|
|
|
| Registros recuperados: 36 | |
|
| |
|
| |
|
|
| Pirhofer-Walzl, K.; Rasmussen , Jim; Høgh-Jensen, Henning; Eriksen, Jørgen; Soegaard, Karen; Rasmussen, Jesper. |
| 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 leaflabelled 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 measured. Neighbouring plants contained greater amounts of N... |
| Tipo: Journal paper |
Palavras-chave: Crop combinations and interactions. |
| Ano: 2012 |
URL: http://orgprints.org/20645/4/20645.pdf |
| |
|
| |
|
|
| Halberg, Niels; Sulser, Timothy B.; Høgh-Jensen, Henning; Rosegrant, Mark W.; Knudsen, Marie Trydeman. |
| The spread of organic and agro-ecological farming (OF) methods in developing countries has raised a debate whether a large scale adoption of OF will increase or decrease global food security. This will however depend on a number of socio-economic factors together with the relative yield levels of OF versus conventional farming systems. Relative yields again depend on a number of agro ecological factors and the characteristics of farming systems before conversion. In areas with intensive high-input agriculture, conversion to OF will most often lead to a reduction in crop yields per ha by 20-45 % in crop rotations integrated with leguminous forage crops. In many areas with low input agricultural systems farmers have little incentive or access to use... |
| Tipo: Book chapter |
Palavras-chave: Food security; Food quality and human health Food systems. |
| Ano: 2006 |
URL: http://orgprints.org/9209/1/9209.pdf |
| |
|
|
| Høgh-Jensen, Henning; Loges, Ralf; Jensen, Erik Steen; Jørgensen, Finn V.; Vinther, Finn P.. |
| Symbiotically fixed nitrogen (N2) is an important input of nitrogen (N) source in many agricultural systems. In spite of this fact, the input of symbiotically fixed N to a particular cropping system is usually not known and exact measurements are costly and laborious. Consequently, there is a demand for an uncomplicated and reliable tool to estimate symbiotic N2 fixation (SNF) in leguminous crops. A simple emperical model is proposed for quantification of SNF in forage legumes under low external input conditions. The model estimates SNF using dry matter yield as input and parameters for (i)N concentration in dry matter and the (ii) proportion of the N in the legume that is derived from the atmosphere. Further, the model includes fixed N not included in the... |
| Tipo: Journal paper |
Palavras-chave: Pasture and forage crops. |
| Ano: 2004 |
URL: http://orgprints.org/3085/1/emperical_model.pdf |
| |
|
| |
|
|
| El-Naggar, Ahmed; El-Araby, Ahmed; de Neergaard, Andreas; Høgh-Jensen, Henning. |
| A major challenge for low¬-external-input farming systems is to secure the N supply. Lack of synchrony between mineralization of organic N sources and plant N requirements is causing many growers to use different techniques to overcome this problem. One of these techniques is the application of soluble water extracts of different farm residues and plants. A field study was conducted to study the crop uptake of applied 15N-labeled alfalfa and clover extracts as compared to the N uptake from15N-glycine and three levels of 15N-(NH4)2SO4. The results show that total N accumulation in the field crops, squash and lettuce, was primarily affected by the amount of added N (P<0.05) and not by the form in which the N was applied (P>0.05). The utilization... |
| Tipo: Journal paper |
Palavras-chave: Crop husbandry. |
| Ano: 2008 |
URL: http://orgprints.org/18305/1/18305.pdf |
| |
|
|
| Høgh-Jensen, Henning. |
| Systems theory differs from classic analytical science by producing statements in the context of a descriptive system rather than seeking to reduce a complex problematic situation to researchable entities. This paper analyses the validity and applicability of systems theory as a scientific approach towards organic farming. The world-views on which organic farming and systems theory build, respectively, are discussed and the methodological consequences of these world views are clarified. The world-view inherent in organic farming (the ontological level), as reflected in stewardship towards nature, the ethic of animal husbandry, and the cycling processes in nature, is harmonious with the underlying ideas of systems theory as regards a hierarchical structure... |
| Tipo: Journal paper |
Palavras-chave: Research methodology and philosophy. |
| Ano: 1998 |
URL: http://orgprints.org/353/1/systems_theory.DOC |
| |
|
|
| Høgh-Jensen, Henning. |
| The last meal of an Iron Age man buried in a Danish bog included at least 60 plant species, including barley, linseed and species we now consider weeds. A modern man relies in contrast on a remarkable small number of crop plants, mostly cereal stables like wheat, rice and maize (Evans, 1998). Both land and people in Sub-Saharan Africa are suffering. Natural resource management is in distress and most rural Africans remain poor and food insecure despite widespread macroeconomic, political and sectorial reforms. Most predictions are that these Africans will remain food insecure in the foreseeable future (Pinstrup-Andersen & Pandya-Lorch, 2001). Innovations are, however, changing this landscape much faster than we could expect. A market-oriented... |
| Tipo: Book chapter |
Palavras-chave: Production systems Crop combinations and interactions Food security; Food quality and human health. |
| Ano: 2011 |
URL: http://orgprints.org/23294/7/23294.pdf |
| |
|
|
| Høgh-Jensen, Henning; Kamalongo, D.; Myaka, F.A.; Adu-Gyamfi, J.J.. |
| Maize is a major food crop in eastern and southern Africa and is often cultivated with insufficient supplies of nutrients. The current studies are aimed at diagnosing any potential nutrient limitation in maize under farmers’ conditions using the nutrient content in ear leaf tissue at tasseling stage. The majority of the maize crops were considered below the critical nitrogen (N) content in the ear leaves with mean N content of 1.84%. Phosphorus (P), B and Cu content appeared critically low at three of the four sites. Unique fingerprinting by multivariate statistics was possible for each site when using the proportion of nutrients in the leaf tissue. The content of six macro elements (N, P, K, S, Mg, Ca) at the tasseling stage were found to be able to... |
