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Registros recuperados: 77
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Crop production and N leaching in arable organic farming Organic Eprints
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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Crop production during the first course of an organic crop rotation trial in Denmark Organic Eprints
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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Crop rotation and its ability to suppress perennial weeds Organic Eprints
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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Crop rotation and its ability to suppress perennial weeds Organic Eprints
Askegaard, Margrethe.
Weed-suppressing crop rotations are essential for sustainable organic arable farming. Preventing spread of perennial weeds will increase crop yields and quality. The tool is a factsheet created for all organic farmers as we all need renewed knowledge on weed-suppression and crop rotation from time to time. The factsheet provides practical recommendations on crop selection and composition of crop rotations in accordance to weed competitiveness and nitrogen demand. An appropriate combination of crops and green manures, designed specifically for the conditions and needs of individual fields, prevents spread of perennial weeds. The factsheet doesn’t only focus on prevention but also provides recommendations in case of high weed pressure. Example: Do not sow...
Tipo: Practice tool Palavras-chave: Soil quality; Crop combinations and interactions; Weed management.
Ano: 2016 URL: http://orgprints.org/31134/7/31134.png
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Crop rotations for grain production Organic Eprints
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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Danske forskere tester sædskifter Organic Eprints
Olesen, Jørgen E.; Rasmussen, Ilse Ankær; Askegaard, Margrethe.
Siden 1997 har fire forskellige sædskifter med forskellige andele af korn været afprøvet. Udbytter og kvælstofudvaskning varierer mellem forsøgsstederne og er afhængig af sædskifte, efterafgrøde og gødning.
Tipo: Newspaper or magazine article Palavras-chave: Farming Systems.
Ano: 2000 URL: http://orgprints.org/369/1/E0050.pdf
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Den langsigtede effekt af kløvergræsgrøngødning og efterafgrøder på udviklingen af kvik og tidsler Organic Eprints
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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Design of an organic farming crop rotation experiment Organic Eprints
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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Effects of catch crop type and root depth on nitrogen leaching and yield of spring barley Organic Eprints
Sapkota, Tek Bahadur; Askegaard, Margrethe; Lægdsmand, Mette; Olesen, Jørgen Eivind.
Catch crop root growth and nitrogen (N) uptake from both shallower and deeper soil layers is important for N management in arable farming system particularly in climates where excess winter precipitation induces N leaching. We simulated the root growth and biomass yield of three common catch crops [chicory (Cichorium intybus L.), fodder radish (Raphanus sativus L.) and perennial ryegrass (Lolium perenne L.)] and their effect on soil mineral N in different soil layers by using the FASSET model. The simulated results of catch crops root growth and mineral N in the soil profile were validated against two years (i.e. 2006 and 2007) of observations taken in Foulum and Flakkebjerg, Denmark. Fodder radish had the deepest root system and depleted N from deeper...
Tipo: Journal paper Palavras-chave: Crop combinations and interactions Cereals; Pulses and oilseeds Air and water emissions.
Ano: 2011 URL: http://orgprints.org/18766/1/18766.pdf
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Efficient nitrogen use from livestock manure Organic Eprints
Askegaard, Margrethe.
This tool is about efficient use of livestock manure, and how optimization will increase yields and reduce nitrogen losses. Thus, the tool is for farmers and their advisors who use livestock manure and higher yields. The tool can be useful regardless of experience. This factsheet is about optimizing the use of limited amounts of nitrogen from livestock manure. The yield response from applying different amounts of nitrogen differs, hence nitrogen needs to be applied with respect to crop, pre-crop, N-need, soil type, and climatic conditions. The result of optimal N-use is higher yields and less N losses. The factsheet provides recommendations on yield effective application of livestock manure in relation to nitrogen fixing crops, spring/winter crops, weed...
Tipo: Practice tool Palavras-chave: Soil quality; Composting and manuring; Farm nutrient management.
Ano: 2016 URL: http://orgprints.org/31131/7/31131.png
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Efficient use of nitrogen from livestock manure Organic Eprints
Askegaard, Margrethe.
Optimized application of nitrogen from livestock manure will reduce nitrogen losses and result in higher yields. Practical recommendation Nitrogen application from livestock manure to winter and spring crops has different effects on crop yields depending on the pre-crop and the amount of ammonium-N provided. The results above show that nitrogen availability from livestock manure is limited. Based on the results, the following recommendations can be made: • If the pre-crop is not nitrogen-fixing, apply 20 to 60 kg of ammonium-N from livestock manure prior to sowing of crops. • Livestock manure application to a spring crop after nitrogen-fixing clover-grass is not yield effective and may bear the risk of nitrogen losses.   • If livestock manure is...
Tipo: Practice tool Palavras-chave: Composting and manuring; Farm nutrient management.
Ano: 2017 URL: http://orgprints.org/31052/1/PA_037_Utilization_of_Nitrogen_QR.pdf
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Elytrigia repens population dynamics under different management schemes in organic cropping systems on coarse sand Organic Eprints
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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Exchangeable potassium and potassium balances in organic crop rotations on a coarse sandy soil Organic Eprints
Askegaard, Margrethe; Eriksen, Jørgen; Olesen, Jørgen E..
Crops on sandy soils (<5% clay) are exposed to K deficiency due to the small release and high leaching losses of K. Reliable tools are needed to improve the K management in cropping systems with limited K input, such as organic farming where import of nutrients are restricted according to the EC regulations. We investigated K balances and exchangeable K (Kexch) changes in an organic crop rotation experiment. Potassium leaching decreased from 42 kg ha-1 in 1998/99 to 21 kg ha-1 in 2000/01 as an average of a crop rotation (spring barley, grass-clover, winter wheat and pea/barley) with manure application and without catch crops. In the same period, spring Kexch decreased from 5.0 to 3.0 mg K 100 g-1 soil (0-20 cm). The retention of the straw K left in the...
