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| Registros recuperados: 21 | |
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| Kristensen, Kristian. |
| The paper shows how the Alpha-design (also known as generalised lattice) may be used for constructing incomplete split-plot designs and describes 4 different methods (A, B, C and D) of construction. Intra-block efficiency factors and theoretical considerations are used to compare the methods. Based on those considerations method B was considered to be the most appropriate method for trials where tests for interaction between the two factors were important and thus this method was used and most of the paper deals with trials based on this construction method. The incomplete split-plots were superior to traditional split-plots in most cases – and the increase in efficiency of the designs can be quite large – especially for comparisons involving the... |
| Tipo: Journal paper |
Palavras-chave: Farming Systems; Crop husbandry. |
| Ano: 2012 |
URL: http://orgprints.org/20879/1/2012_Kristensen_Incomplete_split%2Dplot_designs.pdf |
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| Askegaard, Margrethe; Olesen, Jørgen E.; Kristensen, Kristian. |
| Nitrate leaching from crop rotations supporting organic grain production was investigated from 1997 to 2000 in a field experiment at three locations in Denmark on different soil types. Three experimental factors were included in the experiment in a factorial design: (1) proportion of N2-fixing crops in the rotation (crop rotation), (2) catch crop (with and without), and (3) manure (with and without). Three, four-course rotations were compared, two at each location. The nitrate leaching was measured using ceramic suction cells. Leaching losses from the crop rotation with grass–clover green manure and without catch crops were 104, 54 and 35 kgNha21 yr21 on the coarse sand, the loamy sand, and the sandy loam, respectively. There was no effect of manure... |
| Tipo: Journal paper |
Palavras-chave: Production systems Crop combinations and interactions Composting and manuring Recycling; Balancing and resource management Nutrient turnover Farm nutrient management. |
| Ano: 2005 |
URL: http://orgprints.org/18726/1/18726.pdf |
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| 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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| Kristensen, Kristian; Ericson, Lars. |
| The growing interest in organic farming has increased the interest in examining if different growing characteristics among varieties would explain differences in yield differently in conventional compared to organic systems. This work will focus on that question. The analyses are performed using data from trials with spring barley in Denmark and Sweden. Growing characteristics on diseases, volume weight, grain weight, and lodging will be included in the work. The growing characteristics are included as covariates to see how much of the variation caused by varieties and interaction with varieties that can be explained by the growing characteristic. The model is setup in order to estimate simultaneously the effect of the growing characteristics and the... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Farming Systems; Crop husbandry. |
| Ano: 2007 |
URL: http://orgprints.org/20888/3/20888.pdf |
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| Kristensen, Kristian; Ericson, Lars. |
| The increasing interest in organic farming has increased the interest in examining the importance of the different growing characteristics, such as attack of diseases, grain weight, lodging and heading date. One of the important questions raised was whether the relationship between the growing characteristics and yield would be the same for conventionally and organically grown crop or would some growing characteristics be more important for organically than for conventionally grown crops. This work will focus on that question. The analyses are performed using two datasets with comparable trials in both conventional and organic grown systems for barley (Hordeum vulgare). The two datasets were from Sweden and Denmark. From Sweden 22 conventional and 22... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Farming Systems; Crop husbandry. |
| Ano: 2007 |
URL: http://orgprints.org/20892/4/20892.pdf |
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| Kristensen, Kristian; Willads, Jakob. |
| Incomplete block designs were first used in the statutory variety trials in Denmark in 1979. During the last years the use of incomplete block designs in variety trials has increased and is now used both for performance trials and DUS trials in most of the trials with many entries. The need for incomplete block designs has increased as the number of varieties in many crops has increased. Incomplete block designs are also used in a few other types of designs such as trials with different pesticides. Most of the incomplete block designs have been Alpha-designs. Examples of designs and the efficiency of such designs were presented together with a discussion of the most important benefits and drawbacks of using such designs. |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Technology assessment. |
| Ano: 2003 |
URL: http://orgprints.org/7865/1/7865.pdf |
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| Østergård, Hanne; Kristensen, Kristian; Hovmøller, Mogens; Willas, Jakob. |
| For organic crop production, well-characterised varieties increase the possibilities for controlling diseases and weeds and compensating for deficits in nutrients. Variation in grain yield was studied in about 150 spring barley varieties and variety mixtures and 20 combinations of location, growing system and year. Choice of variety was found to be as important a factor for grain yield as other factors in the management. Some variety mixtures out yielded even the best variety in the mixture, when this was grown in pure stand. Finally, a concept for organic variety testing of spring barley was developed. This Danish project is part of a European COST Network on sustainable low-input cereal production (SUSVAR) which coordinates studies in different countries... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Crop health; Quality; Protection Regulation Crop combinations and interactions Weed management Breeding; Genetics and propagation Biodiversity and ecosystem services. |
