TY - GEN N2 - Grasslands are potential carbon sinks to reduce unprecedented increase in atmospheric CO2. Effect of age (1 to 4-yr-old) and management (slurry, grazing multispecies mixture) of a grass phase mixed crop rotation on carbon sequestration and emissions upon cultivation was compared with 17-yr-old grassland and a pea field as reference. Aboveground and root biomass were determined and soils were incubated to study CO2 emissions after soil disturbance. Aboveground biomass was highest in 1-yr-old grassland with slurry application and lowest in 4-yr-old grassland without slurry application. Root biomass was highest in 4-yr-old grassland, but all 1 to 4-yr-old grasslands were in between the pea field (0.81±0.094 g kg-1 soil) and the 17-yr-old grassland (3.17±0.22 g kg-1 soil). Grazed grasslands had significantly higher root biomass than cut grasslands. There was no significant difference in the CO2 emissions within 1 to 4-yr-old grasslands. Only the 17-yr-old grassland showed markedly higher CO2 emissions (4.9 ± 1.1 g CO2 kg-1 soil). Differences in aboveground and root biomass did not affect CO2 emissions, and slurry application did not either. The substantial increase in root biomass with age but indifference in CO2 emissions across the age and management in temporary grasslands, thus, indicates potential for long-term sequestration of soil C. A1 - Acharya, B.S. A1 - Rasmussen, J. A1 - Eriksen, J. SP - 33 TI - Grassland carbon sequestration and emissions following cultivation in a mixed crop rotation Y1 - 2012/// AV - public UR - https://orgprints.org/id/eprint/22041/ EP - 39 ID - orgprints22041 ER - TY - CONF AV - public UR - https://orgprints.org/id/eprint/53011/ ID - orgprints53011 A1 - Bloch, Nadja F A1 - Martins, Juliana Trindade A1 - Liang, Zhi A1 - Enggrob, Kirsten Lønne A1 - Rasmussen, Jim N2 - Summary of cover crop effect on spontaneous flora diversity and presence and input of carbon to soil after grain legume main crops Y1 - 2023/06/10/ TI - Main crop effect on biodiversity expression in spontaneous flora and C input from cover crop mixtures ER - TY - GEN EP - 347 UR - https://orgprints.org/id/eprint/21137/ ID - orgprints21137 AV - public TI - Interactions between pre- and post-emergence weed harrowing in spring cereals Y1 - 2012/// A1 - Brandsæter, Lars O. A1 - Mangerud, Kjell A1 - Rasmussen, Jesper SP - 338 N2 - Pre- and post-emergence weed harrowing were studied in spring cereals in different environments and with two types of harrows in Norway during 2004?2006. The objectives were to investigate interactions between pre and post-emergence weed harrowing and the importance of harrow type. We hypothesised that pre- and post-emergence harrowing interact positively, that a combination gives more stable weed control effects than pre- and post-emergence weed harrowing used alone, and that a harrow type with bent tines is more aggressive and suitable on hard-packed soils than a harrow with strait tines. The results only supported the last of these hypotheses. Post-emergence weed harrowing controlled a certain percentage of the present weeds, and this percentage was not dependent on pre-emergence weed harrowing. On average, pre-emergence harrowing reduced weed density by 26% and weed biomass by 22%, while the average effect of postemergence harrowing was 47% on weed density and 41% on weed biomass. The combined effect of pre- and post-emergence weed harrowing was 61% on weed density and 54% on weed biomass. The combination did not give more stable weed control effects than preand post-emergence weed harrowing used alone. Preemergence harrowing increased the average crop yield by 6.2%, post-emergence harrowing by 4.0% and the combined effect was 10%. Crop yield was mainly increased on hard-packed soils. Weed and crop responses varied strongly among experiments, but the efficacy of pre- and post-emergence weed harrowing was positively correlated across experiments. Weed species composition was of minor importance regarding weed control. The study indicates that one aggressive postemergence cultivation may be as good as one preemergence and one less aggressive post-emergence cultivation. However, little is known about the interactions between cultivation at different crop and weed growth stages ER - TY - GEN Y1 - 2004/06// TI - Inter-row subsoiling increases marketable yield in potatoes A1 - Bugge Henriksen, Christian A1 - Mølgaard, Jens Peter A1 - Rasmussen, Jesper N2 - Inter-row subsoiling increased average yield of 40-65 mm potatoes by 14 pct during 2001-2003. But there were significant differences between the years. In 2001, the yield increased by 49 pct, whereas it was unaffected or decreased in 2002 and 2003. Better understanding of optimal subsoiling conditions is needed to exploit the benefit of inter-row subsoiling. ID - orgprints3951 UR - https://orgprints.org/id/eprint/3951/ AV - public KW - subsoiling KW - potato KW - loosening PB - DARCOF ER - TY - GEN TI - Kemink subsoiling before and after planting Y1 - 2005/// A1 - Bugge Henriksen, Christian A1 - Rasmussen, Jesper A1 - Søgaard, Carsten SP - 59 N2 - 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 and sugar beet nitrogen uptake from 48.5 to 57.4 kg ha-1. There was no effect of subsoiling before planting on the grain yield of barley. The negative effect of subsoiling after planting was more pronounced in 1999 than in 2000, and more pronounced in spring barley. The study shows that Kemink subsoiling after planting involves a significant risk of crop damage and cannot be expected to improve crop performance in conventional soil management systems in its current form, whereas Kemink subsoiling before planting may have potential as a measure to increase yield of sugar beet and possibly other row crops too, under low nutrient input conditions. EP - 68 UR - https://orgprints.org/id/eprint/1568/ ID - orgprints1568 PB - Elsevier, Netherlands AV - restricted KW - Subsoiling KW - loosening KW - ripping KW - Kemink KW - in-row KW - inter-row ER - TY - GEN N2 - The inclusion of leys in arable cropping is generally found to improve soil fertility. The effect of leys depends on their botanical composition and management, but the significance of individual management factors remains confounded in most studies. We quantified the effects of one- to six-year-old pure grass leys on soil C (0-20 cm) and yields of three subsequent test crops of spring barley (Hordeum vulgare) under-sown with Italian ryegrass (Lolium perenne). Each ley was a mixture of four grass species (Lolium perenne, Festuca pratensis, Phleum pratense, Poa pratensis), exposed to three to four cuts annually. Only mineral fertilizers were applied (225 kg N ha-1 yr-1). The yield of barley was tested at six rates of N fertilizer (0 to 150 kg N ha-1). The effect of leys on nitrate leaching losses was determined in a separate experiment. Grass yields were consistently high during the ley phase (11.2 ? 12.5 t DM ha-1 yr-1), and the amount of N in grass cuts equalled that applied in fertilizers. The annual accumulation of soil C during the ley phase averaged 1.1 t C ha-1. Nitrate leaching losses were halved after ley establishment, remained low until the ley was ploughed, and returned then to pre-ley levels. In the first test crop, the grain yields of barley increased with ley age. However, addition of fertilizer N eliminated the benefits of older leys. In the second and third test crop, grain yields were unaffected by ley age. Although grain N contents in the first test crop were higher following older leys, fertilizer N rate was the dominant factor. More N was removed in barley grain plus straw than was added in N fertilizers (except at 150 kg N ha-1). The amount of soil C remained nearly constant during the test phase, probably due to the use of grass catch crops. We conclude that the main impact on soil fertility of non-leguminous leys, subject to cutting and well-balanced mineral N fertilizer management, is in the accumulation of soil C and reduction of leaching losses of soil nitrate, whereas effects on subsequent cereal crops are small and transient. A1 - Christensen, B.T. A1 - Rasmussen, J. A1 - Eriksen, J. A1 - Hansen, E.M. SP - 29 TI - Soil carbon storage and yields of spring barley following grass leys of different age Y1 - 2009/// AV - restricted UR - https://orgprints.org/id/eprint/16289/ EP - 35 ID - orgprints16289 ER - TY - GEN AV - public UR - https://orgprints.org/id/eprint/31785/ ID - orgprints31785 N2 - Intensively managed grasslands are dominated by highly productive grass-clover mixtures. Increasing crop diversity by inclusion of competitive forbs may enhance biomass production and sustainable biofuel production. Here we examined if one or all of three forbs (chicory, Cichorium intybus L.; caraway, Carum carvi L.; plantain, Plantago lanceolata L.) included in ryegrass-red clover mixtures enhanced above- and below-ground productivity, and assessed their biofuel potentials, based on a three-year experiment with and without fertilisation as cattle slurry. We determined herbage yield, standing root biomass, and estimated methane energy output and greenhouse gas (GHG) emissions per energy unit using life cycle assessment. Results showed that plantain-containing grass-clover mixtures significantly increased herbage yield, while chicory- or caraway-containing mixtures maintained similar yields to the grass-clover mixture. Standing root biomass of the grass-clover mixture was enhanced by inclusion of caraway and plantain, with that of plantain further enhanced by fertilisation. The highest methane energy output was achieved in plantain-containing grass-clover mixtures. All unfertilised mixtures achieved the 60% reduction in GHG emissions compared to fossil fuel, whereas all fertilised mixtures did not meet the 60% reduction target. These findings suggest that including competitive forbs such as plantain in grass-clover mixtures enhances productivity, supporting low-carbon footprint bioenergy production. A1 - Cong, W-F A1 - Jing, J A1 - Rasmussen, J A1 - Søegaard, K A1 - Eriksen, J Y1 - 2017/// TI - Forbs enhance productivity of unfertilised grass-clover leys and support low-carbon bioenergy ER - TY - GEN A1 - De Notaris, Chiara A1 - Enggrob, Ea E. A1 - Olesen, Jørgen E. A1 - Sørensen, Peter A1 - Rasmussen, Jim SP - 1 N2 - Increasing the production of grain legumes in Europe will contribute to protein self-sufficiency and provide direct and indirect environmental benefits, e.g., delivering ecosystem services such as N input via biological N2 fixation (BNF). Faba bean (Vicia faba L.) is the main grain legume cultivated in Europe with increasing interest from the organic sector. Agronomic and economic obstacles exist to the inclusion of grain legumes in cropping systems but could be counterbalanced by accounting for the provision of ecosystem services. Thus, variations in productivity and BNF under different management need to be investigated. We assessed productivity, yield stability and BNF in a common faba bean variety (Boxer), grown for four years (2015-2018) in a long-term crop rotation field experiment at Foulum, Denmark. We compared conventional and organic cropping systems with spring cereals and faba bean, with and without long-term use of animal manure and cover crops. N derived from atmosphere (%Ndfa), determined with the 15N isotope dilution method, varied from 78% to 93% with significant effects of year and cropping system. Conventional treatments had the highest %Ndfa and yield, but the lowest yield stability. Organic treatments had problems with pests and diseases, mainly towards the end of the growing season. Quantity of BNF (qBNF) in aboveground biomass was on average 255 kg N ha-1 in the organic and 334 kg N ha-1 in the conventional systems, which would have been underestimated by up to 50 and 100 kg N ha-1 respectively using standard literature %Ndfa values. A correct estimation of N input via BNF has economic and environmental implications (e.g., fertilization of following crops, N losses); thus, we recommend to account for the effect of management on %Ndfa and qBNF. TI - Faba bean productivity, yield stability and N2-fixation in long-term organic and conventional crop rotations Y1 - 2023/03// AV - public KW - grain legumes; pulses; biological N fixation; plant protein UR - https://orgprints.org/id/eprint/52960/ EP - 34 ID - orgprints52960 ER - TY - GEN AV - restricted ID - orgprints42333 UR - https://orgprints.org/id/eprint/42333/ N2 - Improving or maintaining soil health is crucial to support human needs, with the concept of soil quality connecting soil functions and sustainability concerns. In 2019, we assessed soil chemical, physical and biological properties in a long-term crop rotation experiment initiated in 1997 at Foulum, Denmark, with the aim of determining the long-term soil quality effects of the use of cover crops, animal manure, different crop sequences (with or without a legume-based ley) and organic vs conventional management. The concentration of soil organic carbon has been relatively stable across all treatments for 14 years prior to this investigation; in 2019, we found high aggregate stability, porosity, air permeability and pore organization in all treatments. Bulk density, air permeability and pore organization were affected to some extent by soil and crop management, with bulk density being the lowest in the organic treatment without cover crops, which had the most frequent harrowing. Earthworm density was the greatest in the organic system with grass-clover, especially following the ley year, thanks to a combination of high quality plant input and reduced soil disturbance. From a system perspective, none of the treatments investigated represented extremes, and all maintained good soil quality in the long-term. This indicates that long-term management should take into account the combination of different factors affecting soil quality. A1 - De Notaris, Chiara A1 - Jensen, Johannes L. A1 - Olesen, Jørgen E. A1 - da Silva, Tiago Stumpf A1 - Rasmussen, Jim A1 - Panagea, Ioanna A1 - Rubæk, Gitte H. Y1 - 2021/12// TI - Long-term soil quality effects of soil and crop management in organic and conventional arable cropping systems ER - TY - GEN N2 - Improving or maintaining soil health is crucial to support human needs, with the concept of soil quality connecting soil functions and sustainability concerns. In 2019, we assessed soil chemical, physical and biological properties in a long-term crop rotation experiment initiated in 1997 at Foulum, Denmark, with the aim of determining the long-term soil quality effects of the use of cover crops, animal manure, different crop sequences (with or without a legume-based ley) and organic vs conventional management. The concentration of soil organic carbon has been relatively stable across all treatments for 14 years prior to this investigation; in 2019, we found high aggregate stability, porosity, air permeability and pore organization in all treatments. Bulk density, air permeability and pore organization were affected to some extent by soil and crop management, with bulk density being the lowest in the organic treatment without cover crops, which had the most frequent harrowing. Earthworm density was the greatest in the organic system with grass-clover, especially following the ley year, thanks to a combination of high quality plant input and reduced soil disturbance. From a system perspective, none of the treatments investigated represented extremes, and all maintained good soil quality in the long-term. This indicates that long-term management should take into account the combination of different factors affecting soil quality. A1 - De Notaris, Chiara A1 - Jensen, Johannes Lund A1 - Olesen, Jørgen E. A1 - da Silva, Tiago Stumpf A1 - Panagea, Ioanna A1 - Rubæk, Gitte H. A1 - Rasmussen, Jim Y1 - 2021/12// TI - Long-term soil quality effects of soil and crop management in organic and conventional arable cropping systems KW - Soil health Soil structural stability Soil organic C Earthworms AV - public UR - https://orgprints.org/id/eprint/42332/ ID - orgprints42332 ER - TY - CONF UR - https://doi.org/10.5194/egusphere-egu23-5614 ID - orgprints45834 AV - public KW - soil mineral nitrogen; legumes; carbon input TI - Carbon and nitrogen services from cover crops are optimized by including legumes in mixtures Y1 - 2023/04// A1 - De Notaris, Chiara A1 - Mortensen, Esben A1 - Liang, Zhi A1 - Chiriacò, Maria Vincenza A1 - Rasmussen, Jim N2 - Cover crops are cultivated during unproductive periods to provide ecosystem services, such as preventing nitrogen (N) leaching, and have the potential to increase soil organic carbon (C), thus contributing to climate change mitigation. Their effect on soil C storage depends on C input, which is challenging to quantify due to belowground sampling (roots and C deposited in the soil). Leguminous cover crops (in pure stands or in mixtures) increase the productivity of following main crops due to high N input, but also the risk of N losses, compromising the mitigation effect. As C and N services vary with cover crop type, tradeoffs could be minimized by species selection. The aim of this study was to assess C input from different cover crop species and mixtures, as well as N uptake in their biomass, and their effect on soil mineral N (SMN) and yield of the following crop. We conducted a field experiment in 2020-2021 at Foulum, Denmark (temperate oceanic climate, sandy loam soil), with seven treatments (five cover crops, control with volunteers, and bare soil) replicated four times. Cover crops undersown in spring barley (Hordeum vulgare L.) in May 2020 were: Lolium perenne L. (ryegrass, RG), Trifolium pratense L. (red clover, RC), Plantago lanceolata L. (plantain, PL) and the mixtures RG-PL and RG-PL-RC. On August 24, 2020, after barley harvest, PVC cylinders (diameter: 29.5 cm, height: 30 cm) were inserted in each plot (25 cm depth) and used for 13C-CO2 multiple-pulse isotopic labeling. Two sessions per week were conducted until cover crop sampling in November 2020, when C and N in above- and belowground biomass, as well C deposited in the soil were determined. Monthly soil sampling (20 cm depth) was performed from August 2020 until April 2021 to assess SMN. Then barley was sown to evaluate cover crops residual effect. Aboveground biomass was lowest in RG (1.5 Mg ha-1), and highest in RG-PL-RC (5.4 Mg ha-1). Total C input (above- and belowground) ranged from 1.6 to 4.3 Mg ha-1, with RG-PL-RC (highest) being significantly higher than RG-PL and RG (lowest). The same pattern applied to total N input, ranging from 74 to 202 kg ha-1. All cover crop treatments had lower SMN than bare soil and volunteers in August 2020. SMN increased from August until April 2021 with all cover crops except RG, and decreased with bare soil and volunteers. SMN in April was 15 kg ha-1 higher with RC and RG-PL-RC than RG. Barley yield following leguminous cover crops was comparable to plots fertilized with 100 kg ha-1 of mineral N, while non-legumes to 40 kg ha-1. Overall, the mixture with RC provided the greatest C input and positive residual effect. The small change in SMN in April indicate that biomass N was converted into mineral N and taken up by barley during the growing season, thus not increasing the risk of N losses. ER - TY - CONF AV - restricted UR - https://orgprints.org/id/eprint/52963/ ID - orgprints52963 N2 - Presentation on cover crop N effects A1 - De Notaris, Chiara A1 - Mortensen, Esben Øster A1 - Peixoto, Leanne A1 - Rasmussen, Jim Y1 - 2024/// TI - Predicting cover crop nitrogen residual effect to optimize fertilizer reductions ER - TY - GEN EP - 1 UR - https://orgprints.org/id/eprint/43955/ ID - orgprints43955 KW - Cover crop; grain legume; harvest time AV - restricted TI - Det er udfordrende at dyrke efterafgrøder med succes i Danmark Y1 - 2021/05/28/ N2 - Sædskifter er en af de bedste og mest anerkendte metoder for at skabe bæredygtige dyrkningssystemer. Bælgplanter - både bælgsæd og græsmarksbælgplanter - og efterafgrøder giver en bedre næringsstofudnyttelse og reducerer behovet for gødning. Rigtigt brugt reducerer bælgplanter og efterafgrøder også kvælstoftabet fra dyrkningssystemet og kan samtidig modvirke klimaforandringerne ved at binde kulstof i jorden. Mere end 20 år med efterafgrøder i sædskifteforsøget på Foulumgård har lært os, at det kan være udfordrende at dyrke efterafgrøder med succes i Danmark. Udfordringer som potentielt mindsker værdien af efterafgrøder i dyrkningssystemet og mindsker sikkerheden for at opnå den forventede miljømæssige effekt. A1 - De Notaris, Chiara A1 - Rasmussen, Jim SP - 1 ER - TY - GEN TI - CCRotate Y1 - 2020/// A1 - De Notaris, Chiara A1 - Mortensen, Esben A1 - Liang, Zhi A1 - Rasmussen, Jim N2 - A documentation of field and laboratory operations, aimed at communicating the process behind the results from CCRotate. UR - https://orgprints.org/id/eprint/39279/ ID - orgprints39279 AV - none ER - TY - GEN N2 - Cover crop (CC) mixtures including both legume and non-legume species have the potential to reduce nitrate leaching and increase N availability in the system through biological N2 fixation (BNF). However, the provision of multiple services depends on the biomass expression of functionally diverse species. Cover crop growth can be manipulated through management, but more knowledge is needed on species expression, and the effects on nitrate leaching and BNF. We investigated this in a long-term organic crop rotation experiment, where an undersown legume-based CC mixture, composed of perennial ryegrass (Lolium perenne L.), chicory (Chicorium intybus L.), white clover (Trifolium repens L.) and red clover (Trifolium pratense L.), was grown under different cropping system and fertility management in three consecutive years. We found a linear complementary relation between legume and non-legume biomass when CC growth was the greatest. Non-legume biomass was high under non-N-limiting conditions, while legume biomass and N input via BNF were high where the risk of nitrate leaching was low, as shown by the low and stable nitrate leaching above a threshold of 0.4 Mg clover DM ha?1. Above this threshold, the percentage of N derived from the atmosphere (%Ndfa) was high and stable (91 %), while lower and more variable with lower legume biomass. Overall, our results show that legume-based CC mixtures are self-regulating in terms of nitrate leaching reduction and N input via BNF. A1 - De Notaris, Chiara A1 - Mortensen, Esben Øster A1 - Sørensen, Peter A1 - Olesen, Jørgen E. A1 - Rasmussen, Jim TI - Cover crop mixtures including legumes can self-regulate to optimize N2 fixation while reducing nitrate leaching SN - 01678809 Y1 - 2021/// AV - restricted UR - https://doi.org/10.1016/j.agee.2020.107287 ID - orgprints39270 ER - TY - GEN KW - Catch crop KW - Legumes KW - N fertilizer KW - Organic agriculture KW - Undersowing AV - restricted UR - https://orgprints.org/id/eprint/35015/ EP - 25 ID - orgprints35015 A1 - De Notaris, Chiara A1 - Rasmussen, Jim A1 - Sørensen, Peter A1 - Melander, Bo A1 - Olesen, Jørgen E. SP - 15 N2 - Legume-based cover crop (CC) mixtures can increase nitrogen (N) availability in arable systems, reducing the need for external N inputs, as they retain soil N and fix atmospheric N2. However, they need sufficient biomass accumulation to influence soil N availability. Early establishment through undersowing can improve CC growth and plant N accumulation, but competition with the main crop should be minimized. This study aimed to investigate the effect of main crop inter-row spacing (12, 18, 24 cm), manure application (without, with) and CC undersowing (early, late, no cover crop) on N accumulation in a legume-based CC mixture and the residual N effect on the following crop. We conducted