@misc{orgprints22041, volume = {153}, year = {2012}, author = {B.S. Acharya and J. Rasmussen and J. Eriksen}, pages = {33--39}, journal = {Agriculture, Ecosystems \& Environment}, title = {Grassland carbon sequestration and emissions following cultivation in a mixed crop rotation}, url = {https://orgprints.org/id/eprint/22041/}, abstract = {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{$\pm$}0.094 g kg-1 soil) and the 17-yr-old grassland (3.17{$\pm$}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 {$\pm$} 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. } } @inproceedings{orgprints53011, author = {Nadja F Bloch and Juliana Trindade Martins and Zhi Liang and Kirsten L{\o}nne Enggrob and Jim Rasmussen}, year = {2023}, month = {June}, title = {Main crop effect on biodiversity expression in spontaneous flora and C input from cover crop mixtures}, url = {https://orgprints.org/id/eprint/53011/}, abstract = {Summary of cover crop effect on spontaneous flora diversity and presence and input of carbon to soil after grain legume main crops} } @misc{orgprints21137, year = {2012}, volume = {52}, author = {Lars O. Brands{\ae}ter and Kjell Mangerud and Jesper Rasmussen}, pages = {338--347}, title = {Interactions between pre- and post-emergence weed harrowing in spring cereals}, journal = {Weed Research}, abstract = {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 }, url = {https://orgprints.org/id/eprint/21137/} } @misc{orgprints3951, author = {Christian Bugge Henriksen and Jens Peter M{\o}lgaard and Jesper Rasmussen}, year = {2004}, month = {June}, journal = {Darcof e-news}, title = {Inter-row subsoiling increases marketable yield in potatoes}, publisher = {DARCOF}, keywords = {subsoiling, potato, loosening}, abstract = {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. }, url = {https://orgprints.org/id/eprint/3951/} } @misc{orgprints1568, author = {Christian Bugge Henriksen and Jesper Rasmussen and Carsten S{\o}gaard}, pages = {59--68}, volume = {80}, year = {2005}, title = {Kemink subsoiling before and after planting}, publisher = {Elsevier, Netherlands}, journal = {Soil \& Tillage Research}, url = {https://orgprints.org/id/eprint/1568/}, abstract = {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. }, keywords = {Subsoiling, loosening, ripping, Kemink, in-row, inter-row } } @misc{orgprints16289, pages = {29--35}, author = {B.T. Christensen and J. Rasmussen and J. Eriksen and E.M. Hansen}, volume = {31}, year = {2009}, journal = {European Journal of Agronomy}, title = {Soil carbon storage and yields of spring barley following grass leys of different age}, abstract = {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. }, url = {https://orgprints.org/id/eprint/16289/} } @misc{orgprints31785, journal = {Scientific Reports}, title = {Forbs enhance productivity of unfertilised grass-clover leys and support low-carbon bioenergy}, pages = {1422}, author = {W-F Cong and J Jing and J Rasmussen and K S{\o}egaard and J Eriksen}, volume = {7}, year = {2017}, url = {https://orgprints.org/id/eprint/31785/}, abstract = {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.} } @misc{orgprints52960, doi = {https://doi.org/10.1016/j.fcr.2023.108894}, volume = {295}, pages = {1--34}, author = {Chiara De Notaris and Ea E. Enggrob and J{\o}rgen E. Olesen and Peter S{\o}rensen and Jim Rasmussen}, title = {Faba bean productivity, yield stability and N2-fixation in long-term organic and conventional crop rotations}, journal = {Field Crops Research}, month = {March}, year = {2023}, url = {https://orgprints.org/id/eprint/52960/}, abstract = {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.}, keywords = {grain legumes; pulses; biological N fixation; plant protein} } @misc{orgprints42333, month = {December}, title = {Long-term soil quality effects of soil and crop management in organic and conventional arable cropping systems}, author = {Chiara De Notaris and Johannes L. Jensen and J{\o}rgen E. Olesen and Tiago Stumpf da Silva and Jim Rasmussen and Ioanna Panagea and Gitte H. Rub{\ae}k}, year = {2021}, url = {https://orgprints.org/id/eprint/42333/}, abstract = {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.} } @misc{orgprints42332, doi = {https://doi.org/10.1016/j.geoderma.2021.115383}, volume = {403}, pages = {0--0}, author = {Chiara De Notaris and Johannes Lund Jensen and J{\o}rgen E. Olesen and Tiago Stumpf da Silva and Ioanna Panagea and Gitte H. Rub{\ae}k and Jim Rasmussen}, title = {Long-term soil quality effects of soil and crop management in organic and conventional arable cropping systems}, journal = {Geoderma}, month = {December}, year = {2021}, keywords = {Soil health Soil structural stability Soil organic C Earthworms}, url = {https://orgprints.org/id/eprint/42332/}, abstract = {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.} } @inproceedings{orgprints45834, author = {Chiara De Notaris and Esben Mortensen and Zhi Liang and Maria Vincenza Chiriac{\`o} and Jim Rasmussen}, year = {2023}, booktitle = {Carbon and nitrogen services from cover crops are optimized by including legumes in mixtures}, month = {April}, doi = {doi:10.5194/egusphere-egu23-5614}, title = {Carbon and nitrogen services from cover crops are optimized by including legumes in mixtures}, keywords = {soil mineral nitrogen; legumes; carbon input}, abstract = {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.}, url = {https://orgprints.org/id/eprint/45834/} } @inproceedings{orgprints52963, year = {2024}, author = {Chiara De Notaris and Esben {\O}ster Mortensen and Leanne Peixoto and Jim Rasmussen}, title = {Predicting cover crop nitrogen residual effect to optimize fertilizer reductions}, url = {https://orgprints.org/id/eprint/52963/}, abstract = {Presentation on cover crop N effects} } @misc{orgprints43955, title = {Det er udfordrende at dyrke efterafgr{\o}der med succes i Danmark}, journal = {{\O}kologisk Landbrug}, month = {May}, volume = {666}, year = {2021}, author = {Chiara De Notaris and Jim Rasmussen}, pages = {1--1}, keywords = {Cover crop; grain legume; harvest time}, url = {https://orgprints.org/id/eprint/43955/}, abstract = {S{\ae}dskifter er en af de bedste og mest anerkendte metoder for at skabe b{\ae}redygtige dyrkningssystemer. B{\ae}lgplanter - b{\r a}de b{\ae}lgs{\ae}d og gr{\ae}smarksb{\ae}lgplanter - og efterafgr{\o}der giver en bedre n{\ae}ringsstofudnyttelse og reducerer behovet for g{\o}dning. Rigtigt brugt reducerer b{\ae}lgplanter og efterafgr{\o}der ogs{\r a} kv{\ae}lstoftabet fra dyrkningssystemet og kan samtidig modvirke klimaforandringerne ved at binde kulstof i jorden. Mere end 20 {\r a}r med efterafgr{\o}der i s{\ae}dskiftefors{\o}get p{\r a} Foulumg{\r a}rd har l{\ae}rt os, at det kan v{\ae}re udfordrende at dyrke efterafgr{\o}der med succes i Danmark. Udfordringer som potentielt mindsker v{\ae}rdien af efterafgr{\o}der i dyrkningssystemet og mindsker sikkerheden for at opn{\r a} den forventede milj{\o}m{\ae}ssige effekt.} } @misc{orgprints39279, title = {CCRotate}, author = {Chiara De Notaris and Esben Mortensen and Zhi Liang and Jim Rasmussen}, year = {2020}, abstract = {A documentation of field and laboratory operations, aimed at communicating the process behind the results from CCRotate.}, url = {https://orgprints.org/id/eprint/39279/} } @misc{orgprints39270, title = {Cover crop mixtures including legumes can self-regulate to optimize N2 fixation while reducing nitrate leaching}, doi = {doi:10.1016/j.agee.2020.107287}, journal = {Agriculture, Ecosystems \& Environment}, volume = {309}, year = {2021}, pages = {107287}, author = {Chiara De Notaris and Esben {\O}ster Mortensen and Peter S{\o}rensen and J{\o}rgen E. Olesen and Jim Rasmussen}, abstract = {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.}, url = {https://orgprints.org/id/eprint/39270/} } @misc{orgprints35015, doi = {10.1016/j.fcr.2019.02.008}, pages = {15--25}, author = {Chiara De Notaris and Jim Rasmussen and Peter S{\o}rensen and Bo Melander and J{\o}rgen E. Olesen}, volume = {234}, month = {March}, journal = {Field Crops Research}, title = {Manipulating cover crop growth by adjusting sowing time and cereal interrow spacing to enhance residual nitrogen effects}, year = {2019}, abstract = {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.}, url = {https://orgprints.org/id/eprint/35015/}, keywords = {Catch crop, Legumes, N fertilizer, Organic agriculture, Undersowing} } @unpublished{orgprints35017, title = {Deposition of C and N in the soil from legume-based cover crops ? quantification and mineralization.}, journal = {To be decided}, month = {March}, volume = {0}, year = {2019}, pages = {00--00}, author = {Chiara De Notaris and Jim Rasmussen and Peter S{\o}rensen and J{\o}rgen E. Olesen}, abstract = {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.}, url = {https://orgprints.org/id/eprint/35017/}, keywords = {Catch crops; Leaf-labeling; N fertilizer effect; Soil C sequestration} } @misc{orgprints33225, title = {Legume-based cover crops benefit crop yield and reduce nitrate leaching}, month = {May}, year = {2018}, author = {Chiara De Notaris and Jim Rasmussen and Peter S{\o}rensen and J{\o}rgen E. Olesen}, url = {https://orgprints.org/id/eprint/33225/}, abstract = {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.} } @misc{orgprints32665, year = {2018}, volume = {255}, author = {Chiara De Notaris and Jim Rasmussen and Peter S{\o}rensen and J{\o}rgen E. Olesen}, pages = {1--11}, journal = {Agriculture, Ecosystems and Environment}, title = {Nitrogen leaching: a crop rotation perspective on the effect of N surplus, field management and use of catch crops}, month = {March}, abstract = {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.}, url = {https://orgprints.org/id/eprint/32665/}, keywords = {nitrate leaching, nitrogen balance, nitrogen surplus, catch crop, crop rotation, GDD} } @unpublished{orgprints33053, title = {N fertilizer value of legume-based catch crops}, month = {January}, year = {2018}, author = {Chiara De Notaris and Peter S{\o}rensen and Jim Rasmussen and J{\o}rgen E. Olesen}, url = {https://orgprints.org/id/eprint/33053/}, abstract = {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.} } @inproceedings{orgprints30876, author = {Chiara De Notaris and Peter S{\o}rensen and Jim Rasmussen and J{\o}rgen E. Olesen}, year = {2016}, month = {September}, title = {Row spacing and catch crop establishment in organic arable systems: a way to increase biological N fixation}, abstract = {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.}, url = {https://orgprints.org/id/eprint/30876/} } @misc{orgprints34966, pages = {525--537}, author = {N.R. Dhamala and J. Rasmussen and G Carlsson and K. S{\o}egaard and J. Eriksen}, volume = {424}, year = {2018}, title = {Effecs of including forbs on N2-fixation and N yield in red clover-ryegrass mixtures}, journal = {Plant and Soil}, abstract = {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.}, url = {https://orgprints.org/id/eprint/34966/} } @misc{orgprints31784, volume = {417}, year = {2017}, pages = {169--182}, author = {NR Dhamala and J Eriksen and G Carlsson and K S{\o}egaard and J Rasmussen}, title = {Highly productive forage legume stands show no positive biodiversity effect on yield and N2-fixation}, doi = {DOI 10.1007/s11104-017-3249-2}, journal = {Plant and Soil}, url = {https://orgprints.org/id/eprint/31784/}, abstract = {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.