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| Registros recuperados: 77 | |
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| Olesen, Jørgen E.; Askegaard, Margrethe. |
| The crop rotation is a crucial and integral part of organic farming systems. It must be designed to maintain and exploit soil fertility, and to minimise the impacts on environment, e.g. through nitrate leaching. Crop rotations in organic farming typically include legume crops to provide nitrogen fixation and improve soil fertility. Catch crops are also commonly used, if demands for soil tillage to control perennial weeds allow. This paper presents results on nitrate leaching from a field experiment with comparison of three different crop rotations with and without catch crops designed for organic farming. |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Farming Systems. |
| Ano: 2003 |
URL: http://orgprints.org/3857/1/3857.pdf |
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| Askegaard, Margrethe; Olesen, Jørgen E.; Rasmussen, Ilse A.. |
| A crop rotation experiment was established in 1996/97 at three locations representing different soil types and climates. Three factors were tested: i) crop rotation with different proportions of N2-fixing crops, ii) with and without a catch crop, and iii) with and without animal manure. A green manure crop increased yields in the following cereal crops, but at the rotational level, total yields were larger in crop rotations without a green manure crop. There were positive effects of animal manure and catch crops on yield. However, except for the coarse sandy soil, the yield effects of catch crops and animal manure decreased over time when a grass-clover green manure was included in the rotation. It appeared that the buffering effect of clover can... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Crop combinations and interactions; Specific methods. |
| Ano: 2005 |
URL: http://orgprints.org/4805/4/Askegaard_etal_4p_revised%2Ded.doc |
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| Rasmussen, Ilse A.; Askegaard, Margrethe; Olesen, Jørgen E.. |
| The plant protection carried out in the Danish crop rotation experiment is described. These measures can be quite different in the different systems. While mechanical weed control can be carried out in systems without catch crops, it is not possible to do so in systems with catch crops without affecting the establishment of the catch crop. The occurrence of weeds, pests and diseases is recorded, and the results are described. Since the results are only from the two first years of the experiments, it is not possible to conclude anything about the crop rotations as such. There are however differences related to the other experimental treatments in the experiment: the presence or absence of catch crops and manure. Only in very few cases are the differences... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Weed management Crop health; Quality; Protection Cereals; Pulses and oilseeds. |
| Ano: 1999 |
URL: http://orgprints.org/247/1/DARCOF1.PDF |
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| Askegaard, Margrethe. |
| Nyt fra de økologiske sædskifteforsøg. Af Margrethe Askegaard, Danmarks JordbrugsForskning, Afd. for Plantevækst og Jord Aktiviteter i marken lige nu På Jyndevad er alle afgrøderne høstet og på Foulum mangler kun lupinerne. På Flakkebjerg er kornafgrøderne modne og der ventes kun på tørvejr. Den sidste nedbør var godt for både udlæg, kløvergræs og roer på Flakkebjerg. Der har som forventet været store variationer mellem afgrøder og behandlinger på de enkelte lokaliteter og mellem lokaliteterne. Når korn og frø er tørret og vejet kan vi få sat tal på forskellene. Fra misvækst til god vækst i havren På Foulum har havren hvert år udviklet sig godt og kraftigt, især i gødede parceller. På Flakkebjerg har væksten derimod ikke været så god. I år... |
| Tipo: Newspaper or magazine article |
Palavras-chave: Farming Systems. |
| Ano: 2001 |
URL: http://orgprints.org/394/1/A2001%2D2.pdf |
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| Askegaard, Margrethe; Eriksen, J.. |
| Management decisions significantly affect nitrate-N leaching (N-leaching) from comparable organic fields. The main concern is field management during autumn and themanagement of grass leys. After ploughing-in fertility building crops, like grass-clover leys, effective catch crops are important during autumn and winter for at least two years on sandy soils. On farms with grazing animals the occurrence of “hot spots” should be avoided. These hot spots develop with uneven concentrations of animal manure combined with limited N-uptake in the ley. Management measures to minimize N-leachingmay conflicts with the farmers aim to produce high quality feed and/or to combat yield limiting perennial weeds. It may also conflict with the organic regulations for the... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Crop combinations and interactions; Environmental aspects; Farm nutrient management. |
| Ano: 2013 |
URL: http://orgprints.org/24517/1/24517.pdf |
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| Askegaard, Margrethe. |
