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Bo Melander - One of the best experts on this subject based on the ideXlab platform.

  • influence of mechanical weeding and fertilisation on Perennial Weeds fungal diseases soil structure and crop yield in organic spring cereals
    Acta Agriculturae Scandinavica Section B-soil and Plant Science, 2020
    Co-Authors: Lars Olav Brandsaeter, Kjell Mangerud, Lars Andersson, Trond Borresen, Guro Brodal, Bo Melander
    Abstract:

    There is a need both in organic farming and on farms using integrated pest management for non-chemical measures that control the Perennial weed flora. The effect of mechanical weeding and fertilisa...

  • Influence of mechanical weeding and fertilisation on Perennial Weeds, fungal diseases, soil structure and crop yield in organic spring cereals
    2020
    Co-Authors: Brandsæter, Lars Olav, Mangerud Kjell, Andersson Lars, Børresen Trond, Brodal Guro, Bo Melander
    Abstract:

    There is a need both in organic farming and on farms using integrated pest management for non-chemical measures that control the Perennial weed flora. The effect of mechanical weeding and fertilisation on Perennial Weeds, fungal diseases and soil structure were evaluated in two different experiments in spring cereals. Experiment I included six strategies. The first strategy was (1) without specific measures against Perennial Weeds. The other strategies encompassed one or two seasonal control measures; (2) rhizome/root cutting with minimal soil disturbance in autumn, (3) hoeing with 24 cm row spacing, (4) combined hoeing and disc harrowing in autumn, (5) ‘KvikUp’ harrowing in spring, and (6) ‘KvikUp’ harrowing in spring and autumn. Experiment II included factor (i) inter-row hoeing and (ii) fertilisation level. This experiment included the comparison between normal row spacing (12 cm) with weed harrowing versus double row spacing (=24 cm) in combination with inter-row hoeing and 4 fertilisation levels (50–200 kg N ha−1). In experiment I the strategies consisting of no or one direct weed control measure (1, 2, 3 and 5) clearly did not control the Perennial Weeds. The two seasonal control measures (4 and 6) gave a satisfactory weed control and highest crop yield. The combination of best weed control and no measured harmful effects on soil structure or increase of fungal diseases may explain the highest yields for these strategies. In Experiment II, hoeing and 24 cm spacing gave less Perennial biomass compared to 12 cm spacing. Grain yields increased linearly with increasing nitrogen input. The study shows that both inter-row hoeing and weed harrows, are important elements in integrated pest management practice and organic farming. In addition, our results indicate that efficient mechanical weeding is possible without harmful effects in crop rotation consisting of various spring cereals as regards soil structure and plant health

  • incompatibility between fertility building measures and the management of Perennial Weeds in organic cropping systems
    Agriculture Ecosystems & Environment, 2016
    Co-Authors: Bo Melander, Ilse A Rasmussen, Jorgen E Olesen
    Abstract:

    Abstract Fertility building measures are important components in improving the productivity of organic cropping systems without livestock. However, some measures seem to be incompatible with the control of Perennial Weeds that can have adverse effects such as significant weed competition. The influence of fertility building measures (N 2 -fixing crops in the crop sequence, cover crops and manuring) and the abundance of Perennial Weeds were studied in a long-term crop rotation experiment at two locations in Denmark. The aim was to gain insight into the factors that influence the growth of Perennial weed species occurring in mixed stands. Data were obtained from three cycles of four-year arable crop rotations comprising various cash crops in rotations with and without annual whole-year grass-clover as green manure and subjected to four treatment combinations: with and without animal manure and with and without cover crops. Severe outbreaks of Perennial weed problems did not occur at the location that had the highest soil fertility, whereas the other site demonstrated dynamic growth of Cirsium arvense and Elytrigia repens . Grain legumes tended to promote the growth of C. arvense , while manuring was neutral to C. arvense but beneficial to E. repens . Cover crops assisted the growth of E. repens since prolonged mechanical interventions were not possible. Compatibility was only achieved with grass-clover and C. arvense , meaning that green manure crops suitable for cutting and mulching could offer an important management option against C. arvense but not against E. repens .