} } @misc{orgprints31453, author = {NR Dhamala and J Rasmussen and G Carlsson and K S{\o}egaard and J Eriksen}, pages = {217--230}, volume = {413}, year = {2017}, title = {N transfer in three-species grass-clover mixtures with chicory, ribwort plantain or caraway}, journal = {Plant and Soil}, doi = {10.1007/s11104-016-3088-6}, url = {https://orgprints.org/id/eprint/31453/}, abstract = {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.} } @inproceedings{orgprints31334, journal = {Grassland Science in Europe}, title = {Nitrogen fixation in red clover grown in multi-species mixtures with ryegrass, chicory, plantain and caraway}, author = {NR Dhamala and J Rasmussen and G Carlsson and K S{\o}egaard and J Eriksen}, pages = {576--578}, year = {2016}, volume = {21}, url = {https://orgprints.org/id/eprint/31334/}, abstract = {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.} } @misc{orgprints32973, pages = {457--459}, author = {NR Dhamala and J Rasmussen and WF Cong and G Carlsson and K S{\o}egaard and J Eriksen}, volume = {33}, doi = {10.1111/sum.12368}, year = {2017}, month = {September}, journal = {Soil Use and Management}, title = {Short-term residual N unaffected by forbs in grass-clover mixtures}, keywords = {Grassland, residual effect, chicory, caraway, ribwort plantain}, url = {https://orgprints.org/id/eprint/32973/}, abstract = {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.} } @inproceedings{orgprints52959, year = {2024}, author = {C. Dold and C. DeNotaris and Esben {\O}ster Mortensen and Jim Rasmussen and SO Petersen}, title = {Cover crops and soil tillage differently affect N2O emissions.}, month = {March}, url = {https://orgprints.org/id/eprint/52959/}, abstract = {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.} } @misc{orgprints18293, title = {Source and temperature determine the releases of multiple amino acids from plant materials}, journal = {Agronomy for Sustainable Development}, volume = {30}, year = {2010}, author = {Ahmed El-Naggar and Jim Rasmussen and Andreas de Neergaard and Ahmed El-Araby and Henning H{\o}gh-Jensen}, pages = {679--688}, keywords = {amino acids; organic fertilizers, Plant tea}, abstract = {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.}, url = {https://orgprints.org/id/eprint/18293/} } @misc{orgprints10492, journal = {moMentum}, title = {Udfordring eller mulighed for {\o}kologien}, publisher = {Jordbrugsakademikerne}, pages = {29--31}, author = {A. El-Nagger and A. Ounmaa and E. Muukka and E. Zaleckas and G. Abraityt{\'e} and I. Jansons and J. Rasmussen and J. Ahnstr{\"o}m and K. Pirhofer-Walzl and K. O'Doherty Jensen and K.F. J{\o}rgensen and L. Sarunaite and M. Bleidere and M.T. Knudsen and M. Pugliese and M.H.M. Nielsen and N.B. Muguerza and P. Bakewell-Stone and P.K. Hansen and S.A. Abed-Ali Al-Kufaishi and S. Kobayashi and T. Rydberg and V. Klubova and V. Liorancas and H. H{\o}gh-Jensen}, year = {2005}, volume = {4}, abstract = {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.}, url = {https://orgprints.org/id/eprint/10492/} } @misc{orgprints9333, year = {2006}, author = {Ahmed El-Nagger and Andres Ounmaa and Eija Muukka and Ernestas Zaleckas and Gerda Abraityt{\'e} and Imants Jansons and Jim Rasmussen and Johan Ahnstr{\"o}m and Karin Pirhofer-Walzl and Katherine O?Doherty Jensen and Kirstine F. J{\o}rgensen and Lina Sarunaite and Mara Bleidere and Marie Trydeman Knudsen and Massimo Pugliese and Merete H{\o}jrup M{\o}ller Nielsen and Natalia Bellostas Mugurerza and Petra Bakewell-Stone and Preben Klarskov Hansen and Sermed Adil Abed-Ali Al-Kufaishi and Sofie Kobayashi and Torbj{\"o}rn Rydberg and Vera Klubova and Viktoras Liorancas and Henning H{\o}gh-Jensen}, publisher = {DARCOF/F{\O}JO}, title = {Globalisation as a challenge or opportunity for organic farming}, journal = {DARCOFenews}, number = {1}, month = {March}, abstract = {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.}, url = {https://orgprints.org/id/eprint/9333/}, keywords = {Organic, farming, globalisation, developing countries, global market} } @inproceedings{orgprints17879, title = {Environmental impacts of grazed pastures}, journal = {Grassland Science in Europe 15}, editor = {H. Schnyder}, year = {2010}, author = {J. Eriksen and S. Ledgard and J. Lou and R. Schils and J. Rasmussen}, pages = {880--890}, abstract = {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.}, url = {https://orgprints.org/id/eprint/17879/} } @inproceedings{orgprints17881, title = {Forage legume impact on soil fertility and N balance}, journal = {NJF report 6 (3)}, author = {J. Eriksen and K. S{\o}egaard and M. Askegaard and E.M. Hansen and J. Rasmussen}, pages = {61--65}, year = {2010}, url = {https://orgprints.org/id/eprint/17881/}, abstract = {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. } } @inproceedings{orgprints31335, title = {Kl{\o}vergr{\ae}sblandinger med urter - kulstof, kv{\ae}lstof og biodiversitet}, journal = {Bilag til Plantekongres}, pages = {230--231}, author = {J Eriksen and NR Dhamala and W-F Cong and K S{\o}egaard and J Rasmussen}, year = {2017}, url = {https://orgprints.org/id/eprint/31335/}, abstract = {Urter kan bidrage p{\r a} en r{\ae}kke punkter ? bl.a. {\o}get biodiversitet, kulstoflagring, bedre ressourceudnyttelse og {\o}get udbytte. Men det er vigtigt at kontrollere andelen.} } @inproceedings{orgprints8082, title = {TOLERANCE OF CEREALS TO POST- EMERGENCE WEED HARROWING}, publisher = {Association fran{\c c}aise de protection des plantes (AFPP)}, journal = {Proceedings from AFPP (on CD-rom)}, year = {2006}, author = {Hanne Gundersen and Jesper Rasmussen and Michael N{\o}rremark}, abstract = {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. }, url = {https://orgprints.org/id/eprint/8082/}, keywords = {weed harrowing, mechanical weed control} } @inproceedings{orgprints125, author = {C.B. Henriksen and J. Rasmussen}, pages = {61--68}, editor = {T. Cottis}, year = {2002}, journal = {Den nasjonale kongres for {\o}kologisk jordbrug, Rapport nr. 3 - 2002}, title = {Kamdyrkning (drill) ? et {\o}kologisk alternativ}, publisher = {H{\o}gskolen i Hedmark}, keywords = {soil tillage, ridge tillage, nitrogen, leaching, mineralization, row crops, sugar beet, potato, catch crops }, url = {https://orgprints.org/id/eprint/125/}, abstract = {I projektet CARMINA unders{\o}ges de potentielle fordele ved at anvende kamme som alternativ til pl{\o}jning. Det er tidligere vist at kamme kan reducere udvaskning af kv{\ae}lstof, {\o}ge oms{\ae}tningen af organisk stof og sikre en tidligere s{\r a}ning samt bedre etablering. I CARMINA kombineres kamme med dyrkning af fangafgr{\o}der og inkorporering af husdyrg{\o}dning i en r{\ae}kke nye fors{\o}g.} } @unpublished{orgprints4290, author = {Christian Bugge Henriksen and Jens Peter M{\o}lgaard and Jesper Rasmussen}, year = {2004}, title = {The effect of autumn ridging and inter-row subsoiling on potato tuber yield and quality}, journal = {Soil \& Tillage Research}, url = {https://orgprints.org/id/eprint/4290/}, abstract = {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.}, keywords = {Autumn ridging, inter-row subsoiling, reduced irrigation, Solanum tuberosum, black scurf, common scab.} } @misc{orgprints4599, year = {2005}, author = {Christian Bugge Henriksen and Jesper Rasmussen and Martin Heide J{\o}rgensen and Henning Carlo Thomsen}, journal = {DARCOFenews}, title = {Ridge planting of maize shows promising yield increase}, month = {March}, abstract = {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.}, url = {https://orgprints.org/id/eprint/4599/}, keywords = {ridge planting, ridge till, ridge tillage, ridge culture, corn, maize (Zea mays), row crops, soil temperature, soil moisture, plant nutrients} } @misc{orgprints4287, author = {Christian Bugge Henriksen and Jesper Rasmussen and Martin Heide J{\o}rgensen and Henning Carlo Thomsen}, year = {2004}, month = {December}, title = {Majs p{\r a} kamme viser lovende merudbytte}, journal = {F{\O}JOenyt}, keywords = {kamdyrkning, majs, r{\ae}kkeafgr{\o}der, jordtemperatur, fugtighed, planten{\ae}ringsstoffer}, abstract = {Majs dyrket p{\r a} kamme giver markante merudbytter p{\r a} s{\r a}vel ler- som sandjord. Merudbyttet er p{\r a} op til 60 procent. Kamdyrkning viser ogs{\r a} lovende resultater i proteinafgr{\o}der som hesteb{\o}nne og sojab{\o}nne og afpr{\o}ves nu i vinterraps. }, url = {https://orgprints.org/id/eprint/4287/} } @misc{orgprints4292, year = {2005}, author = {Christian Bugge Henriksen and Jesper Rasmussen and Jens Peter M{\o}lgaard}, title = {The effect of timing of ridging on soil inorganic nitrogen and potato tuber yield and quality }, journal = {Soil \& Tillage Research}, keywords = {Ridging, timing, catch crops, soil inorganic nitrogen, leaching, Solanum tuberosum}, url = {https://orgprints.org/id/eprint/4292/}, abstract = {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{\ensuremath{<}}0.001) and by 8\% from 6.3 to 6.8 mg N/kg soil compared with ploughing in spring (P{\ensuremath{<}}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. } } @misc{orgprints3952, year = {2005}, author = {Christian Bugge Henriksen and Jesper Rasmussen and Carsten S{\o}gaard}, title = {Ridging in autumn as an alternative to mouldboard ploughing in a humid-temperate region}, journal = {Soil \& Tillage Research}, publisher = {Elsevier, Netherlands}, keywords = {Ridging, ridges, ridge tillage, nitrogen, leaching, mineralization, immobilization}, abstract = {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. }, url = {https://orgprints.org/id/eprint/3952/} } @inproceedings{orgprints18829, pages = {133--136}, author = {Annika H{\"o}jer and Kjell Martinsson and S{\o}ren K. Jensen and Anne-Maj Gustavsson}, volume = {6}, editor = {Jim Rasmussen and Margit Schacht and {\'A}slaug Helgad{\'o}ttir}, year = {2010}, series = {NJF Report}, month = {June}, number = {3}, title = {PhytoMilk: Effects of botanical composition and harvest system of legume/grass silage on fatty acid, {\ensuremath{\alpha}}-tocopherol and {\ensuremath{\beta}}-carotene concentration in organic forage and milk}, journal = {The potential of forage legumes to sustain a high agricultural productivity - a Nordic perspective}, url = {https://orgprints.org/id/eprint/18829/}, abstract = {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, {\ensuremath{\alpha}}-tocopherol and {\ensuremath{\beta}}-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 {\ensuremath{\alpha}}-linolenic acid, {\ensuremath{\alpha}}-tocopherol and {\ensuremath{\beta}}-carotene in red clover/grass silage (mixture of three harvests). Milk linoleic and {\ensuremath{\alpha}}-linolenic acid concentration was higher with the two red clover diets but {\ensuremath{\alpha}}-tocopherol, {\ensuremath{\beta}}-carotene and retinol concentration was not affected. }, keywords = {PhytoMilk, legume, grass, dairy cow, fatty acid, vitamin } } @misc{orgprints18194, number = {3}, title = {Weed harrowing and inter-row hoeing in organic grown quinoa (Chenopodium quinoa Willd.)