a field experiment in Denmark with spring wheat as main crop and spring oat as following crop during two pairs of consecutive seasons (2015?2016, 2016?2017). Spring wheat yield was unaffected by inter-row spacing, but it was increased by manure application. In manure treatments, larger inter-row spacing and early CC undersowing increased CC N accumulation by up to 260% (30 kg N ha?1), due to increased light availability. Treatments without manure and with early undersowing gave the highest CC N accumulation, resulting in N fertilizer replacement values of 13?50 kg N ha?1. Thus, increasing main crop inter-row spacing and early undersowing can improve CC growth and N accumulation, and well established legume-based CC could help to stabilize crop yield over time, as suggested by the similar cumulative grain yields (spring wheat+oat) without and with manure. SN - 0378-4290 TI - Manipulating cover crop growth by adjusting sowing time and cereal interrow spacing to enhance residual nitrogen effects Y1 - 2019/03// ER - TY - UNPB N2 - Legume-based cover crops (CC) provide a wide range of ecosystem services, including nitrate leaching reduction, N fertilizer and soil C sequestration effects. However, the scarcity of information on belowground C and N increases the uncertainty on the magnitude of these effects. With the present study, we quantified soil C and N deposition from legume-based CC (two pure legumes and two mixtures) grown under field conditions, in Denmark. To do so, we labeled CC plants with 13C (CO2) and 15N (leaf-labeling) throughout their growing period, by following a frequent multiple-pulse labeling scheme. Then, we incubated labeled CC roots and soil to investigate C and N mineralization. Cover crops with red clover produced about 2.7 Mg ha-1 aboveground biomass, and deposited in the soil approximately 160 kg C ha-1 and 40 kg N ha-1, with approximately equal allocation of C and N to above- and beloground fractions. After four months of incubation at 10 °C, mineralization of root C was 11-18 %, while N mineralization was 39-56 %. Mineral N derived from soil N deposition was on average 7 kg N ha-1, after four months of incubation, accounting for approximately 10 % of the mineral N estimated based on red clover shoot and root biomass. Overall, C and N inputs from legume-based CC are greatly underestimated if soil deposition is not taken into account. In addition, net mineral N derived from soil deposition represents an important contribution to the N fertilizer effect of legume-based CC. SP - 00 A1 - De Notaris, Chiara A1 - Rasmussen, Jim A1 - Sørensen, Peter A1 - Olesen, Jørgen E. Y1 - 2019/03// TI - Deposition of C and N in the soil from legume-based cover crops ? quantification and mineralization. KW - Catch crops; Leaf-labeling; N fertilizer effect; Soil C sequestration AV - restricted UR - https://orgprints.org/id/eprint/35017/ EP - 00 ID - orgprints35017 ER - TY - GEN A1 - De Notaris, Chiara A1 - Rasmussen, Jim A1 - Sørensen, Peter A1 - Olesen, Jørgen E. N2 - The use of cover crops in arable farming is more efficient in nitrate leaching reduction than decreasing the field nitrogen surplus. However, this requires well-developed cover crops. Y1 - 2018/05/16/ TI - Legume-based cover crops benefit crop yield and reduce nitrate leaching AV - public UR - https://orgprints.org/id/eprint/33225/ ID - orgprints33225 ER - TY - GEN SN - 0167-8809 TI - Nitrogen leaching: a crop rotation perspective on the effect of N surplus, field management and use of catch crops Y1 - 2018/03/01/ A1 - De Notaris, Chiara A1 - Rasmussen, Jim A1 - Sørensen, Peter A1 - Olesen, Jørgen E. SP - 1 N2 - Components of the field nitrogen (N) balance (input and surplus) are often used to predict nitrate leaching from agricultural lands. However, management factors, such as use of catch crops, greatly affect the actual loss and are a key to reduce N leaching. The present study is based on the 4th cycle of a long-term crop rotation experiment in Denmark, and it aims to quantify, from a crop rotation perspective, the influence on N leaching from N input and surplus or management factors. The experiment included three cropping systems (two organic and one conventional) with or without use of animal manure and catch crops. N leaching was calculated from measurements of nitrate in soil water sampled with ceramic suction cups installed at 1 m depth in all plots. At the rotation level, over a four years period, N leaching was positively related to N input and surplus. However, the overall effect of N input and surplus on N leaching was lower than the effect of use of catch crops. The response rates of N leaching to increasing N inputs and N surplus were about 0.08 and 0.19-0.25, respectively. Catch crops reduced N leaching by 23 kg N ha-1, irrespective of conventional and organic management system, with legume-based catch crops being as effective as non-legumes. Animal manure increased N leaching in one of the organic systems. The organic system with two years of green manure per rotation cycle was the one at highest risk of N leaching, especially from crops following green manure incorporation. Spring wheat and potatoes were the two crops with highest N leaching, and a stable low level of N leaching was only achieved above a crop-specific threshold in catch crop biomass. EP - 11 UR - https://orgprints.org/id/eprint/32665/ ID - orgprints32665 KW - nitrate leaching KW - nitrogen balance KW - nitrogen surplus KW - catch crop KW - crop rotation KW - GDD AV - restricted ER - TY - UNPB UR - https://orgprints.org/id/eprint/33053/ ID - orgprints33053 AV - restricted Y1 - 2018/01/25/ TI - N fertilizer value of legume-based catch crops N2 - N availability is one of the main factors limiting productivity in organic arable systems. Legume-based catch crops (CC) were shown to both increase N yield and reduce N leaching at the crop rotation scale, but strategies to stabilize their growth are required (De Notaris et al., 2018). The present study showed that early CC sowing time and an increased main crop row space can help stabilize CC growth and increase N accumulation, especially when the conditions for the CC are not favorable. Despite the variations in N accumulated in CC biomass, legume-based catch crops represent a valuable source of N for the subsequent crop, with their fertilizer value being less variable than the N accumulated in CC biomass. A1 - De Notaris, Chiara A1 - Sørensen, Peter A1 - Rasmussen, Jim A1 - Olesen, Jørgen E. ER - TY - CONF N2 - Increasing the row space of spring wheat from 12 to 24 cm, but maintaining the same seeding density, didn´t decrease its yield. On the other hand, it positively influenced the growth of the undersown catch crop, a mixture of red clover, white clover, rye grass and chicory. A1 - De Notaris, Chiara A1 - Sørensen, Peter A1 - Rasmussen, Jim A1 - Olesen, Jørgen E. TI - Row spacing and catch crop establishment in organic arable systems: a way to increase biological N fixation Y1 - 2016/09/05/ AV - public ID - orgprints30876 UR - https://orgprints.org/id/eprint/30876/ ER - TY - GEN N2 - Background: Legume biological nitrogen (N2)-fixation is stimulated by neighboring non-fixing species, but studies of legume N2-fixation in temporary grasslands including non-leguminous forage herb (forb) species are rare. Methodology: We investigated N2-fixation and N yield in a range of species mixtures consisting of three forb species ? chicory (Cichorium intybus L.), ribwort plantain (Plantago lanceolata L.) and caraway (Carum carvi L.) ? mixed into a traditional perennial ryegrass (Lolium perenne L.) and red clover(Trifolium pratense L.) mixture at two fertilisation levels. Results: The percentage of red clover N derived from the atmosphere (%Ndfa) was higher in mixtures than in pure stand, but did not increase with inclusion of forbs. Red clover in all the mixtures derived over 90% of its N from fixation even when fertilised with 216 kg total N ha-1. Forbs affected the amount of N2-fixation by affecting the red clover proportion in the harvested biomass. Conclusions: We conclude that forbs can be included in temporary grasslands with no negative effect on total herbage production and percentage of legume N2-fixation. However, mixtures should not include a high seeding proportion of chicory for a balance between legume and non-legume biomass proportions. A1 - Dhamala, N.R. A1 - Rasmussen, J. A1 - Carlsson, G A1 - Søegaard, K. A1 - Eriksen, J. SP - 525 TI - Effecs of including forbs on N2-fixation and N yield in red clover-ryegrass mixtures Y1 - 2018/// AV - public EP - 537 UR - https://orgprints.org/id/eprint/34966/ ID - orgprints34966 ER - TY - GEN Y1 - 2017/// TI - Highly productive forage legume stands show no positive biodiversity effect on yield and N2-fixation SP - 169 A1 - Dhamala, NR A1 - Eriksen, J A1 - Carlsson, G A1 - Søegaard, K A1 - Rasmussen, J N2 - Background and aims While N2-fixation in diversified grasslands including forage legumes and non-legumes has been widely studied, N2-fixation in swards containing only forage legumes remains unclear. In this study, we investigated N2-fixation in pure stands and mixtures of three forage legumes. Methodology N2-fixation, dry matter (DM) and nitrogen (N) yields were quantified in a field experiment for red clover (Trifolium pratense L.), white clover (Trifolium repens L.) and lucerne (Medicago sativa L.) pure stands and mixtures using the isotope dilution method. Results All three forage legume species derived most (around 85%) of their N from atmospheric N2-fixation (%Ndfa). However, no positive effect of species diversity was found in any of the mixtures. Species composition of the forage legume mixtures affected the amount of N from N2-fixation by affecting DM production and N accumulation of the species, where the seasonal amount of N2-fixation ranged from 370 to 500 kg N ha?1; which was highest in the presence of red clover. Conclusions We found thatmixturesof thethree forage legumes were highly productive, but did not show positive advantages compared to the red clover pure stands in terms of DM, N yield and %Ndfa. UR - https://orgprints.org/id/eprint/31784/ ID - orgprints31784 EP - 182 AV - public ER - TY - GEN A1 - Dhamala, NR A1 - Rasmussen, J A1 - Carlsson, G A1 - Søegaard, K A1 - Eriksen, J SP - 217 N2 - Background and aims There is substantial evidence that legume-derived Nitrogen (N) is transferred to neighboring non-legumes in grassland mixtures. However, there is sparse information about how deep rooted nonlegume forage herbs (forbs) influence N transfer in multi-species grasslands. Methodology Red clover (Trifolium pretense L.) was grown together with perennial ryegrass (Lolium perenne L.) and one of three forb species: chicory (Cichoriumintybus L.), ribwort plantain (Plantago lanceolata L.) or caraway (Carum carvi L.) in a field experiment. During the first year after the establishment, red clover leaves were labeled with 15N-urea to determine the N transfer from red clover to companion ryegrass and forbs. Results On an annual basis, up to 15 % of red clover N was transferred to the companion ryegrass and forbs, but predominantly to the grass. The forb species did not differ in their ability to take up clover N, but biomass production and soil N acquisition was higher in chicory and plantain than in caraway. TI - N transfer in three-species grass-clover mixtures with chicory, ribwort plantain or caraway Y1 - 2017/// AV - restricted EP - 230 UR - https://orgprints.org/id/eprint/31453/ ID - orgprints31453 ER - TY - CONF EP - 578 UR - https://orgprints.org/id/eprint/31334/ ID - orgprints31334 AV - public Y1 - 2016/// TI - Nitrogen fixation in red clover grown in multi-species mixtures with ryegrass, chicory, plantain and caraway SP - 576 A1 - Dhamala, NR A1 - Rasmussen, J A1 - Carlsson, G A1 - Søegaard, K A1 - Eriksen, J VL - 21 N2 - While many studies have investigated effects of species composition and management on N2-fixation dynamics in simple clover-grass mixtures, there is a lack of knowledge about the performance of legumes and their N2-fixation in more species-rich grassland including non-legume forbs. This study investigated N2-fixation and total N yield in grassland mixtures including different combinations of red clover, perennial ryegrass and three deep rooted forbs: chicory, ribwort plantain and caraway, managed without and with slurry application. The percentage of clover N derived from atmosphere (%Ndfa) increased in mixtures, but was unaffected by inclusion of forbs. However, forbs affected the quantity of N2-fixation and total N yield by affecting the red clover proportion in the mixtures. Mixtures composed of grass,clover and plantain or caraway showed higher N2-fixation and N yield than with chicory included. Slurry application reduced N2-fixation due to decreasing clover contents in the sampled biomass. The study highlighted differences among forbs in their influence on legume N2-fixation and total N yield showing that forbs can be included in grasslands without negative effects on red clover performance. ER - TY - GEN EP - 459 UR - https://orgprints.org/id/eprint/32973/ ID - orgprints32973 AV - public KW - Grassland KW - residual effect KW - chicory KW - caraway KW - ribwort plantain TI - Short-term residual N unaffected by forbs in grass-clover mixtures Y1 - 2017/09// A1 - Dhamala, NR A1 - Rasmussen, J A1 - Cong, WF A1 - Carlsson, G A1 - Søegaard, K A1 - Eriksen, J SP - 457 N2 - We determined the effect on residual nitrogen (N) of including forbs (chicory, ribwort plantain and caraway) in perennial ryegrass-red clover mixtures. Although soil N inputs during the grassland phase differed markedly between mixtures, in a pot experiment we found no differences in the potentially mineralizable N of the soil or in the dry matter production and N content of the spring barley test crop. The fertilizer value of the grassland mixtures corresponded to 10 g N/m2, irrespective of forb inclusion. Thus, the inclusion of nonlegume forbs did not negatively affect short-term residual N fertility of legume-based grasslands. ER - TY - CONF Y1 - 2024/03/15/ TI - Cover crops and soil tillage differently affect N2O emissions. A1 - Dold, C. A1 - DeNotaris, C. A1 - Mortensen, Esben Øster A1 - Rasmussen, Jim A1 - Petersen, SO N2 - The case study investigated the impact of different cover crops and tillage strategies on nitrous oxide (N2O) emissions in agricultural soils. Four cover crops were studied: perennial ryegrass (RG), plantain (PL), a combination of RG and PL (RG-PL), and a mix of RG, PL, and red clover (RG-PL-RC). These cover crops were terminated either by shallow rotovation followed by deeper ploughing (ro+plou) or directly by ploughing (plou). N2O flux was continuously measured using automated chambers from March to June 2021. The study found that cumulative N2O-N emissions were generally higher for plou compared to ro+plou, with 2-to-5-fold higher emissions observed in plou for RG-PL, RG, and PL, and the smallest difference in emissions observed for RG-PL-RC. In ro+plou, the lowest and highest cumulative N2O emissions were observed in PL and RG-PL, respectively, while in plou it was RG-PL-RC and RG-PL, respectively. The average soil nitrate (NO3-N) levels increased initially, indicating mineralization and nitrification of residue-N, but gradually decreased thereafter. This decrease in NO3-N levels corresponded with an increase in N2O emissions, suggesting denitrification as the main process of N2O production. UR - https://orgprints.org/id/eprint/52959/ ID - orgprints52959 AV - public ER - TY - GEN AV - restricted KW - amino acids; organic fertilizers KW - Plant tea EP - 688 UR - https://orgprints.org/id/eprint/18293/ ID - orgprints18293 A1 - El-Naggar, Ahmed A1 - Rasmussen , Jim A1 - de Neergaard, Andreas A1 - El-Araby, Ahmed A1 - Høgh-Jensen, Henning SP - 679 N2 - Agricultural crop production is largely dependent on inputs of mineral fertilizers. Mineral fertilizer prices are expected to rise as the competition for fossil energy increases. In order to increase the sustainability of crop production, alternatives to commercial mineral fertilizers are needed. Organic residues and fresh biomass are potentially important sources of nitrogen (N) in crop production. A study was conducted to investigate the impact of temperature on the release rate and profile of amino acids from soybean seeds (Glycine max L.) and fresh young shoots of chicory (Cichorium intybus), alfalfa (Medicago sativa) and red clover (Trifolium pratense) under anaerobic conditions. Plant material was incubated in water at either 15 ?C or 35 ?C, and the temporal release of total N, inorganic N, organic N and amino acids was measured during the 240-h incubation period. Amino acids and other organic N sources constituted significant proportions (20?84%) of the soluble N that was released. The contribution of organic N compounds to total N released decreased when the incubation temperature was raised from 15?C to 35?C, whereas the increase in temperature resulted in a higher total N release for only alfalfa and soybean. Amino acid profiles differed with plant material, incubation temperature and incubation length, with release patterns that only in a few cases could be described by first-order kinetics. Irrespective of the source, short-term liquid composting solutions will contain a low amino acid:inorganic N ratio with multiple amino acids present, which has to be taken into account when calculating the fertilizer effect. To conclude, this study reports, to our knowledge for the first time, the multiple amino acid release profiles from four different plant materials incubated under anaerobic conditions. The findings demonstrate that amino acids constitute significant proportions of the total N released and that the release patterns only for some amino acids followed first-order kinetics. TI - Source and temperature determine the releases of multiple amino acids from plant materials Y1 - 2010/// ER - TY - GEN Y1 - 2005/// TI - Udfordring eller mulighed for økologien SP - 29 A1 - El-Nagger, A. A1 - Ounmaa, A. A1 - Muukka, E. A1 - Zaleckas, E. A1 - Abraityté, G. A1 - Jansons, I. A1 - Rasmussen, J. A1 - Ahnström, J. A1 - Pirhofer-Walzl, K. A1 - O'Doherty Jensen, K. A1 - Jørgensen, K.F. A1 - Sarunaite, L. A1 - Bleidere, M. A1 - Knudsen, M.T. A1 - Pugliese, M. A1 - Nielsen, M.H.M. A1 - Muguerza, N.B. A1 - Bakewell-Stone, P. A1 - Hansen, P.K. A1 - Abed-Ali Al-Kufaishi, S.A. A1 - Kobayashi, S. A1 - Rydberg, T. A1 - Klubova, V. A1 - Liorancas, V. A1 - Høgh-Jensen, H. N2 - 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. UR - https://orgprints.org/id/eprint/10492/ EP - 31 ID - orgprints10492 AV - public PB - Jordbrugsakademikerne ER - TY - GEN TI - Globalisation as a challenge or opportunity for organic farming Y1 - 2006/03// N2 - 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. A1 - El-Nagger, Ahmed A1 - Ounmaa, Andres A1 - Muukka, Eija A1 - Zaleckas, Ernestas A1 - Abraityté, Gerda A1 - Jansons, Imants A1 - Rasmussen, Jim A1 - Ahnström, Johan A1 - Pirhofer-Walzl, Karin A1 - Jensen, Katherine O?Doherty A1 - Jørgensen, Kirstine F. A1 - Sarunaite, Lina A1 - Bleidere, Mara A1 - Knudsen, Marie Trydeman A1 - Pugliese, Massimo A1 - Nielsen, Merete Højrup Møller A1 - Mugurerza, Natalia Bellostas A1 - Bakewell-Stone, Petra A1 - Hansen, Preben Klarskov A1 - Al-Kufaishi, Sermed Adil Abed-Ali A1 - Kobayashi, Sofie A1 - Rydberg, Torbjörn A1 - Klubova, Vera A1 - Liorancas, Viktoras A1 - Høgh-Jensen, Henning ID - orgprints9333 UR - https://orgprints.org/id/eprint/9333/ PB - DARCOF/FØJO KW - Organic KW - farming KW - globalisation KW - developing countries KW - global market AV - public ER - TY - CONF SP - 880 A1 - Eriksen, J. A1 - Ledgard, S. A1 - Lou, J. A1 - Schils, R. A1 - Rasmussen, J. N2 - Large nitrogen (N) surplus and return of excreta-N in localised patches at high N rates in intensively grazed pasture systems markedly increases the risk of N losses to waterways and the atmosphere. Here are described the main routes of N input to grazed pastures, losses via N leaching, methane (CH4) and nitrous oxide (N2O) emissions. Furthermore farm N budgets and N use efficiency in relation to management strategies that can be applied to reduce N losses are discussed. Nitrate leaching increases exponentially with increased inputs and is closely related to urine patches, which also influence the leaching of dissolved organic N. High N2O emission rates in grazed pastures are related to fertiliser-N or N in excreta combined with compaction by animal treading. Grazing may considerably reduce CH3 emissions compared to indoor housing of cows. Pastures are occasionally cultivated due to sward deterioration followed by a rapid and extended period of N mineralization, contributing to an increased potential for losses. Good management of the pasture (e.g. reduced fertiliser input and reduced length of grazing) and of the mixed crop rotation during both the grassland and the arable phase (e.g. delayed ploughing time and a catch crop strategy) can considerably reduce the negative environmental impact of grazing. It is important to consider the whole farm system when evaluating environmental impact. In particular for green house gasses since the pasture may serve as a source of N2O and indirectly of CH3, but also as a sink of CO2 influenced by management practices on the farm. Y1 - 2010/// TI - Environmental impacts of grazed pastures SN - 978-3-86944-021-7 AV - public ED - Schnyder, H. EP - 890 UR - https://orgprints.org/id/eprint/17879/ ID - orgprints17879 ER - TY - CONF AV - public EP - 65 UR - https://orgprints.org/id/eprint/17881/ ID - orgprints17881 SP - 61 A1 - Eriksen, J. A1 - Søegaard, K. A1 - Askegaard, M. A1 - Hansen, E.M. A1 - Rasmussen, J. N2 - Dairy production systems in Europe are to a large extent based on ley-arable rotations. In the ley phase of such rotations nitrogen accumulation occurs as a result of (1) organic carbon accumulation in soil not disturbed by tillage operations and (2) a considerable nitrogen surplus in grasslands, particularly under grazing regimes where a large part of the N in ingested grass is recycled to soil via urine and faeces. The accumulation of N and C in grasslands starts soon after establishment, the rate asymptotically declining with age and depends on practices such as fertiliser level, animal feed composition, stocking density, length of grazing and the botanical composition of the sward. In these pasture systems, key perennial legumes are white clover (Trifolium repens L.) red clover (Trifolium pratense L.) and lucerne (Medicago sativa). They are used because of their valuable contribution to production, feed quality and N inputs via biological fixation of atmospheric N2 (Ledgard et al., 2010) Grassland cultivation almost always results in a substantial residual effect and the mineralization of N often exceeds the requirement of the succeeding crop. Thus, there is a high risk of nitrate leaching following sward cultivation. Management practices to control nitrate losses include delayed ploughing until late winter or spring, the use of efficient catch crops after ploughing and a reduction in fertilizer N application to cereals after ploughing. The objective of this paper is to illustrate by examples the importance of management for N fertility building and efficient utilization in crop rotations containing forage legumes. Y1 - 2010/// TI - Forage legume impact on soil fertility and N balance ER - TY - CONF ID - orgprints31335 UR - https://orgprints.org/id/eprint/31335/ EP - 231 AV - public Y1 - 2017/// TI - Kløvergræsblandinger med urter - kulstof, kvælstof og biodiversitet SP - 230 A1 - Eriksen, J A1 - Dhamala, NR A1 - Cong, W-F A1 - Søegaard, K A1 - Rasmussen, J N2 - Urter kan bidrage på en række punkter ? bl.a. øget biodiversitet, kulstoflagring, bedre ressourceudnyttelse og øget udbytte. Men det er vigtigt at kontrollere andelen. ER - TY - CONF N2 - This study defines crop tolerance to post-emergence weed harrowing as the combined effect of crop resistance and crop recovery. Crop resistance is the ability of the crop to resist soil covering and recovery is the ability to recover in terms of yield. In two experiments, resistance, recovery and tolerance were quantified in barley, oat, wheat and triticale by a new method based on digital image analysis. Important differences in resistance, recovery and tolerance among species were seen and resistance was not linked to recovery. Oat showed higher resistance than wheat, and barley. Triticale showed the lowest resistance. Oat and barley showed both lower ability to recover from soil covering than wheat, and triticale showed complete recovery. Triticale was the most tolerant species followed by wheat, oat and barley. Differences in tolerance caused species dependent crop yield losses in weed-free environments in the range of 0 to 10% for a practical relevant aggressiveness of weed harrowing. A1 - Gundersen, Hanne A1 - Rasmussen, Jesper A1 - Nørremark, Michael TI - TOLERANCE OF CEREALS TO POST- EMERGENCE WEED HARROWING Y1 - 2006/// PB - Association française de protection des plantes (AFPP) KW - weed harrowing KW - mechanical weed control AV - public ID - orgprints8082 UR - https://orgprints.org/id/eprint/8082/ ER - TY - CONF TI - Kamdyrkning (drill) ? et økologisk alternativ Y1 - 2002/// N2 - I projektet CARMINA undersøges de potentielle fordele ved at anvende kamme som alternativ til pløjning. Det er tidligere vist at kamme kan reducere udvaskning af kvælstof, øge omsætningen af organisk stof og sikre en tidligere såning samt bedre etablering. I CARMINA kombineres kamme med dyrkning af fangafgrøder og inkorporering af husdyrgødning i en række nye forsøg. A1 - Henriksen, C.B. A1 - Rasmussen, J. SP - 61 UR - https://orgprints.org/id/eprint/125/ EP - 68 ID - orgprints125 ED - Cottis, T. PB - Høgskolen i Hedmark AV - public KW - soil tillage KW - ridge tillage KW - nitrogen KW - leaching KW - mineralization KW - row crops KW - sugar beet KW - potato KW - catch crops ER - TY - UNPB N2 - Autumn ridging is a modified version of the ridge tillage system. Instead of setting up ridges during the growing season, they are established in autumn and left for the winter. Previous studies have documented positive effects of autumn ridging on potato yield and we hypothesize that applying subsoiling could enhance these effects. To determine the effect of autumn ridging and inter-row subsoiling on potato yield and quality a field experiment was conducted on sandy soil from 2001-2003. Autumn ridging showed comparable yields to ploughing and significantly reduced the incidence of black scurf from 2.5% to 2.2%. Inter-row subsoiling in the growing season significantly increased marketable potato tuber yield from 84.4 hkg/ha to 96.3 hkg/ha and reduced the percentage of malformed potatoes from 9.3% to 7.5%, irrespective of tillage treatment and irrigation level. There was no significant interaction between autumn ridging and subsoiling. The beneficial effect of subsoiling on marketable yield was driven by a 48.5% increase in the dry year 2001. Subsoiling reduced the incidence of common scab from 7.8% to 6.9% when irrigation was reduced. It is concluded that at least three factors may modify the effects of subsoiling: Soil water status in the growing season, precipitation immediately before and after the subsoiling operation, and crop growth stage at the time of subsoiling. A1 - Henriksen, Christian Bugge A1 - Mølgaard, Jens Peter A1 - Rasmussen, Jesper Y1 - 2004/// TI - The effect of autumn ridging and inter-row subsoiling on potato tuber yield and quality AV - restricted KW - Autumn ridging KW - inter-row subsoiling KW - reduced irrigation KW - Solanum tuberosum KW - black scurf KW - common scab. UR - https://orgprints.org/id/eprint/4290/ ID - orgprints4290 ER - TY - GEN TI - Ridge planting of maize shows promising yield increase Y1 - 2005/03// A1 - Henriksen, Christian Bugge A1 - Rasmussen, Jesper A1 - Jørgensen, Martin Heide A1 - Thomsen, Henning Carlo N2 - Ridge planting of maize dramatically increased yield on both sand and sandy loam in 2003-2004. The yield increase was up to 60%. Ridge planting also shows promising results in protein crops such as faba bean and soybean and is currently being tested in winter rape. UR - https://orgprints.org/id/eprint/4599/ ID - orgprints4599 AV - restricted KW - ridge planting KW - ridge till KW - ridge tillage KW - ridge culture KW - corn KW - maize (Zea mays) KW - row crops KW - soil temperature KW - soil moisture KW - plant nutrients ER - TY - GEN TI - Majs på kamme viser lovende merudbytte Y1 - 2004/12// N2 - Majs dyrket på kamme giver markante merudbytter på såvel ler- som sandjord. Merudbyttet er på op til 60 procent. Kamdyrkning viser også lovende resultater i proteinafgrøder som hestebønne og sojabønne og afprøves nu i vinterraps. A1 - Henriksen, Christian Bugge A1 - Rasmussen, Jesper A1 - Jørgensen, Martin Heide A1 - Thomsen, Henning Carlo UR - https://orgprints.org/id/eprint/4287/ ID - orgprints4287 AV - public KW - kamdyrkning KW - majs KW - rækkeafgrøder KW - jordtemperatur KW - fugtighed KW - plantenæringsstoffer ER - TY - GEN AV - restricted KW - Ridging KW - timing KW - catch crops KW - soil inorganic nitrogen KW - leaching KW - Solanum tuberosum ID - orgprints4292 UR - https://orgprints.org/id/eprint/4292/ N2 - Field experiments were conducted on sand and sandy loam from 2000-2002 to determine how timing of ridging affects potato tuber yield and quality depending on soil type and the use of catch crops. On sand, ridging in winter increased nitrogen availability in the 0-50 cm soil layer in spring by 19% from 5.7 to 6.8 mg N/kg soil compared with ridging in autumn (P<0.001) and by 8% from 6.3 to 6.8 mg N/kg soil compared with ploughing in spring (P<0.05). With a total and marketable yield of 27,9 t/ha and 14,2 t/ha respectively, ridging in winter resulted in higher tuber yield than both ridging in autumn and ridging in autumn combined with tilting and re-establishment of ridges in winter. These yield results were comparable to spring ploughing, but because of the ability to perform direct potato planting in the winter ridges on sand workload was significantly reduced. Ridging in autumn slightly improved tuber quality but reduced yields. On sandy loam there was no effect of timing of ridging. Ridging in winter resulted in similar levels of soil inorganic nitrogen and similar tuber yields as ploughing in autumn, but because ridges had to be rotovated in spring before planting to create a sufficiently loose soil, workload was not reduced. It is concluded that ridging in winter in combination with a ryegrass catch crop represents a potent alternative for organic potato production on sand but not on sandy loam. A1 - Henriksen, Christian Bugge A1 - Rasmussen, Jesper A1 - Mølgaard, Jens Peter Y1 - 2005/// TI - The effect of timing of ridging on soil inorganic nitrogen and potato tuber yield and quality ER - TY - INPR A1 - Henriksen, Christian Bugge A1 - Rasmussen, Jesper A1 - Søgaard, Carsten N2 - In the original ridge tillage system as practiced in the US Corn Belt, ridges are formed during the growing season. Several studies have documented that this can reduce leaching of nutrients and improve fertilizer efficiency. This study was conducted to determine whether ridges formed in autumn can be used as an alternative to ploughing to reduce N leaching during autumn and winter, and thereby increase growth and N uptake of a subsequent unfertilized crop. A factorial field experiment with tillage and residues as factors was conducted during 1998-2000. Tillage treatments were autumn ridging and ploughing. Residue treatments were stubble, stubble+straw and stubble+liquid manure in order to create a gradient of C/N ratios. From the time of harvest until planting of a subsequent barley crop (Hordeum vulgare L.), inorganic N was determined 11 times in 1998-1999 and 10 times in 1999-2000 in the 0-10, 10-30, 30-60 and 60-90 cm soil layers. Growth and N uptake of barley was quantified 9 times in both 1999 and 2000. Barley grain and straw yields were determined. Ridging resulted in lower levels of inorganic N in the 30-90 cm soil layer in November and a significantly higher level of inorganic N in the 0-30 cm soil layer in late April, indicating reduced leaching and increased N availability for the subsequent crop. Ridging significantly increased growth, yield and N uptake of barley whereas incorporation of straw generally reduced growth, yield and N uptake. It is concluded that ridging in autumn has a N conserving effect and it is suggested that the potential of ridging in autumn as an alternative to ploughing is further investigated in detailed studies of solute movement, N immobiliza-tion/mineralization and crop performance. TI - Ridging in autumn as an alternative to mouldboard ploughing in a humid-temperate region Y1 - 2005/// PB - Elsevier, Netherlands AV - restricted KW - Ridging KW - ridges KW - ridge tillage KW - nitrogen KW - leaching KW - mineralization KW - immobilization ID - orgprints3952 UR - https://orgprints.org/id/eprint/3952/ ER - TY - CONF N2 - Red clover and high proportion of forage in dairy cow diet increases the concentration of bioactive substances in milk, e.g. unsaturated fatty acids and antioxidants. In the present experiment twenty-four Swedish Red dairy cows were fed three silages in a Latin Square design to study the effect of silage botanical composition and harvest time on milk fatty acid, ?-tocopherol and ?-carotene concentration. The silages were red clover/grass silage (mixture of first and second cut), red clover/grass silage (mixture of first, second and third cut) and birdsfoot trefoil/grass silage (mixture of first and second cut). Botanical composition and harvest system affected silage vitamin and fatty acid concentration with higher concentrations of ?-linolenic acid, ?-tocopherol and ?-carotene in red clover/grass silage (mixture of three harvests). Milk linoleic and ?-linolenic acid concentration was higher with the two red clover diets but ?-tocopherol, ?-carotene and retinol concentration was not affected. SP - 133 VL - 6 A1 - Höjer, Annika A1 - Martinsson, Kjell A1 - Jensen, Søren K. A1 - Gustavsson, Anne-Maj Y1 - 2010/06// TI - PhytoMilk: Effects of botanical composition and harvest system of legume/grass silage on fatty acid, ?-tocopherol and ?-carotene concentration in organic forage and milk SN - 1653 2015 ED - Rasmussen , Jim ED - Schacht, Margit ED - Helgadóttir, Áslaug T3 - NJF Report KW - PhytoMilk KW - legume KW - grass KW - dairy cow KW - fatty acid KW - vitamin AV - public UR - https://orgprints.org/id/eprint/18829/ EP - 136 ID - orgprints18829 ER - TY - GEN Y1 - 2010/// TI - Weed harrowing and inter-row hoeing in organic grown quinoa (Chenopodium quinoa Willd.) SP - 323 A1 - Jacobsen, Sven-Erik A1 - Christiansen, J.L. A1 - Rasmussen, Jesper N2 - Weeds, with their negative influence on both yield and quality, constitute a major problem in the organic production of quinoa, a potential new seed crop for protein feed and human consumption in Europe. To attain effective weed control, mechanical weeding strategies, such as weed harrowing and inter-row hoeing, were studied. Weed harrowing operates over the entire plot with flexible tines, affecting both crop and weeds, whereas inter-row hoeing is performed between the rows, aiming only at the weeds. The study showed that both hoeing and harrowing reduced the quinoa density in one out of two years, whereas there was no effect on quinoa density in the other year. Yield was increased by both methods, but hoeing increased yield more than harrowing due to better weed control. Regression analysis showed that crop yield was related to weed dry matter and showed no indications of higher crop damage associated with weed harrowing. Protein content was low when weeds were not treated, and increased ignificantly when weeds were controlled. As a conclusion, inter-row hoeing was more efficient than weed harrowing with respect to weed control; however, weed harrowing should be optimized in future trials in narrow row spacing systems, and the results. EP - 327 UR - https://orgprints.org/id/eprint/18194/ ID - orgprints18194 AV - restricted ER - TY - GEN N2 - Innovative strategies in free-range pig production is needed to improve the environmental performance of the system. Based on previous studies, inclusion of trees was hypothesized to improve the system?s nitrogen efficiency. We investigated sow elimination behaviour, faeces load and localisation as well as soil mineral nitrogen load in pasture based individual paddocks with and without access to two rows of poplar (Populus sp.) trees. Unlike expected sows showed no preference for eliminating in the zone with poplars but clearly avoided defecating near the hut, feed and water. Soil mineral nitrogen load showed a heterogeneous pattern as also found in previous studies. In comparison to grass, our results indicated that the poplars had an increased winter uptake of nitrate from deeper soil layers. SP - 1 A1 - Jakobsen, M. A1 - Hermansen, J.E. A1 - Andersen, Heidi Mai-Lis A1 - Jørgensen, Uffe A1 - Labouriau, R. A1 - Rasmussen, Jim A1 - Kongsted, A.G. Y1 - 2018/// TI - Elimination behaviour and soil mineral nitrogen load in an organic system with lactating sows ? comparing pasture based systems with and without access to poplar (Populus sp.) trees SN - 2168-3565 print / 2168-3573 online AV - restricted UR - https://orgprints.org/id/eprint/33906/ EP - 25 ID - orgprints33906 ER - TY - GEN AV - restricted KW - lupin weed harrowing mechanical weed control EP - 253 UR - https://orgprints.org/id/eprint/3086/ ID - orgprints3086 SP - 245 A1 - Jensen, Rikke K. A1 - Rasmussen, Jesper A1 - Melander, Bo N2 - 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 covering was also unaffected by year whereas the ability of the crop to resist soil covering was highly affected by year. Lupin showed high tolerance to soil covering but a rather low ability to resist soil covering. Harrowing at multiple growth stages supported the finding that lupin is fairly tolerant to soil covering. Advantages and disadvantages of using soil covering as a measure of crop damage is discussed. In conclusion, weed harrowing in lupin showed positive prospects due to high tolerance to crop soil cover. Y1 - 2004/// TI - Selectivity of weed harrowing in lupin ER - TY - CONF Y1 - 2023/06/10/ TI - How inoculation can improve N2 fixation and yield in soybean under field conditions in Denmark A1 - Martins, Juliana Trindade A1 - Enggrob, Kirsten Lønne A1 - Rasmussen, Jim N2 - Poster presenting the potential to enhance yield of soybean for fresh and mature harvest under Danish conditions UR - https://orgprints.org/id/eprint/52997/ ID - orgprints52997 AV - public ER - TY - CONF UR - https://orgprints.org/id/eprint/53013/ ID - orgprints53013 AV - public TI - Carbon sequestration potential of legume based cropping systems Y1 - 2023/06/10/ A1 - Martins, Juliana Trindade A1 - Liang, Zhi A1 - Enggrob, Kirsten Lønne A1 - Rasmussen, Jim N2 - Results from investigation of grain legume soil C inputs. ER - TY - GEN ID - orgprints52633 UR - https://orgprints.org/id/eprint/52633/ EP - ? AV - restricted TI - Cover crop effects on the growth of perennial weeds in two long-term organic crop rotations Y1 - 2024/01// A1 - Melander, Bo A1 - Rasmussen, Jim A1 - Sørensen, Peter SP - ? N2 - Cover crops are important in organic arable cropping systems because they improve soil fertility and suppress annual weeds in the post-harvest period, but their effectiveness against perennial weeds is less clear. This study analysed outbreaks of perennial weeds in two long-term organic crop rotations with and without cover crops in the period 2011-2022 in Denmark, and in particular examined the effects of cover crops. In addition, the impact of including forage plantain (Plantago lanceolata) in cover crop mixtures on the growth of perennial weeds was studied from 2020 to 2022. Plantain is known to contain secondary metabolites that inhibit nitrification and may influence nitrogen (N) availability. This study found that cover crops did not hinder outbreaks of Cirsium arvense, Sonchus arvensis, Elytrigia repens or other perennial weed species. E. repens actually proliferated more with cover crops whose presence prevented repeated mechanical post-harvest interventions. The crop rotation involving regular cutting of a one-year or two-year green manure crop provided the best management of perennial weeds if repeated post-harvest soil cultivation was conducted in two out of four or five years. This could only be done in the absence of cover crops. Mixing plantain into the cover crop mixtures did not change the outcome of competition between cover crops and perennial weeds in the post-harvest period. Instead, plantain significantly reduced the number of shoots emerging from perennial weeds in the subsequent growing season. The causality of this effect needs further elaboration in order to understand and utilise plantain as a potential source of weed suppression in combination with cover crops. ER - TY - GEN UR - https://orgprints.org/id/eprint/32979/ EP - 270 ID - orgprints32979 AV - restricted PB - Wiley Y1 - 2017/// TI - Non-Chemical Weed Management CY - UK N2 - Non-chemical methods for weed control in arable crops are reviewed. SP - 245 A1 - Melander, Bo A1 - Liebman, Matt A1 - Davis, Adam. S. A1 - Gallandt, Eric A1 - Barberi, Paolo A1 - Moonen, Anna-Camilla A1 - Rasmussen, Jesper A1 - van der Weide, Rommie A1 - Vídotto, Francesco ER - TY - GEN AV - restricted UR - https://doi.org/10.1016/j.agee.2021.107339 ID - orgprints39276 N2 - Cover crops (CC) increase soil fertility via recycling of nutrients such as nitrogen (N) and buildup of soil organic matter, whereby CC contributes to climate change mitigation. The carbon (C) input to soil occurs via the input of plant material (shoot and root) and via phyllo- and rhizodeposition. However, the quantity of phyllo- and rhizodeposition from CC is largely unexamined, although this component potentially has a large contribution to microbial stabilization of C. Isotopic labeling with 13C to trace C flows and 15N to determine N2-fixation was conducted to test the short-term effect of the inclusion of winter vetch as a legume species to a CC mixture. The CC mixtures were established in a long-term experiment (1997?2019) with varying use of manure and CC cropping to test the effect of soil fertility on the behavior of the newly established CC mixtures. A significant reduction in the relative net phyllo- and rhizodeposition was observed with higher soil fertility. Interestingly, the quantity of net phyllo- and rhizodeposition was also reduced with higher soil fertility due to the lower relative phyllo- and rhizodeposition, despite a significantly higher CC biomass. Importantly, adjusting for unrecovered root fragments more than halved the calculated phyllo- and rhizodeposition, indicating that many published estimates are substantially overestimated. The use of CC during autumn provides an important window for C storage with both the input of plant biomass and belowground C investment being drivers of C storage. A1 - Mortensen, Esben Øster A1 - De Notaris, Chiara A1 - Peixoto, Leanne A1 - Olesen, Jørgen E. A1 - Rasmussen, Jim SN - 01678809 TI - Short-term cover crop carbon inputs to soil as affected by long-term cropping system management and soil fertility Y1 - 2021/// ER - TY - CONF Y1 - 1998/// TI - Non-inverting soil tillage as a means of optimising soil tilth N2 - A field experiment was initiated in 1997 with non-inverting soil tillage compared to conventional tillage with annual mouldboard ploughing to either 20 cm depth (CT) or 10 cm depth (RCT). The new system included a non-inverting mechanical loosening of the soil to approximately 35 cm depth combined with a shallow cultivation of the top 5 cm soil by either a rotovator (NIT) or an S-tine harrow (RNIT). The experiment was located on a sandy loam at the organic farmed Rugballegård Experimental Station. A plough pan at 20-35 cm depth was identified by cone penetration measurements. The non-inverting tillage system succeeded in breaking up the plough pan, which reduced the cone index from approximately 1.8 MPa in the CT and RCT treatments to 0.6 MPa in the NIT treatment. A detailed soil profile description of the top 30 cm of the soil indicated that root growth was restricted for especially CT and RCT treatments in the form of thickened and horizontally deflected roots at the interface between the topsoil and the plough pan at approximately 22 cm depth. For RCT a new plough pan was under development just below the present ploughing depth at 10 cm. This also resulted in root growth restriction, but to a lesser extent than the deeper plough pan. A soil drop test was performed to characterise soil fragmentation. Undisturbed cubic soil samples were taken from the 5-15 cm layer and dropped from 75 cm height in to a metal box. The resulting aggregate size distribution differed between the treatments with geometrical mean weight diameter (GMD) of 5.7 mm 7.4 mm and 8.9 mm for CT, RCT and NIT treatments, respectively. The higher degree of fragmentation for the mouldboard ploughed soil may be explained by higher energy input per soil volume by mouldboard ploughing than by non-inverting deep loosening. The results indicate for the 5_15 cm layer, that plant growth conditions were best for CT treated soil, due to a combination of low cone index and small aggregates. For the 20_35 cm layer, the results indicates best plant growth conditions for NIT treated soil due to a low cone index and less restricted root growth. The spring barley/pea mix with grass/clover undersown yielded on average 47.6 hkg/ha. There were no significant differences between treatments. SP - 26 A1 - Munkholm, L.J. A1 - Schjønning, P. A1 - Rasmussen, K.J. VL - 124 ID - orgprints1886 UR - https://orgprints.org/id/eprint/1886/ EP - 33 ED - Børresen, T. AV - public KW - soil KW - non-inverting tillage KW - soil tilth KW - penetration resistance KW - visual soil evaluation ER - TY - GEN KW - Direct drilling; Sandy loam; Denmark; Soil compaction; Spatial effects; Temporal effects AV - restricted PB - Elsevier EP - 173 UR - https://orgprints.org/id/eprint/729/ ID - orgprints729 N2 - Despite more than 30 years of research and practical experience the interest in shallow tillage and especially direct drilling has remained low in Scandinavia. Excessive compaction of the topsoil layer is one of the major problems encountered when adapting shallow tillage and direct drilling in particular. The purpose of this study was to evaluate temporal and spatial effects of two different direct drilling techniques on bulk density and penetration resistance in the near seed environment. A sandy loam growing small grain cereals was followed during the first 3 years after conversion from conventional tillage to direct drilling to reveal short-term changes in soil structure. A field experiment with four blocks was conducted in 1999?2001 where a conventional mouldboard ploughing?harrowing system (PL) was compared with direct drilling performed by either a chisel coulter drill (DD-C) or a single disc drill (DD-D). Effects on density and penetration resistance were measured in the field after first, second and third year of crop establishment (T1, T2 and T3). Bulk density was determined at 0?100 mm depth using a dual probe gamma-ray transmission system. Penetration resistance was recorded in the field at 0?150 mm depth. At