  • Incompatibility between fertility building measures and the management of Perennial Weeds in organic cropping systems
    2016
    Co-Authors: Bo Melander, Rasmussen, Ilse A., Olesen, Jørgen E.
    Abstract:

    Fertility building measures are important components in improving the productivity of organic cropping systems without livestock. However, some measures seem to be incompatible with the control of Perennial Weeds that can have adverse effects such as significant weed competition. The influence of fertility building measures (N2-fixing crops in the crop sequence, cover crops and manuring) and the abundance of Perennial Weeds were studied in a long-term crop rotation experiment at two locations in Denmark. The aim was to gain insight into the factors that influence the growth of Perennial weed species occurring in mixed stands. Data were obtained from three cycles of four-year arable crop rotations comprising various cash crops in rotations with and without annual whole-year grass-clover as green manure and subjected to four treatment combinations: with and without animal manure and with and without cover crops. Severe outbreaks of Perennial weed problems did not occur at the location that had the highest soil fertility, whereas the other site demonstrated dynamic growth of Cirsium arvense and Elytrigia repens. Grain legumes tended to promote the growth of C. arvense, while manuring was neutral to C. arvense but beneficial to E. repens. Cover crops assisted the growth of E. repens since prolonged mechanical interventions were not possible. Compatibility was only achieved with grass-clover and C. arvense, meaning that green manure crops suitable for cutting and mulching could offer an important management option against C. arvense but not against E. repens

  • direct control of Perennial Weeds between crops implications for organic farming
    Crop Protection, 2012
    Co-Authors: Bo Melander, Niels Holst, Ilse A Rasmussen, Preben Klarskov Hansen
    Abstract:

    Perennial Weeds can be a major constraint to organic crop production and direct control actions applied between crops can then be necessary to reduce the problems. We conducted two experiments, one on a sandy loam and one on a sandy soil in Denmark, with the aim of studying the efficacy of different implement types and strategies. The treatments were employed against mixed stands of Perennials after harvest of spring barley in two consecutive years. Time of treatment, cultivation depth and combinations of implements constituted the strategies. Treatment effects were evaluated in the growing season that followed the post-harvest treatments. In the one experiment, repeated tine cultivation caused an 80–90% annual reduction of the population of mainly Cirsium arvense. With treatments conducted in two consecutive years, the accumulated effects reached 99% control. In the second experiment, power take-off driven implements with rotating weeding devices demonstrated similar control efficacies against a mixed stand composing C. arvense, Tussilago farfara, Elytrigia repens and Artemisia vulgaris. One pass was conducted a week after barley harvest followed by another pass 3 weeks later and ending the strategy with mouldboard ploughing in the succeeding spring. Grain yields did not differ among the treatments in the two experiments as a result of the generally high effectiveness exerted by the control strategies. Especially post-harvest control strategies based on rotating weed devices and mouldboard ploughing appear to be effective solutions against mixed stands of Perennials on sandy soils but they do not comply with optimal nutrient management in organic cropping. Therefore, intensive autumn cultivation is only relevant where a Perennial weed problem is uncontrollable by other means.

Lars Olav Brandsaeter - One of the best experts on this subject based on the ideXlab platform.

  • influence of mechanical weeding and fertilisation on Perennial Weeds fungal diseases soil structure and crop yield in organic spring cereals
    Acta Agriculturae Scandinavica Section B-soil and Plant Science, 2020
    Co-Authors: Lars Olav Brandsaeter, Kjell Mangerud, Lars Andersson, Trond Borresen, Guro Brodal, Bo Melander
    Abstract:

    There is a need both in organic farming and on farms using integrated pest management for non-chemical measures that control the Perennial weed flora. The effect of mechanical weeding and fertilisa...