}, journal = {Outlook on Agriculture}, pages = {323--327}, author = {Sven-Erik Jacobsen and J.L. Christiansen and Jesper Rasmussen}, volume = {39}, year = {2010}, abstract = {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. }, url = {https://orgprints.org/id/eprint/18194/} } @misc{orgprints33906, year = {2018}, volume = {.}, author = {M. Jakobsen and J.E. Hermansen and Heidi Mai-Lis Andersen and Uffe J{\o}rgensen and R. Labouriau and Jim Rasmussen and A.G. Kongsted}, pages = {1--25}, title = {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}, journal = {Agroecology and Sustainable Food Systems}, abstract = {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.}, url = {https://orgprints.org/id/eprint/33906/} } @misc{orgprints3086, volume = {44}, year = {2004}, author = {Rikke K. Jensen and Jesper Rasmussen and Bo Melander}, pages = {245--253}, title = {Selectivity of weed harrowing in lupin}, journal = {Weed Research}, abstract = {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.}, url = {https://orgprints.org/id/eprint/3086/}, keywords = {lupin weed harrowing mechanical weed control} } @inproceedings{orgprints52997, month = {June}, title = {How inoculation can improve N2 fixation and yield in soybean under field conditions in Denmark}, author = {Juliana Trindade Martins and Kirsten L{\o}nne Enggrob and Jim Rasmussen}, year = {2023}, abstract = {Poster presenting the potential to enhance yield of soybean for fresh and mature harvest under Danish conditions}, url = {https://orgprints.org/id/eprint/52997/} } @inproceedings{orgprints53013, author = {Juliana Trindade Martins and Zhi Liang and Kirsten L{\o}nne Enggrob and Jim Rasmussen}, year = {2023}, month = {June}, title = {Carbon sequestration potential of legume based cropping systems}, abstract = {Results from investigation of grain legume soil C inputs.}, url = {https://orgprints.org/id/eprint/53013/} } @misc{orgprints52633, year = {2024}, volume = {?}, author = {Bo Melander and Jim Rasmussen and Peter S{\o}rensen}, pages = {?--?}, journal = {Renewable Agriculture and Food Systems}, title = {Cover crop effects on the growth of perennial weeds in two long-term organic crop rotations}, month = {January}, abstract = {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.}, url = {https://orgprints.org/id/eprint/52633/} } @misc{orgprints32979, year = {2017}, address = {UK}, publisher = {Wiley}, journal = {Weed research Expanding Horizons}, title = {Non-Chemical Weed Management}, pages = {245--270}, author = {Bo Melander and Matt Liebman and Adam. S. Davis and Eric Gallandt and Paolo Barberi and Anna-Camilla Moonen and Jesper Rasmussen and Rommie van der Weide and Francesco V{\'i}dotto}, editor = {P.E. Hatcher and Robert J. Froud-Williams}, url = {https://orgprints.org/id/eprint/32979/}, abstract = {Non-chemical methods for weed control in arable crops are reviewed.} } @misc{orgprints39276, doi = {doi:10.1016/j.agee.2021.107339}, title = {Short-term cover crop carbon inputs to soil as affected by long-term cropping system management and soil fertility}, journal = {Agriculture, Ecosystems \& Environment}, pages = {107339}, author = {Esben {\O}ster Mortensen and Chiara De Notaris and Leanne Peixoto and J{\o}rgen E. Olesen and Jim Rasmussen}, year = {2021}, volume = {311}, abstract = {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.}, url = {https://orgprints.org/id/eprint/39276/} } @inproceedings{orgprints1886, pages = {26--33}, author = {L.J. Munkholm and P. Schj{\o}nning and K.J. Rasmussen}, year = {1998}, volume = {124}, editor = {T. B{\o}rresen}, title = {Non-inverting soil tillage as a means of optimising soil tilth}, journal = {NJF-UTREDNING/RAPPORT}, keywords = {soil, non-inverting tillage, soil tilth, penetration resistance, visual soil evaluation}, abstract = {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 Rugballeg{\r a}rd 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.}, url = {https://orgprints.org/id/eprint/1886/} } @misc{orgprints729, year = {2003}, number = {2}, journal = {Soil and Tillage Research}, publisher = {Elsevier}, title = {Spatial and temporal effects of direct drilling on soil structure in the seedling environment}, pages = {163--173}, author = {L.J. Munkholm and P. Schj{\o}nning and K.J. Rasmussen and K. Tanderup}, volume = {71}, abstract = {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{$\times$}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 ({\ensuremath{>}}2.0 MPa) and bulk density levels ({\ensuremath{>}}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.}, url = {https://orgprints.org/id/eprint/729/}, keywords = {Direct drilling; Sandy loam; Denmark; Soil compaction; Spatial effects; Temporal effects} } @unpublished{orgprints57, pages = {1--10}, author = {Lars J Munkholm and Per Schj{\o}nning and Karl J Rasmussen}, year = {2000}, editor = {J.E. Morrison}, title = {Non-inverting Tillage: Early-Stage Effects on Soil Mechanical Behaviour}, journal = {CD-ROM: Proceedings 15th ISTRO Conference, Texas, June 2000}, abstract = {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. }, url = {https://orgprints.org/id/eprint/57/} } @misc{orgprints39, volume = {62}, author = {Lars J. Munkholm and Per Schj{\o}nning and Karl J. Rasmussen}, pages = {1--14}, journal = {Soil and Tillage Research}, title = {Non-inversion tillage effects on soil mechanical properties of a humid sandy loam }, number = {1-2}, month = {October}, year = {2001}, abstract = {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.}, url = {https://orgprints.org/id/eprint/39/} } @misc{orgprints38469, doi = {doi:10.1016/j.soilbio.2020.108008}, pages = {108008}, author = {Leanne Peixoto and Lars Elsgaard and Jim Rasmussen and Yakov Kuzyakov and Callum C. Banfield and Michaela A. Dippold and J{\o}rgen E. Olesen}, volume = {150}, month = {November}, journal = {Soil Biology and Biochemistry}, title = {Decreased rhizodeposition, but increased microbial carbon stabilization with soil depth down to 3.6 m}, year = {2020}, url = {https://orgprints.org/id/eprint/38469/}, abstract = {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.} } @misc{orgprints20614, title = {Effect of deep-rooted plant species on 15Nitrogen uptake and herbage yield in temporary agricultural grasslands}, doi = {10.1007/s11104-013-1694-0}, journal = {Plant and Soil}, pages = {313--325}, author = {K. Pirhofer-Walzl and J. Eriksen and J. Rasmussen and K. S{\o}egaard and H. H{\o}gh-Jensen and J. Rasmussen}, year = {2013}, volume = {371}, keywords = {deep-rooted; shallow-rooted; soil 15N uptake; diversity effect; grass-legume-herb grassland; Cichorium intybus L.}, url = {https://orgprints.org/id/eprint/20614/}, abstract = {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.} } @misc{orgprints43859, year = {2013}, month = {March}, title = {Effect of four plant species on soil 15N-access and herbage yield in temporary agricultural grasslands}, journal = {Plant and Soil}, author = {K. Pirhofer-Walzl and J{\o}rgen Eriksen and Jim Rasmussen and Karen Soegaard and Henning H{\o}gh-Jensen and Jesper Rasmussen}, pages = {313--325}, volume = {371}, doi = {10.1007/s11104-013-1694-0}, abstract = {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.}, url = {https://orgprints.org/id/eprint/43859/} } @inproceedings{orgprints17887, title = {15Nitrogen transfer from legumes to neighbouring plants in multi-species grassland}, journal = {NJF Report 6 (3)}, pages = {75--78}, author = {K. Pirhofer-Walzl and H. H{\o}gh-Jensen and J. Rasmussen and J. Rasmussen and K. S{\o}egaard and J. Eriksen}, year = {2010}, abstract = {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.}, url = {https://orgprints.org/id/eprint/17887/} } @inproceedings{orgprints17886, year = {2010}, pages = {830--832}, author = {K. Pirhofer-Walzl and H. H{\o}gh-Jensen and J. Rasmussen and J. Rasmussen and K. S{\o}egaard and J. Eriksen}, title = {15Nitrogen uptake from shallow- versus deep-rooted plants in multi-species mixtures and monoculture grassland}, journal = {Grassland Science in Europe 15}, abstract = {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.}, url = {https://orgprints.org/id/eprint/17886/} } @misc{orgprints20613, journal = {Plant and Soil}, title = {Nitrogen transfer from forage legumes to nine neighbouring plants in a multi-species grassland }, pages = {71--84}, author = {K. Pirhofer-Walzl and J. Rasmussen and H. H{\o}gh-Jensen and J. Eriksen and K. S{\o}egaard and J. Rasmussen}, volume = {350}, year = {2012}, url = {https://orgprints.org/id/eprint/20613/}, abstract = {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.}, keywords = {15N transfer; Grass-legume-herb grassland; Root characteristics; Trifolium repens L.; Trifolium pratense L.; Medicago sativa L.} } @misc{orgprints20645, volume = {350}, year = {2012}, author = {K. Pirhofer-Walzl and Jim Rasmussen and Henning H{\o}gh-Jensen and J{\o}rgen Eriksen and Karen Soegaard and Jesper Rasmussen}, pages = {71--84}, title = {Nitrogen transfer from forage legumes to nine neighbouring plants in a multi-species grassland}, journal = {Plan and Soil}, url = {https://orgprints.org/id/eprint/20645/}, abstract = {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. } } @misc{orgprints23296, volume = {1}, year = {2013}, author = {Karin Pirhofer-Walzl and J{\o}rgen Eriksen and Jim Rasmussen and Henning H{\o}gh-Jensen and Karin S{\o}egaard and Jesper Rasmussen}, pages = {1--10}, title = {Effect of four plant species on soil 15N-access and herbage yield in temporary agricultural grasslands}, doi = {10.1007/s11104-013-1694-0}, journal = {Plant Soil}, abstract = {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 {\ensuremath{<}}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. }, url = {https://orgprints.org/id/eprint/23296/}, keywords = {competition} } @misc{orgprints19333, journal = {Grass and Forage Sceince}, title = {Forage herbs improve mineral composition of grassland herbage}, year = {2011}, volume = {66}, author = {K. Pirhofer-Walzl and Karen S{\o}egaard and Henning H{\o}gh-Jensen and J{\o}rgen Eriksen and M.A. Sanderson and Jim Rasmussen and Jesper Rasmussen}, pages = {415--423}, keywords = {herbs, forage quality, dairy cows, functional plant groups, grass-clover swards, slurry}, url = {https://orgprints.org/id/eprint/19333/}, abstract = {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.} } @inproceedings{orgprints250, pages = {178}, author = {Ilse A. Rasmussen and Bo Melander and Karsten Rasmussen and Rikke K. Jensen and Preben K. Hansen and Gitte Rasmussen and Svend Christensen and Jesper Rasmussen}, year = {2000}, editor = {T. Alf{\"o}ldi and W. Lockeretz and U. Niggli}, publisher = {vdf Hochschulverlag AG an der ETH Z{\"u}rich}, title = {Recent advances in weed management in cereals in Denmark}, keywords = {weed management, cultural methods, prevention, competition, mechanical weed control}, abstract = {Cultural methods for prevention and improved crop competitiveness against weeds and mechanical weed control.