T2 column samples (diameter: 180 mm, height: 200 mm) were taken with the seed row through the centre. Penetration resistance was determined in these samples in a 10 mm×10 mm grid using a micropenetrometer (3 mm cone base diameter) at 0 to approximately 150 mm depth. Two samples from each treatment were analysed by a medical CT-scanner to determine spatial differences in bulk density. Irrespective of coulter type direct drilling gave a fast compaction of the arable layer below seeding depth when shifting from mouldboard ploughing to direct drilling. Soil strength was substantially higher already in the first year of direct drilling (i.e., maximum 0.4 and 1.2 MPa, for PL and DD-D/DD-C, respectively). Critical high penetration resistance (>2.0 MPa) and bulk density levels (>1.5 g cm-3) were reached at T2 and remained at the same level at T3. The DD-C direct drill produced a more favourable soil environment for crop establishment than the DD-D drill. A layer of approximately 40 mm loose granular soil above seeding depth and no indication of a direct compaction effect was found for the DD-C treatment. In contrast, the field as well as the laboratory results indicated a direct compacting effect for the DD-D drill. Despite the lack of direct compaction effect from the DD-C drill itself, evidence suggest that periodic non-inversion soil loosening of the lower part of the arable layer is needed on direct drilled sandy loam soil in a moist and cool climate. SP - 163 A1 - Munkholm, L.J. A1 - Schjønning, P. A1 - Rasmussen, K.J. A1 - Tanderup, K. Y1 - 2003/// TI - Spatial and temporal effects of direct drilling on soil structure in the seedling environment ER - TY - UNPB TI - Non-inverting Tillage: Early-Stage Effects on Soil Mechanical Behaviour Y1 - 2000/// A1 - Munkholm, Lars J A1 - Schjønning, Per A1 - Rasmussen, Karl J SP - 1 N2 - Organic farmers often claim positive effects of non-inverting and reduced tillage systems. There is a need of quantifying tilth characteristics in the former plough layer of soil converted to such tillage systems. A non-inverting tillage system (NINV) was tested in a field experiment conducted on a Danish sandy loam soil. It included deep loosening and shallow intensive cultivation and was compared to a conventional ploughing-harrowing tillage system (CONV). A hierarchical analytical procedure was applied in studies of soil fragmentation and soil strength characteristics for the 7-14 cm soil layer. A visual description was carried out and ease of fragmentation was evaluated in the field using a soil drop test. Soil strength was measured in the field with a cone penetrometer and a torsional shear box method, and in the laboratory using an annulus shear strength method. Tensile strength was determined in the laboratory on field-sampled aggregates. The CONV treated soil displayed a higher ease of fragmentation in the field in May as well as in September. In general, aggregates from the NINV treated soil were stronger than aggregates from the CONV treatment. The soils had similar friability indices in May. In September, however, a higher friability index was found for the CONV treated soil (k=0.22 and 0.16, respectively for CONV and NINV). The NINV treated soil also displayed the highest soil strength. The soil tilth was evaluated to be best in the CONV treated soil. Supposed meliorating actions during the growing season did not eliminate the differences between the treatments. UR - https://orgprints.org/id/eprint/57/ EP - 10 ID - orgprints57 AV - public ED - Morrison, J.E. ER - TY - GEN Y1 - 2001/10// TI - Non-inversion tillage effects on soil mechanical properties of a humid sandy loam N2 - Optimisation of soil tilth is of paramount importance in organic plant production in order to enhance crop growth. Non-inversion and reduced tillage systems are often claimed to be preferable for organic farming. The purpose of this study was to evaluate the early stage effects of converting a mouldboard-ploughed soil to a non-inversion tillage system. A multi-level experimental strategy including in situ, on-site and laboratory methods was followed in order to relate quantitative measures of soil physical properties directly to soil behaviour in the field. A non-inversion deep soil loosening (0¯35 cm) tillage system (NINV) was compared to a conventional mouldboard ploughing and harrowing tillage system (CONV). The experimental site was located on an organically managed sandy loam soil. The tillage treatments were applied to plots in two fields (B3 and B4) at the experimental site. Limited numbers of measurements were performed in the B3 field during the 1997¯1999 growing seasons. A more comprehensive programme was carried out in the B4 field in May and September 1998. A root-restricting plough pan was detected in the CONV treated soil. The NINV treatment effectively loosened the plough pan resulting in a visibly improved soil structure and a decrease in soil strength. The penetration resistance in the plough pan was reduced from about 1800 kPa in CONV to less than 1000 kPa in NINV when measured at field capacity. The loosening of the plough pan was still evident after 2 years without tillage operations in a perennial grass/clover crop. The topsoil of the CONV treatment had a more desirable tilth than that of the NINV treatment, which had higher soil strength at the 7¯14 cm depth. In accordance with this, the CONV treated topsoil fragmented more readily than the NINV soil in the field. The laboratory measurements on soil from the September sampling showed that the NINV treatment had lower friability index (i.e., friability index of 0.16 and 0.22 for NINV and CONV, respectively) and higher tensile strength of air-dry aggregates. The differences in topsoil tilth were not eliminated by natural soil meliorating processes during the growing season. This paper discusses the early stage effects of converting to non-inversion tillage. A number of years of continued treatment may be required before beneficial effects of non-inversion tillage are manifested in improved topsoil tilth. SP - 1 A1 - Munkholm, Lars J. A1 - Schjønning, Per A1 - Rasmussen, Karl J. EP - 14 UR - https://orgprints.org/id/eprint/39/ ID - orgprints39 AV - restricted ER - TY - GEN UR - https://doi.org/10.1016/j.soilbio.2020.108008 ID - orgprints38469 AV - public Y1 - 2020/11/01/ TI - Decreased rhizodeposition, but increased microbial carbon stabilization with soil depth down to 3.6 m SN - 00380717 N2 - Despite the importance of subsoil carbon (C) deposition by deep-rooted crops in mitigating climate change and maintaining soil health, the quantification of root C input and its microbial utilization and stabilization below 1 m depth remains unexplored. We studied C input by three perennial deep-rooted plants (lucerne, kernza, and rosinweed) grown in a unique 4-m deep RootTower facility. 13C multiple pulse labeling was applied to trace C flows in roots, rhizodeposition, and soil as well as 13C incorporation into microbial groups by phospholipid fatty acids and the long-term stabilization of microbial residues by amino sugars. The ratio of rhizodeposited 13C in the PLFA and amino sugar pools was used to compare the relative microbial stability of rhizodeposited C across depths and plant species. Belowground C allocation between roots, rhizodeposits, and living and dead microorganisms indicated depth dependent plant investment. Rhizodeposition as a fraction of the total belowground C input declined from the topsoil (0?25 cm) to the deepest layer (360 cm), i.e., from 35%, 45%, and 36%?8.0%, 2.5%, and 2.7% for lucerne, kernza, and rosinweed, respectively, where lucerne had greater C input than the other species between 340 and 360 cm. The relative microbial stabilization of rhizodeposits in the subsoil across all species showed a dominance of recently assimilated C in microbial necromass, thus indicating a higher microbial stabilization of rhizodeposited C with depth. In conclusion, we traced photosynthates down to 3.6 m soil depth and showed that even relatively small C amounts allocated to deep soil layers will become microbially stabilized. Thus, deep-rooted crops, in particular lucerne are important for stabilization and storage of C over long time scales in deep soil. A1 - Peixoto, Leanne A1 - Elsgaard, Lars A1 - Rasmussen, Jim A1 - Kuzyakov, Yakov A1 - Banfield, Callum C. A1 - Dippold, Michaela A. A1 - Olesen, Jørgen E. ER - TY - GEN N2 - 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 a shallow-rooted binary mixture and pure stands, 2) deep-rooted grassland plant species (chicory and lucerne) are superior in terms of accessing soil N from 1.2 m soil depth compared with shallow-rooted plant species, 3) shallow-rooted grassland plant species (perennial ryegrass and white clover) are superior in terms of accessing soil N from 0.4 m soil depth compared with deep-rooted plant species and 4) a mixture of deep- and shallow-rooted plant species has access to greater amounts of soil N compared with a shallow-rooted binary mixture. Method: A 15N tracer methodology with 15N enriched ammonium-sulphate placed at three different soil depths (0.4, 0.8 and 1.2 m) was applied to determine the depth dependent soil N-access measured as plant 15N-uptake in pure stands, two-species and four-species grassland plant communities. Important findings: The study showed that herbage yield of the four-species mixture including deep- and shallow rooted grassland plant species was generally greater than both the pure stands and the two-species mixture, besides for lucerne in pure stand. This positive plant diversity effect in the four-species mixture on above-ground herbage yield could not be explained by complementary soil 15N uptake from 0.4, 0.8 and 1.2 m soil depths, even though chicory indicated deep soil 15N uptake. Perennial ryegrass demonstrated relatively deep soil 15N uptake when grown in pure stand, but showed increasing shallow 15N uptake from grown in a two-species to a four-species mixture. Total soil 15N uptake from three soil depths of a mixture 51 comprising two deep-rooted and two shallow-rooted plant species was not greater compared with a shallow-rooted two-species mixture. 15Nitrogen uptake from 1.2 m may have been too small to determine any differences. Legumes stimulated perennial ryegrass in 15N uptake from shallow soil layers, which indicated greater total 15N uptake of mixtures compared with pure stands. SP - 313 A1 - Pirhofer-Walzl, K. A1 - Eriksen, J. A1 - Rasmussen, J. A1 - Søegaard, K. A1 - Høgh-Jensen, H. A1 - Rasmussen, J. Y1 - 2013/// TI - Effect of deep-rooted plant species on 15Nitrogen uptake and herbage yield in temporary agricultural grasslands AV - restricted KW - deep-rooted; shallow-rooted; soil 15N uptake; diversity effect; grass-legume-herb grassland; Cichorium intybus L. EP - 325 UR - https://orgprints.org/id/eprint/20614/ ID - orgprints20614 ER - TY - GEN TI - Effect of four plant species on soil 15N-access and herbage yield in temporary agricultural grasslands Y1 - 2013/03// A1 - Pirhofer-Walzl, K. A1 - Eriksen, Jørgen A1 - Rasmussen, Jim A1 - Soegaard, Karen A1 - Høgh-Jensen, Henning A1 - Rasmussen, Jesper SP - 313 N2 - Aim is to ncrease 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 a shallow-rooted binary mixture and pure stands, 2) deep-rooted grassland plant species (chicory and lucerne) are superior in terms of accessing soil N from 1.2 m soil depth compared with shallow-rooted plant species, 3) shallow-rooted grassland plant species (perennial ryegrass and white clover) are superior in terms of accessing soil N from 0.4 m soil depth compared with deep-rooted plant species and 4) a mixture of deep- and shallow-rooted plant species has access to greater amounts of soil N compared with a shallow-rooted binary mixture. EP - 325 UR - https://orgprints.org/id/eprint/43859/ ID - orgprints43859 AV - public ER - TY - CONF N2 - 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. SP - 75 A1 - Pirhofer-Walzl, K. A1 - Høgh-Jensen, H. A1 - Rasmussen, J. A1 - Rasmussen, J. A1 - Søegaard, K. A1 - Eriksen, J. Y1 - 2010/// TI - 15Nitrogen transfer from legumes to neighbouring plants in multi-species grassland AV - public UR - https://orgprints.org/id/eprint/17887/ EP - 78 ID - orgprints17887 ER - TY - CONF AV - public EP - 832 UR - https://orgprints.org/id/eprint/17886/ ID - orgprints17886 SP - 830 A1 - Pirhofer-Walzl, K. A1 - Høgh-Jensen, H. A1 - Rasmussen, J. A1 - Rasmussen, J. A1 - Søegaard, K. A1 - Eriksen, J. N2 - 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 three different soil depths (40, 80 and 120 cm). To recover 15N, above-ground plant biomass was harvested after 10 days. We described the decline of 15N uptake with depth by using an exponential decay function. The studied plant communities showed the same relative decline in 15N uptake by increasing soil depths, but different capacities in total 15N uptake. Monoculture L. perenne foraged less 15N in all depths compared to the other four plant communities. The relative 15N uptake of individual plant species grown in mixture decreased stronger with depth than in monoculture. Thus, both findings rejected our hypothesis. Y1 - 2010/// TI - 15Nitrogen uptake from shallow- versus deep-rooted plants in multi-species mixtures and monoculture grassland SN - 978-3-86944-021-7 ER - TY - GEN UR - https://orgprints.org/id/eprint/20613/ EP - 84 ID - orgprints20613 AV - public KW - 15N transfer; Grass-legume-herb grassland; Root characteristics; Trifolium repens L.; Trifolium pratense L.; Medicago sativa L. Y1 - 2012/// TI - Nitrogen transfer from forage legumes to nine neighbouring plants in a multi-species grassland N2 - 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 derived from white clover (4.8 gm-2) compared with red clover (2.2 gm-2) and lucerne (1.1 gm-2). Grasses having fibrous roots received greater amounts of N from legumes than dicotyledonous plants which generally have taproots. Slurry application mainly increased N transfer from legumes to grasses. During the growing season the three legumes transferred approximately 40 kg N ha-1 to neighbouring plants. Below-ground N transfer from legumes to neighbouring plants differed among nitrogen donors and nitrogen receivers and may depend on root characteristics and regrowth strategies of plant species in the multi-species grassland. SP - 71 A1 - Pirhofer-Walzl, K. A1 - Rasmussen, J. A1 - Høgh-Jensen, H. A1 - Eriksen, J. A1 - Søegaard, K. A1 - Rasmussen, J. ER - TY - GEN N2 - 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 derived from white clover (4.8 g m-2) compared with red clover (2.2 g m-2) and lucerne (1.1 g m-2). Grasses having fibrous roots received greater amounts of N from legumes than dicotyledonous plants which generally have taproots. Slurry application mainly increased N transfer from legumes to grasses. During the growing season the three legumes transferred approximately 40 kg N ha-1 to neighbouring plants. Below-ground N transfer from legumes to neighbouring plants differed among nitrogen donors and nitrogen receivers and may depend on root characteristics of plant species in the multi-species grassland. SP - 71 A1 - Pirhofer-Walzl, K. A1 - Rasmussen , Jim A1 - Høgh-Jensen, Henning A1 - Eriksen, Jørgen A1 - Soegaard, Karen A1 - Rasmussen, Jesper Y1 - 2012/// TI - Nitrogen transfer from forage legumes to nine neighbouring plants in a multi-species grassland AV - restricted UR - https://orgprints.org/id/eprint/20645/ ID - orgprints20645 EP - 84 ER - TY - GEN EP - 10 UR - https://orgprints.org/id/eprint/23296/ ID - orgprints23296 KW - competition AV - public TI - Effect of four plant species on soil 15N-access and herbage yield in temporary agricultural grasslands Y1 - 2013/// A1 - Pirhofer-Walzl, Karin A1 - Eriksen, Jørgen A1 - Rasmussen , Jim A1 - Høgh-Jensen, Henning A1 - Søegaard, Karin A1 - Rasmussen, Jesper SP - 1 N2 - Positive plant diversity-productivity relationships have been reported for experimental semi-natural grasslands (Cardinale et al. 2006; Hector et al. 1999; Tilman et al. 1996) as well as temporary agricultural grasslands (Frankow-Lindberg et al. 2009; Kirwan et al. 2007; Nyfeler et al. 2009; Picasso et al. 2008). Generally, these relationships are explained, on the one hand, by niche differentiation and facilitation (Hector et al. 2002; Tilman et al. 2002) and, on the other hand, by greater probability of including a highly productive plant species in high diversity plots (Huston 1997). Both explanations accept that diversity is significant because species differ in characteristics, such as root architecture, nutrient acquisition and water use efficiency, to name a few, resulting in composition and diversity being important for improved productivity and resource use (Naeem et al. 1994; Tilman et al. 2002). Plant diversity is generally low in temporary agricultural grasslands grown for ruminant fodder production. Grass in pure stands is common, but requires high nitrogen (N) inputs. In terms of N input, two-species grass-legume mixtures are more sustainable than grass in pure stands and consequently dominate low N input grasslands (Crews and Peoples 2004; Nyfeler et al. 2009; Nyfeler et al. 2011). In temperate grasslands, N is often the limiting factor for productivity (Whitehead 1995). Plant available soil N is generally concentrated in the upper soil layers, but may leach to deeper layers, especially in grasslands that include legumes (Scherer-Lorenzen et al. 2003) and under conditions with surplus precipitation (Thorup-Kristensen 2006). To improve soil N use efficiency in temporary grasslands, we propose the addition of deep-rooting plant species to a mixture of perennial ryegrass and white clover, which are the most widespread forage plant species in temporary grasslands in a temperate climate (Moore 2003). Perennial ryegrass and white clover possess relatively shallow root systems (Kutschera and Lichtenegger 1982; Kutschera and Lichtenegger 1992) with effective rooting depths of <0.7 m on a silt loamy site (Pollock and Mead 2008). Grassland species, such as lucerne and chicory, grow their tap-roots into deep soil layers and exploit soil nutrients and water in soil layers that the commonly grown shallow-rooting grassland species cannot reach (Braun et al. 2010; Skinner 2008). Chicory grown as a catch crop after barley reduced the inorganic soil N down to 2.5 m depth during the growing season, while perennial ryegrass affected the inorganic soil N only down to 1 m depth (Thorup-Kristensen 2006). Further, on a Wakanui silt loam in New Zealand chicory extracted water down to 1.9 m and lucerne down to 2.3 m soil depth, which resulted in greater herbage yields compared with a perennial ryegrass-white clover mixture, especially for dryland plots (Brown et al. 2005). There is little information on both the ability of deep- and shallow-rooting grassland species to access soil N from different vertical soil layers and the relation of soil N-access and herbage yield in temporary agricultural grasslands. Therefore, the objective of the present work was to test the hypotheses 1) that a mixture comprising both shallow- and deep-rooting plant species has greater herbage yields than a shallow-rooting binary mixture and pure stands, 2) that deep-rooting plant species (chicory and lucerne) are superior in accessing soil N from 1.2 m soil depth compared with shallow-rooting plant species, 3) that shallow-rooting plant species (perennial ryegrass and white clover) are superior in accessing soil N from 0.4 m soil depth compared with deep-rooting plant species, 4) that a mixture of deep- and shallow-rooting plant species has greater access to soil N from three soil layers compared with a shallow-rooting two-species mixture and that 5) the leguminous grassland plants, lucerne and white clover, have a strong impact on grassland N acquisition, because of their ability to derive N from the soil and the atmosphere. ER - TY - GEN UR - https://orgprints.org/id/eprint/19333/ EP - 423 ID - orgprints19333 AV - public KW - herbs KW - forage quality KW - dairy cows KW - functional plant groups KW - grass-clover swards KW - slurry Y1 - 2011/// TI - Forage herbs improve mineral composition of grassland herbage SP - 415 A1 - Pirhofer-Walzl , K. A1 - Søegaard, Karen A1 - Høgh-Jensen, Henning A1 - Eriksen, Jørgen A1 - Sanderson, M.A. A1 - Rasmussen , Jim A1 - Rasmussen, Jesper N2 - Provision of an adequate mineral supply in the diets of ruminants fed mainly on grassland herbage can present a challenge if mineral concentrations are suboptimal for animal nutrition. Forage herbs may be included in grassland seed mixtures to improve herbage mineral content, although there is limited information about mineral concentrations in forage herbs. To determine whether herbs have greater macro- and micromineral concentrations than forage legumes and grasses, we conducted a 2-year experiment on a loamy-sand site in Denmark sown with a multi-species mixture comprised of three functional groups (grasses, legumes and herbs). Herb species included chicory (Cichorium intybus L.), plantain (Plantago lanceolata L.), caraway (Carum carvi L.) and salad burnet (Sanguisorba minor L.). We also investigated the effect of slurry application on the macro- and micromineral concentration of grasses, legumes and herbs. In general, herbs had greater concentrations of the macrominerals P, Mg, K and S and the microminerals Zn and B than grasses and legumes. Slurry application indirectly decreased Ca, S, Cu and B concentrations of total herbage because of an increase in the proportion of mineral-poor grasses. Our study indicates that including herbs in forage mixtures is an effective way of increasing mineral concentrations in herbage. ER - TY - CONF PB - vdf Hochschulverlag AG an der ETH Zürich AV - public KW - weed management KW - cultural methods KW - prevention KW - competition KW - mechanical weed control ED - Alföldi, T. ED - Lockeretz, W. ED - Niggli, U. ID - orgprints250 UR - https://orgprints.org/id/eprint/250/ A1 - Rasmussen, Ilse A. A1 - Melander, Bo A1 - Rasmussen, Karsten A1 - Jensen, Rikke K. A1 - Hansen, Preben K. A1 - Rasmussen, Gitte A1 - Christensen, Svend A1 - Rasmussen, Jesper N2 - Cultural methods for prevention and improved crop competitiveness against weeds and mechanical weed control. TI - Recent advances in weed management in cereals in Denmark Y1 - 2000/// ER - TY - GEN AV - public KW - ukrudt KW - ukrudtsbekæmpelse KW - forebyggelse KW - mekanisk bekæmpelse KW - bekæmpelsesbehov KW - konkurrenceevne PB - Danmarks JordbrugsForskning T3 - SP rapport EP - 86 UR - https://orgprints.org/id/eprint/254/ ID - orgprints254 SP - 63 A1 - Rasmussen, Ilse A. A1 - Melander, Bo A1 - Rasmussen, Karsten A1 - Rasmussen, Jesper N2 - I økologisk plantedyrkning er ukrudtsreguleringen baseret på et samspil mellem forebyggelse og bekæmpelse, hvor forebyggelse spiller en langt større rolle end i den konventionelle dyrk-ning. I korn og andre tætsåede afgrøder er forebyggelsen den væsentligste komponent i ukrudtsreguleringen, hvorimod det er den direkte bekæmpelse, der udgør grundlaget for dyrk-ning af rækkeafgrøder så som gulerødder, løg, roer og kartofler. Den økologiske ukrudtsregu-lering kendetegnes ved kompleksitet, da der dels anvendes mange forskellige metoder, og dels anvendes metoder med langsigtede effekter i dyrkningssystemet. Formålet med denne artikel er at give overblik over de anvendte metoder. Artiklen er opbygget således at der først er et afsnit om behovet for ukrudtsregulering, derefter et afsnit om muligheder for forebyggelse mod ukrudt og endelig et afsnit om metoder til di-rekte bekæmpelse. Artiklen afsluttes med at afsnit om forskning vedrørende ukrudtsregule-ring. Artiklen er en gennemgang af principper og metoder - ikke konkrete anvisninger på hvordan