  • control of Perennial Weeds in spring cereals through stubble cultivation and mouldboard ploughing during autumn or spring
    Crop Protection, 2017
    Co-Authors: Lars Olav Brandsaeter, Kjell Mangerud, Marit Helgheim, Therese W Berge
    Abstract:

    Abstract Creeping Perennial Weeds are of major concern in organically grown cereals. In the present study, the effects of different timing of mouldboard ploughing with or without a preceding stubble cultivation period, on Weeds and spring cereals were studied. The experiments were conducted at two sites in Norway during a two and three-year period, respectively, with the treatments repeated on the same plots. The soil cultivation treatments were a stubble disc-harrowing cultivation period followed by mouldboard ploughing and only mouldboard ploughing. The timing of the treatments were autumn or spring. The density and biomass of the aboveground shoots of Cirsium arvense (L.) Scop., Elymus repens (L.) Gould, Sonchus arvensis L. and Stachys palustris L. as well as the total aboveground biomass of the spring cereal crop (oats) were assessed. The control efficiency of C. arvense and S. arvensis was closely related to timing of the cultivation treatments. Cultivation in spring decreased the population of C. arvense and S. arvensis compared to autumn cultivation. For E. repens, timing of the treatments had no significant effect: the important factor was whether stubble cultivation was carried out (best control) or not. The overall best strategy for controlling the present Perennial weed population was stubble cultivation followed by ploughing in spring. However, the associated relative late sowing of the spring cereal crop and lowered crop biomass, were important drawbacks.

  • method timing and duration of bare fallow for the control of cirsium arvense and other creeping Perennials
    Crop Protection, 2015
    Co-Authors: Mette Goul Thomsen, Kjell Mangerud, Hugh Riley, Lars Olav Brandsaeter
    Abstract:

    Abstract The control of Perennial Weeds is of great concern in organic farming. Mouldboard ploughing and other soil tillage operations are the main methods for combating Weeds, often combined with competition from a green manure cover crop. Inclusion of a period with bare fallow may at times become necessary. Repeated soil tillage may however cause erosion and loss of nutrients, more so with autumn tillage than with spring tillage. The timing and effectiveness of the operations are therefore important. The aim of the present work has been to evaluate if autumn ploughing contributes to increased weed reduction if spring fallow is performed, how to combine stubble cultivation, fallow and establishment of a green manure cover-crop and to compare the two and the optimum duration of spring fallow compared to an established green manure cover-crop. The effectiveness of operations varied between weed species and was related to their biology. Overall, the Perennial species studied developed least total biomass in a mown, one-year green manure crop or after complete underground cutting by shallow ploughing after harvest or by deep ploughing in spring. The green manure cover-crop seemed to be established most successfully after stubble harrowing in autumn and spring or when undersown the previous year. Autumn ploughing had little impact on the biomass of Perennial Weeds when spring bare fallow treatments were performed or when a green manure cover-crop was established in spring. Only a high number of harrowings competed well with the undersowing of a green manure cover-crop for the regulation of the individual species, except in the case Elymus repens . The number of fallow operations may be kept to a minimum when followed by a green manure cover-crop, or when such a crop is undersown the previous year. If fallowing in spring is performed, we found no benefit from increasing the number of fallow operations from three to four harrowings. Shallow ploughing after harvest followed by tine harrowing in autumn reduced total Perennial weed biomass to the same extent as two or three harrowings in spring without subsequent ploughing, or two harrowings in spring followed by ploughing. We found in general an increase in cereal yield with the inclusion of a green manure cover crop, preferably undersown in the first experimental year. A prolonged period with fallow treatments had a negative effect on the cereal yield and the number of spring operations for optimization of cereal yield was lower than that required for optimum weed control. We need therefore to find a balance between these two factors.

