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| Registros recuperados: 42 | |
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| Vinther, F.P.. |
| Bælgplanter, herunder de forskellige kløverarter, kan ved knoldbakteriers hjælp bruge luftens kvælstof, og derved udnytte denne uudtømmelige kvælstofkilde. Denne biologiske proces er en forudsætning for at kunne drive økologisk jordbrug, og det har derfor stor interesse at kende størrelsen af N-fikseringen og have kendskab til hvilke faktorer der har betydning, for derved om muligt at kunne optimere produktiviteten og reducere eventuelle miljømæssige effekter af et givet dyrkningssystem. En lang række undersøgelser har vist, at der er en forholdsvis konstant relation mellem høstet kløvertørstof og N-fiksering. I kløvergræs udgør N-fikseringen således 30-35 kg N per tons høstet kløvertørstof. Dvs. at hvis der i en kløvergræs i løbet af vækstsæsonen er... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Nutrient turnover; Pasture and forage crops. |
| Ano: 2004 |
URL: http://orgprints.org/4160/1/4160.ppt |
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| Eriksen, J.; Vinther, F.P.. |
| Cut grassland systems usually have high N efficiency and consequently low nitrate leaching, whereas the introduction of grazing animals increases the loss potential dramatically (Jarvis, 2000). It has been demonstrated that nitrate leaching from unfertilised grass-clover swards is lower than from mineral-N fertilized swards grazed by cattle. The possible explanation for this is that the N2 fixation by pasture legumes is regulated by a natural feedback mechanism driven by soil inorganic N levels. The feedback mechanism acts as a limit to N inputs from legumes and consequently regulates the potential for N losses (Ledgard, 2001). Here is reported 5 years of nitrate leaching from four cropping sequences with different grassland frequency and management for... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Nutrient turnover. |
| Ano: 2004 |
URL: http://orgprints.org/3666/1/3666.doc |
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| Eriksen, J.; Vinther, F.P.; Søegaard, K.. |
| Ændringen i EU's landbrugspolitik (CAP) indebærer en afkobling af landbrugsstøtten og en afvikling af den nuværende hektarstøtte. Derved øges græsmarkernes værdi fordi græs vil konkurrere bedre med de øvrige grovfoderemner rent prismæssigt. I fremtiden forventes derfor en betydelig højere græsandel i kvægbrugenes sædskifter end det er tilfældet i dag. Samtidig betyder strukturudviklingen, at kvæggårdene bliver større og et stigende antal brug ikke kan afgræsse alle marker i sædskiftet, da afgræsning langt fra gården er besværlig eller helt uforeneligt med de daglige rutiner. Disse forhold forventes at bevirke, at der på kvægbrugene fremover vil være græsmarker, som får lov til at blive betydeligt ældre end de 2-3 år, der hidtil har været mest... |
| Tipo: Journal paper |
Palavras-chave: Nutrient turnover. |
| Ano: 2004 |
URL: http://orgprints.org/5478/1/5478.PDF |
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| Eriksen, J.; Vinther, F.P.. |
| Cut grassland systems usually have high N efficiency and consequently low nitrate leaching, whereas the introduction of grazing animals increases the loss potential dramatically (Jarvis, 2000). It has been demonstrated that nitrate leaching from unfertilised grass-clover swards is lower than from mineral-N fertilised swards grazed by cattle. The possible explanation for this is that the N2 fixation by pasture legumes is regulated by a natural feedback mechanism driven by soil inorganic N levels. The feedback mechanism acts as a limit to N inputs from legumes and consequently regulates the potential for N losses (Ledgard, 2001). In this paper we report 5 years (1997-2002) of nitrate leaching from four cropping sequences with different grassland frequency... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Pasture and forage crops; Production systems. |
| Ano: 2003 |
URL: http://orgprints.org/1822/1/Eriksen.doc |
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| Vinther, F.P.. |
| I markforsøg blev det undersøgt hvorvidt samtidig såning af ærter og vinterkorn kunne øge kerneudbytter i kornet. Princippet i dyrkningsmetoden er at ærterne i løbet af efteråret via biologisk N-binding optager luftens kvælstof, som efter ærternes udvintring friggives til kornafgrøden i det tidlige forår. Sammenfattende kunne det konkluderes, at såfremt der ikke er større udgifter forbundet med anskaffelse af ærteudsæd (evt. ærter af egen avl), kan dyrkningssystemet med fordel anvendes. Specielt i år hvor de klimatiske forhold gør det vanskeligt at udbringe gødning tidligt, vil ”ærte-kvælstof” kunne sikre at kornafgrøden kommer godt i gang. |
| Tipo: Report |
Palavras-chave: Nutrient turnover Cereals; Pulses and oilseeds Soil biology. |
| Ano: 2005 |
URL: http://orgprints.org/5938/1/5938.pdf |
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| Vinther, F.P.; Hansen, E.M.; Olesen, J.E.. |
