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Registros recuperados: 13
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Below ground C and N transformation processes in perennial grass-clover mixtures Organic Eprints
Rasmussen, Jim.
Leaching of N from grass-clover mixtures have been found in both organic and inorganic form. The environmental impact of this loss is however not well understood as leaching of organic C acting as energy source for denitrifying microorganisms could reduce the negative impact of N losses. In the present project the sources of N and C loss from perennial grass-clover swards were investigated in two field experiments using 14C and 15N tracers. The main findings of the project show that fresh plant material (< 1 year) does not contribute significantly to DOC leaching, whereas both fresh ryegrass and clover material was shown to contribute to DON and DIN losses. Paper I: Carbon (C) and nitrogen (N) dynamics in a third production year ryegrass-clover...
Tipo: Thesis Palavras-chave: Nutrient turnover; Farm nutrient management; Air and water emissions.
Ano: 2007 URL: http://orgprints.org/10663/1/10663.pdf
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Deposition of C and N in the soil from legume-based cover crops – quantification and mineralization. Organic Eprints
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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DOC and DON from grass-clover - results from a field experiment Organic Eprints
Rasmussen, Jim; Høgh-Jensen, Henning.
The C and N dynamics in perennial grass-clover mixtures are not fully understood although such mixtures dominate temperate grassland. The co-existence of clover and grass involves both competition for and transfer of nutrients between the species. The nutrients that are competed for and transferred may originate from leaky root systems, from a rapid turnover of the fine root systems, or from degradation of more stabile organic material. The aim of the present study was to investigate the origin of dissolved organic C and N in perennial grass-clover mixtures. In an existing grass-clover ley, field mezotrons (cylinders with a diameter 30 cm) were installed in the spring of 2003 to depths of 20, 40 and 60 cm. Suction cups was installed beneath the...
Tipo: Conference paper, poster, etc. Palavras-chave: Air and water emissions.
Ano: 2005 URL: http://orgprints.org/9128/1/9128.pdf
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Elimination behaviour and soil mineral nitrogen load in an organic system with lactating sows – comparing pasture based systems with and without access to poplar (Populus sp.) trees Organic Eprints
Jakobsen, M.; Hermansen, J.E.; Andersen, Heidi Mai-Lis; Jørgensen, Uffe; Labouriau, R.; Rasmussen, Jim; Kongsted, A.G..
Innovative strategies in free-range pig production is needed to improve the environmental performance of the system. Based on previous studies, inclusion of trees was hypothesized to improve the system’s nitrogen efficiency. We investigated sow elimination behaviour, faeces load and localisation as well as soil mineral nitrogen load in pasture based individual paddocks with and without access to two rows of poplar (Populus sp.) trees. Unlike expected sows showed no preference for eliminating in the zone with poplars but clearly avoided defecating near the hut, feed and water. Soil mineral nitrogen load showed a heterogeneous pattern as also found in previous studies. In comparison to grass, our results indicated that the poplars had an increased winter...
Tipo: Journal paper Palavras-chave: Pigs.
Ano: 2018 URL: http://orgprints.org/33906/1/Paper%20II.pdf
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Globalisation as a challenge or opportunity for organic farming Organic Eprints
El-Nagger, Ahmed; Ounmaa, Andres; Muukka, Eija; Zaleckas, Ernestas; Abraityté, Gerda; Jansons, Imants; Rasmussen, Jim; Ahnström, Johan; Pirhofer-Walzl, Karin; Jensen, Katherine O’Doherty; Jørgensen, Kirstine F.; Sarunaite, Lina; Bleidere, Mara; Knudsen, Marie Trydeman; Pugliese, Massimo; Nielsen, Merete Højrup Møller; Mugurerza, Natalia Bellostas; Bakewell-Stone, Petra; Hansen, Preben Klarskov; Al-Kufaishi, Sermed Adil Abed-Ali; Kobayashi, Sofie; Rydberg, Torbjörn; Klubova, Vera; Liorancas, Viktoras; Høgh-Jensen, Henning.