}, url = {https://orgprints.org/id/eprint/250/} } @misc{orgprints254, editor = {Erik Steen Kristensen}, pages = {63--86}, author = {Ilse A. Rasmussen and Bo Melander and Karsten Rasmussen and Jesper Rasmussen}, title = {Regulering af ukrudt}, publisher = {Danmarks JordbrugsForskning}, journal = {{\O}kologisk Planteproduktion}, series = {SP rapport}, year = {1997}, keywords = {ukrudt, ukrudtsbek{\ae}mpelse, forebyggelse, mekanisk bek{\ae}mpelse, bek{\ae}mpelsesbehov, konkurrenceevne}, url = {https://orgprints.org/id/eprint/254/}, abstract = {I {\o}kologisk plantedyrkning er ukrudtsreguleringen baseret p{\r a} et samspil mellem forebyggelse og bek{\ae}mpelse, hvor forebyggelse spiller en langt st{\o}rre rolle end i den konventionelle dyrk-ning. I korn og andre t{\ae}ts{\r a}ede afgr{\o}der er forebyggelsen den v{\ae}sentligste komponent i ukrudtsreguleringen, hvorimod det er den direkte bek{\ae}mpelse, der udg{\o}r grundlaget for dyrk-ning af r{\ae}kkeafgr{\o}der s{\r a} som guler{\o}dder, l{\o}g, roer og kartofler. Den {\o}kologiske ukrudtsregu-lering kendetegnes ved kompleksitet, da der dels anvendes mange forskellige metoder, og dels anvendes metoder med langsigtede effekter i dyrkningssystemet. Form{\r a}let med denne artikel er at give overblik over de anvendte metoder. Artiklen er opbygget s{\r a}ledes at der f{\o}rst 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 bek{\ae}mpelse. Artiklen afsluttes med at afsnit om forskning vedr{\o}rende ukrudtsregule-ring. Artiklen er en gennemgang af principper og metoder - ikke konkrete anvisninger p{\r a} hvordan ukrudtsbek{\ae}mpelsen i praksis skal udf{\o}res. Disse kan f.eks. findes i ?Ukrudtsbe-k{\ae}mpelse p{\r a} {\o}kologiske brug? udgivet af Landbrugets R{\r a}dgivningscenter (Anonym 95) og i andre af de citerede kilder. } } @misc{orgprints261, volume = {20}, pages = {14}, author = {Ilse A. Rasmussen and Jesper Rasmussen}, number = {217}, title = {Beskidte r{\ae}kkeafgr{\o}der giver ukrudt i kornet}, journal = {{\O}kologisk Jordbrug}, publisher = {{\O}kologisk Landsforening}, month = {May}, year = {2000}, keywords = {r{\ae}kkkeafgr{\o}der, majs, ukrudtsbek{\ae}mpelse, s{\ae}dskifte, korn}, abstract = {Mislykkes bek{\ae}mpelsen af ukrudt i r{\ae}kkeafgr{\o}der, kan det give store ukrudtsproblemer flere {\r a}r senere, viser ny resultater fra danske fors{\o}g.}, url = {https://orgprints.org/id/eprint/261/} } @misc{orgprints17875, author = {J. Rasmussen and J. Eriksen and E.S. Jensen and H. H{\o}gh-Jensen}, pages = {293--297}, volume = {46}, year = {2010}, title = {Root size fractions of ryegrass and white clover contributes differently to C and N inclusion in SOM}, journal = {Biology and Fertility of Soils}, abstract = {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.}, url = {https://orgprints.org/id/eprint/17875/} } @misc{orgprints16290, author = {J. Rasmussen and B. Gjettermann and J. Eriksen and E.S. Jensen and H. H{\o}gh-Jensen}, pages = {3031--3039}, volume = {40}, year = {2008}, title = {Fate of 15N- and 14C from labelled plant material: Recovery in perennial ryegrass-clover mixtures and in pore water of the sward}, journal = {Soil Biology \& Biochemistry}, abstract = {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.}, url = {https://orgprints.org/id/eprint/16290/} } @inproceedings{orgprints17882, author = {J. Rasmussen and K. S{\o}egaard and J. Eriksen}, pages = {69--72}, year = {2010}, title = {Biomass production and N2-fixation in seven grass-legume mixtures}, abstract = {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.}, url = {https://orgprints.org/id/eprint/17882/} } @misc{orgprints17196, volume = {28}, author = {Jesper Rasmussen}, pages = {22--23}, year = {2010}, journal = {Agrologisk}, title = {Ukrudtsharven kan afl{\o}se kemi}, publisher = {Dansk Agrarforlag A/S}, month = {June}, url = {https://orgprints.org/id/eprint/17196/}, abstract = {I 75 ud af 100 tilf{\ae}lde kan en effektiv ukrudtsharvning i v{\r a}rbyg erstatte kemi ? uden at det g{\r a}r ud over {\o}konomien. Men det kr{\ae}ver forskning og innovation } } @misc{orgprints17194, year = {2010}, address = {www.videnskab.dk}, author = {Jesper Rasmussen}, title = {Ukrudtsharvning - effektiv i {\o}kologisk landbrug}, publisher = {www.videnskab.dk}, month = {April}, abstract = {En optimal gennemf{\o}rt ukrudtsharvning er konkurrencedygtig med spr{\o}jtemidler i 3 ud af 4 tilf{\ae}lde. Ukrudtsharvning er derfor en interessant bek{\ae}mpelsesmetode, der b{\o}r udvikles.}, url = {https://orgprints.org/id/eprint/17194/} } @misc{orgprints17064, year = {2010}, author = {Jesper Rasmussen}, pages = {16--16}, journal = {Landbrugsavisen}, title = {Punkts{\r a}ning giver mindre ukrudt}, month = {April}, keywords = {sowing, mechanical weed control, weed germination}, abstract = {I langsomtspirende {\o}kologiske afgr{\o}der som guler{\o}dder og s{\r a}l{\o}g b{\o}r jorden forstyrres s{\r a} ledt som muligt i forbindelse med s{\r a}ning. Det f{\r a}r mindre ukrudt til at spire i r{\ae}kkerne. Med punkts{\r a}ning forstyrres jorden minimalt ved s{\r a}ning, og det giver mindre ukrudt i r{\ae}kkerne. }, url = {https://orgprints.org/id/eprint/17064/} } @misc{orgprints17040, month = {March}, title = {Intelligent ukrudtsbek{\ae}mpelse}, publisher = {{\O}kologisk Landsforening}, journal = {{\O}kologi \& Erhverv}, pages = {16--16}, author = {Jesper Rasmussen}, year = {2010}, keywords = {robotic weeding, robotter, mekanisk ukrudtsbek{\ae}mpelse}, url = {https://orgprints.org/id/eprint/17040/}, abstract = {Personlig refleksion over begrebet intelligent ukrudtsbek{\ae}mpelse og trends i forskningen. I klummen ses der tilbage p{\r a} 25 {\r a}rs forskning og det paradigmeskift, som er sket. } } @misc{orgprints17195, month = {January}, publisher = {www.videnskab.dk}, title = {{\O}kologisk forskning er trov{\ae}rdig}, author = {Jesper Rasmussen}, year = {2010}, url = {https://orgprints.org/id/eprint/17195/}, abstract = {I videnskabelige kredse g{\o}r man meget ud af at holde viden og holdninger adskilt, fordi det skaber utrov{\ae}rdighed, hvis den forskningsbaserede viden er farvet af forskernes personlige holdninger. Objektivitet og trov{\ae}rdighed er en dyd.} } @misc{orgprints17192, title = {Ukrudt - en del af helheden}, publisher = {www.videnskab.dk}, month = {September}, year = {2009}, address = {http://www.videnskab.dk}, author = {Jesper Rasmussen}, url = {https://orgprints.org/id/eprint/17192/}, abstract = {Hvordan griber man ukrudt an i et {\o}kologisk landbrug? Og hvordan t{\ae}nker man i det hele taget ukrudt ind i {\o}kologiens v{\ae}rdis{\ae}t?} } @inproceedings{orgprints15202, author = {Jesper Rasmussen}, pages = {286--288}, year = {2009}, title = {Ukrudtsharvning - mod et mere nuanceret vejledningsgrundlag}, journal = {Sammendrag af indl{\ae}g Plantekongres 2009}, keywords = {Weed harrowing, image analysis, technology, decision support syttems}, url = {https://orgprints.org/id/eprint/15202/}, abstract = {Indl{\ae}gget beskriver forfatterens motivation til at genoptage forskning i ukrudtsharvning, en vision og eksempler p{\r a} de seneste {\r a}rs resultater. Der l{\ae}gges v{\ae}gt p{\r a} samspillet mellem ny teknologi og beslutningsalgoritmer. } } @inproceedings{orgprints15687, author = {Jesper Rasmussen}, pages = {142--145}, year = {2009}, title = {Unifying parameters in mechanical weed control research - report of the roundtable}, journal = {Proceedings 8th EWRS Workshop on Physical and Cultural Weed Control}, url = {https://orgprints.org/id/eprint/15687/}, abstract = {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}, keywords = {weed harrowing, models, statistics} } @misc{orgprints14262, author = {Jesper Rasmussen}, pages = {13}, volume = {28}, month = {August}, journal = {Maskinbladet}, title = {Mindre ukrudt med punkts{\r a}ning}, number = {447}, year = {2008}, keywords = {s{\r a}tiknik}, abstract = {Baggrunden for at inddrage punkts{\r a}ning i ukrudtsprojekt i relation til {\o}kologisk jordbrug beskrives.}, url = {https://orgprints.org/id/eprint/14262/} } @misc{orgprints2530, year = {2004}, month = {April}, number = {311}, title = {Falsk s{\r a}bed sparer tid til roehakning}, journal = {{\O}kologisk Jordbrug}, pages = {8}, author = {Jesper Rasmussen}, volume = {24}, abstract = {Etablerer man et falsk s{\r a}bed i roemarken, kan man gl{\ae}de sig over mindre ukrudt, men samtidig falder udbyttet. I artiklen pr{\ae}senteres en model, som kan anvendes til at beregne hvor meget tid der kan spares til h{\r a}ndhakning ved at uds{\ae}tte s{\r a}tidspunktet og hvor meget udbytte der tabes. }, url = {https://orgprints.org/id/eprint/2530/}, keywords = {h{\r a}ndhakning, tidsforbrug} } @inproceedings{orgprints2500, author = {Jesper Rasmussen}, year = {2004}, title = {Are we making progress in mechanical weed control research? }, url = {https://orgprints.org/id/eprint/2500/}, abstract = {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 {\ensuremath{<}} 0.01) and researchers engaged in herbicide technology (N=13) held more dominant positions than the rest P {\ensuremath{<}} 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. }, keywords = {systems, paradigms} } @inproceedings{orgprints2443, pages = {115--122}, author = {Jesper Rasmussen}, year = {2004}, title = {Are we making progress in mechanical weed control research? }, journal = {Proceedings 6th EWRS Workshop on Physical and Cultural Weed Control, Lillehammer, Norway, 115-122.}, keywords = {questionnaire}, url = {https://orgprints.org/id/eprint/2443/}, abstract = {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 {\ensuremath{<}} 0.01) and researchers engaged in herbicide technology (N=13) held more dominant positions than the rest (P {\ensuremath{<}} 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. } } @misc{orgprints1785, publisher = {Blackwell Publishing}, title = {Punch planting, flame weeding and stale seedbed for weed control in row crops}, journal = {Weed Research}, year = {2003}, volume = {43}, pages = {393--403}, author = {Jesper Rasmussen}, keywords = {Punch planting, flame weeding, stale seedbed, delayed sowing, organic farming, weed control, row crops}, abstract = {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 {\copyright} 2003 European Weed Research Society. For further information on Weed Research please refer to www.blackwellpublishing.com/wre" }, url = {https://orgprints.org/id/eprint/1785/} } @misc{orgprints436, author = {Jesper Rasmussen}, pages = {6--7}, volume = {11}, year = {2002}, month = {October}, journal = {KVL-Mosaik}, title = {Hvad karakteriserer god undervisning?}, publisher = {KVL}, number = {3}, keywords = {undervisning, l{\ae}ring}, abstract = {P{\ae}dagogisk Udvalg udskrev tidligere p{\r a} {\r a}ret en prisopgave med det form{\r a}l at f{\r a} kvalificerede forslag til, hvordan undervisningen kan se ud p{\r a} fremtidens KVL. Mosaik bringer en forkortet version af 1. pr{\ae}mien.}, url = {https://orgprints.org/id/eprint/436/} } @inproceedings{orgprints433, title = {Alternative jordbearbejdningsmetoder}, author = {Jesper Rasmussen}, year = {2000}, keywords = {jordbearbejdning}, abstract = {Pr{\ae}sentation om alternative jordbearbejdningsmetoder.}, url = {https://orgprints.org/id/eprint/433/} } @misc{orgprints14987, volume = {48}, pages = {523--532}, author = {Jesper Rasmussen and Bo Martin Bibby and Anders P. Schou}, year = {2008}, number = {6}, title = {Investigating the selectivity of weed harrowing with new methods}, journal = {Weed Research}, publisher = {Blackwell Publishing}, abstract = {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. }, url = {https://orgprints.org/id/eprint/14987/}, keywords = {Physical weed control, digital image analysis, crop damage, row spacing, harrowing direction, timing} } @inproceedings{orgprints17880, journal = {Grassland Science in Europe 15}, title = {The contribution of grass and clover root turnover to N leaching}, author = {Jesper Rasmussen and {\'A}. Helgad{\'o}ttir and B. Frankow-Lindberg and R. Loges and J. Eriksen}, pages = {1028--1030}, editor = {H. Schnyder}, year = {2010}, abstract = {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.