ukrudtsbekæmpelsen i praksis skal udføres. Disse kan f.eks. findes i ?Ukrudtsbe-kæmpelse på økologiske brug? udgivet af Landbrugets Rådgivningscenter (Anonym 95) og i andre af de citerede kilder. Y1 - 1997/// TI - Regulering af ukrudt ER - TY - GEN Y1 - 2000/05// TI - Beskidte rækkeafgrøder giver ukrudt i kornet N2 - Mislykkes bekæmpelsen af ukrudt i rækkeafgrøder, kan det give store ukrudtsproblemer flere år senere, viser ny resultater fra danske forsøg. A1 - Rasmussen, Ilse A. A1 - Rasmussen, Jesper UR - https://orgprints.org/id/eprint/261/ ID - orgprints261 AV - public KW - rækkkeafgrøder KW - majs KW - ukrudtsbekæmpelse KW - sædskifte KW - korn PB - Økologisk Landsforening ER - TY - GEN A1 - Rasmussen, J. A1 - Eriksen, J. A1 - Jensen, E.S. A1 - Høgh-Jensen, H. SP - 293 N2 - 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 divided into two classes: large roots, retained on a 1-cm sieve, and small roots, passing a 1-cm sieve but retained on a 100-A mu m sieve. Large root biomass increased during the two growing seasons, and small root biomass increased during the growing seasons but decreased during autumn and winter. White clover roots lost C-14 and N-15 almost twice as fast as ryegrass roots. The disappearance pattern of C-14 and N-15 from dual-labelled ryegrass and white clover roots and the C and N contents of the recovered root material indicate that large roots are determining soil C pool build-up, whereas small roots determine soil N pool build-up. TI - Root size fractions of ryegrass and white clover contributes differently to C and N inclusion in SOM Y1 - 2010/// AV - restricted EP - 297 UR - https://orgprints.org/id/eprint/17875/ ID - orgprints17875 ER - TY - GEN AV - restricted UR - https://orgprints.org/id/eprint/16290/ ID - orgprints16290 EP - 3039 SP - 3031 A1 - Rasmussen, J. A1 - Gjettermann, B. A1 - Eriksen, J. A1 - Jensen, E.S. A1 - Høgh-Jensen, H. N2 - 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 plough layer. No evidence of plant uptake of dual-labelled organic compounds from the dual-labelled residues could be observed. N in pore water from the plough layer during autumn and winter had a constant content of dissolved organic N (DON) and an increasing content of dissolved inorganic N (DIN). A positive correlation between aboveground clover biomass harvested in the growth season and total N in pore water indicated that decaying roots from the living clover could be a major source of the 10 kg N ha-1 being lost with pore water during autumn and winter. The presence of 15N in pore water shifted from the DON fraction in autumn to the DIN fraction in late winter, with strong indications that 15N originated from the living ryegrass. However, 15N in pore water originating from plant residues only constituted 1.5% of the total dissolved N from the plough layer. Y1 - 2008/// TI - Fate of 15N- and 14C from labelled plant material: Recovery in perennial ryegrass-clover mixtures and in pore water of the sward ER - TY - CONF UR - https://orgprints.org/id/eprint/17882/ EP - 72 ID - orgprints17882 AV - public TI - Biomass production and N2-fixation in seven grass-legume mixtures Y1 - 2010/// A1 - Rasmussen, J. A1 - Søegaard, K. A1 - Eriksen, J. SP - 69 N2 - Inclusion of forage legumes in low-input grassland mixtures improves biomass production and soil fertility trough addition of nitrogen (N) from N2-fixation. The impacts of different mixture of legumes and companion grasses on the N production of the forage mixture have rarely been investigated under comparable soil and climatic conditions. We conducted a field experiment on a sandy soil at two nitrogen levels with seven two-species grassland mixtures: alfalfa (Medicago sativa), bird?s-foot trefoil (Lotus corniculatus), red clover (Trifolium pratense), or white clover (Trifolium repens) in mixture with perennial ryegrass (Lolium perenne), and white clover in mixture with meadow fescue (Festuca pratensis), timothy (Phleum pratense), or hybrid ryegrass (Lolium hybridum). Red clover and alfalfa fixed 400-500 kg N ha-1 and bird ?s-foot trefoil just above 100 kg N ha-1 in aboveground biomass. The white clover N fixation was affected by the companion grass species and ranged from 150 to 175 kg N ha-1. Fertilization had different effects on N2-fixation among the legumes, but also significant effects on white clover N2-fixation depending on the companion grass species. ER - TY - GEN AV - public PB - Dansk Agrarforlag A/S UR - https://orgprints.org/id/eprint/17196/ EP - 23 ID - orgprints17196 SP - 22 A1 - Rasmussen, Jesper N2 - I 75 ud af 100 tilfælde kan en effektiv ukrudtsharvning i vårbyg erstatte kemi ? uden at det går ud over økonomien. Men det kræver forskning og innovation Y1 - 2010/06// TI - Ukrudtsharven kan afløse kemi ER - TY - GEN ID - orgprints17194 UR - https://orgprints.org/id/eprint/17194/ PB - www.videnskab.dk AV - public TI - Ukrudtsharvning - effektiv i økologisk landbrug Y1 - 2010/04/24/ CY - www.videnskab.dk N2 - En optimal gennemført ukrudtsharvning er konkurrencedygtig med sprøjtemidler i 3 ud af 4 tilfælde. Ukrudtsharvning er derfor en interessant bekæmpelsesmetode, der bør udvikles. A1 - Rasmussen, Jesper ER - TY - GEN Y1 - 2010/04/02/ TI - Punktsåning giver mindre ukrudt SP - 16 A1 - Rasmussen, Jesper N2 - I langsomtspirende økologiske afgrøder som gulerødder og såløg bør jorden forstyrres så ledt som muligt i forbindelse med såning. Det får mindre ukrudt til at spire i rækkerne. Med punktsåning forstyrres jorden minimalt ved såning, og det giver mindre ukrudt i rækkerne. UR - https://orgprints.org/id/eprint/17064/ EP - 16 ID - orgprints17064 KW - sowing KW - mechanical weed control KW - weed germination AV - public ER - TY - GEN EP - 16 UR - https://orgprints.org/id/eprint/17040/ ID - orgprints17040 PB - Økologisk Landsforening KW - robotic weeding KW - robotter KW - mekanisk ukrudtsbekæmpelse AV - public TI - Intelligent ukrudtsbekæmpelse Y1 - 2010/03/12/ N2 - Personlig refleksion over begrebet intelligent ukrudtsbekæmpelse og trends i forskningen. I klummen ses der tilbage på 25 års forskning og det paradigmeskift, som er sket. A1 - Rasmussen, Jesper SP - 16 ER - TY - GEN UR - https://orgprints.org/id/eprint/17195/ ID - orgprints17195 PB - www.videnskab.dk AV - public TI - Økologisk forskning er troværdig Y1 - 2010/01/19/ A1 - Rasmussen, Jesper N2 - I videnskabelige kredse gør man meget ud af at holde viden og holdninger adskilt, fordi det skaber utroværdighed, hvis den forskningsbaserede viden er farvet af forskernes personlige holdninger. Objektivitet og troværdighed er en dyd. ER - TY - GEN UR - https://orgprints.org/id/eprint/17192/ ID - orgprints17192 AV - public PB - www.videnskab.dk Y1 - 2009/09/04/ TI - Ukrudt - en del af helheden CY - http://www.videnskab.dk N2 - Hvordan griber man ukrudt an i et økologisk landbrug? Og hvordan tænker man i det hele taget ukrudt ind i økologiens værdisæt? A1 - Rasmussen, Jesper ER - TY - CONF N2 - Indlægget beskriver forfatterens motivation til at genoptage forskning i ukrudtsharvning, en vision og eksempler på de seneste års resultater. Der lægges vægt på samspillet mellem ny teknologi og beslutningsalgoritmer. A1 - Rasmussen, Jesper SP - 286 TI - Ukrudtsharvning - mod et mere nuanceret vejledningsgrundlag Y1 - 2009/// KW - Weed harrowing KW - image analysis KW - technology KW - decision support syttems AV - public UR - https://orgprints.org/id/eprint/15202/ EP - 288 ID - orgprints15202 ER - TY - CONF AV - public KW - weed harrowing KW - models KW - statistics EP - 145 UR - https://orgprints.org/id/eprint/15687/ ID - orgprints15687 N2 - This report summarises (i) the introduction given at the initiation of the roundtable discussion about unifying parameters in mechanical weed control and (ii) the following discussion at the EWRS Physical and Cultural Weed Control Group meeting in Zaragoza 2009 A1 - Rasmussen, Jesper SP - 142 TI - Unifying parameters in mechanical weed control research - report of the roundtable Y1 - 2009/// ER - TY - GEN ID - orgprints14262 UR - https://orgprints.org/id/eprint/14262/ AV - public KW - såtiknik Y1 - 2008/08// TI - Mindre ukrudt med punktsåning N2 - Baggrunden for at inddrage punktsåning i ukrudtsprojekt i relation til økologisk jordbrug beskrives. A1 - Rasmussen, Jesper ER - TY - GEN ID - orgprints2530 UR - https://orgprints.org/id/eprint/2530/ KW - håndhakning KW - tidsforbrug AV - public TI - Falsk såbed sparer tid til roehakning Y1 - 2004/04// A1 - Rasmussen, Jesper N2 - Etablerer man et falsk såbed i roemarken, kan man glæde sig over mindre ukrudt, men samtidig falder udbyttet. I artiklen præsenteres en model, som kan anvendes til at beregne hvor meget tid der kan spares til håndhakning ved at udsætte såtidspunktet og hvor meget udbytte der tabes. ER - TY - CONF ID - orgprints2500 UR - https://orgprints.org/id/eprint/2500/ KW - systems KW - paradigms AV - public Y1 - 2004/// TI - Are we making progress in mechanical weed control research? A1 - Rasmussen, Jesper N2 - This study investigates whether researchers? perceptions of good research are in agreement with current research practice as reflected in Weed Research. A high degree of agreement is assumed to indicate progress. The instrument used to survey researchers perceptions was a questionnaire consisting of 28 items related to (1) research methodologies, (2) research priorities, (3) quality of publications, (4) future developments in technology and agriculture and (5) general attitudes to alternative and conventional agriculture. Questions about gender and personal research engagement were also laid down in the questionnaire. The questionnaire was sent out by e-mail to about 140 researchers on the mailing list of the EWRS ? Physical and Cultural Weed Control Group and 60 questionnaires were completed and returned. An analysis of all Weed Research publications in the period 1998-2003 investigated current research practices. The questionnaire showed that researchers in the working group are not specialized. Of the respondents, only 4 researchers (7%) used 50% or more of their research hours on mechanical weed control but a total of 44 researchers (73%) were active within this area. Views on research and agriculture varied significantly within the group and two counter paradigms were identified often refereed to as alternative and dominant. The alternative paradigm was connected with organic farming and the dominant paradigm was connected with conventional agriculture. Alternative paradigmatic positions prevailed among the respondents although strong dominant positions were also represented. Females (N=15) held more alternative positions than males (P < 0.01) and researchers engaged in herbicide technology (N=13) held more dominant positions than the rest P < 0.05. By using an alternative-dominant scale, it was evident that respondents? perceptions of good research was linked to basic values and beliefs that determine the overall understanding of how agriculture works and should be developed. Alternative perceptions of good research, however, seemed to be inconsistent with the current research practice as reflected in Weed Research. Consistency between ideals and reality should result in (1) more multidisciplinary studies to facilitate broader perspectives on weed control, (2) more studies carried out on working farms, (3) more system approaches that include whole agro-ecosystems with farmers and other stakeholders, (4) value inquiries, (5) participative research and (6) reflective approaches. Papers published in Weed Research clearly demonstrate, that alternative research in the ideal is different from research in reality. The main difference between alternative and dominant research is in what gets studied, not in how it is studied. In conclusion, research in physical and cultural weed control may be evaluated successful in a dominant paradigmatic perspective but progress is very limited in an alternative paradigmatic perspective. There seems to exist a mismatch between ideals and reality in weed research, which challenges ideals as well as practice. ER - TY - CONF SP - 115 A1 - Rasmussen, Jesper N2 - This study investigates whether researchers? perceptions of good research are in agreement with current research practice as reflected in Weed Research. A high degree of agreement is assumed to indicate progress. The instrument used to survey researchers perceptions was a questionnaire consisting of 28 items related to (1) research methodologies, (2) research priorities, (3) quality of publications, (4) future developments in technology and agriculture and (5) general attitudes to alternative and conventional agriculture. Questions about gender and personal research engagement were also laid down in the questionnaire. The questionnaire was sent out by e-mail to about 140 researchers on the mailing list of the EWRS ? Physical and Cultural Weed Control Group and 60 questionnaires were completed and returned. An analysis of all Weed Research publications in the period 1998-2003 investigated current research practices. The questionnaire showed that researchers in the working group are not specialized. Of the respondents, only 4 researchers (7%) used 50% or more of their research hours on mechanical weed control but a total of 44 researchers (73%) were active within this area. Views on research and agriculture varied significantly within the group and two counter paradigms were identified often refereed to as alternative and dominant. The alternative paradigm was connected with organic farming and the dominant paradigm was connected with conventional agriculture. Alternative paradigmatic positions prevailed among the respondents although strong dominant positions were also represented. Females (N=15) held more alternative positions than males (P < 0.01) and researchers engaged in herbicide technology (N=13) held more dominant positions than the rest (P < 0.05). By using an alternative-dominant scale, it was evident that respondents? perceptions of good research was linked to basic values and beliefs that determine the overall understanding of how agriculture works and should be developed. Alternative perceptions of good research, however, seemed to be inconsistent with the current research practice as reflected in Weed Research. Consistency between ideals and reality should result in (1) more multidisciplinary studies to facilitate broader perspectives on weed control, (2) more studies carried out on working farms, (3) more system approaches that include whole agro-ecosystems with farmers and other stakeholders, (4) value inquiries, (5) participative research and (6) reflective approaches. Papers published in Weed Research clearly demonstrate, that alternative research in the ideal is different from research in reality. The main difference between alternative and dominant research is in what gets studied, not in how it is studied. In conclusion, research in physical and cultural weed control may be evaluated successful in a dominant paradigmatic perspective but progress is very limited in an alternative paradigmatic perspective. There seems to exist a mismatch between ideals and reality in weed research, which challenges ideals as well as practice. Y1 - 2004/// TI - Are we making progress in mechanical weed control research? AV - public KW - questionnaire ID - orgprints2443 UR - https://orgprints.org/id/eprint/2443/ EP - 122 ER - TY - GEN Y1 - 2003/// TI - Punch planting, flame weeding and stale seedbed for weed control in row crops SP - 393 A1 - Rasmussen, Jesper N2 - Punch planting is introduced as a new method to reduce weeds within rows in organically grown crops. In this method a hole is punched in the soil, and a seed is dropped into it, without seedbed preparation and soil disturbance outside the hole. In two years, punch planting with flame weeding, normal planting with flame weeding and normal planting without flame weeding were compared in fodder beet for five planting dates. Each planting date represented a lag-period since establishment of the stale seedbed. Over all planting times and years, punch planting with flame weeding reduced intra-row weed densities by 30% at the 2-4 leaves stage of fodderbeet compared to normal drilling with flame weeding. Punch planting with flame weeding also reduced intra-row weed densities by 50% compared to normal drilling without flame weeding. There was no generally improved performance of punch planting with flame weeding over years by later planting, but delayed planting reduced intra-row weed densities significantly. Over two years, 240 day degrees Celsius (four weeks) planting delay reduced intra-row weed densities in the range of 68% to 86% depending on plant establishment procedure. Punch planting with flame weeding offers a promising method of weed control in organic farming. "This is a preprint of an Article accepted for publication in Weed Research © 2003 European Weed Research Society. For further information on Weed Research please refer to www.blackwellpublishing.com/wre" EP - 403 UR - https://orgprints.org/id/eprint/1785/ ID - orgprints1785 KW - Punch planting KW - flame weeding KW - stale seedbed KW - delayed sowing KW - organic farming KW - weed control KW - row crops AV - public PB - Blackwell Publishing ER - TY - GEN EP - 7 UR - https://orgprints.org/id/eprint/436/ ID - orgprints436 PB - KVL KW - undervisning KW - læring AV - public TI - Hvad karakteriserer god undervisning? Y1 - 2002/10// A1 - Rasmussen, Jesper SP - 6 N2 - Pædagogisk Udvalg udskrev tidligere på året en prisopgave med det formål at få kvalificerede forslag til, hvordan undervisningen kan se ud på fremtidens KVL. Mosaik bringer en forkortet version af 1. præmien. ER - TY - CONF N2 - Præsentation om alternative jordbearbejdningsmetoder. A1 - Rasmussen, Jesper TI - Alternative jordbearbejdningsmetoder Y1 - 2000/// KW - jordbearbejdning AV - public ID - orgprints433 UR - https://orgprints.org/id/eprint/433/ ER - TY - GEN SP - 523 A1 - Rasmussen, Jesper A1 - Bibby, Bo Martin A1 - Schou, Anders P. N2 - 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 selectivity in one out of two experiments. Whether repeated passes with the harrowing were carried out in the same orientation along the rows or in alternative orientations forth and back was unimportant. There were indications that high driving speed decreases selectivity and that repeated passes with low driving speed are better than single treatments with high driving speed. Impacts on selectivity, however, were small and only significant at high degrees of weed control. Timing had no significant impact on selectivity. Y1 - 2008/// TI - Investigating the selectivity of weed harrowing with new methods AV - public KW - Physical weed control KW - digital image analysis KW - crop damage KW - row spacing KW - harrowing direction KW - timing PB - Blackwell Publishing EP - 532 UR - https://orgprints.org/id/eprint/14987/ ID - orgprints14987 ER - TY - CONF A1 - Rasmussen, Jesper A1 - Helgadóttir, Á. A1 - Frankow-Lindberg, B. A1 - Loges, R. A1 - Eriksen, J. SP - 1028 N2 - Sources of inorganic and organic N leaching from grass-clover mixtures at field sites in Denmark, Germany and Iceland were investigated. Grass or clover was labelled with 15N-urea four times (autumn 2007, spring, summer and autumn 2008) prior to the leaching season in autumn and winter 2008. Soil water was sampled at 30 cm depth and analyzed for 15N-enrichment of dissolved inorganic N (DIN) and dissolved organic N (DON). Most 15N was recovered in DON for both labelled grass and clover at all sites. At the Danish site, grass and clover contributed more to the DON pool than the DIN whereas the opposite was observed at the German and Icelandic sites. The results show that both clover and grass contribute directly to N leaching from the root zone in mixtures, and that clover contribution is higher than grass. Furthermore, the present study indicates that roots active in the growth season prior to the drainage period contribute more to N leaching than roots active in the growth season the previous year, which is consistent with estimates of root longevity at the three sites. SN - 978-3-86944-021-7 TI - The contribution of grass and clover root turnover to N leaching Y1 - 2010/// AV - public ED - Schnyder, H. ID - orgprints17880 UR - https://orgprints.org/id/eprint/17880/ EP - 1030 ER - TY - CONF ID - orgprints432 UR - https://orgprints.org/id/eprint/432/ AV - public KW - kamme KW - jordbearbejdning KW - samdyrkning KW - sortsblandinger Y1 - 2002/// TI - Kamdyrkning i stedet for pløjning N2 - I projektet CARMINA undersøges de potentielle fordele ved at anvende kamme som alternativ til pløjning. Det er tidligere vist at kamme kan reducere udvaskning af kvælstof, øge omsætningen af organisk stof og sikre en tidligere såning samt bedre etablering. I CARMINA kombineres kamme med dyrkning af fangafgrøder og inkorporering af husdyrgødning i en række nye forsøg. A1 - Rasmussen, Jesper A1 - Henriksen, Christian Bugge ER - TY - CONF AV - public UR - https://orgprints.org/id/eprint/421/ ID - orgprints421 A1 - Rasmussen, Jesper A1 - Henriksen, Christian Bugge N2 - Jordløsning - er det svaret? Jesper Rasmussen & Christian Bugge Henriksen, Den Kgl. Veterinær og Landbohøjskole I stort set alle forsøg verden over har planter reageret positivt på en effektiv løsning af jorden i dybden. Når dybe jordløsninger alligevel ikke spiller nogen nævneværdig rolle i økologisk jordbrug, skyldes det, at det dels har vist sig svært at løsne joden effektivt i dybden med de eksisterende traktorredskaber, og dels er vanskeligt at fastholde en løs jord, hvis der fortsat foregår tung trafik på den. I forbindelse med dyrkning af højværdiafgrøder synes der basis for at eksperimentere med en kombination af effektiv løsning i dybden og kontrolleret trafik i faste kørespor. I forsøg er der opnået højere udbytter, lave brændstofforbrug og et lavere gødningsforbrug i sådanne systemer. Dybe jordløsninger uden for vækstsæsonen (grubning) Hvis det handler om at undgå de problemer med overfladevand på markerne, som i stigende omfang præger landskabet efterår og vinter er dybe jordløsninger med grubbere ikke løsningen. Løsningen på disse problemer ligger i forebyggelsen. I såvel konventionel som økologisk dyrkning har anvendelsen af stadig tungere maskiner nået en smertegrænse, da jorden i bogstaveligste forstand giver efter. Færdsel med tunge maskiner på våd jord trykker ikke blot jorden sammen i pløjelaget men også under pløjelaget. En gyllevogn med en akselbelastning på 10-15 tons kan lave trykskader i mere end 1 meters dybde. Dybe trykskader er varige. Jorden kan ikke selv reparere dem, og det er usikkert i hvor høj grad de kan repareres ved hjælp af grubning. Det er veldokumenteret, at en positiv effekt af grubning ikke holder lige så længe som en negativ effekt af jordpakning. Grubning kombineret med efterfølgende tung trafik er derfor ingen god løsning. Ophør af tung trafik på våd jord er den løsning, som der hør stræbes efter. Kompakte lag under pløjedybden anses nu for at være almindelige i danske jorde, men i hvor høj grad de har praktisk betydning for plantevæksten er usikkert. Danske forsøg har ikke vist entydige positive effekter af dyb jordløsning. I første halvdel af 90'erne blev der foretaget en del forsøg med grubning i Danmark med forskellige redskaber - heriblandt Springer Agromeliorator. Dyb jordløsning havde generelt ringe indflydelse på plantevæksten, og kun i få tilfælde blev der målt sikre merudbytter. Resultaterne var uafhængige af grubbernes udformning. Der var ikke tegn på at grubningerne øgede mineraliseringen i jorden. Konklusionen på forsøgene blev, at hvis der er sket skade på jordstrukturen under pløjelaget, kan man forsøge at genskabe jordens dyrkningsegenskaber ved en dybdegående jordløsning. Der gives dog ingen garanti for om det lykkes. I begyndelsen af århundredet blev der udført en række forsøg med forskellige pløjedybder og dyb jordløsning i 40 cm dybde. Forsøgene var fastliggende og blev gennemført på såvel ler- som sandjord. De var ikke anlagt for at reparere trykskader, men fordi man havde en formodning om, at dyb jordløsning var en fordel i forbindelse med gødskning med store mængder staldgødning. Løsningerne blev derfor kun foretaget forud for roer og kartofler, der fik tilført staldgødning. Jordløsningerne gav generelt meget små merudbytter, og det kunne ikke eftervises, at der var et specielt behov for at løsne jorden i forbindelse med anvendelse af store mængder staldgødning. Danske forsøg synes således at vise, at der er ikke er behov for dybe jordløsninger med grubbere på almindelig landbrugsjord, selvom der ofte forekommer kompakte jordlag under pløjedybden. Der kan være flere årsager til dette: 1) På trods af kompakte lag er der intet reelt behov for jordløsning, 2) I forsøgene har jordløsningerne ikke været optimale eller 3) Jordløsningens effekt er så kortvarig, at den ikke kan måles på de efterfølgende afgrøder. Den internationale litteraturen er rig på dokumentation af alle 3 forhold. 