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| Registros recuperados: 129 | |
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| Chatskikh, Dmitri; Olesen, Jørgen E.; Berntsen, Jørgen; Regina, Kristiina; Yamulki, Sirwan. |
| Local adaptations of the IPCC methodology (http://www.ipcc.ch) are applied in different countries. They include a combination of theoretical, experimental and simulation methods for evaluating the activity and factors indicated N2O emission. The N2O emission from agricultural soil is considered an important source both for environmental impact and non-industrial losses of nitrogen (Petersen, Olesen, 2002). In this study a multifactorial approach, based on dynamic modelling, is used at a farm/field level to estimate N2O emission from grassland. For this purpose an algorithm for modeling of gaseous N2O emission was developed and analyzed. In the algorithm, based on the conceptual process-oriented model HIP (Davidson et al., 2000), both nitrification and... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Air and water emissions. |
| Ano: 2003 |
URL: http://orgprints.org/4130/1/4130.doc |
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| Jensen, Maja M.; Jørgensen, Henry; Halekoh, Ulrich; Olesen, Jørgen E.; Lauridsen, Charlotte. |
| The aim of the current study was to investigate if there are any health effects of long-term consumption of organically grown crops using a rat model. Crops were retrieved over two years from along-term field trial at three different locations in Denmark, using three different cultivation systems(OA, organic based on livestock manure; OB, organic based on green manure; and C, conventional with mineral fertilizers and pesticides)with two field replicates. The cultivation system had an impact on the nutritional quality, affecting γ-tocopherol, some amino acids, and fatty acid composition. Additionally, the nutritional quality was affected by harvest year and location. However, harvest year and location rather than cultivation system affected the measured health... |
| Tipo: Journal paper |
Palavras-chave: Food security; Food quality and human health. |
| Ano: 2012 |
URL: http://orgprints.org/21074/1/21074.pdf |
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| Liang, Zhi; Elsgaard, Lars; Nicolaisen, Mette; Lyhne-Kjæbye, Annemette; Olesen, Jørgen E.. |
| Aims Mechanisms of subsoil carbon sequestration from deep-rooted plants are elusive, but may contribute to climate change mitigation. This study addressed the role of root chemistry on carbon mineralization and microbiology in a temperate agricultural subsoil (60 and 300 cm depth)compared to topsoil (20 cm depth). Methods Roots from different plant species were chemically characterized and root-induced CO2 production was measured in controlled soil incubations (20 weeks). Total carbon losses, β-glucosidase activity, carbon substrate utilization, and bacterial gene copy numbers were determined. After 20 weeks, resultant carbon mineralization responses to mineral nitrogen (N) were tested. Results Root-induced carbon losses were significantly lower in... |
| Tipo: Journal paper |
Palavras-chave: Soil biology. |
| Ano: 2018 |
URL: http://orgprints.org/33966/1/Liang2018_Article_CarbonMineralizationAndMicrobi.pdf |
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| Djurhuus, Jørgen; Olesen, Jørgen E.. |
| A field experiment is conducted which focuses on different aspects of crop rotations for cereal production in organic farming. Three factors are included in the experiment in a factorial design: A) fraction of grass-clover and pulses in the rotation (crop rotation), B) catch crop (with or without catch crop or bi-cropped clover), and C) manure (with or without animal manure applied as slurry). The experiment is conducted at four locations (Jyndevad, Foulum, Flakkebjerg and Holeby), representing different soil types and climate regions in Denmark. There are 64 experimental plots at both Jyndevad and Foulum, 72 at Flakkebjerg and 12 at Holeby. In autumn 1996 soil samples were taken for soil chemical and physical characterisation. The soil horizons were... |
| Tipo: Report |
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| Ano: 2000 |
URL: http://orgprints.org/1814/1/D0033.doc |
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| Olesen, Jørgen E.. |
| Climate change is without doubt one of the greatest challenges mankind has ever faced. This is not least due to the enormous consequences that climate change will have for the world’s ecosystems and for our living conditions. At the same time, climate change is a colossal political problem, in which the world’s democracies run the risk not being able to carry out the decisions that have to be made. The political and democratic problem builds on the very limited understanding that there is a connection between emissions of greenhouse gases, climate change and their impact on the living conditions of individual people. In reality, there is both a spatial and a temporal separation between emissions and effects. The world’s industrialised countries, which... |
