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Registros recuperados: 13
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15Nitrogen transfer from legumes to neighbouring plants in multi-species grassland Organic Eprints
Pirhofer-Walzl, K.; Høgh-Jensen, H.; Rasmussen, J.; Rasmussen, J.; Søegaard, K.; Eriksen, J..
This study investigates the N transfer from legumes to neighbouring plants, grasses, legumes and herbs in a temperate grassland. In a field experiment white clover (Trifolium repens), red clover (Trifolium pratense) and lucerne (Medicago sativa) were leaf-labelled with 15N enriched urea. The 15N tracer was measured in above-ground plant tissue of eight neighbouring plants in two subsequent harvests in 2008. The three legumes donated 15N to all neighbouring plants, of which grasses, white and red clover were strong receivers. Results show that N transfer increases with N application and from the 1st to the 2nd cut.
Tipo: Conference paper, poster, etc. Palavras-chave: Biodiversity and ecosystem services.
Ano: 2010 URL: http://orgprints.org/17887/4/17887.pdf
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15Nitrogen uptake from shallow- versus deep-rooted plants in multi-species mixtures and monoculture grassland Organic Eprints
Pirhofer-Walzl, K.; Høgh-Jensen, H.; Rasmussen, J.; Rasmussen, J.; Søegaard, K.; Eriksen, J..
Only few studies have explored the importance of functional diversity in temperate agricultural grasslands in relation to nitrogen (N) uptake. This study investigates the consequence of growing deep-rooted plants together with grass-clover mixtures in terms of N uptake efficiency from deep soil layers. The objective was to compare the N uptake of the shallow-rooted grassland species Lolium perenne and Trifolium repens; and the deep-rooted species Cichorium intybus and Medicago sativa in monocultures and mixtures. We hypothesized that growing deep-rooted plant species in mixture with shallow-rooted species increases the N uptake from deep soil layers partly through competition. A 15N tracer study was carried out with 15N enriched ammonium-sulphate placed at...
Tipo: Conference paper, poster, etc. Palavras-chave: Biodiversity and ecosystem services.
Ano: 2010 URL: http://orgprints.org/17886/1/EGF_conference_for_organic_e_prints.pdf
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Afrika – Fremtidens Økologiske Kontinent? Organic Eprints
Egelyng, H.; Vaarst, M.; Hermansen, J.E.; Høgh-Jensen, H..
Afrikanske bønders forbrug af fossil energi er lavt – og deres forurening med nitrat, sprøjtegifte og klimagasser er begrænset.
Tipo: Newspaper or magazine article Palavras-chave: Community development.
Ano: 2008 URL: http://orgprints.org/14814/1/Afrika_fremtidens_okologiske_kontinent.pdf
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Effect of deep-rooted plant species on 15Nitrogen uptake and herbage yield in temporary agricultural grasslands Organic Eprints
Pirhofer-Walzl, K.; Eriksen, J.; Rasmussen, J.; Søegaard, K.; Høgh-Jensen, H.; Rasmussen, J..
Aims: Increase of plant diversity has been suggested to enhance grassland productivity and resource use efficiency. Most studies on agricultural grasslands have focused on functional diversity of mixtures comprising legumes and non-legumes, but there is little knowledge of plant nutrient acquisition from deep- and shallow-rooted grassland plant species. To investigate whether deep-rooted (chicory: Cichorium intybus L.; Lucerne: Medicago sativa L.) and shallow-rooted (perennial ryegrass: Lolium perenne L.; white clover: Trifolium repens L.) grassland plant species differ in herbage yield and depth dependent soil N-access, we investigated in the field if 1) a mixture comprising shallow- and deep-rooted grassland plant species has greater herbage yields than...
Tipo: Journal paper Palavras-chave: Pasture and forage crops.
Ano: 2012 URL: http://orgprints.org/20614/4/20614.pdf
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Fate of 15N- and 14C from labelled plant material: Recovery in perennial ryegrass-clover mixtures and in pore water of the sward Organic Eprints
Rasmussen, J.; Gjettermann, B.; Eriksen, J.; Jensen, E.S.; Høgh-Jensen, H..