| The appropriate combination of crops and green manures prevents spread of perennial weeds and increases crop yields and quality. Weed-suppressing crop rotations are absolutely essential for sustainable organic arable farming. Practical recommendation Basic rules • Implement green manures, such as clover or lucerne, in at least 20 % of the rotation. • Do not grow more than 50 % of cereals with low weed competitiveness in the rotation. Do not cultivate such crops for more than 2 consecutive years. • In fields with prevalent high weed pressure cultivate only crops with high weed competitiveness. Points to consider in case of high weed pressure: • Do not grow grain legumes where perennial weeds are a problem. Late harvest in combination with loose... |
| Tipo: Practice tool |
Palavras-chave: Crop combinations and interactions Crop health; Quality; Protection Weed management. |
| Ano: 2017 |
URL: http://orgprints.org/31053/1/PA_038_Crop_Rotation_QR.pdf |
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| Askegaard, Margrethe. |
| Nyt fra Forskningscenter for Økologisk Jordbrug – fra det økologiske sædskifteforsøg. Af Margrethe Askegaard, forsker ved Danmarks JordbrugsForskning Lige nu i marken Vi er kommet rigtig godt fra start på alle de fire forsøgslokaliteter. Afgrøderne udvikler sig godt og ensartet. Der har endnu ikke vist sig problemer med sygdomme og skadedyr, heller ikke i sukkerroerne på Flakkebjerg og Holeby. Dog ser vi på alle lokaliteterne bladrandbillernes tydelige visitkort langs bladrandene af ærteplanterne. Det syn har vi dog vænnet os til – sådan ser ærterne bare ud. Stankelbenlarver har vi heldigvis ikke set noget til siden 1998 på Jyndevad, hvor de ødelagde flere af vores parceller med vårhvede efter kløvergræs. Vi ser begyndende tegn på kvælstofmangel i... |
| Tipo: Newspaper or magazine article |
Palavras-chave: Farming Systems. |
| Ano: 2000 |
URL: http://orgprints.org/396/1/A2000%2D1.pdf |
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| Olesen, Jørgen E.; Hansen, Elly M.; Askegaard, Margrethe; Rasmussen, Ilse A.. |
| The effect of nitrogen (N) supply and weeds on grain yield of spring barley was investigated in an organic farming crop rotation experiment on three different soil types in Denmark from 1997 to 2001. Three experimental factors were included in the experiment in a factorial design: 1) crop rotation (lupin or pea/barley as previous crop to barley), 2) cover crop (with and without), and 3) manure (with and without). The crop rotations included grass-clover as a green manure crop. Animal manure was applied as slurry in rates corresponding to 40% of the N demand of the cereal crops. Application of 50 kg NH4-N ha-1 in manure (slurry) increased barley grain DM yield by 1.0 to 1.3 Mg DM ha-1, whereas the use of cover crops (primarily perennial ryegrass)... |
| Tipo: Journal paper |
Palavras-chave: Farming Systems. |
| Ano: 2007 |
URL: http://orgprints.org/3852/2/3852.pdf |
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| Rasmussen, Ilse A.; Askegaard, Margrethe; Olesen, Jørgen E.. |
| Danish experiments with cereal-based organic crop rotations have shown that the short-term results (the first course, up to four years after conversion) are different from those obtained in the longer-term (the second course, fifth to eighth year after conversion). Yield gain from use of manure increased from the first to the second course on a sandy soil, but decreased on loamier soils. Yield gain from leguminous catch crops increased from the first to the second course in a crop rotation without grass-clover. Some of these effects were caused by buffering effects of the grass-clover, other effects were caused by changes in soil fertility over time. |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Crop combinations and interactions. |
| Ano: 2006 |
URL: http://orgprints.org/7680/1/Rasmussen_IA_et_al.doc |
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| Rasmussen, Ilse A.; Askegaard, Margrethe; Olesen, Jørgen E.. |
| In long-term organic crop rotation experiments for cereal production, stubble cultivation to control perennial weeds increased nitrogen leaching compared to catch crops grown after harvest. Stubble cultivation contributed to the control of Elymus repens on a sandy soil, but not to the control of Cirsium arvense on a loamy soil. Manure application had a tendency to decrease E. repens density in one rotation at the sandy soil. Grass-clover green manure decreased C. arvense in the succeeding crops. Despite high infestations of perennial weeds, yields were at the same level with as without stubble cultivation. The results point to an important dilemma in organic farming: should the farmer control perennial weeds in the stubble at the expense of losing nitrogen... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Specific methods. |
| Ano: 2005 |
URL: http://orgprints.org/4451/4/Rasmussen_etal_4p_revised%2Ded.doc |
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| Søegaard, Karen; Sehested, Jakob; Eriksen, Jørgen; Askegaard, Margrethe; Mogensen, Lisbeth; Jensen, Søren K.. |