}, url = {https://orgprints.org/id/eprint/17880/} } @inproceedings{orgprints432, year = {2002}, author = {Jesper Rasmussen and Christian Bugge Henriksen}, title = {Kamdyrkning i stedet for pl{\o}jning}, keywords = {kamme, jordbearbejdning, samdyrkning, sortsblandinger}, abstract = {I projektet CARMINA unders{\o}ges de potentielle fordele ved at anvende kamme som alternativ til pl{\o}jning. Det er tidligere vist at kamme kan reducere udvaskning af kv{\ae}lstof, {\o}ge oms{\ae}tningen af organisk stof og sikre en tidligere s{\r a}ning samt bedre etablering. I CARMINA kombineres kamme med dyrkning af fangafgr{\o}der og inkorporering af husdyrg{\o}dning i en r{\ae}kke nye fors{\o}g.}, url = {https://orgprints.org/id/eprint/432/} } @inproceedings{orgprints421, title = {Jordl{\o}sninger - er det svaret? }, author = {Jesper Rasmussen and Christian Bugge Henriksen}, year = {2000}, url = {https://orgprints.org/id/eprint/421/}, abstract = { Jordl{\o}sning - er det svaret? Jesper Rasmussen \& Christian Bugge Henriksen, Den Kgl. Veterin{\ae}r og Landboh{\o}jskole I stort set alle fors{\o}g verden over har planter reageret positivt p{\r a} en effektiv l{\o}sning af jorden i dybden. N{\r a}r dybe jordl{\o}sninger alligevel ikke spiller nogen n{\ae}vnev{\ae}rdig rolle i {\o}kologisk jordbrug, skyldes det, at det dels har vist sig sv{\ae}rt at l{\o}sne joden effektivt i dybden med de eksisterende traktorredskaber, og dels er vanskeligt at fastholde en l{\o}s jord, hvis der fortsat foreg{\r a}r tung trafik p{\r a} den. I forbindelse med dyrkning af h{\o}jv{\ae}rdiafgr{\o}der synes der basis for at eksperimentere med en kombination af effektiv l{\o}sning i dybden og kontrolleret trafik i faste k{\o}respor. I fors{\o}g er der opn{\r a}et h{\o}jere udbytter, lave br{\ae}ndstofforbrug og et lavere g{\o}dningsforbrug i s{\r a}danne systemer. Dybe jordl{\o}sninger uden for v{\ae}ksts{\ae}sonen (grubning) Hvis det handler om at undg{\r a} de problemer med overfladevand p{\r a} markerne, som i stigende omfang pr{\ae}ger landskabet efter{\r a}r og vinter er dybe jordl{\o}sninger med grubbere ikke l{\o}sningen. L{\o}sningen p{\r a} disse problemer ligger i forebyggelsen. I s{\r a}vel konventionel som {\o}kologisk dyrkning har anvendelsen af stadig tungere maskiner n{\r a}et en smertegr{\ae}nse, da jorden i bogstaveligste forstand giver efter. F{\ae}rdsel med tunge maskiner p{\r a} v{\r a}d jord trykker ikke blot jorden sammen i pl{\o}jelaget men ogs{\r a} under pl{\o}jelaget. En gyllevogn med en akselbelastning p{\r a} 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 h{\o}j grad de kan repareres ved hj{\ae}lp af grubning. Det er veldokumenteret, at en positiv effekt af grubning ikke holder lige s{\r a} l{\ae}nge som en negativ effekt af jordpakning. Grubning kombineret med efterf{\o}lgende tung trafik er derfor ingen god l{\o}sning. Oph{\o}r af tung trafik p{\r a} v{\r a}d jord er den l{\o}sning, som der h{\o}r str{\ae}bes efter. Kompakte lag under pl{\o}jedybden anses nu for at v{\ae}re almindelige i danske jorde, men i hvor h{\o}j grad de har praktisk betydning for plantev{\ae}ksten er usikkert. Danske fors{\o}g har ikke vist entydige positive effekter af dyb jordl{\o}sning. I f{\o}rste halvdel af 90'erne blev der foretaget en del fors{\o}g med grubning i Danmark med forskellige redskaber - heriblandt Springer Agromeliorator. Dyb jordl{\o}sning havde generelt ringe indflydelse p{\r a} plantev{\ae}ksten, og kun i f{\r a} tilf{\ae}lde blev der m{\r a}lt sikre merudbytter. Resultaterne var uafh{\ae}ngige af grubbernes udformning. Der var ikke tegn p{\r a} at grubningerne {\o}gede mineraliseringen i jorden. Konklusionen p{\r a} fors{\o}gene blev, at hvis der er sket skade p{\r a} jordstrukturen under pl{\o}jelaget, kan man fors{\o}ge at genskabe jordens dyrkningsegenskaber ved en dybdeg{\r a}ende jordl{\o}sning. Der gives dog ingen garanti for om det lykkes. I begyndelsen af {\r a}rhundredet blev der udf{\o}rt en r{\ae}kke fors{\o}g med forskellige pl{\o}jedybder og dyb jordl{\o}sning i 40 cm dybde. Fors{\o}gene var fastliggende og blev gennemf{\o}rt p{\r a} s{\r a}vel ler- som sandjord. De var ikke anlagt for at reparere trykskader, men fordi man havde en formodning om, at dyb jordl{\o}sning var en fordel i forbindelse med g{\o}dskning med store m{\ae}ngder staldg{\o}dning. L{\o}sningerne blev derfor kun foretaget forud for roer og kartofler, der fik tilf{\o}rt staldg{\o}dning. Jordl{\o}sningerne gav generelt meget sm{\r a} merudbytter, og det kunne ikke eftervises, at der var et specielt behov for at l{\o}sne jorden i forbindelse med anvendelse af store m{\ae}ngder staldg{\o}dning. Danske fors{\o}g synes s{\r a}ledes at vise, at der er ikke er behov for dybe jordl{\o}sninger med grubbere p{\r a} almindelig landbrugsjord, selvom der ofte forekommer kompakte jordlag under pl{\o}jedybden. Der kan v{\ae}re flere {\r a}rsager til dette: 1) P{\r a} trods af kompakte lag er der intet reelt behov for jordl{\o}sning, 2) I fors{\o}gene har jordl{\o}sningerne ikke v{\ae}ret optimale eller 3) Jordl{\o}sningens effekt er s{\r a} kortvarig, at den ikke kan m{\r a}les p{\r a} de efterf{\o}lgende afgr{\o}der. Den internationale litteraturen er rig p{\r a} dokumentation af alle 3 forhold. 1) Behovet for jordl{\o}sning kan ikke bestemmes entydigt, men der findes simple registreringsmetoder, som kan give et klart fingerpeg som for eksempel visuel bed{\o}mmelse af rodv{\ae}ksten samt penetrometerm{\r a}linger. 2) Betingelsen for at opn{\r a} et tilfredsstillende resultat med jordl{\o}sning er, at jorden er tilpas t{\o}r. Grubning af v{\r a}d jord kan forv{\ae}rre jordpakningen. 3) Tung trafik kort tid efter jordl{\o}sningen kan presse jorden sammen igen efter en ellers vellykket jordl{\o}sning. Jordl{\o}sning som en del af den prim{\ae}r jordbearbejdning I den klassiske litteratur om {\o}kologisk jordbearbejdning er det ofte blevet fremf{\o}rt, at den ideelle prim{\ae}re jordbearbejdning best{\r a}r af en kombination af overfladisk intensiv jordbearbejdning med en dybere jordl{\o}sning. Der findes en r{\ae}kke forskellige redskaber, som er udformet efter dette princip. Interessen for jordl{\o}sning som en del af den prim{\ae}re jordbearbejdning har is{\ae}r v{\ae}ret stor i forbindelse med reduceret jordbearbejdning i USA og Canada. Her er der gennemf{\o}rt talrige fors{\o}g og opn{\r a}et gode resultater i majs- og sojab{\o}nner under foruds{\ae}tning af en effektiv kemisk ukrudtsbek{\ae}mpelse. Under {\o}kologiske dyrkningsforhold har det vist sig vanskeligt at h{\r a}ndtere ukrudtet uden brug af plov. Danske igangv{\ae}rende fors{\o}g har ikke vist klare udbyttefor{\o}gelser med jordl{\o}sning i forbindelse med overfladisk prim{\ae}r jordbearbejdning. Jordl{\o}sninger i v{\ae}ksts{\ae}sonen Jordl{\o}sninger i v{\ae}ksts{\ae}sonen, der har til form{\r a}l at stimulere jordens biologiske oms{\ae}tning af kv{\ae}lstof, foreligger der kun f{\r a} fors{\o}g med. Der foreligger b{\r a}de positive og negative resultater. P{\r a} grovsandet jord er der opn{\r a}et merudbytter i kartoffel og p{\r a} lerjord er der opn{\r a}et merudbytter i vinterhvede. Der forekommer dog ogs{\r a} negative udslag i vinterhvede og bederoer p{\r a} lerjord. Der er endnu mange usikkerhedsmomenter forbundet med jordl{\o}sning i v{\ae}ksts{\ae}sonen. Effektive jordl{\o}sninger En r{\ae}kke fors{\o}g verden over har vist, at stort set alle afgr{\o}der reagerer positivt p{\r a} en effektivt l{\o}snet jord. Der har v{\ae}ret udf{\o}rt fors{\o}g med s{\r a}vel gravning i 50 centimeters dybde, gravning i cirka 25 cm dybde og l{\o}sning i 25 cm dybde og endelig opgravning af jorden lag for lag i 90 cm dybde, hvorefter den er lagt tilbage lagvis. S{\r a}danne effektive jordl{\o}sninger, som blandt andet kendes fra h{\o}jbede, har givet langt st{\o}rre effekter end almindelige jordl{\o}sninger. I en r{\ae}kke fors{\o}g er der fundet store udbyttefor{\o}gelser i s{\r a}vel landbrugs- som havebrugsafg{\o}rder. Effekterne er is{\ae}r store hvis den effektive jordl{\o}sning kombineres med kontrollerede trafiksystemer med faste k{\o}respor. Effektiv l{\o}sning med kontrolleret trafiksystemer synes is{\ae}r interessante i intensive dyrkningssystemer med r{\ae}kkeafgr{\o}der. I England har der v{\ae}ret gennemf{\o}rt fors{\o}g med en traktordreven "double-digger", der i princippet udf{\o}rer samme arbejde som gravning i dobbelt dybde med h{\r a}nden. Resultaterne var klart bedre end dem der blev opn{\r a}et med traditionelle grubbere. I Holland har dyb jordl{\o}sning i kontrollerede trafiksystemer med faste k{\o}respor givet udbyttefor{\o}gelser mellem 0-10\% over en {\r a}rr{\ae}kke i intensive dyrkningssystemer med kartofler, roer og vinterhvede. I systemerne blev der desuden opn{\r a}et reduktioner p{\r a} cirka 50\% af traktorbr{\ae}ndstofforbruget og cirka 10\% af g{\o}dningsforbruget. Det forekommer oplagt at unders{\o}ge mulighederne for at effektiv l{\o}sning af jorden i systemer med kontrolleret trafik under danske {\o}kologiske dyrkningsbetingelser. } } @misc{orgprints642, pages = {10--12}, author = {Jesper Rasmussen and Pernille Kaltoft}, volume = {148}, month = {April}, number = {8}, title = {Holdninger pr{\ae}ger jordbrugsvidenskaben}, journal = {Jord og Viden}, year = {2003}, abstract = {I artiklen redeg{\o}res der for nogle af de mekanismer, som g{\o}r, at jordbrugsvidenskaben kan blive ideologisk ensrettet, hvis ikke de v{\ae}rdier og holdninger som ligger bag g{\o}res synlige og {\r a}ben for diskussion. Artiklen bygger delvis p{\r a} unders{\o}gelsesresultater.}, url = {https://orgprints.org/id/eprint/642/}, keywords = {v{\ae}rdier, holdninger, ideologi} } @misc{orgprints641, volume = {20}, year = {2003}, pages = {347--363}, author = {Jesper Rasmussen and Pernille Kaltoft}, number = {4}, title = {Alternative versus conventional attitudes in higher agricultural education}, journal = {Alternative Agriculture \& Horticulture}, keywords = {paradigms, idelogy, values}, url = {https://orgprints.org/id/eprint/641/}, abstract = {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. } } @misc{orgprints4032, year = {2003}, pages = {4}, author = {Jesper Rasmussen and Pernille Kaltoft}, number = {284}, title = {Fortalere for genteknologi p{\r a} vanskelig opgave blandt {\o}kologer}, journal = {{\O}kologisk Jordbrug}, keywords = {holdinger gen-debat paradigmer}, abstract = {Holdningen til bioteknologi er en klar indikator for den generelle holdning til {\o}kologisk jordbrug}, url = {https://orgprints.org/id/eprint/4032/} } @misc{orgprints435, year = {2002}, number = {3}, journal = {KVL-Mosaik}, publisher = {KVL}, title = {Ensidige holdninger i undervisningen - hvad stiller vi op med dem?