cm depth was analyzed for content and composition of phospholipid fatty acids (PLFAs), and for the distribution of urea-derived 13C among individual PLFAs. Carbon dioxide emissions were quantified and the contributions derived from urea assessed. Initial changes in PLFA composition were greater at the lower level of urea, as revealed by a principal... |
| Tipo: Journal paper |
Palavras-chave: Soil biology. |
| Ano: 2004 |
URL: http://orgprints.org/4061/1/4061.pdf |
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| Carter, Mette S.; Sørensen, Peter; Petersen, Søren O.; Ma, Xiuzhi; Ambus, Per. |
| More efficient use of green manure-derived nitrogen (N) may improve crop yields and reduce environmental impacts in stockless organic arable farming. In this 3-month incubation study, we tested a new strategy where green manure leys are harvested and preserved until the following spring either as compost mixed with straw or as silage of harvested ley biomass. Grass-clover compost or silage was soil-incorporated by either simulated ploughing (green manure placed at 15 cm depth) or harrowing (green manure mixed into the upper 5-cm soil horizon) in order to assess treatment effects on net release of plant-available N, nitrous oxide (N2O) fluxes, and soil respiration. Grass-clover silage provided the highest net N release with similar results for the two... |
| Tipo: Journal paper |
Palavras-chave: Nutrient turnover; Air and water emissions. |
| Ano: 2014 |
URL: http://orgprints.org/25158/7/25158.pdf |
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| Dalgaard, Tommy; Olesen, Jørgen E.; Petersen, B.M.; Petersen, Søren O.; Jørgensen, Uffe; Kristensen, Troels; Hutchings, Nicholas J.; Gyldenkerne, Steen; Hermansen, J.E.. |
| Greenhouse gas (GHG) emissions from agriculture are a significant contributor to total Danish emissions. Consequently, much effort is currently given to the exploration of potential strategies to reduce agricultural emissions. This paper presents results from a study estimating agricultural GHG emissions in the form of methane, nitrous oxide and carbon dioxide (including carbon sources and sinks, and the impact of energy consumption/bioenergy production) from Danish agriculture in the years 1990-2010. An analysis of possible measures to reduce the GHG emissions indicated that a 50-70% reduction of agricultural emissions by 2050 relative to 1990 is achievable, including mitigation measures in relation to the handling of manure and fertilisers,... |
| Tipo: Journal paper |
Palavras-chave: Nutrient turnover; Air and water emissions; Buildings and machinery; Landscape and recreation; Farm nutrient management. |
| Ano: 2011 |
URL: http://orgprints.org/19044/4/19044.pdf |
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| Carter, Mette S.; Sørensen, Peter; Petersen, Søren O.; Ambus, Per. |
| This 3-month incubation study showed that ensiled grass-clover was a better nitrogen (N) source than a composted grass-clover and straw mix (grass-clover:straw, 4:1, w:w), owing to the high content of labile compounds compared to the more degraded compost. Our study also indicated that emissions of the strong greenhouse gas nitrous oxide (N2O) can be reduced by incorporating green manure using harrowing instead of ploughing. The silage-derived N release by the end of the incubation was equivalent to 38-42 kg N ha-1, which corresponded to one third of the N applied in silage, with no difference between ploughing and harrowing. In contrast, no net release of mineral N was detected from the composted grass-clover. |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Composting and manuring; Nutrient turnover; Air and water emissions. |
| Ano: 2013 |
URL: http://orgprints.org/24520/1/24520.pdf |
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| Li, Xiaoxi; Petersen, Søren O.; Sørensen, Peter; Olesen, Jørgen E.. |
| Abstract Legume-based catch crops (LBCCs) may act as an important source of nitrogen (N) in organic crop rotations because of biological N fixation. However, the potential risk of high nitrous oxide (N2O) emissions needs to be taken into account when including LBCCs in crop rotations. Here, we report the results from a one-year field experiment, which investigated N availability and N2O emissions as affected by three LBCCs, i.e., red clover (CL), red clover–ryegrass mixture (GC) and winter vetch (WV), two non-LBCCs, i.e., perennial ryegrass (GR) and fodder radish (FR), and a control (CO) without catch crops. The effect of two catch crop management strategies was also tested: autumn harvest of the catch crop versus incorporation of whole-crop residues by... |