| Ano: 2006 |
URL: http://orgprints.org/8136/1/Hanne_Oestergaard_spring_barley_varieties.pdf |
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| Kristensen, Kristian; Bigongiali, Federica; Østergård, Hanne. |
| The paper shows, how incomplete split-plot designs can be constructed from -designs and how they can be analysed. The incomplete split-plot design can be regarded as both a practical and statistical compromise between traditional split-plot design and randomised complete block design. The efficiency of the design is compared to traditional split-plot design and randomised complete block design using data from 5 trials carried out using incomplete split-plot designs in Denmark through 2004-2007. The comparisons showed that the incomplete split-plot design were superior to traditional split-plot design in most cases – and in all cases when comparing differences among treatments in the whole-plot factor. The incomplete split-plot design was in many cases... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Farming Systems; Crop husbandry. |
| Ano: 2008 |
URL: http://orgprints.org/20887/3/20887.pdf |
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| Kristensen, Kristian; Ericson, Lars. |
| The interest in organic grown cereals has increased the need for variety tests under organic growing systems and/or the knowledge on whether growth characteristics describe yield differently under conventional and organic conditions. This paper is a contribution to that question by examining the relationships between some important growth characteristics in barley trials in both systems in Northern Sweden and in Denmark. Mixed model analyses were used for regressions of growth characteristics (or transformations of those) on yield (and log-transformed yield), allowing the slope to depend on the growing system. The analyses showed that diseases seemed to have a less negative effect on yield in the organic growing system than in the conventional growing... |
| Tipo: Journal paper |
Palavras-chave: Farming Systems; Crop husbandry. |
| Ano: 2008 |
URL: http://orgprints.org/20878/4/20878.pdf |
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| Hansen, Preben Klarskov; Willas, Jakob; Kristensen, Kristian. |
| A screening programme for crop variety competitiveness would ideally be based on only a few, non-destructive measurements of key growth traits. In this study we measured the weed suppressive ability of 79 varieties of spring barley in two ways: 1) directly, by weed coverage assessments under weedy conditions at three Danish locations in 2002-2004, and 2) indirectly, by non-destructive measurements of varietal growth traits under weed-free conditions in 17 other experiments in Denmark in 2001-2003. Based on just four varietal growth traits (reflectance, leaf area index, leaf angle and culm length), we successfully developed a method for indexing the weed suppressive ability of spring barley varieties. The suppressive index ranged from 12% in ‘Lux’ and 55%... |
| Tipo: Journal paper |
Palavras-chave: Crop combinations and interactions Weed management Breeding; Genetics and propagation. |
| Ano: 2008 |
URL: http://orgprints.org/11294/2/11294.pdf |
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| Husted, Søren; Laursen, Kristian Holst; Larsen, Erik Huusfeldt; Kapolna, Emese; Knuthsen, Pia; Søltoft, Malene; Bügel, Susanne; Mark, Alicja Budek; Lauridsen, Charlotte; Jacobsen, Maja; Jørgensen, Henry; Halekoh, Ulrich; Kristensen, Kristian. |
| Trace elements, bioactive secondary metabolites and vitamins are among the most important quality parameters in plants. Yet, very little information is available on their content, bioavailability and health effects in organically grown plant food products. The main objective of OrgTrace is to study the impact of different agricultural management practices relevant for organic farming on the ability of cereal and vegetable crops to absorb trace elements from the soil and to synthesize bioactive compounds (secondary metabolites, antioxidant vitamins and phytates) with health promoting effects. Based on different plant products produced in OrgTrace, diets were composed and the bioavailabilities of health promoting substances were analyzed in a human... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: "Organics" in general; Farming Systems; Soil; Food systems. |
| Ano: 2011 |
URL: http://orgprints.org/18877/4/18877.pdf |
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| Oestergaard, Hanne; Kristensen, Kristian; Jensen, Jakob W.. |
| Fifty spring barley varieties grown under organic as well as conventional growing conditions in experimental fields in four combinations of year and site were studied. The yield varied greatly within and between environments (years and sites) and systems. Furthermore, the variation among varieties was substantial and differed among different environments and systems. Associations between observed grain yield of these varieties and disease and growth characteristics assessed in the official conventional variety testing were compared between the organic and the conventional system. Using factorial regression analysis, the best model was found for predicting the observed grain yield each year from these characteristics in the previous year. In this model, the... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Breeding; Genetics and propagation. |
| Ano: 2005 |
URL: http://orgprints.org/4437/4/Oestergaard_etal_4p_revised%2Ded.doc |
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| Registros recuperados: 21 | |
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