Tipo: Journal paper Palavras-chave: Nutrient turnover Crop combinations and interactions Cereals; Pulses and oilseeds Air and water emissions Composting and manuring.
Ano: 2003 URL: http://orgprints.org/3898/1/3898.pdf
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Exchangeable potassium in soil as indicator of potassium status in an organic crop rotation on loamy sand. Organic Eprints
Askegaard, Margrethe; Eriksen, Jørgen.
In organic agriculture, where K may be a limited resource, reliable tools are important in the assessment of K availability in the soil in order to avoid K deficiency. We investigated the effect of four organic farming systems on the exchangeable K in the plough layer of a six-course crop rotation from 1994 to 1997. The accumulated K balances over the four years varied between -49 and +120 kg K ha-1 and the corresponding exchangeable K (0-20 cm) in autumn 1997 was 7.1 and 9.6 mg K 100 g soil-1, respectively, as an average of the crop rotation. The exchangeable K fraction responded to the K application in manure and to the crop in the rotation. In an additional experiment, no yield response to K was found, despite a low level of exchangeable K. The...
Tipo: Journal paper Palavras-chave: Farming Systems.
Ano: 2002 URL: http://orgprints.org/391/1/AE2002.pdf
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Fangafgrøder i sædskiftet øger udbyttet i vårsæd Organic Eprints
Olesen, Jørgen E.; Rasmussen, Ilse Ankær; Askegaard, Margrethe.
Efterafgrøder af rajgræs og kløver gav udbyttestigninger i vårbyg på ca. 10 hkg/ha på sandjorden, men kun ca. 3 hkg/ha på lerjorden. Effekten varierede betydeligt mellem årene. Også total udbyttet i ært/byg til modenhed blev øget ved anvendelse af fangafgrøder.
Tipo: Newspaper or magazine article Palavras-chave: Farming Systems.
Ano: 2001 URL: http://orgprints.org/373/1/E0053.pdf
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Forsøg med efterafgrøder på sandjord Organic Eprints
Askegaard, Margrethe.
Brug af efterafgrøder er en forudsætning for at kunne reducere udvaskningen af næringsstoffer på sandjorde. Spørgsmålet er hvilke efterafgrøder man skal vælge. I systemer med lille eller ingen brug af husdyrgødning er det også aktuelt at undersøge mulighederne for at anvende efterafgrøder af arter der kan fiksere luftens kvælstof. For at få belyst disse spørgsmål anlagde vi sidste år en række forsøg på Jyndevad forsøgsstation. Dette års høst er netop opgjort.
Tipo: Newspaper or magazine article Palavras-chave: Crop combinations and interactions.
Ano: 2002 URL: http://orgprints.org/1628/1/Efterafgroeder.pdf
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Growing cover crops in organic arable crop rotations: Best practices from Denmark Organic Eprints
Askegaard, Margrethe.
When sown correctly at the right time, in the right position within the rotation, cover crops retain nutrients, conserve water, prevent soil erosion, improve soil fertility and quality, and suppress weeds. Growing cover crops is recognized as a climate-smart agricultural practice. Practical recommendation Where to position and when to time cover crops in the rotation? • Grow cover crops in the 1st and 2nd year after ploughing of clover-grass to avoid nitrogen losses. • Grow nitrogen fixing cover crops on soils with low fertility. • Sow cover crops into or immediately after the main crop. In row crops, sow the cover crop in combination with the last hoeing. If the harvest of the main crop is rather early, sow the cover crop after harvest. • The...
Tipo: Practice tool Palavras-chave: Soil quality Crop combinations and interactions Cereals; Pulses and oilseeds Weed management Farm nutrient management.
Ano: 2017 URL: http://orgprints.org/31051/13/PA_036_Cover_Crops_QR.pdf
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Growing cover crops in organic arable crop rotations: best practices from Denmark Organic Eprints
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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Growth dynamics of perennial weeds in long-termed organic 8 cropping systems on two locations in Denmark Organic Eprints
Melander, Bo; Rasmussen, Ilse A.; Askegaard, Margrethe; Olesen, Jørgen E..
The dynamics of perennial weeds in organic crop rotations.
Tipo: Journal paper Palavras-chave: Weed management.
Ano: 2014 URL: http://orgprints.org/25686/7/25686.pdf
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Herbs in grasslands - effect of slurry and grazing/cutting on species composition and nutritive value Organic Eprints
Søegaard, Karen; Eriksen, Jørgen; Askegaard, Margrethe.
Herbs are established in many organic grasslands due to their expected beneficial properties for nutritive value and biodiversity. However, knowledge about grassland herbs is limited. Three mixtures were therefore established at different grazing/cutting management and slurry applications. The competitiveness of the species varied greatly. Plantain (Plantago lanceolata) and lucerne (Medicago sativa) competed best under cutting; in contrast, chicory (Cichorium intybus) competed best under grazing. Caraway (Carum carvi), burnet (Poterium sanguisorba) and lotus (Lotus corniculatus) had a relative low competitiveness. Slurry application did not affect the proportion of non-leguminous herbs. The nutritive value differed: caraway had the highest and plantain the...
Tipo: Conference paper, poster, etc. Palavras-chave: Pasture and forage crops.
Ano: 2008 URL: http://orgprints.org/14677/1/editor_soegaard.pdf
Registros recuperados: 77
Primeira ... 1234 ... Última
 

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