  • control of Perennial Weeds based on weed biology and environmental considerations
    2013
    Co-Authors: Mette Goul Thomsen, Kjell Mangerud, Lars Olav Brandsaeter, Hugh Riley
    Abstract:

    Timing, type and duration of tillage operations and cropping practices are of importance for reducing the regeneration of Perennial Weeds and also for minimizing the environmental impacts of such operations. In the present work and with reference to previous publications we find that, based on the knowledge gained on growth patterns, sensitivity to competition, growth potential of roots and mechanical and management measures it is possible to coordinate control of Perennial Weeds with considerations of yield and reduced environmental impact.

  • effects of repeated clover undersowing in spring cereals and stubble treatments in autumn on elymus repens sonchus arvensis and cirsium arvense
    Crop Protection, 2012
    Co-Authors: Lars Olav Brandsaeter, Goul M Thomsen, K Waernhus
    Abstract:

    Cover crops are included in cropping systems in order to achieve various ecological benefits. In stockless organic cereal systems in Scandinavia, nitrogen is commonly supplied by undersowing a legume shortly after sowing. Retarding the growth of annual Weeds is considered an additional benefit of using cover crops. However, studies on the influence of undersown cover crops on the growth of Perennial Weeds are lacking. In this paper we present data from a four- year field experiment on the growth of Cirsium arvense (L.) Scop., Sonchus arvensis L. and Elymus repens (L.) Gould., in cereals with and without undersown red clover (Trifolium pratense L.), combined with contrasting stubble treatments after harvest. Clover did not significantly reduce the growth of any of the weed species. Regression analyses showed, however, that the growth of C. arvense and S. arvensis increased with increasing clover biomass at low densities of clover, whereas at higher densities it decreased with increasing biomass of clover. Amongst the stubble treatments, shallow ploughing followed by harrowing gave the best control of all weed species. The effect was most pronounced on E. repens, and least on S. arvensis, for which neither the number nor the weed biomass were significantly different from the untreated control. Rotary tilling gave a similar effect, but again less pronounced on S. arvensis. Mowing suppressed E. repens to some degree, tended to suppress S. arvensis (n.s.) but had no effect on C. arvense. The growth and survival of seed-propagated plants of the same species were studied in a one-year field experiment and in a greenhouse experiment, the latter only including the species S. arvensis and C. arvense. The use of a cover crop reduced the number of leaves per plant in S. arvensis both in the field and in the greenhouse. The same effect was found for C. arvense, but only in the greenhouse experiment. In the latter, above-ground biomass of the cover crop explained 67% of the variation in total biomass of S. arvensis and 47% of that for C. arvense. From a practical point of view, the study has shown that undersown red clover has only marginal effects on Perennial Weeds, in contrast to various stubble treatments which influence strongly on weed growth. In general, soil tillage suppresses Perennial Weeds best, but mowing may be a more environmentally friendly alternative for some weed species, such as. E. repens.

Ilse A Rasmussen - One of the best experts on this subject based on the ideXlab platform.

  • incompatibility between fertility building measures and the management of Perennial Weeds in organic cropping systems
    Agriculture Ecosystems & Environment, 2016
    Co-Authors: Bo Melander, Ilse A Rasmussen, Jorgen E Olesen
    Abstract:

    Abstract Fertility building measures are important components in improving the productivity of organic cropping systems without livestock. However, some measures seem to be incompatible with the control of Perennial Weeds that can have adverse effects such as significant weed competition. The influence of fertility building measures (N 2 -fixing crops in the crop sequence, cover crops and manuring) and the abundance of Perennial Weeds were studied in a long-term crop rotation experiment at two locations in Denmark. The aim was to gain insight into the factors that influence the growth of Perennial weed species occurring in mixed stands. Data were obtained from three cycles of four-year arable crop rotations comprising various cash crops in rotations with and without annual whole-year grass-clover as green manure and subjected to four treatment combinations: with and without animal manure and with and without cover crops. Severe outbreaks of Perennial weed problems did not occur at the location that had the highest soil fertility, whereas the other site demonstrated dynamic growth of Cirsium arvense and Elytrigia repens . Grain legumes tended to promote the growth of C. arvense , while manuring was neutral to C. arvense but beneficial to E. repens . Cover crops assisted the growth of E. repens since prolonged mechanical interventions were not possible. Compatibility was only achieved with grass-clover and C. arvense , meaning that green manure crops suitable for cutting and mulching could offer an important management option against C. arvense but not against E. repens .