1) Behovet for jordløsning kan ikke bestemmes entydigt, men der findes simple registreringsmetoder, som kan give et klart fingerpeg som for eksempel visuel bedømmelse af rodvæksten samt penetrometermålinger. 2) Betingelsen for at opnå et tilfredsstillende resultat med jordløsning er, at jorden er tilpas tør. Grubning af våd jord kan forværre jordpakningen. 3) Tung trafik kort tid efter jordløsningen kan presse jorden sammen igen efter en ellers vellykket jordløsning. Jordløsning som en del af den primær jordbearbejdning I den klassiske litteratur om økologisk jordbearbejdning er det ofte blevet fremført, at den ideelle primære jordbearbejdning består af en kombination af overfladisk intensiv jordbearbejdning med en dybere jordløsning. Der findes en række forskellige redskaber, som er udformet efter dette princip. Interessen for jordløsning som en del af den primære jordbearbejdning har især været stor i forbindelse med reduceret jordbearbejdning i USA og Canada. Her er der gennemført talrige forsøg og opnået gode resultater i majs- og sojabønner under forudsætning af en effektiv kemisk ukrudtsbekæmpelse. Under økologiske dyrkningsforhold har det vist sig vanskeligt at håndtere ukrudtet uden brug af plov. Danske igangværende forsøg har ikke vist klare udbytteforøgelser med jordløsning i forbindelse med overfladisk primær jordbearbejdning. Jordløsninger i vækstsæsonen Jordløsninger i vækstsæsonen, der har til formål at stimulere jordens biologiske omsætning af kvælstof, foreligger der kun få forsøg med. Der foreligger både positive og negative resultater. På grovsandet jord er der opnået merudbytter i kartoffel og på lerjord er der opnået merudbytter i vinterhvede. Der forekommer dog også negative udslag i vinterhvede og bederoer på lerjord. Der er endnu mange usikkerhedsmomenter forbundet med jordløsning i vækstsæsonen. Effektive jordløsninger En række forsøg verden over har vist, at stort set alle afgrøder reagerer positivt på en effektivt løsnet jord. Der har været udført forsøg med såvel gravning i 50 centimeters dybde, gravning i cirka 25 cm dybde og løsning i 25 cm dybde og endelig opgravning af jorden lag for lag i 90 cm dybde, hvorefter den er lagt tilbage lagvis. Sådanne effektive jordløsninger, som blandt andet kendes fra højbede, har givet langt større effekter end almindelige jordløsninger. I en række forsøg er der fundet store udbytteforøgelser i såvel landbrugs- som havebrugsafgørder. Effekterne er især store hvis den effektive jordløsning kombineres med kontrollerede trafiksystemer med faste kørespor. Effektiv løsning med kontrolleret trafiksystemer synes især interessante i intensive dyrkningssystemer med rækkeafgrøder. I England har der været gennemført forsøg med en traktordreven "double-digger", der i princippet udfører samme arbejde som gravning i dobbelt dybde med hånden. Resultaterne var klart bedre end dem der blev opnået med traditionelle grubbere. I Holland har dyb jordløsning i kontrollerede trafiksystemer med faste kørespor givet udbytteforøgelser mellem 0-10% over en årrække i intensive dyrkningssystemer med kartofler, roer og vinterhvede. I systemerne blev der desuden opnået reduktioner på cirka 50% af traktorbrændstofforbruget og cirka 10% af gødningsforbruget. Det forekommer oplagt at undersøge mulighederne for at effektiv løsning af jorden i systemer med kontrolleret trafik under danske økologiske dyrkningsbetingelser. Y1 - 2000/// TI - Jordløsninger - er det svaret? ER - TY - GEN N2 - I artiklen redegøres der for nogle af de mekanismer, som gør, at jordbrugsvidenskaben kan blive ideologisk ensrettet, hvis ikke de værdier og holdninger som ligger bag gøres synlige og åben for diskussion. Artiklen bygger delvis på undersøgelsesresultater. A1 - Rasmussen, Jesper A1 - Kaltoft, Pernille SP - 10 TI - Holdninger præger jordbrugsvidenskaben Y1 - 2003/04// KW - værdier KW - holdninger KW - ideologi AV - public UR - https://orgprints.org/id/eprint/642/ EP - 12 ID - orgprints642 ER - TY - GEN SP - 347 A1 - Rasmussen, Jesper A1 - Kaltoft, Pernille N2 - From radical positions it is argued that it will take paradigmatic transformations to develop a sustainable agriculture and that values and attitudes have to be changed. To find out if teachers and students in higher agricultural education are motivated for radical changes a survey based on the Alternative-Conventional Agriculture Paradigm Scale (ACAP-scale) was conducted. The ACAP-scale shows how people relate to the alternative and conventional agricultural paradigm and it shows their overall understanding of how agriculture works and relates to the physical and social environment. This study showed that the ACAP-scale is a suitable method for quantitative assessment of attitudes to agriculture in a broader context. Among students and faculty members at the Royal Veterinary and Agricultural University, Denmark there exists significant differences in paradigmatic positions. Students? course choices are, to some extent, influenced by their paradigmatic position, some courses enrol followers of either the alternative or the conventional agricultural paradigm, and females and older students hold more alternative views than males and younger students. It is concluded that the wide range of values and attitudes among students and teachers calls for new teaching methods, where values and attitudes are integrated. It cannot be taken for granted that teachers and students share the radical visions of sustainability as sometimes presupposed of bodies working for sustainable development. Y1 - 2003/// TI - Alternative versus conventional attitudes in higher agricultural education KW - paradigms KW - idelogy KW - values AV - public UR - https://orgprints.org/id/eprint/641/ EP - 363 ID - orgprints641 ER - TY - GEN AV - public KW - holdinger gen-debat paradigmer UR - https://orgprints.org/id/eprint/4032/ ID - orgprints4032 N2 - Holdningen til bioteknologi er en klar indikator for den generelle holdning til økologisk jordbrug A1 - Rasmussen, Jesper A1 - Kaltoft, Pernille TI - Fortalere for genteknologi på vanskelig opgave blandt økologer Y1 - 2003/// ER - TY - GEN TI - Ensidige holdninger i undervisningen - hvad stiller vi op med dem? Y1 - 2002/10// A1 - Rasmussen, Jesper A1 - Kaltoft, Pernille SP - 15 N2 - Holdninger og værdier må nødvendigvis spille en rolle i Landbohøjskolens uddannelser, da uddannelserne retter sig mod professioner, som udøves i et værdipluralistisk samfund. Vi kan derfor ikke lade som om, værdier og holdninger enten ikke eksisterer eller er ens for alle. Dette udfordrer den grundholdning, som præger Landbohøjskolen, hvor såkaldt objektiv faglighed er i højsædet. UR - https://orgprints.org/id/eprint/435/ EP - 17 ID - orgprints435 PB - KVL AV - public KW - holdninger KW - værdier ER - TY - CONF Y1 - 2002/// TI - De nye konsulenter og deres holdninger til økologisk jordbrug SP - 31 A1 - Rasmussen, Jesper A1 - Kaltoft, Pernille N2 - Holdninger er vigtige, selvbekræftende og konservative Nogle holdninger er overfladiske, mens andre er dybe, da de er kædet sammen med basale værdier hos det enkelte menneske. Det er de dybere holdninger, vi beskæftiger os med i det følgende. Denne type holdninger har betydning for hvordan vi oplever og forstår verden, og hvordan vi handler. Holdningerne og værdierne hjælper os med at finde sammenhæng og mening i tilværelsen, og de får os til at føle harmoni mellem det vi opfatter som rigtigt, og det vi gør. Holdninger er selvbekræftende, fordi vi har behov for at opleve sammenhæng mellem oplevelse, forståelse og handling. De dybe holdninger er konservative, fordi vi ikke kan ændre dem fra den ene dag til den anden. Dette er godt, fordi vi ville komme i konflikt med os selv og omverdenen, hvis vi hyppigt skiftede holdninger, og det er dårligt, fordi holdninger kan være uhensigtsmæssige og hæmme en god udvikling. Kortlægning af de nye konsulenters holdninger Der er ingen, som har kortlagt konsulenters holdninger til økologisk jordbrug, eller holdningernes betydning for rådgivningen. Vi har derfor valgt at tegne et billede af de holdninger, som præger de studerende, når de forlader Landbohøjskolen. Dette billede er sammensat af to dele. En beskrivelse af det undervisningsmiljø, som de uddannes i, og en spørgeskemaundersøgelse. Undervisningskulturen på Landbohøjskolen Nyuddannede kandidater er i vid udstrækning præget af den naturvidenskabelige grundholdning, der ofte præsenteres som hævet over det den også er - en holdning. Verden søges beskrevet og forstået objektivt, og det er såkaldt værdifri viden, der betragtes som altafgørende i undervisningen. Holdningsspørgsmål fortrænges fra de sammenhænge, hvor de øver indflydelse. Det kan være spørgsmål om hvad der er vigtig viden, hvordan denne viden kan og bør anvendes, og hvilken samfundsudvikling den understøtter. Da vi ikke længere lever i en verden, hvor det er indiskutabelt, hvad der er godt eller skidt, er det vigtigt at få koblet et bredere perspektiv på undervisningen, end den som den naturvidenskabelige grundholdning levner plads til. Dette kan gøres på to måder. Ved at styrke undervisningen i etik og videnskabsteori og/eller ved at integrere holdningsaspekter i den faglige undervisning. Det er især førstnævnte metode, som har vundet indpas på Landbohøjskolen. I de senere år er den valgfrie undervisning i etik og videnskabsteori således blevet styrket, og det er nu besluttet at gøre den obligatorisk for alle studerende. Den anden strategi, hvor holdningsaspekter integreres direkte i den faglige undervisning er sjælden, men den er taget op på kurserne i økologisk jordbrug, hvor de studerende trænes i at analysere hvor og hvordan holdninger gør sig gældende i forhold til det faglige. Berettigelsen af selvstændige kurser i økologisk jordbrug er løbende til debat på Landbohøjskolen. Kursernes berettigelse er blandt andet, at de træner de studerende i at arbejde med tværfaglige problemstillinger i relation til økologisk jordbrug og lærer dem at forholde sig til det økologiske jordbrugs visioner, principper og praksis i et overordnet bæredygtighedsperspektiv. Mange finder imidlertid at den almene undervisning er dækkende for alle typer jordbrug og bestræbelser på bæredygtighed. Et flertal af de studerende som ønsker at blive konsulenter vælger almene kurser frem for de økologiske. Holdningsundersøgelse på Landbohøjskolen En ny undersøgelse (Rasmussen & Kaltoft, 2002) viser, at der både findes positive og negative holdninger til økologisk jordbrug repræsenteret på Landbohøjskolen. Negative holdninger fremkommer, når man ikke ser meningsgivende sammenhænge mellem det, som det økologiske jordbrug står for, og det der fremmer en god udvikling. Dette misforhold gør, at man føler modvilje, ubehag eller måske endog aggressivitet i forhold til økologisk jordbrug. Positive holdninger fremkommer, når man netop finder meningsgivende sammenhæng mellem det økologiske jordbrug, og det der skal til for at fremme en god udvikling. Blandt såvel undervisere som studerende findes hele spektret af holdninger til økologisk jordbrug, fra stærkt negative til stærkt positive. De studerende som tager kurser i økologisk jordbrug, er generelt positive overfor økologisk jordbrug, og det er kun få, som er meget negative. Dette er måske ikke så overraskende, da kurserne netop vedkender sig at have en kritisk og konstruktiv tilgang til økologisk jordbrug og derfor repræsenterer en positiv holdning til økologisk jordbrug. Mere overraskende er det, at nogle af de almene kurser, som præsenterer sig som holdningsneutrale og hylder den værdifri tilgang til fagligheden, rekrutterer studerende med stærke negative holdninger til økologisk jordbrug. Blandt disse kurser er nogle centrale produktionsorienterede kurser, som anses for mere eller mindre obligatoriske for de studerende, som ønsker at blive planteavlskonsulenter. På disse kurser havde de studerende endog meget negative holdninger til økologiske jordbrug. De mest positive havde holdninger, der svarede til de mest negative blandt dem som valgte kurser i økologisk jordbrug. Dem som havde de mest negative holdninger var aggressive overfor økologisk jordbrug og havde svært ved at diskutere dets berettigelse. På de pågældende kurser var de studerende som gennemsnit mere negative overfor økologisk jordbrug, end dem som arbejdede i den agro-kemiske branche i USA i begyndelsen af 90'erne. Så stærke holdninger indebærer blandt andet en klar afvisning af landbrugets miljøproblemer. I undersøgelsen havde kvindelige studerende klart mere positive holdninger til økologisk jordbrug end mandlige, og der var meget klar overvægt af kvindelige studerende på kurserne i økologisk jordbrug og klar overvægt af mandlige studerende på de klassiske planteavlskurser Undersøgelsen synes således at vise, at de studerende som satser på konsulentjobs inden for planteavl er mere negative overfor økologisk jordbrug end deres medstuderende. Det tyder også på, at de er mere negative end hortonomstuderende og veterinærstuderende, som også indgik i undersøgelsen. Konsekvenserne Erfaringerne viser, at der er mange, der er sluppet godt fra at have kastet sig ud i jobs med tilknytning til økologisk jordbrug uden på forhånd at have meget positive holdninger til det. Dette taler for, at holdningerne måske ikke er så væsentlige, som man kunne tro. Det er givetvis meget få, der vælger at arbejde med økologisk jordbrug, hvis de har stærke negative holdninger til det. Det vil de sandsynligvis slet ikke kunne klare, uden at skabe konflikter i dem selv eller deres omgivelser. I ovennævnte undersøgelse indgik en lille gruppe økologikonsulenter som referencegruppe. Ingen af disse havde stærke negative holdninger til økologisk jordbrug. Med negative holdninger til økologisk jordbrug har man svært ved at finde mening og logik i de ideer og principper, som ligger til grund for økologisk jordbrug, og man vil opleve en indre konflikt ved at skulle identificere sig med dem. En sådan holdningsmæssig konflikt vil typisk blive løst på to måder. Der kan ske en holdningsændring, det der ofte kaldes "indre omlægning", eller der kan ske en udskillelse, hvor det der skaber konflikt fortrænges. Det vil sige, at der ensidigt vil blive fokuseret på det der synes renset for holdninger, og som forekommer almengyldigt på tværs af dyrkningsretning, det faktuelt faglige. Herved løsrives fagligheden og rådgivning fra det økologiske jordbrugs egenlogik. Hvorvidt dette er til gavn for den økologiske landmand og det økologiske jordbrug er tvivlsomt, men i hvor høj grad det er en ulempe må være op til diskussion. Reference Rasmussen, J & Kaltoft, P (2002) Quantitative assessment of alternative versus conventional attitudes in higher agricultural education. Biological Agriculture & Horticulture (accepted) UR - https://orgprints.org/id/eprint/450/ ID - orgprints450 EP - 33 AV - public KW - holdninger KW - værdier PB - Landbrugets Rådgivningscenter & Forskningscenter for Økologisk Jordbrug ER - TY - GEN UR - https://orgprints.org/id/eprint/4031/ ID - orgprints4031 EP - 452 KW - weed control KW - crop damage KW - competition KW - selectivity AV - restricted Y1 - 2004/// TI - Tolerance of competitive spring barley cultivars to weed harrowing N2 - Two experiments were conducted in 14 spring barley cultivars to investigate if crop tolerance to post-emergence weed harrowing is related to morphological traits that reflect competitiveness. The experiments were carried out in organically grown fields where low weed densities and biomass production were assumed to be without significant influence on crop growth. The experiments showed that different cultivars responded differently to post-emergence weed harrowing in terms of yield reduction. Taller and higher yielding cultivars with high LAIs tended to be less tolerant to post-emergence weed harrowing than shorter and lower yielding cultivars with low LAIs. This conclusion, however, is only valid for 13 out of 14 cultivars because one very tall cultivar was tolerant to harrowing. Even if the tallest and highest yielding cultivars were damaged the most, they remained the highest yielding cultivars after weed harrowing. This study is the first attempt to relate competitiveness of cereal cultivars to tolerance to harrowing, and it is thought provoking that competitiveness and tolerance is found to be counterproductive SP - 446 A1 - Rasmussen, Jesper A1 - Kurtzmann, J.I. A1 - Jensen, A. ER - TY - GEN N2 - Lad os skille viden og holdninger og få en sober debat om det økologiske jordbrugs muligheder og begrænsninger. Sådan lød det, da økobloggen så dagens lys for et års tid siden. Lykkedes det så? Dette spørgsmål diskuteres i blogindlægget. A1 - Rasmussen, Jesper A1 - Langer, Vibeke TI - Økodebatten: En cocktail af viden og holdninger Y1 - 2010/07/26/ PB - www.videnskab.dk AV - public KW - holdninger UR - https://orgprints.org/id/eprint/17313/ ID - orgprints17313 ER - TY - GEN KW - vaues reflexive objectivity constitutive values funding quality subjectivity AV - restricted EP - 188 UR - https://orgprints.org/id/eprint/3087/ ID - orgprints3087 A1 - Rasmussen, Jesper A1 - Langer, Vibeke A1 - Alrøe, Hugo Fjelsted SP - 181 N2 - An analysis of peer reviews of 84 organic farming grant applications, submitted to The Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (FORMAS) in 2001 was carried out to investigate whether peer reviews were influenced by the peer reviewers? affiliation to organic agriculture research and to what degree peer reviewers distinguish between scientific quality and societal relevance. Fifteen reviewers were grouped in three groups (1) scientists with affiliation to organic farming research, (2) scientists without affiliation to organic farming research and (3) users of the research. The scientist groups assessed societal relevance of the grant applications and scientific quality as a sum of three scientific criteria and the user group assessed solely societal relevance. The analysis showed poor agreements between reviewer ratings with respect to societal relevance and all scientific criteria expect applicant?s qualifications. The scientists? affiliation to organic farming research created systematic biases in the peer review process. Scientists, who were experienced in organic farming research, were more in agreement with the users concerning the relevance of grant applications than reviewers without this experience. Regardless of affiliation to organic farming, both scientific reviewer groups did not clearly distinguish between societal relevance and scientific quality of the grant applications. The study challenges the idea of an objective science. In practice, the contextual values, which are associated with the traditional norms of good agriculture, were not clearly distinguished from the constitutive values of science, which are associated with the norms of good science. The reviewers? engagement in organic farming research was important in the review process, and the best way to handle this ?problem? is discussed in the paper. TI - Bias in peer review of organic farming grant applications Y1 - 2006/// ER - TY - GEN SP - 436 A1 - Rasmussen, Jesper A1 - Mathiasen, Helle A1 - Bibby, Bo Martin N2 - The timing of post-emergence weed harrowing was evaluated for two years in spring barley with crop-weed selectivity and crop recovery as the key parameters measured. selectivity describes the relationship between weed control and crop soil cover immediately after harrowing, with crop soil cover as the percentage of the crop that has been covered by soil due to harrowing. Crop recovery describes the relationship between crop yield loss and crop soil cover in the absence of weeds. Neither selectivity nor crop recovery was affected by timing within a period of two weeks in the early growth stages of spring barley. Selectivity was unaffected by year and 80% weed control was associated with crop soil cover in the range of 23?33%, for all combinations of year and growth stage. Crop recovery was affected by year, with an average crop yield loss of 3.5% caused by 25% crop soil cover in 2007 and complete recovery in 2008. A detailed study of crop growth and weed density in the period just after harrowing, showed that the recovery processes of crop and weeds were influenced by timing of harrowing, but this had no impacts on crop yield. In conclusion, timing of post-emergence weed harrowing was not found to be crucial, given the condition that the aggressiveness of cultivation was adjusted to the growth stage. Y1 - 2010/// TI - Timing of post-emergence weed harrowing AV - restricted UR - https://orgprints.org/id/eprint/17844/ ID - orgprints17844 EP - 446 ER - TY - GEN SP - 338 A1 - Rasmussen, Jesper A1 - Nielsen, Helle H. A1 - Gundersen, Hanne N2 - 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 experiments, four experiments with species of small-grains, barley, oat, wheat and triticale, and two experiments with barley cultivars with different abilities to suppress weeds. The order of species? tolerance to weed harrowing was triticale > wheat > barley > oat and the differences were mainly caused by different abilities to recover from soil covering. At 25% soil covering, grain yield loss in triticale was 0.5% (95%-CI: -2.3%-3.3%), in wheat 2.5% (95%-CI: -0.1%-5.0%), in barley 3.7% (95%-CI: 1.3%-6.1%), and in oat 6.5% (95%-CI: 4.3%-8.6%). Tolerance, resistance and recovery, however, were influenced by year, especially for oat and barley. There was no evidence of differences between barley cultivars in terms of tolerance indicating that differences among species are more important than differences among cultivars. Selectivity analysis made it possible to calculate the crop yield loss due to crop damage associated with a certain percentage of weed control. In triticale, 80% weed control was associated with 22% crop soil cover on average, which reduced grain yield 0.4% on average in the absence of weeds. Corresponding values for wheat, barley and oat were 23%, 21% and 20% crop soil cover and 2.3%, 3.6% and 5.1% grain yield loss. Y1 - 2009/// TI - Tolerance and selectivity of cereal species and cultivars to postemergence weed harrowing AV - restricted KW - mechanical weed control KW - statistics KW - models digital image analysis EP - 345 UR - https://orgprints.org/id/eprint/15781/ ID - orgprints15781 ER - TY - GEN TI - På vej mod den intelligente ukrudtsharve Y1 - 2009/// A1 - Rasmussen, Jesper A1 - Nørremark, Michael SP - 26 N2 - En ukrudtsharve, der automatisk indstiller sig efter bekæmpelsesbehovet, er ikke længere en urealistisk fremtidsdrøm. Teknikken eksisterer, og om ganske få år vil vi se den brugt i forbindelse med marksprøjter. I