During one intensive week in October 2005, the authors were gathered to discuss the impact that globalisation has on the Organic Food Systems and the opportunities that globalisation opens up for developing these systems. The meeting took place as a Ph.D. course under the auspices of the Research School of Organic Farming and Food Systems (SOAR; www.soar.dk). All participants research within Organic Agriculture and Food Production in one way or another.
Tipo: Journal paper Palavras-chave: Food security; Food quality and human health "Organics" in general Food systems Markets and trade Values; Standards and certification.
Ano: 2006 URL: http://orgprints.org/9333/1/9333.pdf
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In situ carbon and nitrogen dynamics in ryegrass-clover mixtures: Transfers, deposition and leaching Organic Eprints
Rasmussen, Jim; Eriksen, Jørgen; Jensen, Erik Steen; Esbensen, Kim H.; Høgh-Jensen, Henning.
Carbon (C) and nitrogen (N) dynamics in ryegrass-clover mixtures were investigated in field mezotrons installed to depths of 20, 40 and 60 cm and equipped with suction cups to collect percolating pore water. Ryegrass and clover leaves were cross-labelled with 14C- and 15N-enriched urea and the fate of the two tracers was studied for three months during summer. Transfer of 14C occurred mainly from ryegrass to clover, whereas the largest transfer of 15N was in the opposite direction. The average transfer of N from clover was 40% (±3.1, n=9) of N in ryegrass, whereas the fraction of N in clover donated by ryegrass was 5% (±1.2, n=9). The amount of 14C transferred from ryegrass to clover was 1.7% (±0.1, n=9) of the 14C-activity in the total aboveground biomass...
Tipo: Journal paper Palavras-chave: Nutrient turnover; Air and water emissions.
Ano: 2007 URL: http://orgprints.org/10390/1/10390.pdf
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Legume-based cover crops benefit crop yield and reduce nitrate leaching Organic Eprints
De Notaris, Chiara; Rasmussen, Jim; Sørensen, Peter; Olesen, Jørgen E..
The use of cover crops in arable farming is more efficient in nitrate leaching reduction than decreasing the field nitrogen surplus. However, this requires well-developed cover crops.
Tipo: Web product Palavras-chave: Soil quality.
Ano: 2018 URL: http://orgprints.org/33225/1/index.html
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Manipulating cover crop growth by adjusting sowing time and cereal interrow spacing to enhance residual nitrogen effects Organic Eprints
De Notaris, Chiara; Rasmussen, Jim; Sørensen, Peter; Melander, Bo; Olesen, Jørgen E..
Legume-based cover crop (CC) mixtures can increase nitrogen (N) availability in arable systems, reducing the need for external N inputs, as they retain soil N and fix atmospheric N2. However, they need sufficient biomass accumulation to influence soil N availability. Early establishment through undersowing can improve CC growth and plant N accumulation, but competition with the main crop should be minimized. This study aimed to investigate the effect of main crop inter-row spacing (12, 18, 24 cm), manure application (without, with) and CC undersowing (early, late, no cover crop) on N accumulation in a legume-based CC mixture and the residual N effect on the following crop. We conducted a field experiment in Denmark with spring wheat as main crop and spring...
Tipo: Journal paper Palavras-chave: Crop combinations and interactions; Farm nutrient management.
Ano: 2019 URL: http://orgprints.org/35015/1/De%20Notaris%202019_cover%20crop%26row%20spacing.pdf
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N fertilizer value of legume-based catch crops Organic Eprints
De Notaris, Chiara; Sørensen, Peter; Rasmussen, Jim; Olesen, Jørgen E..
N availability is one of the main factors limiting productivity in organic arable systems. Legume-based catch crops (CC) were shown to both increase N yield and reduce N leaching at the crop rotation scale, but strategies to stabilize their growth are required (De Notaris et al., 2018). The present study showed that early CC sowing time and an increased main crop row space can help stabilize CC growth and increase N accumulation, especially when the conditions for the CC are not favorable. Despite the variations in N accumulated in CC biomass, legume-based catch crops represent a valuable source of N for the subsequent crop, with their fertilizer value being less variable than the N accumulated in CC biomass.