}, month = {October}, volume = {11}, pages = {15--17}, author = {Jesper Rasmussen and Pernille Kaltoft}, abstract = {Holdninger og v{\ae}rdier m{\r a} n{\o}dvendigvis spille en rolle i Landboh{\o}jskolens uddannelser, da uddannelserne retter sig mod professioner, som ud{\o}ves i et v{\ae}rdipluralistisk samfund. Vi kan derfor ikke lade som om, v{\ae}rdier og holdninger enten ikke eksisterer eller er ens for alle. Dette udfordrer den grundholdning, som pr{\ae}ger Landboh{\o}jskolen, hvor s{\r a}kaldt objektiv faglighed er i h{\o}js{\ae}det.}, url = {https://orgprints.org/id/eprint/435/}, keywords = {holdninger, v{\ae}rdier} } @inproceedings{orgprints450, title = {De nye konsulenter og deres holdninger til {\o}kologisk jordbrug}, publisher = {Landbrugets R{\r a}dgivningscenter \& Forskningscenter for {\O}kologisk Jordbrug}, journal = {Kongresbilag {\O}kologi-Kongres 2002}, pages = {31--33}, author = {Jesper Rasmussen and Pernille Kaltoft}, year = {2002}, keywords = {holdninger, v{\ae}rdier}, abstract = {Holdninger er vigtige, selvbekr{\ae}ftende og konservative Nogle holdninger er overfladiske, mens andre er dybe, da de er k{\ae}det sammen med basale v{\ae}rdier hos det enkelte menneske. Det er de dybere holdninger, vi besk{\ae}ftiger os med i det f{\o}lgende. Denne type holdninger har betydning for hvordan vi oplever og forst{\r a}r verden, og hvordan vi handler. Holdningerne og v{\ae}rdierne hj{\ae}lper os med at finde sammenh{\ae}ng og mening i tilv{\ae}relsen, og de f{\r a}r os til at f{\o}le harmoni mellem det vi opfatter som rigtigt, og det vi g{\o}r. Holdninger er selvbekr{\ae}ftende, fordi vi har behov for at opleve sammenh{\ae}ng mellem oplevelse, forst{\r a}else og handling. De dybe holdninger er konservative, fordi vi ikke kan {\ae}ndre 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 d{\r a}rligt, fordi holdninger kan v{\ae}re uhensigtsm{\ae}ssige og h{\ae}mme en god udvikling. Kortl{\ae}gning af de nye konsulenters holdninger Der er ingen, som har kortlagt konsulenters holdninger til {\o}kologisk jordbrug, eller holdningernes betydning for r{\r a}dgivningen. Vi har derfor valgt at tegne et billede af de holdninger, som pr{\ae}ger de studerende, n{\r a}r de forlader Landboh{\o}jskolen. Dette billede er sammensat af to dele. En beskrivelse af det undervisningsmilj{\o}, som de uddannes i, og en sp{\o}rgeskemaunders{\o}gelse. Undervisningskulturen p{\r a} Landboh{\o}jskolen Nyuddannede kandidater er i vid udstr{\ae}kning pr{\ae}get af den naturvidenskabelige grundholdning, der ofte pr{\ae}senteres som h{\ae}vet over det den ogs{\r a} er - en holdning. Verden s{\o}ges beskrevet og forst{\r a}et objektivt, og det er s{\r a}kaldt v{\ae}rdifri viden, der betragtes som altafg{\o}rende i undervisningen. Holdningssp{\o}rgsm{\r a}l fortr{\ae}nges fra de sammenh{\ae}nge, hvor de {\o}ver indflydelse. Det kan v{\ae}re sp{\o}rgsm{\r a}l om hvad der er vigtig viden, hvordan denne viden kan og b{\o}r anvendes, og hvilken samfundsudvikling den underst{\o}tter. Da vi ikke l{\ae}ngere lever i en verden, hvor det er indiskutabelt, hvad der er godt eller skidt, er det vigtigt at f{\r a} koblet et bredere perspektiv p{\r a} undervisningen, end den som den naturvidenskabelige grundholdning levner plads til. Dette kan g{\o}res p{\r a} to m{\r a}der. Ved at styrke undervisningen i etik og videnskabsteori og/eller ved at integrere holdningsaspekter i den faglige undervisning. Det er is{\ae}r f{\o}rstn{\ae}vnte metode, som har vundet indpas p{\r a} Landboh{\o}jskolen. I de senere {\r a}r er den valgfrie undervisning i etik og videnskabsteori s{\r a}ledes blevet styrket, og det er nu besluttet at g{\o}re den obligatorisk for alle studerende. Den anden strategi, hvor holdningsaspekter integreres direkte i den faglige undervisning er sj{\ae}lden, men den er taget op p{\r a} kurserne i {\o}kologisk jordbrug, hvor de studerende tr{\ae}nes i at analysere hvor og hvordan holdninger g{\o}r sig g{\ae}ldende i forhold til det faglige. Berettigelsen af selvst{\ae}ndige kurser i {\o}kologisk jordbrug er l{\o}bende til debat p{\r a} Landboh{\o}jskolen. Kursernes berettigelse er blandt andet, at de tr{\ae}ner de studerende i at arbejde med tv{\ae}rfaglige problemstillinger i relation til {\o}kologisk jordbrug og l{\ae}rer dem at forholde sig til det {\o}kologiske jordbrugs visioner, principper og praksis i et overordnet b{\ae}redygtighedsperspektiv. Mange finder imidlertid at den almene undervisning er d{\ae}kkende for alle typer jordbrug og bestr{\ae}belser p{\r a} b{\ae}redygtighed. Et flertal af de studerende som {\o}nsker at blive konsulenter v{\ae}lger almene kurser frem for de {\o}kologiske. Holdningsunders{\o}gelse p{\r a} Landboh{\o}jskolen En ny unders{\o}gelse (Rasmussen \& Kaltoft, 2002) viser, at der b{\r a}de findes positive og negative holdninger til {\o}kologisk jordbrug repr{\ae}senteret p{\r a} Landboh{\o}jskolen. Negative holdninger fremkommer, n{\r a}r man ikke ser meningsgivende sammenh{\ae}nge mellem det, som det {\o}kologiske jordbrug st{\r a}r for, og det der fremmer en god udvikling. Dette misforhold g{\o}r, at man f{\o}ler modvilje, ubehag eller m{\r a}ske endog aggressivitet i forhold til {\o}kologisk jordbrug. Positive holdninger fremkommer, n{\r a}r man netop finder meningsgivende sammenh{\ae}ng mellem det {\o}kologiske jordbrug, og det der skal til for at fremme en god udvikling. Blandt s{\r a}vel undervisere som studerende findes hele spektret af holdninger til {\o}kologisk jordbrug, fra st{\ae}rkt negative til st{\ae}rkt positive. De studerende som tager kurser i {\o}kologisk jordbrug, er generelt positive overfor {\o}kologisk jordbrug, og det er kun f{\r a}, som er meget negative. Dette er m{\r a}ske ikke s{\r a} overraskende, da kurserne netop vedkender sig at have en kritisk og konstruktiv tilgang til {\o}kologisk jordbrug og derfor repr{\ae}senterer en positiv holdning til {\o}kologisk jordbrug. Mere overraskende er det, at nogle af de almene kurser, som pr{\ae}senterer sig som holdningsneutrale og hylder den v{\ae}rdifri tilgang til fagligheden, rekrutterer studerende med st{\ae}rke negative holdninger til {\o}kologisk jordbrug. Blandt disse kurser er nogle centrale produktionsorienterede kurser, som anses for mere eller mindre obligatoriske for de studerende, som {\o}nsker at blive planteavlskonsulenter. P{\r a} disse kurser havde de studerende endog meget negative holdninger til {\o}kologiske jordbrug. De mest positive havde holdninger, der svarede til de mest negative blandt dem som valgte kurser i {\o}kologisk jordbrug. Dem som havde de mest negative holdninger var aggressive overfor {\o}kologisk jordbrug og havde sv{\ae}rt ved at diskutere dets berettigelse. P{\r a} de p{\r a}g{\ae}ldende kurser var de studerende som gennemsnit mere negative overfor {\o}kologisk jordbrug, end dem som arbejdede i den agro-kemiske branche i USA i begyndelsen af 90'erne. S{\r a} st{\ae}rke holdninger indeb{\ae}rer blandt andet en klar afvisning af landbrugets milj{\o}problemer. I unders{\o}gelsen havde kvindelige studerende klart mere positive holdninger til {\o}kologisk jordbrug end mandlige, og der var meget klar overv{\ae}gt af kvindelige studerende p{\r a} kurserne i {\o}kologisk jordbrug og klar overv{\ae}gt af mandlige studerende p{\r a} de klassiske planteavlskurser Unders{\o}gelsen synes s{\r a}ledes at vise, at de studerende som satser p{\r a} konsulentjobs inden for planteavl er mere negative overfor {\o}kologisk jordbrug end deres medstuderende. Det tyder ogs{\r a} p{\r a}, at de er mere negative end hortonomstuderende og veterin{\ae}rstuderende, som ogs{\r a} indgik i unders{\o}gelsen. Konsekvenserne Erfaringerne viser, at der er mange, der er sluppet godt fra at have kastet sig ud i jobs med tilknytning til {\o}kologisk jordbrug uden p{\r a} forh{\r a}nd at have meget positive holdninger til det. Dette taler for, at holdningerne m{\r a}ske ikke er s{\r a} v{\ae}sentlige, som man kunne tro. Det er givetvis meget f{\r a}, der v{\ae}lger at arbejde med {\o}kologisk jordbrug, hvis de har st{\ae}rke negative holdninger til det. Det vil de sandsynligvis slet ikke kunne klare, uden at skabe konflikter i dem selv eller deres omgivelser. I ovenn{\ae}vnte unders{\o}gelse indgik en lille gruppe {\o}kologikonsulenter som referencegruppe. Ingen af disse havde st{\ae}rke negative holdninger til {\o}kologisk jordbrug. Med negative holdninger til {\o}kologisk jordbrug har man sv{\ae}rt ved at finde mening og logik i de ideer og principper, som ligger til grund for {\o}kologisk jordbrug, og man vil opleve en indre konflikt ved at skulle identificere sig med dem. En s{\r a}dan holdningsm{\ae}ssig konflikt vil typisk blive l{\o}st p{\r a} to m{\r a}der. Der kan ske en holdnings{\ae}ndring, det der ofte kaldes "indre oml{\ae}gning", eller der kan ske en udskillelse, hvor det der skaber konflikt fortr{\ae}nges. Det vil sige, at der ensidigt vil blive fokuseret p{\r a} det der synes renset for holdninger, og som forekommer almengyldigt p{\r a} tv{\ae}rs af dyrkningsretning, det faktuelt faglige. Herved l{\o}srives fagligheden og r{\r a}dgivning fra det {\o}kologiske jordbrugs egenlogik. Hvorvidt dette er til gavn for den {\o}kologiske landmand og det {\o}kologiske jordbrug er tvivlsomt, men i hvor h{\o}j grad det er en ulempe m{\r a} v{\ae}re op til diskussion. Reference Rasmussen, J \& Kaltoft, P (2002) Quantitative assessment of alternative versus conventional attitudes in higher agricultural education. Biological Agriculture \& Horticulture (accepted) }, url = {https://orgprints.org/id/eprint/450/} } @misc{orgprints4031, title = {Tolerance of competitive spring barley cultivars to weed harrowing}, journal = {Weed Research}, pages = {446--452}, author = {Jesper Rasmussen and J.I. Kurtzmann and A. Jensen}, volume = {44}, year = {2004}, url = {https://orgprints.org/id/eprint/4031/}, abstract = {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}, keywords = {weed control, crop damage, competition, selectivity} } @misc{orgprints17313, title = {{\O}kodebatten: En cocktail af viden og holdninger}, publisher = {www.videnskab.dk}, month = {July}, year = {2010}, author = {Jesper Rasmussen and Vibeke Langer}, keywords = {holdninger}, abstract = {Lad os skille viden og holdninger og f{\r a} en sober debat om det {\o}kologiske jordbrugs muligheder og begr{\ae}nsninger. S{\r a}dan l{\o}d det, da {\o}kobloggen s{\r a} dagens lys for et {\r a}rs tid siden. Lykkedes det s{\r a}? Dette sp{\o}rgsm{\r a}l diskuteres i blogindl{\ae}gget.}, url = {https://orgprints.org/id/eprint/17313/} } @misc{orgprints3087, journal = {Agriculture and Human Values}, title = {Bias in peer review of organic farming grant applications}, number = {2}, author = {Jesper Rasmussen and Vibeke Langer and Hugo Fjelsted Alr{\o}e}, pages = {181--188}, volume = {23}, year = {2006}, abstract = {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.}, url = {https://orgprints.org/id/eprint/3087/}, keywords = {vaues reflexive objectivity constitutive values funding quality subjectivity } } @misc{orgprints17844, author = {Jesper Rasmussen and Helle Mathiasen and Bo Martin Bibby}, pages = {436--446}, volume = {50}, year = {2010}, title = {Timing of post-emergence weed harrowing}, journal = {Weed Research}, url = {https://orgprints.org/id/eprint/17844/}, abstract = {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. } } @misc{orgprints15781, title = {Tolerance and selectivity of cereal species and cultivars to postemergence weed harrowing}, journal = {Weed Science}, year = {2009}, volume = {57}, pages = {338--345}, author = {Jesper Rasmussen and Helle H. Nielsen and Hanne Gundersen}, keywords = {mechanical weed control, statistics, models digital image analysis,}, url = {https://orgprints.org/id/eprint/15781/}, abstract = {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 {\ensuremath{>}} wheat {\ensuremath{>}} barley {\ensuremath{>}} 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.