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| Registros recuperados: 21 | |
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| Oelofse, Myles; Jensen, Lars Stoumann; Magid, Jakob. |
| Soil fertility management in organic sys- tems, regulated by the organic standards, should seek to build healthy, fertile soils and reduce reliance on external inputs. The use of nutrients from conventional sources, such as animal manures from conventional farms, is currently permitted, with restrictions, in the organic regulations. However, the reliance of organic agriculture on the conventional system is considered problematic. In light of this, the organic sector in Denmark has recently decided to gradually phase out, and ultimately ban, the use of conventional ma- nures and straws in organic agriculture in Denmark. Core focal areas for phasing out conventional nutrients are as follows: (1) amendments to crop selection and rotations, (2) alternative... |
| Tipo: Journal paper |
Palavras-chave: Soil quality Recycling; Balancing and resource management Nutrient turnover Farm nutrient management History of organics. |
| Ano: 2013 |
URL: http://orgprints.org/27911/1/Myles%20Phasing%20out%20implications%20personal%20copy%202013.pdf |
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| Oelofse, Myles; Jensen, Lars Stoumann; Magid, Jakob. |
| Soil fertility management in organic systems, regulated by the organic standards, should seek to build healthy, fertile soils and reduce reliance on external inputs. The use of nutrients from conventional sources, such as animal manures from conventional farms, is currently permitted, with restrictions, in the organic regulations. However, the reliance of organic agriculture on the conventional system is considered problematic. In light of this, the organic sector in Denmark has recently decided to phase out, and ultimately ban, the use of conventional manures and straws in organic agriculture in Denmark by 2021. Core focal areas for phasing out conventional nutrients are 1) amendments to crop selection and rotations, 2) alternative nutrient sources... |
| Tipo: Journal paper |
Palavras-chave: Soil quality Composting and manuring Recycling; Balancing and resource management Nutrient turnover Farm nutrient management Quality and evaluation of inputs. |
| Ano: 2011 |
URL: http://orgprints.org/19839/3/19839.pdf |
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| Wang, Yaosheng; Thorup-Kristensen, Kristian; Jensen, Lars Stoumann; Magid, Jakob. |
| Background and Aims A number of root and root hair traits have been proposed as important for acquisition of P. However, it remains unknown whether these traits are most important in determining macro- and micronutrient uptake at low soil fertility. This study investigated the variations in root and root hair traits among spring wheat genotypes and examined which root and root hair traits are most important for high uptake of macro- and micronutrients. Methods Six spring wheat genotypes were grown in a soil with low nutrient availability. The root and root hair traits as well as the content of macro- and micronutrients were identified. Results A significant genetic variability in root and root hair traits was found. High root growth vigour and long and... |
| Tipo: Journal paper |
Palavras-chave: Soil quality Composting and manuring Breeding; Genetics and propagation. |
| Ano: 2014 |
URL: http://orgprints.org/27912/8/27912.pdf |
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| Wang, Yaosheng; Andersen, Sven Bode; Thorup-Kristensen, Kristian; Jensen, Lars Stoumann; Magid, Jakob. |
| Root and root hairs of plants have been intensively studied in solution culture; however, correlation of such measurements in solution culture with development in soil is poorly understood. This study compared growth of roots and root hairs as well as uptake of macro- and micronutrients of six spring wheat varieties in solution culture under P stress and P abundance and in a low fertility soil. Results showed that root length and surface area under P stress was significantly positively correlated with that in the low fertility soil, while no such correlation was apparent for root hair length and density. In absolute terms the root length, surface area, root hair length and density of spring wheat varieties were substantially higher in soil than in solution... |
| Tipo: Journal paper |
Palavras-chave: Soil quality Breeding; Genetics and propagation. |
| Ano: 2014 |
URL: http://orgprints.org/27913/3/27913.pdf |
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| Pedersen, Anders; Zhang, Kefeng; Jensen, Lars Stoumann; Thorup-Kristensen, Kristian. |
| Plant soil and atmosphere models are commonly used to predict crop yield and associated environmental consequences. Such models often include complex modelling of water movement, soil organic matter turnover and above ground plant growth. However, the root modelling in these models is often very simple, partly due to a limited access to experimental data. Here we propose a root model developed to describe root growth, root density and nitrogen uptake. The model focuses on annual crops, and attempts to model root growth of different crop species and row crops and its significance for nitrogen uptake from different parts of the soil volume. |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Crop combinations and interactions; Biodiversity and ecosystem services. |
| Ano: 2007 |
URL: http://orgprints.org/10745/1/10745.pdf |
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| Pedersen, Anders; Zhang, Kefeng; Thorup-Kristensen, Kristian; Jensen, Lars Stoumann. |