  • A physiologically-based model of Cirsium arvense and Tussilago farfara growth and control
    2012
    Co-Authors: Niels Holst, Marleen Riemens, Ilse A Rasmussen
    Abstract:

    Perennial herbs can be difficult to manage because of their underground storage organs which live sheltered from observation and control. In this paper, we describe the development of a population dynamics model for two Perennial Weeds, Cirsium arvense and Tussilago farfara. The model is physiologically based and includes plant growth and development, and mowing as a control option. Model performance was compared with field data from monospecific stands of C. arvense in Denmark and Netherlands and of T. farfara in Denmark. Finally, optimal mowing strategies were explored with the model.

  • direct control of Perennial Weeds between crops implications for organic farming
    Crop Protection, 2012
    Co-Authors: Bo Melander, Niels Holst, Ilse A Rasmussen, Preben Klarskov Hansen
    Abstract:

    Perennial Weeds can be a major constraint to organic crop production and direct control actions applied between crops can then be necessary to reduce the problems. We conducted two experiments, one on a sandy loam and one on a sandy soil in Denmark, with the aim of studying the efficacy of different implement types and strategies. The treatments were employed against mixed stands of Perennials after harvest of spring barley in two consecutive years. Time of treatment, cultivation depth and combinations of implements constituted the strategies. Treatment effects were evaluated in the growing season that followed the post-harvest treatments. In the one experiment, repeated tine cultivation caused an 80–90% annual reduction of the population of mainly Cirsium arvense. With treatments conducted in two consecutive years, the accumulated effects reached 99% control. In the second experiment, power take-off driven implements with rotating weeding devices demonstrated similar control efficacies against a mixed stand composing C. arvense, Tussilago farfara, Elytrigia repens and Artemisia vulgaris. One pass was conducted a week after barley harvest followed by another pass 3 weeks later and ending the strategy with mouldboard ploughing in the succeeding spring. Grain yields did not differ among the treatments in the two experiments as a result of the generally high effectiveness exerted by the control strategies. Especially post-harvest control strategies based on rotating weed devices and mouldboard ploughing appear to be effective solutions against mixed stands of Perennials on sandy soils but they do not comply with optimal nutrient management in organic cropping. Therefore, intensive autumn cultivation is only relevant where a Perennial weed problem is uncontrollable by other means.

  • the value of catch crops and organic manures for spring barley in organic arable farming
    Field Crops Research, 2007
    Co-Authors: Jorgen E Olesen, Margrethe Askegaard, E M Hansen, Ilse A Rasmussen
    Abstract:

    Abstract The effect of nitrogen (N) supply and Weeds on grain yield of spring barley was investigated from 1997 to 2004 in an organic farming crop rotation experiment in Denmark on three different soil types varying from coarse sand to sandy loam. Two experimental factors were included in the experiment in a factorial design: (1) catch crop (with and without), and (2) manure (with and without). The crop rotation included grass-clover as a green manure crop. Animal manure was applied as slurry in rates corresponding to 40% of the N demand of the cereal crops. Application of 50 kg NH 4 -N ha −1 in manure (slurry) increased average barley grain DM yield by 1.0–1.3 Mg DM ha −1 , whereas the use of catch crops (primarily Perennial ryegrass) increased grain DM yield by 0.2–0.4 Mg DM ha −1 with the smallest effect on the loamy sand and sandy loam soils and the greatest effect on the coarse sandy soil. Model estimations showed that the average yield reduction from Weeds varied from 0.2 to 0.4 Mg DM ha −1 depending on weed species and density. The yield effects of N supply were more predictable and less variable than the effects of weed infestation. The infestation level of leaf diseases was low and not a significant source of yield variation. The apparent recovery efficiency of N in grains (N use efficiency, NUE) from NH 4 -N in applied manure varied from 29 to 38%. The NUE of above-ground N in catch crops sampled in November prior to the spring barley varied from 16 to 52% with the largest value on the coarse sandy soil and the smallest value on the sandy loam soil. A comparison of grain yield levels obtained at the different locations with changes in soil organic matter indicated a NUE of 21–26% for soil N mineralisation, which is smaller than that for the mineral N applied in manure. However, this estimate is uncertain and further studies are needed to quantify differences in NUE from various sources of N. The proportion of Perennial Weeds in total biomass increased during the experiment, particularly in treatments without manure application. The results show that manure application is a key factor in maintaining good crop yields in arable organic farming on sandy soils, and in securing crops that are sufficiently competitive against Perennial Weeds.