} } @misc{orgprints15707, number = {1}, publisher = {Sveriges lantbruksuniversitet (SLU)}, title = {P{\r a} vej mod den intelligente ukrudtsharve}, journal = {Forskningsnytt om {\o}kologisk landbruk i Norden}, pages = {26--28}, author = {Jesper Rasmussen and Michael N{\o}rremark}, year = {2009}, url = {https://orgprints.org/id/eprint/15707/}, abstract = {En ukrudtsharve, der automatisk indstiller sig efter bek{\ae}mpelsesbehovet, er ikke l{\ae}ngere en urealistisk fremtidsdr{\o}m. Teknikken eksisterer, og om ganske f{\r a} {\r a}r vil vi se den brugt i forbindelse med markspr{\o}jter. I de senere {\r a}r har vi arbejdet p{\r a} at udvikle de beslutningsst{\o}ttemodeller, som den automatiske harve skal bruge, og vi har udviklet et billedbehandlingsprogram, som bruges til at bestemme harvningens umiddelbare effekt p{\r a} afgr{\o}den. Programmet har flere anvendelsesmuligheder og kan bruges af alle.} } @misc{orgprints10694, month = {March}, title = {Forskning i ukrudtsharvning f{\r a}r nyt liv med digital billedbehandling }, journal = {F{\O}JOenyt}, author = {Jesper Rasmussen and Michael N{\o}rremark}, year = {2007}, abstract = {Digital billedbehandling udfylder et metodem{\ae}ssigt tomrum i forhold til ukrudtsharvning. Med udvikling af en ny billedbehandlingsprocedure er det ikke l{\ae}ngere n{\o}dvendigt at anvende visuelle bed{\o}mmelser af afgr{\o}detild{\ae}kningen ved ukrudtsharvning. Artiklen giver eksempler p{\r a} hvordan digital billedbehandling kan anvnedes. }, url = {https://orgprints.org/id/eprint/10694/} } @inproceedings{orgprints10758, author = {Jesper Rasmussen and Michael N{\o}rremark}, pages = {123--129}, year = {2007}, journal = {Proceedings 7th EWRS Workshop on Physical and Cultural Weed Control}, title = {Digital images for assessing soil cover of crop plants}, keywords = {weed harrowing, ukrudtsharvning, strigling, }, abstract = {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. }, url = {https://orgprints.org/id/eprint/10758/} } @inproceedings{orgprints10759, author = {Jesper Rasmussen and Michael N{\o}rremark}, year = {2007}, title = {Digital images for assessing soil cover of crop plants}, abstract = {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. }, url = {https://orgprints.org/id/eprint/10759/} } @misc{orgprints10474, number = {4}, title = {Digital image analysis offers new possibilities in weed harrowing research}, journal = {Zemdirbyste/Agriculture}, pages = {155--165}, author = {Jesper Rasmussen and Michael N{\o}rremark}, year = {2006}, volume = {93}, abstract = {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.}, url = {https://orgprints.org/id/eprint/10474/}, keywords = {Mechanical weed control} } @inproceedings{orgprints13688, title = {New Technologies Call for New Research Priorities in Physical Weed Control with Low Selectivity}, author = {Jesper Rasmussen and Michael N{\o}rremark and Bo Martin Bibby}, year = {2008}, abstract = {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.}, url = {https://orgprints.org/id/eprint/13688/} } @misc{orgprints11007, author = {Jesper Rasmussen and Michael N{\o}rremark and Bo Martin Bibby}, pages = {299--310}, volume = {47}, year = {2007}, title = {Assessment of leaf cover and crop soil cover in weed harrowing research using digital images}, journal = {Weed Research}, url = {https://orgprints.org/id/eprint/11007/}, abstract = {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.} } @inproceedings{orgprints52964, author = {Jim Rasmussen}, year = {2024}, month = {January}, title = {Effekten af samdyrkning p{\r a} korn-b{\ae}lgs{\ae}d og efterafgr{\o}de blandinger}, url = {https://orgprints.org/id/eprint/52964/}, abstract = {Pr{\ae}sentation af resultater omkring hvordan samdyrkning kan bidrage til effekter i dyrkningssystemet} } @inproceedings{orgprints52965, author = {Jim Rasmussen}, year = {2024}, title = {Hvordan p{\r a}virker efterafgr{\o}der med b{\ae}lgplanter kv{\ae}lstof- og kulstofdynamikkerne?}, abstract = {Pr{\ae}sentation af efterafgr{\o}ders effekt p{\r a} C og N dynamik i plante-jord systemet}, url = {https://orgprints.org/id/eprint/52965/} } @inproceedings{orgprints53019, year = {2023}, author = {Jim Rasmussen}, title = {Danske b{\ae}lgfrugter - skal spises b{\r a}de gr{\o}nne og modne}, month = {November}, url = {https://orgprints.org/id/eprint/53019/}, abstract = {Presentation on the potentials to expand grain legume use into fresh products for human consumption} } @inproceedings{orgprints53018, title = {B{\ae}lgfrugter og samdyrkning}, month = {October}, year = {2023}, author = {Jim Rasmussen}, url = {https://orgprints.org/id/eprint/53018/}, abstract = {Opl{\ae}g omkring b{\ae}lgfrugter til human konsum og effekter af samdyrkning} } @unpublished{orgprints52962, title = {Kulstofopbygning og efterafgr{\o}der}, month = {October}, year = {2023}, author = {Jim Rasmussen}, keywords = {soil organic matter; cover crops; mixtures}, abstract = {Pr{\ae}sentation om potentiale i opbygning af kulstof via efterafgr{\o}der}, url = {https://orgprints.org/id/eprint/52962/} } @inproceedings{orgprints52987, year = {2023}, author = {Jim Rasmussen}, title = {Temadag om Gr{\o}nne proteiner - inspiration til landbrugsskolel{\ae}rere}, month = {May}, url = {https://orgprints.org/id/eprint/52987/}, abstract = {Temadag om gr{\o}nne proteiner med fokus p{\r a} b{\ae}lgfrugter (Jim) og gr{\o}n biorafinering (Lene St{\o}dkilde)} } @misc{orgprints45121, title = {GrainLegsGo: Friske b{\ae}lgfrugter til human konsum}, author = {Jim Rasmussen}, year = {2021}, abstract = {Baggrund: En mere b{\ae}redygtig og gr{\o}nnere europ{\ae}isk landbrugssektor kr{\ae}ver {\ae}ndringer i vores kost fra k{\o}d til planteproteinkilder. En st{\o}rre produktion af b{\ae}lgfrugter kan forbedre dyrkningssystemerne gennem {\o}get jordfrugtbarhed, diversificerede afgr{\o}der og reducerede klima- og milj{\o}p{\r a}virkninger. Alligevel er det danske {\o}kologiske areal, som er dyrket med b{\ae}lgplanter, meget lavt, og kun en lille del heraf er til konsum for mennesker. Form{\r a}l: GrainLegsGo vil {\o}ge dyrkningen af friske b{\ae}lgfrugter til human konsum, samtidig med at det giver milj{\o}- og klimafordele og fremmer cirkul{\ae}r bio{\o}konomi. Projektet bringer n{\o}gleinteressenter sammen, {\o}ger forbrugernes bevidsthed og fremmer dyrkningen af nye og traditionelle b{\ae}lgfrugter til frisk h{\o}st. Ved at optimere dyrkningen af b{\ae}lgplanter {\o}ger GrainLegsGo effektiviteten og produktiviteten i {\o}kologiske dyrkningssystemer, ogs{\r a} takket v{\ae}re mere produktive efterafgr{\o}der og f{\ae}rre tilf{\ae}lde af skadedyr og sygdomme.}, url = {https://orgprints.org/id/eprint/45121/} } @unpublished{orgprints39913, publisher = {Internal report}, title = {Lessons learned from 23 years of cover cropping}, author = {Jim Rasmussen}, pages = {1--7}, address = {Viborg}, year = {2021}, url = {https://orgprints.org/id/eprint/39913/}, abstract = {A summary of mainly learnings from the CropSys long-term experiment on cover crop services.} } @misc{orgprints39670, month = {November}, journal = {{\O}kologisk Landbrug}, title = {B{\ae}lgplanters mange bidrag til klimakampen}, pages = {10--10}, author = {Jim Rasmussen}, year = {2020}, volume = {659}, abstract = {Unders{\o}gelser peger p{\r a}, at efterafgr{\o}deblandinger med b{\ae}lgplanter {\o}ger kv{\ae}lstof- og kulstoftilf{\o}rslen til gavn for b{\r a}de jordfrugtbarheden og klimaet.}, url = {https://orgprints.org/id/eprint/39670/} } @phdthesis{orgprints10663, title = {Below ground C and N transformation processes in perennial grass-clover mixtures}, month = {January}, year = {2007}, school = {Faculty of Life Sciences, University of Copenhagen}, author = {Jim Rasmussen}, abstract = {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 ({\ensuremath{<}} 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 {$\pm$}3.1, n=9) of N in ryegrass, whereas the fraction of N in clover donated by ryegrass was 5\% ({$\pm$}1.2, n=9). The amount of 14C transferred from ryegrass to clover was 1.7\% ({$\pm$}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\% ({$\pm$} 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. }, url = {https://orgprints.org/id/eprint/10663/} } @misc{orgprints10390, title = {In situ carbon and nitrogen dynamics in ryegrass-clover mixtures: Transfers, deposition and leaching}, journal = {Soil Biology \& Biochemistry}, author = {Jim Rasmussen and J{\o}rgen Eriksen and Erik Steen Jensen and Kim H. Esbensen and Henning H{\o}gh-Jensen}, pages = {804--815}, year = {2007}, volume = {39}, url = {https://orgprints.org/id/eprint/10390/}, abstract = {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\% ({$\pm$}3.1, n=9) of N in ryegrass, whereas the fraction of N in clover donated by ryegrass was 5\% ({$\pm$}1.2, n=9). The amount of 14C transferred from ryegrass to clover was 1.7\% ({$\pm$}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\% ({$\pm$} 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.}, keywords = {carbon(14), nitrogen(15), suction cup, DOC, DIN, DON} } @inproceedings{orgprints9128, title = {DOC and DON from grass-clover - results from a field experiment}, author = {Jim Rasmussen and Henning H{\o}gh-Jensen}, year = {2005}, url = {https://orgprints.org/id/eprint/9128/}, abstract = {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. } } @unpublished{orgprints3542, year = {2004}, author = {Jim Rasmussen and Henning H{\o}gh-Jensen}, title = {Origin and composition of Dissolved Organic C and N from grass-clover mixtures }, keywords = {Organic carbon, organic nitrogen, suction cup, grass, clover}, abstract = {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. }, url = {https://orgprints.org/id/eprint/3542/} } @misc{orgprints19451, year = {2012}, title = {N2-fixation and residual N effect of four legume species and four companion grass species}, journal = {European Journal of Agronomy}, number = {1}, author = {Jim Rasmussen and Karen S{\o}egaard and Karin Pirhofer-Walzl and J{\o}rgen Eriksen}, pages = {66--74}, volume = {1}, doi = {doi.org/10.1016/j.eja.2011.09.003}, keywords = {N2-fixation, N transfer, residual N effect, companion species, forage legume}, url = {https://orgprints.org/id/eprint/19451/}, abstract = {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.} } @misc{orgprints20635, journal = {European Journal of Agronomy}, title = {N2-fixation and residual effect of four legume species and four companion grass species}, pages = {66--74}, author = {J. Rasmussen and K. S{\o}egaard and J. Eriksen}, year = {2012}, volume = {36}, url = {https://orgprints.org/id/eprint/20635/}, abstract = {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.