de senere år har vi arbejdet på at udvikle de beslutningsstøttemodeller, som den automatiske harve skal bruge, og vi har udviklet et billedbehandlingsprogram, som bruges til at bestemme harvningens umiddelbare effekt på afgrøden. Programmet har flere anvendelsesmuligheder og kan bruges af alle. UR - https://orgprints.org/id/eprint/15707/ ID - orgprints15707 EP - 28 PB - Sveriges lantbruksuniversitet (SLU) AV - public ER - TY - GEN ID - orgprints10694 UR - https://orgprints.org/id/eprint/10694/ AV - public TI - Forskning i ukrudtsharvning får nyt liv med digital billedbehandling Y1 - 2007/03// A1 - Rasmussen, Jesper A1 - Nørremark, Michael N2 - Digital billedbehandling udfylder et metodemæssigt tomrum i forhold til ukrudtsharvning. Med udvikling af en ny billedbehandlingsprocedure er det ikke længere nødvendigt at anvende visuelle bedømmelser af afgrødetildækningen ved ukrudtsharvning. Artiklen giver eksempler på hvordan digital billedbehandling kan anvnedes. ER - TY - CONF ID - orgprints10758 UR - https://orgprints.org/id/eprint/10758/ EP - 129 AV - public KW - weed harrowing KW - ukrudtsharvning KW - strigling KW - Y1 - 2007/// TI - Digital images for assessing soil cover of crop plants SP - 123 A1 - Rasmussen, Jesper A1 - Nørremark, Michael N2 - 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 timing within a two weeks interval. Crop recovery, defined as the ability of the crop to recover from soil cover was determined in winter wheat and highly influenced by timing of weed harrowing. Increasing intensities of harrowing in growth stage (BBCH) 22 in winter wheat increased crop yields whereas crop yields declined by increasing intensities in growth stage 23 due to differences in the crop recovery capacity. Resistance defined as the capacity of the crop to resist soil cover was tested in barley, field pea and mixtures of barley and field pea. No differences were found between the crops. Future aims in mechanical weed control research are discussed in the context of the availability of unbiased crop soil cover data. ER - TY - CONF AV - public UR - https://orgprints.org/id/eprint/10759/ ID - orgprints10759 N2 - 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 timing within a two weeks interval. Crop recovery, defined as the ability of the crop to recover from soil cover was determined in winter wheat and highly influenced by timing of weed harrowing. Increasing intensities of harrowing in growth stage (BBCH) 22 in winter wheat increased crop yields whereas crop yields declined by increasing intensities in growth stage 23 due to differences in the crop recovery capacity. Resistance defined as the capacity of the crop to resist soil cover was tested in barley, field pea and mixtures of barley and field pea. No differences were found between the crops. Future aims in mechanical weed control research are discussed in the context of the availability of unbiased crop soil cover data. A1 - Rasmussen, Jesper A1 - Nørremark, Michael Y1 - 2007/// TI - Digital images for assessing soil cover of crop plants ER - TY - GEN N2 - Two field experiments were carried out in winter wheat to determine the optimal intensity and timing of weed harrowing. Each experiment was designed to create a series of intensities by increasing the number of passes at varying growth stages. Visual assessments and digital image processing were used to assess crop soil cover associated with weed harrowing. The study showed that winter wheat responded differently to weed harrowing at different growth stages. In autumn, the crop was severely damaged due to high degrees of crop soil cover and poor recovery resulting in crop yield losses in the range of 7 % to 22 %. In early spring, the crop showed some variability in the ability to recover from soil cover. The best results in spring were obtained at growth stage 22 (BBCH). Increasing number of passes resulted in increasing crop yields in the range of 2 % to 5 % and increasing degrees of weed control in the range of 22 % to 62 %. The role of digital image analysis in future weed harrowing research is discussed. SP - 155 A1 - Rasmussen, Jesper A1 - Nørremark, Michael Y1 - 2006/// TI - Digital image analysis offers new possibilities in weed harrowing research KW - Mechanical weed control AV - restricted EP - 165 UR - https://orgprints.org/id/eprint/10474/ ID - orgprints10474 ER - TY - CONF N2 - 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 and to suggest standards for estimation and statistical test of the analytical parameters. The overall aim is to help researchers deliver reliable parameter estimates that may help to predict the optimal intensity and timing of physical weed control with low selectivity and, thereby, contribute to the theoretical and methodological framework of physical weed control. Selectivity and crop recovery are suggested as key parameters because they are crucial in predictive models and are less influenced by site-specific soil conditions and implement settings than other parameters. Selectivity is defined as the ratio between weed control and crop-soil cover and crop recovery is defined as the ability of the crop to recover from soil coverage. Both parameters depend on the intensity of tillage. To facilitate comparisons between different studies, it is suggested that the crop soil cover associated with 80% weed control and the relative crop yield loss associated with 25% crop-soil cover are calculated with 95%-confidence intervals. Experimental protocols needed to make such calculations are outlined and factors that influence - or may influence - selectivity and recovery are listed and research priorities are given. Crop tolerance has previously been used to express the susceptibility of the crop to physical weed control, but crop recovery is shown to be more useful in decision support models than crop tolerance. Recent studies using the new digital image analysis tool and the above suggested parameter estimation procedure show that timing of weed harrowing is of lesser importance if the intensity of tillage is correctly adjusted to the growth stage compared with prediction of the optimal intensity in sitespecific conditions. This latter issue remains the major challenge for future development. A1 - Rasmussen, Jesper A1 - Nørremark, Michael A1 - Bibby, Bo Martin Y1 - 2008/// TI - New Technologies Call for New Research Priorities in Physical Weed Control with Low Selectivity AV - public ID - orgprints13688 UR - https://orgprints.org/id/eprint/13688/ ER - TY - GEN N2 - Objective assessment of crop soil cover, defined as the percentage of leaf cover that has been buried in soil due to weed harrowing, is crucial to further progress in post-emergence weed harrowing research. Up to now, crop soil cover has been assessed by visual scores, which are biased and context dependent. The aim of this study was to investigate whether digital image analysis is a feasible method to estimate crop soil cover in the early growth stages of cereals. Two main questions were examined: (1) how to capture suitable digital images under field conditions with a standard high-resolution digital camera and (2) how to analyse the images with an automated digital image analysis procedure. The importance of light conditions, camera angle, size of recorded area, growth stage and direction of harrowing were investigated in order to establish a standard for image capture and an automated image analysis procedure based on the excess green colour index was developed. The study shows that the automated digital image analysis procedure provided reliable estimations of leaf cover, defined as the as the proportion of pixels in digital images determined to be green, which were used to estimate crop soil cover. A standard for image capture is suggested and it is recommended to use digital image analysis to estimated crop soil cover in future research. The prospects of using digital image analysis in future weed harrowing research are discussed. SP - 299 A1 - Rasmussen, Jesper A1 - Nørremark, Michael A1 - Bibby, Bo Martin Y1 - 2007/// TI - Assessment of leaf cover and crop soil cover in weed harrowing research using digital images AV - public EP - 310 UR - https://orgprints.org/id/eprint/11007/ ID - orgprints11007 ER - TY - CONF AV - restricted UR - https://orgprints.org/id/eprint/52964/ ID - orgprints52964 A1 - Rasmussen, Jim N2 - Præsentation af resultater omkring hvordan samdyrkning kan bidrage til effekter i dyrkningssystemet TI - Effekten af samdyrkning på korn-bælgsæd og efterafgrøde blandinger Y1 - 2024/01// ER - TY - CONF TI - Hvordan påvirker efterafgrøder med bælgplanter kvælstof- og kulstofdynamikkerne? Y1 - 2024/// A1 - Rasmussen, Jim N2 - Præsentation af efterafgrøders effekt på C og N dynamik i plante-jord systemet UR - https://orgprints.org/id/eprint/52965/ ID - orgprints52965 AV - restricted ER - TY - CONF AV - restricted UR - https://orgprints.org/id/eprint/53019/ ID - orgprints53019 N2 - Presentation on the potentials to expand grain legume use into fresh products for human consumption A1 - Rasmussen, Jim TI - Danske bælgfrugter - skal spises både grønne og modne Y1 - 2023/11/22/ ER - TY - CONF AV - restricted UR - https://orgprints.org/id/eprint/53018/ ID - orgprints53018 N2 - Oplæg omkring bælgfrugter til human konsum og effekter af samdyrkning A1 - Rasmussen, Jim TI - Bælgfrugter og samdyrkning Y1 - 2023/10/30/ ER - TY - UNPB TI - Kulstofopbygning og efterafgrøder Y1 - 2023/10// A1 - Rasmussen, Jim N2 - Præsentation om potentiale i opbygning af kulstof via efterafgrøder UR - https://orgprints.org/id/eprint/52962/ ID - orgprints52962 AV - restricted KW - soil organic matter; cover crops; mixtures ER - TY - CONF ID - orgprints52987 UR - https://orgprints.org/id/eprint/52987/ AV - restricted TI - Temadag om Grønne proteiner - inspiration til landbrugsskolelærere Y1 - 2023/05/02/ A1 - Rasmussen, Jim N2 - Temadag om grønne proteiner med fokus på bælgfrugter (Jim) og grøn biorafinering (Lene Stødkilde) ER - TY - GEN AV - public UR - https://orgprints.org/id/eprint/45121/ ID - orgprints45121 A1 - Rasmussen, Jim N2 - Baggrund: En mere bæredygtig og grønnere europæisk landbrugssektor kræver ændringer i vores kost fra kød til planteproteinkilder. En større produktion af bælgfrugter kan forbedre dyrkningssystemerne gennem øget jordfrugtbarhed, diversificerede afgrøder og reducerede klima- og miljøpåvirkninger. Alligevel er det danske økologiske areal, som er dyrket med bælgplanter, meget lavt, og kun en lille del heraf er til konsum for mennesker. Formål: GrainLegsGo vil øge dyrkningen af friske bælgfrugter til human konsum, samtidig med at det giver miljø- og klimafordele og fremmer cirkulær bioøkonomi. Projektet bringer nøgleinteressenter sammen, øger forbrugernes bevidsthed og fremmer dyrkningen af nye og traditionelle bælgfrugter til frisk høst. Ved at optimere dyrkningen af bælgplanter øger GrainLegsGo effektiviteten og produktiviteten i økologiske dyrkningssystemer, også takket være mere produktive efterafgrøder og færre tilfælde af skadedyr og sygdomme. TI - GrainLegsGo: Friske bælgfrugter til human konsum Y1 - 2021/// ER - TY - UNPB N2 - A summary of mainly learnings from the CropSys long-term experiment on cover crop services. SP - 1 A1 - Rasmussen, Jim Y1 - 2021/// TI - Lessons learned from 23 years of cover cropping CY - Viborg AV - restricted PB - Internal report UR - https://orgprints.org/id/eprint/39913/ EP - 7 ID - orgprints39913 ER - TY - GEN Y1 - 2020/11/17/ TI - Bælgplanters mange bidrag til klimakampen N2 - Undersøgelser peger på, at efterafgrødeblandinger med bælgplanter øger kvælstof- og kulstoftilførslen til gavn for både jordfrugtbarheden og klimaet. SP - 10 A1 - Rasmussen, Jim UR - https://orgprints.org/id/eprint/39670/ ID - orgprints39670 EP - 10 AV - public ER - TY - THES UR - https://orgprints.org/id/eprint/10663/ ID - orgprints10663 AV - restricted PB - Faculty of Life Sciences, University of Copenhagen Y1 - 2007/01// TI - Below ground C and N transformation processes in perennial grass-clover mixtures N2 - Leaching of N from grass-clover mixtures have been found in both organic and inorganic form. The environmental impact of this loss is however not well understood as leaching of organic C acting as energy source for denitrifying microorganisms could reduce the negative impact of N losses. In the present project the sources of N and C loss from perennial grass-clover swards were investigated in two field experiments using 14C and 15N tracers. The main findings of the project show that fresh plant material (< 1 year) does not contribute significantly to DOC leaching, whereas both fresh ryegrass and clover material was shown to contribute to DON and DIN losses. Paper I: Carbon (C) and nitrogen (N) dynamics in a third production year ryegrass-clover mixture were investigated in the field. Cylinders (diameter 29.7 cm) were 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% (SE ±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 plant biomass found in the unlabelled clover, and with a transfer from clover to ryegrass being 0.4% (± 0.1, n=9). 15N-enriched compounds were not detected in percolating pore water, which may be caused by either dilution from irrigation or low availability of leachable N compounds. 14C was found solely as 14CO2 in the pore water indicating that dissolved organic carbon (DOC) did not originate from fresh root deposits. Transfer of 14C between the two species in the mixed crop alongside with high transfer of 15N despite a large percolation of pore water indicates that part of the N transfer occurred in non-leachable N-forms. The amount of N transferred between the two species was found to depend on the ratio between dry matter accumulated in the donating and receiving species, the 14C-allocation within the receiving species and the root turnover rate in the soil. Paper II: The below ground C and N dynamics leading to carbon (C) and nitrogen (N) leaching from perennial ryegrass-clover mixtures are not well understood. A 16 months field experiment was conducted to investigate the fate of dual-labelled ryegrass and clover residues. Litterbags containing 14C- and 15N-labelled ryegrass or clover roots or leaves were inserted into the sward of a first production year ryegrass-clover mixture in early spring. The presence of 14C and 15N was monitored in harvested biomass, roots, soil, and pore water percolating from the plough layer. The large root biomass was found to increase during the study period, whereas small root biomass increased during the growth seasons and decreased in autumn and winter. The increase in large roots corresponded to a net build up of 33 kg N ha-1 during the 16 month experiment. For small roots a net build up of 91 kg N ha-1 was found; this including an off-season decrease of 19 kg N ha-1. Uptake of 15N resembled release patterns from residues in the litterbags, with 14C data showing that only a minor proportion of N was taken up in organic form. Total N leaching from the plough layer increased during autumn and winter, having a fairly constant content of dissolved organic nitrogen (DON) and an increasing content of dissolved inorganic nitrogen (DIN). The presence of 15N in pore water shifted from the DON fraction in autumn to the DIN fraction in late winter, with strong indications that 15N originated from ryegrass. This proportion, however, only constituted one percent of the total N being leached. Positive correlation between harvested clover biomass and total N being leached indicated that decaying clover could be a major source of the 10 kg N ha-1 being lost with pore water during autumn and winter. A1 - Rasmussen, Jim ER - TY - GEN EP - 815 UR - https://orgprints.org/id/eprint/10390/ ID - orgprints10390 KW - carbon(14) KW - nitrogen(15) KW - suction cup KW - DOC KW - DIN KW - DON AV - restricted TI - In situ carbon and nitrogen dynamics in ryegrass-clover mixtures: Transfers, deposition and leaching Y1 - 2007/// N2 - 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 found in the unlabelled clover, and with a transfer from clover to ryegrass being 0.4% (± 0.1, n=9). 15N-enriched compounds were not detected in percolating pore water, which may be caused by either dilution from irrigation or low availability of leachable N compounds. 14C was found solely as 14CO2 in the pore water indicating that dissolved organic carbon (DOC) did not originate from fresh root deposits. Transfer of 14C between the two species in the mixed crop alongside with high transfer of 15N despite a large percolation of pore water indicates that part of the N transfer occurred either in the form of organic compounds or by direct transfer via mycorrhizal mycelium. The amount of N transferred between the two species was found to depend on the ratio between dry matter accumulated in the donating and receiving species, the 14C-allocation within the receiving species and the root turnover rate in the soil. A1 - Rasmussen, Jim A1 - Eriksen, Jørgen A1 - Jensen, Erik Steen A1 - Esbensen, Kim H. A1 - Høgh-Jensen, Henning SP - 804 ER - TY - CONF TI - DOC and DON from grass-clover - results from a field experiment Y1 - 2005/// N2 - 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 mezotrons in order to sample the soil solution during the growth season. In late June 2004 cross-labelling of clover and grass populations in the mezotrons was done by leaf labelling (5 days) of either grass or clover using 15N- and 14C-labelled urea. During the following 3 months the percolating soil solution was sampled either after heavy rain or after irrigation of the mezotrons and the content 15N- and 14C-labelled compounds were determined. Leaf material was harvested at tree times during the growth season and at the end of the growth season the mezotrons was excavated and the distribution of 15N and 14C in the plants and soil determined. 14C was detected in the percolating soil solution imediately after leaf-labelling was initiated, with the highest amounts occuring from labelled grass. The peak of 14C reached the depths of 20 and 40 cm between 3-10 and 5-15 days respectively after labelling was initiated while no 14C was detected beneath the 60 cm mezotrons. The majority of 14C in soil solution was identified to be 14CO2 originating either from root respiration or from biomass respiration of 14C-labelled root parts or root exudates. The transfer of 14C was higher from grass to clover than vice versa. This transfer of 14C properly occurs as 14CO2 exchange between the leaves or in the root zone. Transfer of 15N was highest from clover to grass, while the transfer from grass to clover was negligible. These observations confirm previous investigations of 15N transfer between grass and clover. No clear connection was found between the transfer of 14C and 15N. After excavation of the mezotrons 14C was found in higher amounts and at larger depths in the soil for grass compared to clover. The results from this experiment point to that in a grass-clover ley carbon would primarily originate from grass and nitrogen would come from clover. The depths at which 14CO2 is found in the soil solution seem to be somewhat related to the depth of 14C-labelled root material meaning that the rooting profile of a crop influence the deposition of carbon and nitrogen in the soil matrix. These findings add significant new dimensions to our current understanding of processes governing the build up of soil fertility under grass-clover leys. A1 - Rasmussen, Jim A1 - Høgh-Jensen, Henning UR - https://orgprints.org/id/eprint/9128/ ID - orgprints9128 AV - public ER - TY - UNPB AV - public KW - Organic carbon KW - organic nitrogen KW - suction cup KW - grass KW - clover ID - orgprints3542 UR - https://orgprints.org/id/eprint/3542/ A1 - Rasmussen, Jim A1 - Høgh-Jensen, Henning N2 - 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 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 study is - to determine the origin of DOC and DON in grass-clover mixtures - to determine the composition of DOC and DON from the species - to investigate the transfer of C and N between grass and clover Method: In a third year grass-clover ley at the KVL research fields, mezotrons were installed to depths of 20, 40 and 60 cm in January 2003. In June 2004 suction cups will be installed underneath the mezotrons. In the middle of June leaf labeling of either grass or clover will be done using 15N- and 14C urea. At day 3, 7, 14 and 28 after the labeling samples from the leaves of grass and clover and of the percolating water will be taken. Samples will be analyzed for content of 15N and 14C. Attempts will be made to fractionate DOC and DON in the soil solution in classes according to molecular weight and proportion of aromatic compounds. After the last field sampling mezotrons will be excavated and the distribution of 15N and 14C between plant and soil compartments will be determined. Y1 - 2004/// TI - Origin and composition of Dissolved Organic C and N from grass-clover mixtures ER - TY - GEN KW - N2-fixation KW - N transfer KW - residual N effect KW - companion species KW - forage legume AV - public EP - 74 UR - https://orgprints.org/id/eprint/19451/ ID - orgprints19451 N2 - Inclusion of forage legumes in low-input forage mixtures improves herbage production and soil fertility through addition of nitrogen (N) from N2-fixation. The impact of different grass-legume mixtures on the N contribution of the forage mixture has rarely been investigated under comparable soil and climatic conditions. We conducted a field experiment on a sandy soil at two nitrogen levels with seven two-species forage mixtures: alfalfa, bird?s-foot trefoil, red clover, or white clover in mixture with perennial ryegrass, and white clover in mixture with meadow fescue, timothy, or hybrid ryegrass. We found high N2-fixation of more than 300 kg N ha-1 from both red clover and alfalfa even when the two mixtures received 300 kg total-N ha-1 in cattle slurry. The addition of cattle slurry N fertilizer lowered N2-fixation for white clover and red clover as expected, but for bird?s-foot trefoil and alfalfa no changes in the proportion of N derived from N2-fixation was observed. We conclude that the competition for available soil N from perennial ryegrass in mixture was an important factor for the proportion of N in alfalfa, white clover, and bird?s-foot trefoil obtained from N2-fixation. White clover had a high proportion of N derived from atmosphere for all companion grasses despite significant differences in white clover proportion. Although the perennial ryegrass-alfalfa mixture in the grass phase yielded more than twice the N from N2-fixation compared to white clover in the perennial ryegrass mixture, this did not in the following year lead to higher residual N effects of alfalfa. Both in terms of N yield in the grass phase and N yield in the subsequent spring barley red clover contributed most to the improvement of soil N fertility. SP - 66 A1 - Rasmussen, Jim A1 - Søegaard, Karen A1 - Pirhofer-Walzl, Karin A1 - Eriksen, Jørgen Y1 - 2012/// TI - N2-fixation and residual N effect of four legume species and four companion grass species SN - 1161-0301 ER - TY - GEN AV - restricted EP - 74 UR - https://orgprints.org/id/eprint/20635/ ID - orgprints20635 SP - 66 A1 - Rasmussen, J. A1 - Søegaard, K. A1 - Eriksen, J. N2 - Inclusion of forage legumes in low-input forage mixtures improves herbage production and soil fertility through addition of nitrogen (N) from N2-fixation. The impact of different grass?legume mixtures on the N contribution of the forage mixture has rarely been investigated under comparable soil and climatic conditions. We conducted a field experiment on a sandy soil at two nitrogen levels with seven twospecies forage mixtures: alfalfa, bird?s-foot trefoil, red clover, or white clover in