| Tipo: Journal paper |
Palavras-chave: Cereals; Pulses and oilseeds Nutrient turnover Air and water emissions Farm nutrient management. |
| Ano: 2015 |
URL: http://orgprints.org/28131/2/28131.pdf |
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| Petersen, Søren O.; Ambus, Per; Elsgaard, Lars; Schjønning, P.; Olesen, Jørgen E.. |
| The potential for N2O emissions outside the main growing season may be influenced by long-term effects of cropping system. This was investigated by collecting intact soil cores (100 cm3, 0-4 cm depth) under winter wheat in three organic cropping systems and a conventional reference within a long-term crop rotation experiment. Average annual inputs of C in crop residues and manure ranged from 1.7 to 3.3 Mg ha-1. A simulated freeze-thaw cycle resulted in a flush of CO2 during the first 48 h, which could be mainly from microbial sources. Other samples were adjusted to approximately –10, -30 or –100 hPa and amended with excess 15NO3- prior to freezing and thawing. Denitrification was the main source of N2O during a 72-h incubation at 22C, as judged from N2O... |
| Tipo: Journal paper |
Palavras-chave: Soil biology; Air and water emissions; Farm nutrient management. |
| Ano: 2013 |
URL: http://orgprints.org/22014/1/22014.pdf |
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| Petersen, Søren O.; Simek, Miloslav; Stamatiadis, Stamatis; Yamulki, Sirwan. |
| Traditionally, dairy cattle spend a substantial part of the year on pastures. For organic farming within EU it is specified that ”all mammals must have access to pasturage or an open-air exercise area” which they must be able to use whenever ”weather conditions and the state of the ground permits” (Council Regulation [EEC] No 2092/91 ). Dairy production systems are characterized by a considerable N surplus, and N deposited during grazing represents a significant risk for environmental losses, including N2O emissions. Excess N is excreted mainly in the urine, the composition of which is influenced by factors such as lactation stage, sward quality and intake of supplements. Resulting N concentrations in urine patches can range from 20 to 80 g N m-2, and... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Dairy cattle. |
| Ano: 2004 |
URL: http://orgprints.org/4079/1/4079.pdf |
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| Petersen, Søren O.. |
| Soil carbon storage and nitrous oxide (N2O) emissions are both important for the greenhouse gas balance of agricultural soil, but difficult to verify under field conditions due to high spatial and temporal variability. Carbon stock changes are particularly elusive because they occur over decades, and future climate or management changes may revert current trends. Emissions of N2O from arable soil are derived mainly from the short-term (<1 yr) turnover of crop residues, fertilizers and manure, which indicates that mitigation options may be found with a better understanding of management effects on soil C and N cycling and N2O emissions. This presentation will describe N2O studies within long-term crop rotation experiments that allow side-by-side... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Nutrient turnover; Soil tillage; Air and water emissions; Farm nutrient management. |
| Ano: 2011 |
URL: http://orgprints.org/22016/1/22016.PDF |
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| Carter, Mette S.; Sørensen, Peter; Petersen, Søren O.; Ma, Xiuzhi; Ambus, Per. |
| More efficient use of green manure-derived nitrogen (N) may improve crop yields and reduce environmental impacts in stockless organic arable farming. In this 3-month incubation study, we tested a new strategy where green manure leys are harvested and preserved until the following spring either as compost mixed with straw or as silage of harvested ley biomass. Grass-clover compost or silage was soil-incorporated by either simulated ploughing (green manure placed at 15 cm depth) or harrowing (green manure mixed into the upper 5-cm soil horizon) in order to assess treatment effects on net release of plant-available N, nitrous oxide (N2O) fluxes, and soil respiration. Grass-clover silage provided the highest net N release with similar results for the two... |
| Tipo: Journal paper |
Palavras-chave: Nutrient turnover; Air and water emissions. |
| Ano: 2014 |
URL: http://orgprints.org/27643/25/Carter%20et%20al.%202014_BFOS.pdf |
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| Registros recuperados: 27 | |
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