Tipo: Conference paper, poster, etc. Palavras-chave: Nutrient turnover; Denmark; Farm nutrient management.
Ano: 2018 URL: http://orgprints.org/33053/1/De%20Notaris_N%20workshop%20abstract.doc
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Nitrogen leaching: a crop rotation perspective on the effect of N surplus, field management and use of catch crops Organic Eprints
De Notaris, Chiara; Rasmussen, Jim; Sørensen, Peter; Olesen, Jørgen E..
Components of the field nitrogen (N) balance (input and surplus) are often used to predict nitrate leaching from agricultural lands. However, management factors, such as use of catch crops, greatly affect the actual loss and are a key to reduce N leaching. The present study is based on the 4th cycle of a long-term crop rotation experiment in Denmark, and it aims to quantify, from a crop rotation perspective, the influence on N leaching from N input and surplus or management factors. The experiment included three cropping systems (two organic and one conventional) with or without use of animal manure and catch crops. N leaching was calculated from measurements of nitrate in soil water sampled with ceramic suction cups installed at 1 m depth in all plots. At...
Tipo: Journal paper Palavras-chave: Air and water emissions; Farm nutrient management.
Ano: 2017 URL: http://orgprints.org/31728/1/AGEE18205.pdf
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Nitrogen leaching: a crop rotation perspective on the effect of N surplus, field management and use of catch crops Organic Eprints
De Notaris, Chiara; Rasmussen, Jim; Sørensen, Peter; Olesen, Jørgen E..
Components of the field nitrogen (N) balance (input and surplus) are often used to predict nitrate leaching from agricultural lands. However, management factors, such as use of catch crops, greatly affect the actual loss and are a key to reduce N leaching. The present study is based on the 4th cycle of a long-term crop rotation experiment in Denmark, and it aims to quantify, from a crop rotation perspective, the influence on N leaching from N input and surplus or management factors. The experiment included three cropping systems (two organic and one conventional) with or without use of animal manure and catch crops. N leaching was calculated from measurements of nitrate in soil water sampled with ceramic suction cups installed at 1 m depth in all plots. At...
Tipo: Journal paper Palavras-chave: Air and water emissions; Farm nutrient management.
Ano: 2018 URL: http://orgprints.org/32665/1/De%20Notaris%202018_N%20leaching.pdf
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Origin and composition of Dissolved Organic C and N from grass-clover mixtures Organic Eprints
Rasmussen, Jim; Høgh-Jensen, Henning.
The C and N dynamics in perennial grass-clover mixtures are not fully understood although such mixtures dominate temperate grassland. The co-existence of clover and grass involves both competition for and transfer of nutrients between the species. The nutrients may originate from leaky root systems, from a rapid turnover of the fine root systems, or from degradation of more stabile organic material. The aim of the study is - to determine the origin of DOC and DON in grass-clover mixtures - to determine the composition of DOC and DON from the species - to investigate the transfer of C and N between grass and clover Method: In a third year grass-clover ley at the KVL research fields, mezotrons were installed to depths of 20, 40 and 60 cm in...
Tipo: Conference paper, poster, etc. Palavras-chave: Nutrient turnover; Specific methods.
Ano: 2004 URL: http://orgprints.org/3542/1/3542.ppt
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Row spacing and catch crop establishment in organic arable systems: a way to increase biological N fixation Organic Eprints
De Notaris, Chiara; Sørensen, Peter; Rasmussen, Jim; Olesen, Jørgen E..
Increasing the row space of spring wheat from 12 to 24 cm, but maintaining the same seeding density, didn´t decrease its yield. On the other hand, it positively influenced the growth of the undersown catch crop, a mixture of red clover, white clover, rye grass and chicory.
Tipo: Conference paper, poster, etc. Palavras-chave: Crop combinations and interactions; Nutrient turnover; Weed management; Farm nutrient management.
Ano: 2016 URL: http://orgprints.org/30876/1/Session%203-57-58.pdf
Registros recuperados: 13
Primeira ... 1 ... Última
 

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