The below ground C and N dynamics leading to organic and inorganic N leaching from perennial ryegrass-clover mixtures are not well understood. Based on the hypothesis that four different plant materials would degrade differently, a 16 months field experiment was conducted to determine (i) the source strength of labelled plant residues in dissolved inorganic N (DIN) and dissolved organic N (DON) in pore water from the plough layer, and (ii) the plant uptake of organically bound N. Litterbags containing 14C- and 15N-labelled ryegrass or clover roots or leaves were inserted into the sward of a ryegrass-clover mixture in early spring. The fate of the released 14C and 15N was monitored in harvested biomass, roots, soil, and pore water percolating from the...
Tipo: Journal paper Palavras-chave: Nutrient turnover; Soil biology; Air and water emissions.
Ano: 2008 URL: http://orgprints.org/16290/1/16290.pdf
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Life cycle assessment of fossil energy use and greenhouse gas emissions in Chinese pear production Organic Eprints
Liu , Y.; Langer, V.; Høgh-Jensen, H.; Egelyng, H..
An environmental life cycle assessment (LCA) was performed in China to investigate environmental consequences of the life cycle of pears in terms of fossil energy use and greenhouse gas emissions. The assessment identified activities that contributed significantly to pears’ environmental impacts from the cradle to the point of sale. Cultivation was identified as having the greatest greenhouse gas emissions in pear production chains, followed by the process of storage and transportation. The contribution from fossil energy use differed in the production chains since environmental performance does not follow the farming system (organic-conventional) but is co-determined by topography and thus machine use, by market demands to seasonality of products and...
Tipo: Journal paper Palavras-chave: "Organics" in general; Environmental aspects.
Ano: 2010 URL: http://orgprints.org/18291/1/18291.pdf
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Market Integration Shape Organic Farmers’ Organisation Organic Eprints
Sultan, T.; Mursal, A.; Salam, S.G.; Liu, Y.; Oelofse, M.; Knudsen, M.T.; El-Araby, A.; Delve, R.J.; Hauser, M.; Kledal, P.; Egelyng, H.; Halberg, N.; Høgh-Jensen, H..
Increasing consumption of organic products in globalised food chains will require the involvement of thousands more smallholder farmers in many regions of the world. A study of Egypt, China and Uganda identified the three key factors of property rights regimes, cultural differences and social organisation as determents of the supply chain organization and farmers’ degree of direct integration in the export markets. Patterns are emerging where smallholder farmers are being socially and economically linked to larger farmers who may do some processing before the raw materials are handed over to the contracting company. Where transactions costs are high, local communities may develop and contract out the land directly to exporting companies who farm using...
Tipo: Conference paper, poster, etc. Palavras-chave: Policy environments and social economy "Organics" in general Markets and trade Processing; Packaging and transportation Produce chain management.
Ano: 2008 URL: http://orgprints.org/11664/1/Sultan_11664_ed.pdf
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New Challenges in Underprivileged Regions Call for People-Centered Research for Development Organic Eprints
Høgh-Jensen, H.; Oelofse, M.; Egelyng, H..
The need for enhancing food production and availability in underprivileged regions of the world requires the attention of scientists. This article explores the possibilities for rethinking agricultural research for development (R4D) in the light of new challenges characterized by a high degree of scientific uncertainty along with associated intense political differences of interest. New challenges that particularly influence food production in underprivileged regions include global climate change, globalization of food chains, and emerging low-carbon energy systems. We argue that by applying the people-centered sustainable livelihoods approach as a research paradigm in R4D, researchers may be more successful in producing knowledge that is useful to...
Tipo: Journal paper Palavras-chave: Production systems; "Organics" in general.
Ano: 2010 URL: http://orgprints.org/18540/1/18540.pdf
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Nitrogen transfer from forage legumes to nine neighbouring plants in a multi-species grassland Organic Eprints
Pirhofer-Walzl, K.; Rasmussen, J.; Høgh-Jensen, H.; Eriksen, J.; Søegaard, K.; Rasmussen, J..
Legumes play a crucial role in nitrogen supply to grass-legume mixtures for ruminant fodder. To quantify N transfer from legumes to neighbouring plants in multi-species grasslands we established a grass-legume-herb mixture on a loamy-sandy site in Denmark. White clover (Trifolium repens L.), red clover (Trifolium pratense L.) and lucerne (Medicago sativa L.) were leaf-labelled with 15N enriched urea during one growing season. N transfer to grasses (Lolium perenne L. and xfestulolium), white clover, red clover, lucerne, birdsfoot trefoil (Lotus corniculatus L.), chicory (Cichorium intybus L.), plantain (Plantago lanceolata L.), salad burnet (Sanguisorba minor L.)and caraway (Carum carvi L.) was assessed. Neighbouring plants contained greater amounts of N...