| Tipo: Newspaper or magazine article |
Palavras-chave: Crop combinations and interactions; Air and water emissions. |
| Ano: 2009 |
URL: http://orgprints.org/16315/1/16315.pdf |
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| Olesen, Jørgen E.; Askegaard, Margrethe; Rasmussen, Ilse A.. |
| The possibilities for increasing grain yields and reducing N leaching losses in organic ce-real production through manipulation of crop rotation design were investigated in a field experiment on different soil types in Denmark from 1997 to 2000. Three experimental fac-tors were included in the experiment in a factorial design: 1) proportion of grass-clover and pulses in the rotation, 2) catch crop (with and without), and 3) manure (with and with-out). Three four-course rotations were compared (Table 1). Two of the rotations had one year of grass-clover as a green manure crop, either followed by spring wheat or by winter wheat. The grass-clover was replaced by winter cereals in the third rotation. Animal ma-nure was applied as slurry in rates corresponding... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Cereals; Pulses and oilseeds. |
| Ano: 2003 |
URL: http://orgprints.org/1809/1/B0071.doc |
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| Olesen, Jørgen E.; Askegaard, Margrethe; Rasmussen, Ilse Ankær. |
| Three factors are included in a factorial field experiment: 1) fraction of grass-clover and pulses in the rotation (crop rotation), 2) catch crop (with or without catch crop), and 3) manure (with or without animal manure). Manure is applied as slurry in rates corresponding to 40 % of the nitrogen demand. Grain yields for three sites and three years of the experiment are presented for two four-course rotations. One rotation has a green-manure crop, which is replaced by winter wheat in the other rotation. The use of manure significantly increased grain yield of the cereal crops in most cases. The positive effects of the catch crops were mainly observed in the spring cereals. The largest rotation yields were obtained in the crop rotation without a... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Farming Systems. |
| Ano: 2000 |
URL: http://orgprints.org/357/1/B0048.pdf |
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| Olesen, Jørgen E.; Rasmussen, Ilse Ankær; Askegaard, Margrethe. |
| There is an increasing demand for organically grown cereal grains in Denmark, which is expected to cause a change in the typical organic farm structure away from dairy farming and towards arable farming. Such a change may reduce the stability of the farming systems, because of decreasing soil fertility and problems with weed control. There have only been a limited number of studies under temperate conditions in Europe and North America, where different crop rotations have been compared under organic farming or similar production conditions. |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Farming Systems. |
| Ano: 2000 |
URL: http://orgprints.org/360/1/B0050.pdf |
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| Rasmussen, Ilse A.; Thomsen, Henning C.; Askegaard, Margrethe; Olesen, Jørgen E.. |
| Kløvergræs opformerer kvik, men reducerer tidsler. Efterafgrøder opformerer kvik, men ikke tidsler, sammenlignet med stubbearbejdning. Når man har problemer med rodukrudt, er det vigtigt at forstå, hvordan sædskifte og andre kulturforanstaltninger påvirker rodukrudtet, både på kort og langt sigt. Desværre findes der kun få data for den langsigtede effekt af kløvergræs som grøngødning og efterafgrøder på rodukrudt. I det økologiske sædskifteforsøg (Askegaard et al. 2004), som blev anlagt i 1996, har vi fulgt udviklingen af især kvik og tidsler frem til nu, og det giver os mulighed for at udtale os om betydningen af de forskellige faktorer. |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Crop combinations and interactions; Weed management. |
| Ano: 2006 |
URL: http://orgprints.org/7923/1/7923_paper.pdf |
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| De Notaris, Chiara; Rasmussen, Jim; Sørensen, Peter; Olesen, Jørgen E.. |
| Legume-based cover crops (CC) provide a wide range of ecosystem services, including nitrate leaching reduction, N fertilizer and soil C sequestration effects. However, the scarcity of information on belowground C and N increases the uncertainty on the magnitude of these effects. With the present study, we quantified soil C and N deposition from legume-based CC (two pure legumes and two mixtures) grown under field conditions, in Denmark. To do so, we labeled CC plants with 13C (CO2) and 15N (leaf-labeling) throughout their growing period, by following a frequent multiple-pulse labeling scheme. Then, we incubated labeled CC roots and soil to investigate C and N mineralization. Cover crops with red clover produced about 2.7 Mg ha-1 aboveground biomass, and... |