mixture with perennial ryegrass, and white clover in mixture with meadow fescue, timothy, or hybrid ryegrass. We found high N2- fixation of more than 300 kg N ha?1 from both red clover and alfalfa even when the two mixtures received 300 kg total-N ha?1 in cattle slurry. The addition of cattle slurry N fertilizer lowered N2-fixation for white clover and red clover as expected, but for bird?s-foot trefoil and alfalfa no changes in the proportion of N derived from N2-fixation was observed. We conclude that the competition for available soil N from perennial ryegrass in mixture was an important factor for the proportion of N in alfalfa, white clover, and bird?s-foot trefoil obtained from N2-fixation. White clover had a high proportion of N derived from atmosphere for all companion grasses despite significant differences in white clover proportion. Although the perennial ryegrass?alfalfa mixture in the grass phase yielded more than twice the N from N2-fixation compared to white clover in the perennial ryegrass mixture, this did not in the following year lead to higher residual N effects of alfalfa. Both in terms of N yield in the grass phase and N yield in the subsequent spring barley red clover contributed most to the improvement of soil N fertility. Y1 - 2012/// TI - N2-fixation and residual effect of four legume species and four companion grass species ER - TY - CONF Y1 - 2011/// SN - 978-87-91949-75-3 TI - Erfaringer med nye teknologier i rækkeafgrøder N2 - Ukrudt inde i rækkerne i udplantede grønsagskulturer kan nu bekæmpe med automatiserede mekaniske rensere. I udsåede kulturer er det vanskeligere. SP - 175 A1 - Rasmussen, Jesper EP - 177 UR - https://orgprints.org/id/eprint/18219/ ID - orgprints18219 KW - Intra-row weeds KW - robotic KW - machine vision KW - Robocrop KW - Robovator KW - cycloid hoe AV - public ER - TY - GEN N2 - There is much emphasis on technical aspects related to sensor or mapping techniques, which enable so-called intelligent cultivators to target the intra-row spaces within crop rows. This study investigates (i) an expected advantage of an intelligent rotor tine cultivator (the cycloid hoe) in terms of crop-weed selectivity and (ii) an expected synergistic effect between punch planting and post-emergence weed harrowing in terms of improved crop-weed selectivity. Selectivity is defined as the relationship between weed control and associated crop density decline one week after cultivation, and punch planting is a sowing technique where holes are created in the ground with a minimum of soil disturbance and seeds are inserted into them, without soil disturbance outside the holes. Two experiments were carried out with the cycloid hoe in organic sugar beets. The rotation tines were guided by RTK-GPS relative to geo-referenced sugar beets, and tines were moved into the row when there was enough space between crop plants to cultivate, and kept outside, when they were predicted to strike a crop plant. The selectivity of the cycloid hoe was tested against two machine variants without intelligent guidance: the rotor tine cultivator in a locked mode, where tines rotate within the crop row without taking crop plants into consideration, and an ordinary flex tine weed harrow. The experiments showed no differences between the three machine variants in terms of selectivity. Five experiments with punch planting in sugar beets and carrots showed no synergistic effects between plant establishment procedures and selectivity of post-emergence weed harrowing. Even if punch planting and automated intelligent rotor tine cultivation were not combined, the results indicate that there is no reason to believe that a combination contributes significantly to the solution of the main problem in mechanical intra-row weed control in direct sown crops, low selectivity, which still remains a major challenge. Future studies on precision intra-row cultivation should focus on cutting implements instead of tine implements which manly works through soil burial. SP - 327 A1 - Rasmussen, Jesper A1 - Griepentrog, Hans W. A1 - Nielsen, J. A1 - Henriksen, Christian Bugge Y1 - 2012/// TI - Automated intelligent rotor tine cultivation and punch planting to improve the selectivity of mechanical intra-row weed control AV - restricted UR - https://orgprints.org/id/eprint/21136/ EP - 337 ID - orgprints21136 ER - TY - GEN N2 - The article describes the possibilities for weed monitoring by small Unmanned Aircraft Systems (UAS). It also describes the ASETA project, which is a multidisciplinary project combining cooperating airborne and ground-based vehicles with advanced sensors to identify the positions of weeds in agricultural fields. A1 - Rasmussen, Jesper A1 - Harbo La-Cour, Anders SP - 20 TI - Ukrudt i fugleperspektiv Y1 - 2011/08/12/ AV - public UR - https://orgprints.org/id/eprint/19315/ EP - 20 ID - orgprints19315 ER - TY - CONF Y1 - 2011/05/11/ TI - Less intra-row weeds ? experiences with a punch planter and a cycloid hoe based on GPS A1 - Rasmussen, Jesper A1 - Henriksen, Christian Bugge A1 - Griepentrog, Hans W. N2 - Experiences with a punch planter and an intelligent rotary tine weeder are summarized. The objectives were to investigate (1) to what extent punch planting and pre-emergence flame weeding can reduce intra-row weed emergence in direct sown crops like onion, carrot and sugar beet, (2) to what extent an intelligent intra-row weeder, a cycloid hoe based on RTK-GPS technology, can control intra-row weeds without damaging the crop in direct sown crops, (3) and to what extent there exists synergy between punch planting with pre-emergence flame weeding and mechanical intra-row weeding. ID - orgprints18777 UR - https://orgprints.org/id/eprint/18777/ AV - public KW - mechanical weed control PB - EWRS ER - TY - GEN AV - restricted UR - https://orgprints.org/id/eprint/20109/ EP - 498 ID - orgprints20109 A1 - Rasmussen, Jesper A1 - Henriksen, Christian Bugge A1 - Griepentrog, Hans W. A1 - Nielsen, Jon SP - 489 N2 - 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 difference between N and N+F quantifies the effect of pre-emergence flame weeding, and the difference between N+F and P+F is defined to quantify the effect of the punch planting. Punch planting reduced the average intra-row weed density by 37% (95%-CI: 29%-46%) in onion, but had no effect in sugar beet. Pre-emergence flame weeding reduced the average intra-row weed density by 59% (95%-CI: 53%-64%) in onion and by 47% (95%-CI: 44%-51%) in sugar beet. Delayed sowing only reduced weed emergence in 2008. In carrot, punch planting reduced the average intra-row density by 34% (95%-CI: 19%-47%). In all crops, there were complex interactions between plant establishment procedure, year and delay of sowing. The implications of the technical inadequacies of the used dipper drill (MK III) are discussed, and it is concluded that technical improvements are required to improve crop establishment and to reduce weed emergence in the crop rows. TI - Punch planting, flame weeding and delayed sowing to reduce intra-row weeds in row crops Y1 - 2011/// ER - TY - GEN EP - 294 UR - https://orgprints.org/id/eprint/17843/ ID - orgprints17843 AV - restricted PB - Springer Y1 - 2010/// SN - 978-90-481-9276-2 TI - Mechanical weed control CY - London N2 - 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 tillage methods are burring in soil, uprooting,and tearing plants into pieces. Especially for whole crop and intra-row cultivators, successful weed control is highly influenced by appropriate adjustment of the intensity (aggressiveness) of cultivation according to the variations of soil resistance, crop and weed resistance to cultivation and the competitive interactions between crop and weeds. Site-specific weed management aims to identify the spatial and temporal variability of weeds and manage them correspondingly. New technologies for sensing crops and weeds in real-time and robotics allow a precise operation of mechanical tools, to improve efficacy of control and reduce operation costs. Hence in this chapter, implements for mechanical weeding are described together with their options for site-specific weed control strategies. Harrows and rotary hoes are used for whole crop treatment, but it is essential to find the right timing and intensity to obtain the best selectivity and yield response. Different implements attached to the same vehicle are combined together attempting more selective weed control,like the in-row cultivator, the rotary harrow, and the precision hoe. Lately, there are prototypes intending automatic adjustment of the aggressiveness for the springtine harrow and autonomous guidance for hoes, thus getting closer to a real-time site-specific weed management approach. SP - 279 A1 - Rueda-Ayala, Victor A1 - Rasmussen, Jesper A1 - Gerhards, Roland ER - TY - GEN N2 - Crop tolerance and weed control in winter wheat were investigated to evaluate the influence of post-emergence weed harrowing at different crop growth stages on selectivity, crop recovery and crop yield. The importance of growth stage was investigated in autumn (Denmark) and spring (Germany). Selectivity was chosen as a measure of the relationship between weed control and crop soil cover, with crop recovery as a measure of how crop yield was affected by soil cover in the absence of weeds. Selectivity was unaffected by crop growth stage in autumn and spring. In autumn, 80% weed control was associated with 6% crop soil cover, whereas in spring, 80% weed control corresponded to 26% crop soil cover. Crop recovery was higher in late growth stages in autumn and spring. With 25% crop soil cover, crop yield losses occurred in the ranges of 1?4% in autumn and 0.3?0.8% in spring. Weed control experiments revealed that the maximum crop yield response to harrowing was comparable with herbicide treatment. The average yield gain was 13% in autumn (Denmark) and 27% in spring (Germany). This study contributes parameter estimates that can be used in future models to evaluate optimum harrowing intensity. A1 - Rueda?Ayala , Victor A1 - Rasmussen, Jesper A1 - Gerhards , Roland A1 - Fournaise , N.A. SP - 478 TI - The influence of post-emergence weed harrowing on selectivity, crop recovery and crop yield in different growth stages of winter wheat Y1 - 2011/// AV - restricted ID - orgprints20110 UR - https://orgprints.org/id/eprint/20110/ EP - 488 ER - TY - GEN N2 - Direct drilling has often been reported to increase density and strength and to affect pore continuity and tortuosity of the upper soil layers. In this study these aspects were studied for three texturally differing soils 4?6 years after initiation of continuous trials with direct drilling and mouldboard ploughing. The soils studied were a coarse sandy soil (Korntved, 5% clay), a sandy loam (Ballum, 8% clay) and a silty loam (Højer, 19% clay). The crop rotation at Korntved was spring barley and winter rye while at Ballum and Højer it was spring barley and winter wheat. Both crops were grown every year. All fields had been mouldboard ploughed for decades prior to the trial period. The ploughed treatment (PL) was imposed in the autumn and the seedbed preparation and drilling were performed with an S-tined seedbed harrow and a traditional drill. The direct drilled (DD) treatment received no tillage other than the drilling which was performed by a triple-disc drill. Straw and stubble were burned. In the 4th, 5th and 6th years of the trial period, minimally disturbed soil cores were taken from the 4 to 8, 14 to 18 and 24 to 28 cm depths, i.e. two horizons above the ploughing depth of 20 cm, and one horizon below this depth. Longer cores were sampled in the 18?27 cm depth in order to include this transition layer. Furthermore, in the 4th year of the trial period shear strength was measured in the field at 2-week intervals in the spring with a vane shear tester in the two upper layers mentioned. All samplings and measurements took place in the field grown with spring barley. In the laboratory air diffusivity and air permeability were measured at field-sampled water content and again when the soil cores were drained to a matric potential of -100 hPa. Cone penetration resistance was measured with a 2 mm diameter penetrometer. Separate core samples from the 14 to 18 cm depth of the Korntved and Højer soils were used for estimating soil cohesion and soil internal friction by a shear annulus method at field-sampled water content. For all soils, DD increased soil bulk density in the two upper soil layers. The shear vane tester also generally estimated higher shear strength for the DD compared to the PL treatment. The shear annulus measurements in the laboratory revealed no differences between tillage treatments for the Korntved soil, while a tendency of higher cohesion and internal soil friction was found for the DD treatment on the Højer soil. The cone penetration measurements indicated a stronger top-soil and fewer high-strength soil elements in the 24?28 cm horizon for the DD than for the PL treatment. Generally the DD treatment had lower volume of macropores (i.e. pores>30 m) in the 4?8 and 14?18 cm depths than the PL treatment. This was reflected in reduced air diffusivities and air permeabilities for these horizons. An exception was the 14?18 cm depth of the Ballum soil, where increased air diffusivity and air permeability was measured at field-sampled water content. Continuity indices calculated from air diffusivity and air permeability measurements showed that the DD soil from the 4 to 8 and 14 to 18 cm depths had less continuous and more tortuous macropores than the ploughed soil. A1 - Schjønning, P. A1 - Rasmussen, K.J. SP - 69 TI - Soil strength and soil pore characteristics for direct-drilled and ploughed soils Y1 - 2000/// PB - Elsevier KW - Direct drilling; Ploughing; Soil strength; Soil pore characteristics; Pore continuity; Plough pan AV - restricted UR - https://orgprints.org/id/eprint/728/ EP - 82 ID - orgprints728 ER - TY - GEN TI - Jordbearbejdning i økologisk jordbrug ? pløjedybde og ikke-vendende jordløsning [Soil tillage in organic farming ? ploughing depth and non-inversion deep tillage] Y1 - 2002/11// A1 - Schjønning, Per A1 - Rasmussen, Karl J. A1 - Munkholm, Lars J. A1 - Nielsen, Peter S. N2 - I perioden 1996 til 2000 gennemførtes et markforsøg med forskellige jordbearbejdnings-systemer på Den økologiske Forsøgsstation Rugballegaard. Forsøgsarealet blev omlagt til økologisk drift i forbindelse med projektets start i 1996. Undersøgelserne gennemførtes i et fem-marks skifte, der ligeledes blev kørt ind i forbindelse med projektet. Det drejer sig om et såkaldt blandet sædskifte med byg/ært m. udlæg, 1. års kløvergræs, 2. års kløvergræs, havre og vinterhvede. Forsøget blev anlagt i fem marker (B1-B5), hvilket indebærer, at alle skiftets afgrøder blev dyrket hvert år. Fire forskellige jordbearbejdningssystemer blev undersøgt i et randomiseret blokforsøg med 4 blokke. De fire behandlinger omfattede to systemer med pløjning, nemlig led A med 20 cm pløjedybde og led B med 10-12 cm pløjedybde; hertil kom to systemer (C og D) med ikke-vendende løsning af jorden til 35-40 cm dybde. Til dette formål blev opbygget et specielt ud-styr i forbindelse med projektet. Der blev dog anvendt kommercielt tilgængelige gåsefod-stænder fra det tyske firma Dutzi. Disse blev monteret på en svær bulle, der også gav mulig-hed for ophængning af en Howard tandfræser. På denne var der monteret løftehitch, hvori en konventionel Nordsten slæbeskær-såmaskine kunne monteres. Forsøgsled C (?fuld? Dutzi) omfattede en bearbejdning med hele denne ?ekvipage? i én arbejdsgang, mens der i led D (?delt? Dutzi) blev gennemført en separat bearbejdning med Dutzi-tænderne efterfulgt af så-ning med tandfræser og såmaskine. Omlægning af græsmarken skete for alle systemer med traditionel pløjning til 20 cm dybde. Anvendelsen af Dutzi-udstyret krævede meget stor trækkraft og der var ikke nævneværdig mindskelse af dette ved at anvende løsnetænderne separat. Jordløsningen var i både C og D meget effektiv og gav anledning til en markant mindskelse af den mekaniske modstand i jordlaget fra ca. 20 til ca. 35 cm dybde, hvor der på arealet generelt fandtes en kompakt pløje-sål. Effekten på den mekaniske modstand i jorden viste sig at vedvare i minimum 2 år. Den ændrede jordfysiske tilstand gav forbedrede betingelser for bl.a. rodvækst og knoldbakterier (Rhizobium). De undersøgte bearbejdningsmetoder gav ikke entydige ændringer i ukrudtstrykket. Generelt (for alle bearbejdninger) var der problemer med at styre ukrudtet i vinterhveden. En tendens til forøget ukrudtstryk i udlægsmarken efter Dutzi-behandling i forhold til pløjning gav ikke øgede problemer, idet forskellen udlignede sig ved høst af dæksæden som helsæd. Der var heller ikke entydige tendenser i bearbejdningernes indflydelse på udbyttet af afgrøderne. Der var en tendens til, at Dutzi-løsning gav et lidt højere råprotein-indhold i helsæds- og kløver-græsudbyttet end pløjning. Både Dutzi-bearbejdningen og den overfladiske pløjning må betragtes som realistiske mulig-heder i et økologisk sædskifte som det undersøgte. En sikker konklusion om systemernes suc-ces vil kræve undersøgelser gennem mere end en rotation. Desuden kan resultaterne tænkes at være anderledes i andre sædskifter. Ploven vil fortsat være nødvendig i mange økologiske jordbrug p.g.a. behovet for at nedmulde flerårige afgrøder og halm-rig staldgødning mm. I stedet for fuld overgang til ikke-vendende jordløsning, forekommer det realistisk at reducere pløjedybden til det mindst mulige og fore-tage en evt. påkrævet mekanisk løsning af dybere jordlag med maskinel, der bryder jorden op til den ønskede dybde uden at vende den. Her er Dutzi-tænderne (separat eller i forbindelse med et kombisæt) én af flere muligheder. Der bør gennemføres forsøgsserier på forskellige jordtyper, hvor forskellige systemer testes med henblik på optimering af jordstruktur og biodiversitet i jorden, udbyttets størrelse og kvalitet, ukrudtsbekæmpelse samt med henblik på minimering af arbejdstid og forbrug af fos-silt brændstof. Sådanne undersøgelser bør dække de vigtigste kombinationer af jordtype, sæd-skifte og gødskningsstrategi mm. og gennemføres i så langt et tidsrum, at det er muligt at vur-dere de nævnte succeskriterier efter en nødvendig overgangsfase. UR - https://orgprints.org/id/eprint/188/ ID - orgprints188 AV - public T3 - DJF Rapport, Markbrug ER - TY - CONF UR - https://orgprints.org/id/eprint/17832/ ID - orgprints17832 EP - 144 ED - Rasmussen, J. ED - Schacht, M. ED - Helgadottir, A. KW - Grassland species KW - mineral KW - vitamin KW - feeding value AV - public Y1 - 2010/10/05/ TI - Vitamin and mineral content and feeding value of different legumes and grass species grown in seven legume-grass mixtures N2 - The aim was to examine if including a range of grassland species could help to balance the diet on organic dairy farms compared with traditional mixtures. Four different grass species and four legume species were grown and harvested in mixtures with one grass and one legume for two growing seasons. The species turned out to have very individual mineral, vitamin and fiber profiles and organic matter digestibility, not influenced by year. Among the legumes red clover (Trifolium pratense) and white clover (Trifolium repens) had the highest feeding value and red clover had further a high content of Co, Cu and Zn. Lucerne (Medicago sativa) had as red clover a high growth potential in mixture but had in general a low content of macro and micro minerals with exception of Se. Lotus (Lotus corniculatus) had a low competitive strength, and the effect of the whole herbage was therefore limited even that the content of the vitamins were high. Among the grasses perennial ryegrass (Lolium perenne) generally had the highest feeding value, and a higher content of the macro and micro minerals and of vitamins as well than the other grasses (hybrid ryegrass (Lolium hybridum), meadow fescue (Festuca pratensis) and timothy (Phleum pratense)). The only exception was meadow fescue, which had a higher content of alfa-tocopherol. SP - 141 A1 - Søegaard, K. A1 - Sehested, J. A1 - Jensen, S.K. ER - TY - CONF EP - 87 UR - https://orgprints.org/id/eprint/20621/ ID - orgprints20621 AV - public Y1 - 2011/02/08/ TI - Dyrkning af kløvergræs N2 - Vitaminer, mineraler og foderværdi i forskellige græsmarksarter samt bælgplanternes N-dynamik samt kløvertræthed SP - 79 A1 - Søegaard, K. A1 - Rasmussen, J. A1 - Sehested, J. A1 - Jensen, S.K. A1 - Eriksen, J ER - TY - GEN Y1 - 2020/07/10/ TI - Flerårigt sædskifte med tætning som alternativ til pligtige efterafgrøder N2 - Dette er en rapport om anvendelsen af N-fikserende efterafgrøder som pligtige efterafgrøder, skrevet på foranledning af en bestilling fra Landbrugsstyrelsen. Det vurderes, at der gennemsnitligt set ikke er risiko for øget kvælstofudvaskning (på kort og længere sigt) ved anvendelse kvælstoffikserende efterafgrøder i artsblanding med ikke-fikserende arter i forhold til anvendelse af ikke-fikserende efterafgrøder. Dette er under forudsætning af, at der indregnes en gødningsmæssig eftervirkning på ca. 50 kg N/ha både på bedrifter under og over 80 kg N/ha i husdyrgødning. SP - 1 A1 - Sørensen, Peter A1 - De Notaris, Chiara A1 - Hansen, E.M. A1 - Thomsen, Ingrid Kaag A1 - Rasmussen, Jim ID - orgprints39300 UR - https://orgprints.org/id/eprint/39300/ EP - 14 AV - public ER - TY - CONF A1 - Vanhala, P. A1 - Kurstjens, D. A1 - Ascard, J. A1 - Bertram, A. A1 - Cloutier, D.C. A1 - Mead, A. A1 - Raffaelli, M. A1 - Rasmussen, Jesper SP - 194 N2 - A prerequisite for good research is the use of appropriate methodology. In order to aggregate sound research methodology, this paper presents some tentative guidelines for physical weed control research in general, and flame weeding, weed harrowing and intra-row cultivation in particular. Issues include the adjustment and use of mechanical weeders and other equipment, the recording of impact factors that affect weeding performance, methods to assess effectiveness, the layout of treatment plots, and the conceptual models underlying the experimental designs (e.g. factorial comparison, dose response). First of all, the research aims need to be clearly defined, an appropriate experimental design produced and statistical methods chosen accordingly. Suggestions on how to do this are given. For assessments, quantitative measures would be ideal, but as they require more resources, visual classification may in some cases be more feasible. The timing of assessment affects the results and their interpretation. When describing the weeds and crops, one should list the crops and the most abundantly present weed species involved, giving their density and growth stages at the time of treatment. The location of the experimental field, soil type, soil moisture and amount of fertilization should be given, as well as weather conditions at the time of treatment. The researcher should describe the weed control equipment and adjustments accurately, preferably according to the prevailing practice within the discipline. Things to record are e.g. gas pressure, burner properties, burner cover dimensions and LPG consumption in flame weeding; speed, angle of tines, number of passes and direction in weed harrowing. The authors hope this paper will increase comparability among experiments, help less experienced scientists to prevent mistakes and essential omissions, and foster the advance of knowledge on non-chemical weed management. TI - Guidelines for physical weed control research: flame weeding, weed harrowing and intra-row cultivation Y1 - 2004/// AV - public KW - weed harrowing KW - flame weeding KW - statistical methods KW - experimental designs UR - https://orgprints.org/id/eprint/2445/ EP - 225 ID - orgprints2445 ER -