| Tipo: Journal paper |
Palavras-chave: "Organics" in general; Crop husbandry. |
| Ano: 2009 |
URL: http://orgprints.org/18303/1/18303.pdf |
| |
|
|
| Oelofse, Myles; Høgh-Jensen, Henning; Abreu, Lucimar Santiago de; Almeida, Gustavo Fonseca de; El-Araby, Ahmed; Hui, Qiao Yu; Sultan, Tursinbek; de Neergaard, Andreas. |
| Certified organic agriculture stipulates a range of principles and standards, which govern farmer practices. The recent global expansion of organic agriculture has raised new challenges for organic agriculture, particularly whether management practices in organic farms are subject to the forces of conventionalisation. We studied changes in agroecological practices in certified organic farms in China,Brazil and Egypt. The study takes departure in the conventionalisation hypothesis and the analysis is framed using organic and agroecological principles. The study focuses on agroecological design principles, inherent to organic agriculture, of diversity in crop production, pest, disease and weed management, and soil fertility management. The research design... |
| Tipo: Journal paper |
Palavras-chave: "Organics" in general; Systems research and participatory research; Food systems; Policy environments and social economy; Research methodology and philosophy; Knowledge management. |
| Ano: 2011 |
URL: http://orgprints.org/23292/7/23292.pdf |
| |
|
|
| Høgh-Jensen, Henning; Søegaard, K.. |
| The current study examined the capacity of different temporary grassland legume-grass mixtures under different N supply levels to supply similar amounts of elements in systems where the herbage is cut and feed. Mixtures showed a good robustness in supplying equal amounts of mineral elements in the combined herbage as well as equal concentrations in dry matter of mineral elements compared to the same species in monocultures. The reasons for the mixed systems to be able to buffer differences in N supply levels as well as different compositions of the mixtures were that legume leaves and stems had similar concentrations of mineral elements, whether in monocultures or in mixtures with grasses. Grasses in mixture with legumes had however higher N, Ca, S, Zn, Cu... |
| Tipo: Journal paper |
Palavras-chave: Health and welfare Crop health; Quality; Protection. |
| Ano: 2012 |
URL: http://orgprints.org/23287/7/23287.pdf |
| |
|
| |
|
|
| Gylfadóttir, Thórey; Helgadóttir, Áslaug; Høgh-Jensen, Henning. |
| The interspecific transfer of nitrogen (N) between white clover (Trifolium repens) and smooth meadow grass (Poa pratensis) in legume-based grasslands was assessed under North European field conditions using 15N individual plant leaf labelling. On average 50% of N in the grass was transferred from the white clover and about 6% of N in white clover was transferred from the grass. This corresponds to 2.5 and 0.3 g N m-2 being transferred over the growing season between the two species respectively and demonstrates that a significant part of the total N of the grass is coming through interspecific transfer. The majority of the 15N transferred was within a period of 20 days at relatively low soil temperatures. This implies that there is a need for a new focus... |
| Tipo: Journal paper |
Palavras-chave: Landscape and recreation; Farm nutrient management; Biodiversity and ecosystem services. |
| Ano: 2007 |
URL: http://orgprints.org/11466/1/11466.pdf |
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
|
|
| Oelofse, Myles; Høgh-Jensen, Henning; de Abreu, L.S.; de Almeira, G.F.; Hui, Q.Y.; de Neergaard, Andreas. |
| Increased demand for certified organic products has led to an increase in the number of certified organic farms in developing countries. Knowledge of farmer nutrient management practices on certified organic farms in developing countries is limited. Thus, the aim of this study was to investigate the impact of the adoption of certified organic agriculture on farm nutrient flows and nutrient budgets, and evaluate to which degree organic farms comply with organic principles relating to nutrient management. The study is based on five case studies of different types of certified organic farming systems in Brazil, Egypt and China. Farm nutrient flows and nutrient budgets for nitrogen, phosphorous and potassium were created for each farm. Four of the five... |
| Tipo: Journal paper |
Palavras-chave: Farm nutrient management. |
| Ano: 2010 |
URL: http://orgprints.org/18298/1/18298.pdf |
| |
|
|
| Nielsen, Bea; Thamsborg, Stig Milan; Hansen, Hanne; Ranvig, Hans; Høgh-Jensen, Henning. |
| Two trials were conducted to examine the effect of chicory included in or as additional plots of the ryegrass–white clover pastures on growth, naturally acquired nematode infections and selectivity of chicory by lambs. In Experiment 1, 31 weaned Texel lambs (36±7 kg) grazed either ryegrass–white clover (CTRL) or ryegrass–white clover–hicory pastures (CHIC). In Experiment 2, 30 weaned Shropshire lambs (32±7 kg) grazed either ryegrass–white clover (CTRL) or ryegrass–white clover with access to small additional chicory plots, which corresponded to 3% (CHIC-LO) or 6% of the total grazing area (CHIC-HI). No consistent differences in live weight gain and nematode faecal egg counts were observed in lambs grazing the different pasture types. Sward height on the... |
| Tipo: Journal paper |
Palavras-chave: Feeding and growth. |
| Ano: 2009 |
URL: http://orgprints.org/18302/1/Nielsen_2009_Livestock-Science.pdf |
| |
|
|
| 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 |
| |
| Registros recuperados: 36 | |
|
|
|