| Tipo: Journal paper |
Palavras-chave: Nutrient turnover. |
| Ano: 2019 |
URL: http://orgprints.org/35017/1/CC%20lab_all_20190314.docx |
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| Olesen, Jørgen E.; Askegaard, Margrethe; Rasmussen, Ilse Ankær. |
| A field experiment is conducted which focuses on crop rotations for cereal production in organic farming. The objective of the experiment is to explore the possibilities for both short-term and long-term increases in organic cereal production through manipulation of crop rotation design on different soil types. This paper describes the design of a rather complex experiment, and later papers will describe and discuss the results. Three factors are included in the experiment in a factorial design with two replicates: A) fraction of grass-clover and pulses in the rotation (crop rotation), B) catch crop (with or without catch crop or bi-cropped clover), and C) manure (with or without animal manure applied as slurry). All fields in all rotations are represented... |
| Tipo: Journal paper |
Palavras-chave: Farming Systems. |
| Ano: 2000 |
URL: http://orgprints.org/346/1/A0018.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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| Hutchings, Nicholas J.; Petersen, Bjørn M.; Olesen, Jørgen E.; Berntsen, Jørgen. |
| The presence of grazing animals contributes to a much greater spatial heterogeneity in the cycling of C and N within grasslands, compared to arable land. This is primarily due to the deposition of excreta in patches rather than evenly over the field. However, an additional source of heterogeneity is introduced because grazing animals do not evenly utilise the grassland. Herbage contaminated by their faeces will tend to be rejected, as will poor quality (low digestibility) vegetation. There is therefore good reason to expect that C and N cycling will be highly spatially variable in grazed grassland. Hitherto, grassland models have assumed C and N dynamics to be uniform within a field. In this paper, modelling is used to investigate the potential effect of... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Air and water emissions. |
| Ano: 2004 |
URL: http://orgprints.org/4132/1/4132.doc |
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| Olesen, Jørgen E.. |
| Moderne landbrugssystemer har en kraftig indflydelse på det omgivende miljø, og i Danmark er der særlig fokus på nitratudvaskning og drivhusgasemissioner fra landbruget. På det globale skala er lattergas (N2O) en af de væsentlige drivhusgasser (Mosier et al., 1998), og i Danmark er landbruget langt den største kilde til udledning af lattergas. Der stilles i stigende grad krav til landbruget om-kring reduktion af drivhusgasudledningerne, og tiltag til reduktion af udledningerne af N2O og me-toder til lagring af kulstof i jorden er derfor påkrævede. Bæredygtige landbrugssystemer skal også opfylde behovet for tilstrækkelige mængder og kvalitet i fødevarerne. Økologisk jordbrug har visse fordele i disse sammenhænge, men der er også behov for forbedringer. I... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Crop combinations and interactions; Air and water emissions. |
| Ano: 2009 |
URL: http://orgprints.org/16312/1/16312.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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| Rasmussen, Ilse A.; Melander, Bo; Askegaard, Margrethe; Kristensen, Kristian; Olesen, Jørgen E.. |
| Elytrigia repens is a rhizomatous perennial weed prevalent in organic cropping systems in Scandinavia. This study analysed the population dynamics of E. repens in a long-term crop rotation experiment on coarse sand in Denmark in order to gain insights into the factors influencing its population changes, especially those important for outbreaks of E. repens infestations. Data were obtained from three cycles of four-year crop rotations with various cash crops and annual grass-clover subjected to four treatment combinations: with and without animal manure and with and without catch crops. E. repens was controlled by different tillage and mowing strategies between and within crops. Pulses and spring cereals caused the highest population increases, especially... |
| Tipo: Journal paper |
Palavras-chave: Weed management. |
| Ano: 2014 |
URL: http://orgprints.org/25677/13/25677.pdf |
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| Registros recuperados: 129 | |
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