| The impacts of crop rotation and input of organic matter in the form of green manure crops, straw residues and incorporation of catch crops on crop yield, nitrogen uptake, microbial biomass and activity was studied in unfertilised crop rotations differing in input of plant residues, i.e. high-input rotations with a grass-clover crop and catch crops included and low-input cereal rotations without catch crops. The parameters studied included substrate induced respiration (SIR), hydrolysis of fluorescein diacetate (FDA), arylsulfatase activity (ASA), N mineralisation, N2O emission, and soil respiration. These parameters were measured in bare soil plots, to estimate the effects of previous years crops and input of plant residues. In neighbouring plots crop... |
| Tipo: Journal paper |
Palavras-chave: Nutrient turnover; Soil biology; Soil quality; Air and water emissions. |
| Ano: 2004 |
URL: http://orgprints.org/4012/1/Vinther%2C_Hansen_Olesen_2004.pdf |
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| Vinther, F.P.. |
| Bælgplanter, herunder de forskellige kløverarter, kan ved knoldbakteriers hjælp (symbiose) optage luftens kvælstof (N2), og derved udnytte denne uudtømmelige kvælstofkilde. Processen er simpelt-hen forudsætningen for at kunne drive økologisk jordbrug, og det har derfor stor interesse at kende størrelsen af N-fikseringen og have kendskab til hvilke faktorer der har betydning for derved om muligt at kunne optimere produktiviteten og reducere eventuelle miljømæssige effekter af et givet dyrkningssystem. |
| Tipo: Newspaper or magazine article |
Palavras-chave: Nutrient turnover; Pasture and forage crops. |
| Ano: 2003 |
URL: http://orgprints.org/4162/1/4162.pdf |
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| Vinther, F.P.; Dahlmann-Hansen, L.. |
| The success of organic cropping systems depends on symbiotic N2 fixation by leguminous crops, and it is important to explore new management systems to improve the nitrogen input through N2 fixation. During two growing seasons the possible advantage of growing fababean in ridges in comparison to the traditional method on the flat was studied. Differences in soil physical parameters resulted in a significantly greater microbial activity and a deeper root system at the flowering stage when grown in ridges than on the flat. Consequently, the amount of fixed N at flowering was significantly greater in ridges than in flat soil. However, during the period from flowering until harvest, when the major part of the N uptake and N2 fixation took place the differences... |
| Tipo: Journal paper |
Palavras-chave: Nutrient turnover Cereals; Pulses and oilseeds Soil biology Soil tillage. |
| Ano: 2005 |
URL: http://orgprints.org/5203/1/5203.pdf |
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| Vinther, F.P.. |
| The denitrification process, including emission of nitrous oxide (N2O), is an important process both from an agricultural and environmental point of view. However, the process is, due to its high spatial and temporal variability, very difficult and resource demanding to quantify, and the only alternative is often to use simulation models. However, simulation models often need more input information than what is available. Therefore, a simple empirical model - SimDen - for quantifying the denitrification is presented, where only information about soil type and fertilisation are needed as input variables. Basically, the denitrification in SimDen is calculated as (N2O-emission) x (N2/N2O-ratio): - The N2O-emission is derived from input of N and emission... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Nutrient turnover; Air and water emissions. |
| Ano: 2005 |
URL: http://orgprints.org/5759/1/5759.pdf |
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| Hansen, E.M.; Eriksen, J.; Vinther, F.P.. |
| Har man problemer med kløvertræthed i sine marker kan en løsning være, at dyrke grønbyg (byg høstet ved begyndende skridning) med udlæg af italiensk (ital.) rajgræs. Nye forsøg beskrevet her viser, at dyrkning af grønbyg med udlæg af ital. rajgræs giver mulighed for at reducere udvaskningen af kvælstof (N) til et minimum og samtidig opnå en stor produktion af grovfoder. I modsætning hertil er der normalt stor risiko for udvaskning af kvælstof ved ompløjning af kløvergræs på sandjorde. |
| Tipo: Journal paper |
Palavras-chave: Nutrient turnover. |
| Ano: 2005 |
URL: http://orgprints.org/5475/1/5475.PDF |
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| Hansen, E.M.; Eriksen, J.; Vinther, F.P.. |
| The objective of the study was to prevent the accumulation of high concentrations of mineral N in the soil during the drainage season by growing the presumably most effective catch crop, Italian ryegrass, undersown in barley as a green crop for silage on sandy soil. Further more, to examine the effect on two fields with different management of the grass-clover ley and therefore a different mineralization potential after ploughing. The green barley/Italian ryegrass treatment was compared with barley grown to maturity with and without an undersown conventional catch crop of perennial ryegrass. |
| Tipo: Journal paper |
Palavras-chave: Nutrient turnover; Air and water emissions. |