| Urter i græsmarken er blevet undersøgt i forsøg på fem økologiske kvægbrug og ved Foulum. Vækst, konkurrenceevne, foderværdi og mineralindhold i de enkelte arter i tre forskellige blandinger er undersøgt for betydningen af gylletilførsel, slæt/afgræsning og markens alder, og variation mellem gårde er beskrevet. De enkelte urter viste generelt det samme mønster på de forskellige steder, hvilket gør det muligt med generelle konklusioner. En oversigt over konklusioner for de enkelte urter er vist på sidste side af bilaget. Cikorie og vejbred var de stærkeste og indeholdt derudover en stor andel mineraler. Kommen var også forholdsvis stærk, især under slætforhold. Bibernelle og kællingetand var forholdsvis svage konkurrenter, men mange steder var der dog en... |
| Tipo: Report chapter |
Palavras-chave: Farming Systems; Animal husbandry; Feeding and growth; Farm nutrient management. |
| Ano: 2010 |
URL: http://orgprints.org/17910/1/17910.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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| Askegaard, Margrethe. |
| This tool is about growing cover crops in the best way in an organic arable crop rotation. Thus, the tool is for organic farmers and their advisors who want a successful implementation of and increased knowledge on growing cover crops – regardless of experience. Cover crops can if used properly have tremendous effect on soil quality, nutrient leaching/losses, weed pressure, and soil erosion – common challenges in arable farming. The tool helps to identify when to grow cover crops and where to position them in the rotation. Furthermore, it suggests cover crop species suitable for different soil types, degree of crop competition, existing N-pool in the field and how much seed is needed pr. ha. Structured as a factsheet, the tool provides... |
| Tipo: Practice tool |
Palavras-chave: Crop combinations and interactions; Soil; Weed management; Farm nutrient management. |
| Ano: 2016 |
URL: http://orgprints.org/31133/7/31133.png |
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| Askegaard, Margrethe; Eriksen, Jørgen. |
| . In organic farming, potassium (K) deficiency may become a significant problem due to import restrictions. Knowledge about potential K leaching in systems with different K budgets is therefore important for effective agricultural management. We investigated the effect of four organic farming systems (two livestock densities in combination with two types of organic manure) on crop yields, K leaching and K balances in a six course crop rotation from 1993/94 to 1997/98. Average K concentrations in soil water extracted by means of ceramic suction cups at 1 m depth were 0.6 mg K l-1 corresponding to a K leaching loss of 1.5 kg ha-1 yr-1,which was less than expected from values reported in the literature. Variation in K budgets from –12 to +30 kg ha-1 yr-1 did... |
| Tipo: Journal paper |
Palavras-chave: Farming Systems. |
| Ano: 2000 |
URL: http://orgprints.org/390/1/AE2000.pdf |
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| Rasmussen, Ilse A.; Askegaard, Margrethe; Olesen, Jørgen E.. |
| Der er igangsat forsøg med økologiske sædskifter på fire forskellige steder i Danmark, afspejlende forskellige klima- og jordbundsforhold. De fire sædskifter har forskellig andel af kvælstoffikserende afgrøder hhv. korn til modenhed, med og uden fangafgrøder og med og uden husdyrgødning. Forsøgene har været gennemført i 1997 og 1998. I forsøgene er bl.a. registreret ukrudt. Det er for tidligt at sige noget om ukrudtets udvikling i de forskellige sædskifter. Der er mest ukrudt i vintersæden begge forsøgsår alle steder. I 1997 er der i de vårsåede afgrøder mest ukrudt i byg/ært. Der er signifikant mest ukrudt i de gødede led af vinterhveden i forhold til de ugødede i Flakkebjerg 1997 og Foulum 1998. Ukrudtsbekæmpelsen har kun haft signifikant effekt på... |
| Tipo: Report chapter |
Palavras-chave: Production systems Weed management Cereals; Pulses and oilseeds. |
| Ano: 1999 |
URL: http://orgprints.org/245/1/16.PVK990125.PDF |
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| Askegaard, Margrethe; Olesen, Jørgen E.; Kristensen, Kristian. |
| Nitrate leaching from crop rotations supporting organic grain production was investigated from 1997 to 2000 in a field experiment at three locations in Denmark on different soil types. Three experimental factors were included in the experiment in a factorial design: (1) proportion of N2-fixing crops in the rotation (crop rotation), (2) catch crop (with and without), and (3) manure (with and without). Three, four-course rotations were compared, two at each location. The nitrate leaching was measured using ceramic suction cells. Leaching losses from the crop rotation with grass–clover green manure and without catch crops were 104, 54 and 35 kgNha21 yr21 on the coarse sand, the loamy sand, and the sandy loam, respectively. There was no effect of manure... |
| Tipo: Journal paper |
Palavras-chave: Production systems Crop combinations and interactions Composting and manuring Recycling; Balancing and resource management Nutrient turnover Farm nutrient management. |
| Ano: 2005 |
URL: http://orgprints.org/18726/1/18726.pdf |
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| Registros recuperados: 77 | |
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