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| Registros recuperados: 65 | |
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| Rasmussen, Jesper; Bibby, Bo Martin; Schou, Anders P.. |
| In six field experiments it was investigated whether row spacing, timing, direction and orientation of post-emergence weed harrowing in spring barley influenced the selectivity and whether it is important that increasing intensities of harrowing are generated either by increasing number of passes or increasing driving speed. Selectivity was defined as the relationship between crop burial in soil immediately after treatment and weed control. To estimate crop burial, digital image analysis was used in order to make the estimations objective. The study showed that narrow row spacing decreased selectivity in a late growth stage (21) whereas row spacing in the range of 5.3 cm to 24 cm had no effects in an early growth stage (12). Harrowing across rows decreased... |
| Tipo: Journal paper |
Palavras-chave: Weed management; Technology transfer. |
| Ano: 2008 |
URL: http://orgprints.org/14987/1/14987.pdf |
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| Rasmussen, Jesper; Henriksen, Christian Bugge; Griepentrog, Hans W.; Nielsen, Jon. |
| Punch planting has recently been suggested to reduce intra-row weeds in organically grown row crops. In this method holes are punched in the ground with a minimum of soil disturbance and seeds are inserted into them, without soil disturbance outside the hole. The first experiments with a tractor-mounted prototype of a dibber drill (MK III) are presented here. In two years, three plant establishment procedures were compared at five different sowing dates in sugar beet and direct-sown onion. The plant establishment procedures were 1) normal sowing and mechanical control of weeds in the stale seedbed (N), 2) N + pre-emergence flame weeding (N+F), and 3) punch planting and flame weeding to control weeds in the seedbed and prior to crop emergence (P +F). The... |
| Tipo: Journal paper |
Palavras-chave: Weed management. |
| Ano: 2010 |
URL: http://orgprints.org/17904/1/17904.pdf |
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| 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 |
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| Rasmussen, Jesper; Nørremark, Michael; Bibby, Bo Martin. |
| A web-based digital image analysis tool (IMAGING Crop Response Analyser) has been developed, tested and made public (www.imaging-crops.dk). This new technology makes possible objective estimations of crop-soil cover (i.e. how much crop is buried with soil) associated with post-emergence weed control with spring tine harrows, rotary hoes and other weeders. Objective estimation of crop-soil cover offers new possibilities to improve decision support of physical weed control practises with low selectivity because trade-offs between weed control and resulting injury to the associated crop now may be quantified, communicated and incorporated into models. The objective of this resentation is to suggest key parameters and research priorities for future research... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Weed management; Technology assessment. |
| Ano: 2008 |
URL: http://orgprints.org/13688/1/13688.pdf |
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| Rasmussen, Jesper; Nørremark, Michael. |
| The main drawback by using crop soil cover in weed harrowing research is that it is assessed by visual scores, which are biased and context dependent. This problem may be solved by using digital image analysis. In this paper a new image capture standard and digital image analysis procedure was used to illustrate three key issues in relation to weed harrowing; selectivity, resistance and recovery. All issues require reliable assessments of crop soil cover. Crop soil cover was deduced from assessments of leaf cover, which is defined as the proportion of pixels in digital images determined to be green. Objective assessments of leaf cover and crop soil cover showed that the selectivity of weed harrowing in winter wheat and spring barley was unaffected by... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Weed management. |
| Ano: 2007 |
URL: http://orgprints.org/10759/1/10759.pdf |
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| Rasmussen, Ilse A.; Melander, Bo; Rasmussen, Karsten; Jensen, Rikke K.; Hansen, Preben K.; Rasmussen, Gitte; Christensen, Svend; Rasmussen, Jesper. |
| Cultural methods for prevention and improved crop competitiveness against weeds and mechanical weed control. |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Weed management Cereals; Pulses and oilseeds. |
| Ano: 2000 |
URL: http://orgprints.org/250/1/management.PDF |
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| Rueda-Ayala, Victor; Rasmussen, Jesper; Gerhards, Roland. |
| Side effects of herbicides and increasing prevalence of organic farming nduce the need of further developments in mechanical weed control. Mechanical weed control is mainly associated with cultivating tillage (e.g. tertiary tillage), but also primary and secondary tillage influence weeds. Cultivating tillage is performed in growing crops with harrows, hoes, brushes and a number of special tools for intra-row weed control. Inter-row cultivations have been used in many decades in row crops and perform in general well. To increase their capacity and accuracy, guidance systems are important to steer the hoes along the rows. The success of inter- and intra-row cultivation is highly influenced by selectivity factors. The control mechanisms of all cultivating... |
| Tipo: Book chapter |
Palavras-chave: Soil tillage; Weed management. |
| Ano: 2010 |
URL: http://orgprints.org/17843/4/17843.pdf |
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| Bugge Henriksen, Christian; Rasmussen, Jesper; Søgaard, Carsten. |
| The Kemink Exact Soil Management System is a non-inversion soil management system based on subsoiling, ridges and controlled traffic. Previous studies have documented benefits of the Kemink system used in its entirety, but the isolated effect of Kemink subsoiling has not been investigated before. To determine the isolated effect of Kemink subsoiling before and after planting two field experiments in sugar beet and barley were conducted in 1999 and 2000 under low nutrient input conditions in a conventional soil management system without recognized compaction problems. Kemink subsoiling after planting generally showed a negative effect on the growth and yield of both crops, whereas subsoiling before planting increased sugar beet yield from 8.4 to 9.5 t ha-1... |
| Tipo: Journal paper |
Palavras-chave: Cereals; Pulses and oilseeds Production systems Root crops Soil tillage. |
| Ano: 2005 |
URL: http://orgprints.org/1568/1/1568.pdf |
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| Rasmussen, Jesper; Nielsen, Helle H.; Gundersen, Hanne. |
| Post-emergence weed harrowing and other cultivation methods to control weeds in early crop growth stages may result in crop damage due to low selectivity between crop and weeds. Crop tolerance to cultivation plays an important role but it has not been clearly defined and analysed. We introduce a procedure for analysing crop tolerance based on digital image analysis. Crop tolerance is defined as the ability of the crop to avoid yield loss from cultivation in the absence of weeds, and it has two components: resistance and recovery. Resistance is the ability of the crop to resist soil covering and recovery is the ability of recover from it. Soil covering is the percentage of the crop that has been buried due to cultivation. We analysed data from six field... |
| Tipo: Journal paper |
Palavras-chave: Weed management. |
| Ano: 2009 |
URL: http://orgprints.org/15781/1/15781.pdf |
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| Jensen, Rikke K.; Rasmussen, Jesper; Melander, Bo. |
| Three field experiments were conducted in lupin in 1997, 1998 and 1999 to study two aspects of selectivity of post-emergence weed harrowing; the ability of the crop to resist soil covering (the initial damage effect), and the ability of the crop to tolerate soil covering (the recovery effect). Each year soil covering curves and crop tolerance curves were established in three early growth stages of lupin. Soil covering curves connected weed control and crop soil cover in weedy plots, and crop tolerance curves connected crop yield and crop soil cover in weed-free plots. The experiments showed that both resistance and tolerance were unaffected by the growth stage of lupin within the range from the cotyledon to the 7 to 8 leaf growth stages. Tolerance to soil... |
| Tipo: Journal paper |
Palavras-chave: Weed management. |
| Ano: 2004 |
URL: http://orgprints.org/3086/1/wre_396.pdf |
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| Registros recuperados: 65 | |
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