| Ano: 2007 |
URL: http://orgprints.org/10621/1/10621.doc |
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| Eriksen, J.P.; Vinther, F.P.; Søegaard, K.. |
| In the future there is expected to be a higher proportion of grass in the dairy crop rotation than today. Changes in the EU Common Agricultural Policy stipulate that subsidies should be decoupled from production. Pastures are thus better able to compete economically with other roughage/feedstuff sources. Also, the development in farm size is dramatic and as dairy farms grow bigger, an increasing number of farms cannot use the entire crop rotation for grazing. The management of dairy cattle grazing becomes increasingly difficult with distance to the milking parlour, and on these farms we already experience grass-intensive rotations located close to the farm buildings. Because of these conditions grass leys are expected to become older than the 2-3... |
| Tipo: Journal paper |
Palavras-chave: Nutrient turnover. |
| Ano: 2004 |
URL: http://orgprints.org/5479/1/5479.PDF |
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| Vinther, F.P.. |
| Significant amounts of plant biomass and fixed N are incorporated into soil as roots, nodules and root exudates during the growth of grass-clover, which consequently is exposed to soil microbial degradation when the field is ploughed. This has major implications for our understanding of the potential contributions of legumes in the N economics and losses in grass-clover cropping systems. We have studied the effects of grass-clover pasture age and cutting frequency (simulated grazing) on the development of the above ground as well as the below ground plant biomass, with emphasis on below-harvest contribution to the total N2 fixation. |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Nutrient turnover; Pasture and forage crops. |
| Ano: 2004 |
URL: http://orgprints.org/3368/1/3368.pdf |
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| Eriksen, J.; Vinther, F.P.. |
| In a field experiment at Research Centre Foulum a suction cup technique was used to investigate nitrate leaching from grassland depending on composition (grass-clover or perennial ryegrass), management (grazing or cutting) and age of the swards. In 1997-2001 was investigated the successive nitrate leaching from 4-7 year old grazed grass-clover and ryegrass with cut plots of similar age and spring barley as reference. In 2000-2001 the simultaneous nitrate leaching from newly established swards, swards grazed for 1 and 7 years and swards cut for 7 years was investigated. In the newly established swards nitrate leaching from grass-clover and ryegrass were similar but at increasing sward age nitrate leaching from the fertilized ryegrass increased dramatically... |
| Tipo: Book chapter |
Palavras-chave: Nutrient turnover. |
| Ano: 2002 |
URL: http://orgprints.org/160/1/cfp404.pdf |
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| Vinther, F.P.; Hansen, E.M.; Olesen, J.E.. |
| The impacts of crop rotation and input of organic matter in the form of straw residues and incorporation of catch crops on crop yield, nitrogen uptake and microbial biomass and activity was studied in a field experiment initiated in 1996 at Research Centre Foulum. The parameters studied included substrate-induced respiration (SIR) from where microbial biomass C was calculated, hydrolysis of fluorescein diacetate (FDA), arylsulfatase activity (ASA), N mineralisation, N2O emission, and soil respiration. These experiments were carried out in bare soil plots to measure the effects of previous crops and input of organic matter. In 2001 measurements were carried out in four treatments where the crops in 2000 were winter wheat (W-w), pea-barley (P-b),... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Nutrient turnover Soil quality Production systems Soil biology Air and water emissions Cereals; Pulses and oilseeds. |
| Ano: 2002 |
URL: http://orgprints.org/1790/1/Finn_Vinther_abstract.doc |
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| Gjettermann, B.; Styczen, M.; Hansen, H.C.B.; Vinther, F.P.; Hansen, S.. |
| Because dissolved organic matter (DOM) plays an important role is terrestrial C-,N-and P-balances and transport of these three components to aquatic environments, there is a need to include it in models. This paper presents the concept of the newly developed DOM modules implemented in the DAISY model with focus on the quantification of DOM sorption/desorption and microbial-driven DOM turnover. The kinetics of DOM sorption/desorption is described by the deviation of the actual DOM concentration in solution from the equilibrium concentration, Ceq. The Ceq is soil specific and estimated from pedotransfer functions taking into account the soil content of organic matter, Al and Fe oxides. The turnover of several organic matter pools including one DOM pool are... |
| Tipo: Journal paper |
Palavras-chave: Soil. |
| Ano: 2008 |
URL: http://orgprints.org/21148/1/21148.pdf |
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| Registros recuperados: 42 | |
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