} } @inproceedings{orgprints18219, title = {Erfaringer med nye teknologier i r{\ae}kkeafgr{\o}der}, author = {Jesper Rasmussen}, pages = {175--177}, year = {2011}, keywords = {Intra-row weeds, robotic, machine vision, Robocrop, Robovator, cycloid hoe}, abstract = {Ukrudt inde i r{\ae}kkerne i udplantede gr{\o}nsagskulturer kan nu bek{\ae}mpe med automatiserede mekaniske rensere. I uds{\r a}ede kulturer er det vanskeligere.}, url = {https://orgprints.org/id/eprint/18219/} } @misc{orgprints21136, volume = {52}, year = {2012}, author = {Jesper Rasmussen and Hans W. Griepentrog and J. Nielsen and Christian Bugge Henriksen}, pages = { 327-- 337}, journal = {Weed Research}, title = {Automated intelligent rotor tine cultivation and punch planting to improve the selectivity of mechanical intra-row weed control}, abstract = {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. }, url = {https://orgprints.org/id/eprint/21136/} } @misc{orgprints19315, author = {Jesper Rasmussen and Anders Harbo La-Cour}, pages = {20--20}, volume = {31}, month = {August}, journal = {{\O}kologi \& Erhverv}, title = {Ukrudt i fugleperspektiv}, number = {462}, year = {2011}, url = {https://orgprints.org/id/eprint/19315/}, abstract = {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.} } @inproceedings{orgprints18777, title = {Less intra-row weeds ? experiences with a punch planter and a cycloid hoe based on GPS}, publisher = {EWRS}, month = {May}, year = {2011}, author = {Jesper Rasmussen and Christian Bugge Henriksen and Hans W. Griepentrog}, pages = {11}, keywords = {mechanical weed control}, url = {https://orgprints.org/id/eprint/18777/}, abstract = {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.} } @misc{orgprints20109, author = {Jesper Rasmussen and Christian Bugge Henriksen and Hans W. Griepentrog and Jon Nielsen}, pages = {489--498}, year = {2011}, volume = {51}, journal = {Weed Research}, title = {Punch planting, flame weeding and delayed sowing to reduce intra-row weeds in row crops}, url = {https://orgprints.org/id/eprint/20109/}, abstract = {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. } } @misc{orgprints17843, editor = {E-C Oerke and R Gerhards and G Menz and RA Sikora}, author = {Victor Rueda-Ayala and Jesper Rasmussen and Roland Gerhards}, pages = {279--294}, address = {London}, year = {2010}, publisher = {Springer}, title = {Mechanical weed control}, journal = {Precision Crop Protection ? the Challenge and Use of Heterogeneity}, abstract = {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. }, url = {https://orgprints.org/id/eprint/17843/} } @misc{orgprints20110, journal = {Weed Research}, title = {The influence of post-emergence weed harrowing on selectivity, crop recovery and crop yield in different growth stages of winter wheat}, volume = {51}, year = {2011}, author = {Victor Rueda?Ayala and Jesper Rasmussen and Roland Gerhards and N.A. Fournaise }, pages = {478--488}, url = {https://orgprints.org/id/eprint/20110/}, abstract = {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. } } @misc{orgprints728, number = {1-2}, journal = {Soil and Tillage Research}, title = {Soil strength and soil pore characteristics for direct-drilled and ploughed soils}, publisher = {Elsevier}, year = {2000}, volume = {57}, pages = {69--82}, author = {P. Schj{\o}nning and K.J. Rasmussen}, url = {https://orgprints.org/id/eprint/728/}, abstract = {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 (H{\o}jer, 19\% clay). The crop rotation at Korntved was spring barley and winter rye while at Ballum and H{\o}jer 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 H{\o}jer 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 H{\o}jer 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{\ensuremath{>}}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. }, keywords = {Direct drilling; Ploughing; Soil strength; Soil pore characteristics; Pore continuity; Plough pan } } @misc{orgprints188, series = {DJF Rapport, Markbrug}, month = {November}, title = {Jordbearbejdning i {\o}kologisk jordbrug ? pl{\o}jedybde og ikke-vendende jordl{\o}sning [Soil tillage in organic farming ? ploughing depth and non-inversion deep tillage]}, author = {Per Schj{\o}nning and Karl J. Rasmussen and Lars J. Munkholm and Peter S. Nielsen}, year = {2002}, abstract = {I perioden 1996 til 2000 gennemf{\o}rtes et markfors{\o}g med forskellige jordbearbejdnings-systemer p{\r a} Den {\o}kologiske Fors{\o}gsstation Rugballegaard. Fors{\o}gsarealet blev omlagt til {\o}kologisk drift i forbindelse med projektets start i 1996. Unders{\o}gelserne gennemf{\o}rtes i et fem-marks skifte, der ligeledes blev k{\o}rt ind i forbindelse med projektet. Det drejer sig om et s{\r a}kaldt blandet s{\ae}dskifte med byg/{\ae}rt m. udl{\ae}g, 1. {\r a}rs kl{\o}vergr{\ae}s, 2. {\r a}rs kl{\o}vergr{\ae}s, havre og vinterhvede. Fors{\o}get blev anlagt i fem marker (B1-B5), hvilket indeb{\ae}rer, at alle skiftets afgr{\o}der blev dyrket hvert {\r a}r. Fire forskellige jordbearbejdningssystemer blev unders{\o}gt i et randomiseret blokfors{\o}g med 4 blokke. De fire behandlinger omfattede to systemer med pl{\o}jning, nemlig led A med 20 cm pl{\o}jedybde og led B med 10-12 cm pl{\o}jedybde; hertil kom to systemer (C og D) med ikke-vendende l{\o}sning af jorden til 35-40 cm dybde. Til dette form{\r a}l blev opbygget et specielt ud-styr i forbindelse med projektet. Der blev dog anvendt kommercielt tilg{\ae}ngelige g{\r a}sefod-st{\ae}nder fra det tyske firma Dutzi. Disse blev monteret p{\r a} en sv{\ae}r bulle, der ogs{\r a} gav mulig-hed for oph{\ae}ngning af en Howard tandfr{\ae}ser. P{\r a} denne var der monteret l{\o}ftehitch, hvori en konventionel Nordsten sl{\ae}besk{\ae}r-s{\r a}maskine kunne monteres. Fors{\o}gsled C (?fuld? Dutzi) omfattede en bearbejdning med hele denne ?ekvipage? i {\'e}n arbejdsgang, mens der i led D (?delt? Dutzi) blev gennemf{\o}rt en separat bearbejdning med Dutzi-t{\ae}nderne efterfulgt af s{\r a}-ning med tandfr{\ae}ser og s{\r a}maskine. Oml{\ae}gning af gr{\ae}smarken skete for alle systemer med traditionel pl{\o}jning til 20 cm dybde. Anvendelsen af Dutzi-udstyret kr{\ae}vede meget stor tr{\ae}kkraft og der var ikke n{\ae}vnev{\ae}rdig mindskelse af dette ved at anvende l{\o}snet{\ae}nderne separat. Jordl{\o}sningen var i b{\r a}de 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 p{\r a} arealet generelt fandtes en kompakt pl{\o}je-s{\r a}l. Effekten p{\r a} den mekaniske modstand i jorden viste sig at vedvare i minimum 2 {\r a}r. Den {\ae}ndrede jordfysiske tilstand gav forbedrede betingelser for bl.a. rodv{\ae}kst og knoldbakterier (Rhizobium). De unders{\o}gte bearbejdningsmetoder gav ikke entydige {\ae}ndringer i ukrudtstrykket. Generelt (for alle bearbejdninger) var der problemer med at styre ukrudtet i vinterhveden. En tendens til for{\o}get ukrudtstryk i udl{\ae}gsmarken efter Dutzi-behandling i forhold til pl{\o}jning gav ikke {\o}gede problemer, idet forskellen udlignede sig ved h{\o}st af d{\ae}ks{\ae}den som hels{\ae}d. Der var heller ikke entydige tendenser i bearbejdningernes indflydelse p{\r a} udbyttet af afgr{\o}derne. Der var en tendens til, at Dutzi-l{\o}sning gav et lidt h{\o}jere r{\r a}protein-indhold i hels{\ae}ds- og kl{\o}ver-gr{\ae}sudbyttet end pl{\o}jning. B{\r a}de Dutzi-bearbejdningen og den overfladiske pl{\o}jning m{\r a} betragtes som realistiske mulig-heder i et {\o}kologisk s{\ae}dskifte som det unders{\o}gte. En sikker konklusion om systemernes suc-ces vil kr{\ae}ve unders{\o}gelser gennem mere end en rotation. Desuden kan resultaterne t{\ae}nkes at v{\ae}re anderledes i andre s{\ae}dskifter. Ploven vil fortsat v{\ae}re n{\o}dvendig i mange {\o}kologiske jordbrug p.g.a. behovet for at nedmulde fler{\r a}rige afgr{\o}der og halm-rig staldg{\o}dning mm. I stedet for fuld overgang til ikke-vendende jordl{\o}sning, forekommer det realistisk at reducere pl{\o}jedybden til det mindst mulige og fore-tage en evt. p{\r a}kr{\ae}vet mekanisk l{\o}sning af dybere jordlag med maskinel, der bryder jorden op til den {\o}nskede dybde uden at vende den. Her er Dutzi-t{\ae}nderne (separat eller i forbindelse med et kombis{\ae}t) {\'e}n af flere muligheder. Der b{\o}r gennemf{\o}res fors{\o}gsserier p{\r a} forskellige jordtyper, hvor forskellige systemer testes med henblik p{\r a} optimering af jordstruktur og biodiversitet i jorden, udbyttets st{\o}rrelse og kvalitet, ukrudtsbek{\ae}mpelse samt med henblik p{\r a} minimering af arbejdstid og forbrug af fos-silt br{\ae}ndstof. S{\r a}danne unders{\o}gelser b{\o}r d{\ae}kke de vigtigste kombinationer af jordtype, s{\ae}d-skifte og g{\o}dskningsstrategi mm. og gennemf{\o}res i s{\r a} langt et tidsrum, at det er muligt at vur-dere de n{\ae}vnte succeskriterier efter en n{\o}dvendig overgangsfase. }, url = {https://orgprints.org/id/eprint/188/} } @inproceedings{orgprints17832, year = {2010}, editor = {J. Rasmussen and M. Schacht and A. Helgadottir}, pages = {141--144}, author = {K. S{\o}egaard and J. Sehested and S.K. Jensen}, title = {Vitamin and mineral content and feeding value of different legumes and grass species grown in seven legume-grass mixtures}, journal = {The potential of forage legumes to sustain a high agricultural productivity - a Nordic perspective}, month = {October}, url = {https://orgprints.org/id/eprint/17832/}, abstract = {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. }, keywords = {Grassland species, mineral, vitamin, feeding value} } @inproceedings{orgprints20621, month = {February}, title = {Dyrkning af kl{\o}vergr{\ae}s}, pages = {79--87}, author = {K. S{\o}egaard and J. Rasmussen and J. Sehested and S.K. Jensen and J Eriksen}, year = {2011}, url = {https://orgprints.org/id/eprint/20621/}, abstract = {Vitaminer, mineraler og foderv{\ae}rdi i forskellige gr{\ae}smarksarter samt b{\ae}lgplanternes N-dynamik samt kl{\o}vertr{\ae}thed} } @misc{orgprints39300, year = {2020}, author = {Peter S{\o}rensen and Chiara De Notaris and E.M. Hansen and Ingrid Kaag Thomsen and Jim Rasmussen}, pages = {1--14}, title = {Fler{\r a}rigt s{\ae}dskifte med t{\ae}tning som alternativ til pligtige efterafgr{\o}der}, month = {July}, url = {https://orgprints.org/id/eprint/39300/}, abstract = {Dette er en rapport om anvendelsen af N-fikserende efterafgr{\o}der som pligtige efterafgr{\o}der, skrevet p{\r a} foranledning af en bestilling fra Landbrugsstyrelsen. Det vurderes, at der gennemsnitligt set ikke er risiko for {\o}get kv{\ae}lstofudvaskning (p{\r a} kort og l{\ae}ngere sigt) ved anvendelse kv{\ae}lstoffikserende efterafgr{\o}der i artsblanding med ikke-fikserende arter i forhold til anvendelse af ikke-fikserende efterafgr{\o}der. Dette er under foruds{\ae}tning af, at der indregnes en g{\o}dningsm{\ae}ssig eftervirkning p{\r a} ca. 50 kg N/ha b{\r a}de p{\r a} bedrifter under og over 80 kg N/ha i husdyrg{\o}dning.} } @inproceedings{orgprints2445, title = {Guidelines for physical weed control research: flame weeding, weed harrowing and intra-row cultivation }, journal = {Proceedings 6th EWRS Workshop on Physical and Cultural Weed Control, 194-225}, author = {P. Vanhala and D. Kurstjens and J. Ascard and A. Bertram and D.C. Cloutier and A. Mead and M. Raffaelli and Jesper Rasmussen}, pages = {194--225}, year = {2004}, keywords = {weed harrowing, flame weeding, statistical methods, experimental designs}, abstract = {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. }, url = {https://orgprints.org/id/eprint/2445/} }