Lars Andersson - One of the best experts on this subject based on the ideXlab platform.

Antonio Evidente - One of the best experts on this subject based on the ideXlab platform.

  • phomachalasins a d 26 oxa 16 and 15 cytochalasans produced by phoma exigua var exigua a potential mycoherbicide for cirsium arvense biocontrol
    Tetrahedron, 2011
    Co-Authors: Antonio Evidente, Alessio Cimmino, Anna Andolfi, Alexander Berestetskiy, Andrea Motta
    Abstract:

    Phoma exigua var. exigua, a fungal pathogen isolated from Cirsium arvense and Sonchus arvensis, proposed as a biocontrol agent of this noxious Perennial Weeds, produces in liquid and solid cultures different phytotoxic metabolites with potential herbicidal activity. The phytotoxic cytochalasins B, F, Z2, and Z3 and deoxaphomin were previously identified together with p-hydroxybenzaldehyde. Using spectroscopic methods, four new cytochalasins, termed phomachalasins A–D, were isolated and characterized as three new closely related 26-oxa[16] and one new [15]cytochalasans. They belong to a new subgroup of cytochalasans bearing a 1,2,3,4,6,7-hexasubstituted bicycle[3.2.0]heptene joined to the macrocyclic ring. None of the four new metabolites showed phytotoxic or antimicrobial activity. The lack of both phytotoxic and antimicrobial activities showed by all phomachalasins A–D was probably due to the strong modification of both functionalities and conformational freedom of the macrocyclic ring caused by its junction with the bulky and quite rigid new bicycle, namely bicycle[3.2.0]heptene.

  • production of phytotoxins by phoma exigua var exigua a potential mycoherbicide against Perennial thistles
    Journal of Agricultural and Food Chemistry, 2008
    Co-Authors: Alessio Cimmino, Anna Andolfi, Alexander Berestetskiy, Antonio Evidente
    Abstract:

    The potential of the different Phoma exigua var. exigua strains for the biocontrol of the Perennial Weeds Sonchus arvensis and Cirsium arvense, occurring throughout temperate regions of the world, has been evaluated in previous studies. The majority of the above strains produced ascosonchine, a newly discovered enol tautomer of 4- pyridylpyruvic acid, whereas strains C-177 and S-9, though virulent to Weeds, did not produce the above metabolite. In this study, it was demonstrated that the above two strains, grown in liquid and solid cultures, produced p-hydroxybenzaldehyde, cytochalasins B, F, Z2 and Z3, and deoxaphomin. When assayed on the leaves of both C. arvense and S. arvensis, p-hydroxybenzaldehyde was inactive, whereas deoxaphomin demonstrated the highest level of toxicity on leaves of S. arvensis. Cytochalasin Z2 appeared to be the less toxic cytochalasan on both plants according to the lack of the secondary hydroxyl group on C-7. Production of cytochalasins by P. exigua var. exigua strains isolated from C. arvense and S. arvensis is discussed in relation to chemotaxonomy and the biocontrol potential of the fungus.