| We present a 2-D model for simulation of root density and plant nitrogen (N) uptake for crops grown in agricultural systems, based on a modification of the root density equation originally proposed by Gerwitz and Page (1974). A root system form parameter was introduced to describe the distribution of root length vertically and horizontally in the soil profile. The form parameter can vary from 0 where root density is evenly distributed through the soil profile, to 8 where practically all roots are found near the surface. The root model has other components describing root features, such as specific root length and plant N uptake kinetics. The same approach is used to distribute root length horizontally, allowing simulation of root growth and plant N uptake... |
| Tipo: Journal paper |
Palavras-chave: Nutrient turnover; Farm nutrient management; Air and water emissions. |
| Ano: 2009 |
URL: http://orgprints.org/16106/1/16106.pdf |
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| Pedersen, Anders; Thorup-Kristensen, Kristian; Jensen, Lars Stoumann. |
| This model analysis of catch crop effects on nitrate retention covered three soil texture classes sand, loamy sand, sandy loam) and three precipitation regimes in a temperate climate representative for northern Europe (annual precipitation 709-1026 mm) for a period of 43 years. Simulations were made with two catch crops (ryegrass and Brassica) with different rooting depths, and soil N effects in the next spring were analysed to 0.25, 0.75 and 2.0 m depth to represent the catch crop effect on following crops with different rooting depths. Nitrate retained without a catch crop was generally located in deeper soil layers. In the low precipitation regime the overall fraction of nitrate retained in the 0-2.0 m soil profile was 0.23 for the sandy soil, 0.69 for... |
| Tipo: Journal paper |
Palavras-chave: Soil; Farm nutrient management; Air and water emissions. |
| Ano: 2009 |
URL: http://orgprints.org/16122/1/16122.pdf |
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| Wang, Yaosheng; Thorup-Kristensen, Kristian; Jensen, Lars Stoumann; Magid, Jakob. |
| Rodsystemer er vigtige for planters optagelse af vand og næringsstoffer og dermed for vækst og ud-bytte, specielt under forhold med lav tilgæn- gelighed af jordens næringsstoffer. I det økologiske RDD projekt RoCo har vi undersøgt rodvækst, rodfordeling og roddybde samt rodhårs- karakteristika for forskellige sorter af vårhvede. Resultaterne af vores forsøg viser, at der er en stor variation i rod- og rodhårskarakteristika mellem forskellige vårhvedesorter, og disse er afgørende for, samt gene- tisk relateret til, afgrødens vækst og optagelse af næringsstoffer. Derfor er vital rodvækst og lange og tætte rodhår vigtige mål for selektion og fremtidig forædling af vårhvede til økologisk jordbrug. |
| Tipo: Newspaper or magazine article |
Palavras-chave: Soil quality Nutrient turnover Breeding; Genetics and propagation. |
| Ano: 2014 |
URL: http://orgprints.org/27914/7/27914.pdf |
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| de Neergaard, Andreas; Hauggaard-Nielsen, Henrik; Jensen, Lars Stoumann; Magid, Jakob. |
| Using data from a decomposition study, we aimed to test the parameterisation of the soil organic matter module of the DAISY model, and link measurable plant litter fractions (lignin, water-soluble) with the model defined plant litter pools. Shoot and root material from perennial ryegrass and white clover was incubated in a sandy loam soil at 9 °C for 94 days. Accumulated CO2 evolution, soil mineral nitrogen (N) and soil microbial biomass-N were measured during the incubation. Marked differences in decomposition rates between above- and below-ground material as well as between the two plant species were observed. The DAISY model was used to interpret the incubation results. Decomposition rates and utilisation efficiencies were modified, under the constraint... |
| Tipo: Journal paper |
Palavras-chave: Crop husbandry. |
| Ano: 2002 |
URL: http://orgprints.org/1333/1/1333.pdf |
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| Pedersen, Anders; Thorup-Kristensen, Kristian; Jensen, Lars Stoumann. |
| A model analysis of catch crop effects on nitrate leaching was carried out covering three soil types and three precipitation regimes in temperate climate. Catch crops with varying root properties (barssica and rye grass) were used to analyse the effect on nitrate retention in different soil layers. Climate data was taken from 3 different precipitation regimes over 43 years with an average annual amount of rainfall of 709, 796 and 1026 mm. The three soil types were typical Danish sandy soil, a loamy sand soil and a sandy loam. These soil types cover 65 % of the Danish arable area. Simulations covered a winter season from harvest to 1 May the following year. To illustrate the effect of rooting depth of the succeeding crop soil mineral N content is calculated... |
| Tipo: Journal paper |
Palavras-chave: Farm nutrient management; Denmark. |
| Ano: 2009 |
URL: http://orgprints.org/9341/2/9341.pdf |
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| Jensen, Lars Stoumann; Pedersen, Anders; Magid, Jakob; Nielsen, Niels Erik. |
| It is a well-known fact that catch crops have a significant effect on availability and loss of soil inorganic nitrogen (Thorup-Kristensen et al., 2003) and recently marked effects on soil inorganic sulphur dynamics have also been shown (Eriksen and Thorup-Kristensen 2002; Eriksen et al., 2004). However, we know much less about the effect of catch crops on phosphorous (P) and potassium (K) mobilisation and availability for the next crop. After several years of organic cash crop production, e.g. vegetables and cereals, yield levels may gradually be limited by soil P and K availability, depending on the initial status at conversion to organic production principles. This is particularly the case during the establishment phase of certain vegetable cultures... |
| Tipo: Journal paper |
Palavras-chave: Nutrient turnover Farm nutrient management Recycling; Balancing and resource management Air and water emissions. |
| Ano: 2005 |
URL: http://orgprints.org/6165/1/6165.pdf |
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| Registros recuperados: 21 | |
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