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| Dalgaard, Tommy; Hutchings, Nicholas J.; Dragosits, U.; Olesen, J.E.; Kjeldsen, Chris; Drouet, J.L.; Cellier, P.. |
| The aim of this study is to illustrate the importance of farm scale heterogeneity on nitrogen (N) losses in agricultural landscapes. Results are exemplified with a chain of N models calculating farm-N balances and distributing the N-surplus to N-losses (volatilisation, denitrification, leaching) and soil-N accumulation/release in a Danish landscape. Possible non-linearities in upscaling are assessed by comparing average model results based on (i) individual farm level calculations and (ii) averaged inputs at landscape level. Effects of the non-linearities that appear when scaling up from farm to landscape are demonstrated. Especially in relation to ammonia losses the non-linearity between livestock density and N-loss is significant (p > 0.999), with... |
| Tipo: Journal paper |
Palavras-chave: Air and water emissions; Landscape and recreation; Farm nutrient management. |
| Ano: 2011 |
URL: http://orgprints.org/19043/4/19043.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.; Chatskikh, Dmitri; Berntsen, Jørgen; Hutchings, Nicholas J.. |
| Danmark har underskrevet Kyoto-protokollen, som forpligter til en reduktion i samfundets udledning af drivhusgasser på 21 procent i perioden fra 1990 til 2010. Med hensyn til reduktion af landbrugets udledning af drivhusgasser har fokus hidtil været på reduktion af kvælstofanvendelsen. I den nationale opgørelse beregnes lattergasudledningen som 1,25 procent af den udbragte kvælstofmængde. De nye modelberegninger, som præsenteres her, viser at dette er en alt for simpel måde at beregne lattergasudledningen på. Der er dels store forskelle mellem jordtyper, og dels er den procentvise udledning større ved høje kvælstofniveauer end ved lave niveauer. Det sidste forhold kan gøre økologisk jordbrug interessant som redskab i klimapolitikken, da... |
| Tipo: Journal paper |
Palavras-chave: Air and water emissions. |
| Ano: 2004 |
URL: http://orgprints.org/4077/1/4077.doc |
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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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