Tipo: Journal paper Palavras-chave: Pasture and forage crops.
Ano: 2012 URL: http://orgprints.org/20613/4/20613.pdf
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Root size fractions of ryegrass and white clover contributes differently to C and N inclusion in SOM Organic Eprints
Rasmussen, J.; Eriksen, J.; Jensen, E.S.; Høgh-Jensen, H..
Grass-clover mixtures are essential in many low-N-input cropping systems, but the importance of various root fractions for the below-ground N dynamics are not well understood. This may be due to the difficulties of studying root longevity and turnover in situ in mixtures. The present field study, investigated (1) the development in root biomass over two growing seasons and (2) the turnover of dual N-15- and C-14-labelled ryegrass and white clover root material. Litter bags containing various dual-labelled plant materials were incubated in cylinders inserted in the topsoil of a young ryegrass-clover ley. Disappearance of C-14 and N-15 from the litter bag material were studied for 1 year following incubation. Four times during two growing seasons, roots were...
Tipo: Journal paper Palavras-chave: Farming Systems; Biodiversity and ecosystem services.
Ano: 2010 URL: http://orgprints.org/17875/4/17875.pdf
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The sustainable livelihoods approach: A frame for furthering our understanding of organic farming systems Organic Eprints
Oelofse, M.; Høgh-Jensen, H..
The rapid development of organic agriculture on a global scale has led to an increased inclusion of producers in developing and transitional countries in the organic food chain. In order to enhance the theoretical frame for the analysis and understanding of the impact that inclusion in the organic food chain has on producers and their families, an analysis was conducted of the use of the Sustainable Livelihoods Approach (SLA). The SLA provides a holistic and integrative approach which researchers can use as the overriding frame for their research. The application of the approach is recommended as it enables us to maintain important elements of the sustainability vision, yet emphasises that a number of assets influence farmers’ livelihoods and it maintains...
Tipo: Conference paper, poster, etc. Palavras-chave: Research methodology and philosophy.
Ano: 2008 URL: http://orgprints.org/11662/1/Oelofse_11662_ed.doc
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Udfordring eller mulighed for økologien Organic Eprints
El-Nagger, A.; Ounmaa, A.; Muukka, E.; Zaleckas, E.; Abraityté, G.; Jansons, I.; Rasmussen, J.; Ahnström, J.; Pirhofer-Walzl, K.; O'Doherty Jensen, K.; Jørgensen, K.F.; Sarunaite, L.; Bleidere, M.; Knudsen, M.T.; Pugliese, M.; Nielsen, M.H.M.; Muguerza, N.B.; Bakewell-Stone, P.; Hansen, P.K.; Abed-Ali Al-Kufaishi, S.A.; Kobayashi, S.; Rydberg, T.; Klubova, V.; Liorancas, V.; Høgh-Jensen, H..
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: Newspaper or magazine article Palavras-chave: "Organics" in general Values; Standards and certification.
Ano: 2005 URL: http://orgprints.org/10492/1/10492.pdf
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Yields and accumulations of N and P in farmer-managed intercrops of maize-pigeonpea in semi-arid Africa Organic Eprints
Myaka, F. M.; Sakala, W. D.; Adu-Gyamfi, J. J.; Kamalongo, D.; Ngwira, A.; Odgaard, R.; Nielsen, N. E.; Høgh-Jensen, H..
Maize (Zea mays L.) is a major staple food in Sub-Saharan Africa but low soil fertility, limited resources and droughts keep yields low. Cultivation of maize intercropped with pigeonpea (Cajanus cajan L. Millsp.) is common in some areas of eastern and southern Africa. The objectives of this study were (1) to investigate dry matter, nitrogen (N) and phosphorus (P) accumulation in different plant components of maize-pigeonpea intercropping systems and (2) to report the effects of the intercrops on soil fertility. Maize-pigeonpea intercrops were compared to sole maize grown using farmers’ practices. Intercropping maize and pigeonpea increased (P<0.05) total system yield compared to sole maize in terms of biomass, N and P accumulation. Pigeonpea planted in...
Tipo: Journal paper Palavras-chave: Food security; Food quality and human health Farm nutrient management Recycling; Balancing and resource management.
Ano: 2006 URL: http://orgprints.org/9306/1/9306.pdf
Registros recuperados: 13
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