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| Registros recuperados: 27 | |
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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.; Stamatiadis, Stamatis; Christofides, C.; Yamulki, Sirwan; Bol, . Roland. |
| Introduction For Western Europe it is estimated that, on average, 8% of total N excreted by dairy cattle is deposited during grazing (IPCC, 1997). The intake and excretion of N is influenced by factors such as feed composition, lactation stage and pasture quality, and the excretion of excess N as urea in the urine can therefore vary considerably. Urea can lead to high ammonium levels in the soil which may influence N dynamics and gaseous emissions. This laboratory study was conducted to investigate short-term effects of urea concentration on N2O emissions. Methods Solutions containing 0 (CTL), 5 (LU) and 10 g l-1 urea-N (HU) were added to sieved and repacked soil cores of pasture soil at a rate of 4 l m-2. Also, 5 g l-1 urea-N was added to soil... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Dairy cattle. |
| Ano: 2003 |
URL: http://orgprints.org/1296/1/12th_N_workshop_180903.ppt |
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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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| 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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| 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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| 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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| Registros recuperados: 27 | |
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