| 1. |
- Chopin, Pierre, et al.
(author)
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The reflection of principles and values in worldwide organic agricultural research viewed through a crop diversification lens. A bibliometric review
- 2023
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In: Agronomy for Sustainable Development. - : Springer Science and Business Media LLC. - 1774-0746 .- 1773-0155. ; 43
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Journal article (peer-reviewed)abstract
- Organic agriculture and organic food have expanded in recent decades but have undergone conventionalisation. Some claim that this contradicts some or all of the principles of ‘health’, ‘ecology’, ‘fairness’ and ‘care’ established by the International Federation of Organic Agricultural Movement (IFOAM). It is currently unclear how research on organic food/agriculture is structured, whether it embraces these principles, or how key crop diversification, driving sustainability, are addressed. To fill these knowledge gaps, we conducted a bibliometric analysis of 10,030 peer-reviewed articles published from 1945 to 2021 with topic and textual analysis. Our main findings were the following: (1) research is compartmentalised into scales and disciplines, with at field-scale ‘weed’, ‘soil’, ‘pest and disease’ management and ‘livestock farming’ seldom addressed together, or with environmental assessment separated from socioeconomic studies at farm scale. (2) The proportion of publications on ‘consumers’ preferences’ and ‘product quality’ research almost tripled in 20 years, from 10 to 27%, emphasizing the consumer orientation of research on organic agriculture and organic food. (3) Only 4% of articles covered all four IFOAM principles, while associated values such as ‘resilience’, ‘integrity’, ‘equity’, ‘transparency’ and ‘justice’ were even less frequently addressed. (4) Fewer diversification practices have been tested in organic than in conventional agriculture research, with fewer articles on ‘crop mixtures’ or ‘bee-friendly crops’ and a smaller range of legumes considered. (5) Research on genetic improvement and processing of organic legumes is lacking, which could constrain adoption of legumes in organic farming even more than in conventional agriculture. These results indicate a need for increasing interdisciplinary efforts at field level, with systematic measurement of multiple processes (weed-nutrient-pest dynamics). Future studies on organic agriculture should combine several diversification practices and legumes, with relevant indicators addressing the IFOAM values explicitly, and consider the whole value chain by linking producers with consumers.
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| 2. |
- Daouti, Eirini Lamprini, et al.
(author)
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Seed predation is key to preventing population growth of the weed Alopecurus myosuroides
- 2022
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In: Journal of Applied Ecology. - : Wiley. - 0021-8901 .- 1365-2664. ; 59, s. 471-482
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Journal article (peer-reviewed)abstract
- Seed predation can reduce the abundance and spread of unwanted vegetation in agricultural and other semi-natural ecosystems. However, knowledge of how variations in seed predation rates affect plant species population dynamics is needed for decision making and knowledge-based ecosystem management. We developed a stage-classified stochastic matrix population model for Alopecurus myosuroides Huds. (blackgrass), an annual plant species thriving as a weed in temperate agroecosystems of Western and Northern Europe. The model was parameterised using empirical demographic data from long-term experiments in Swedish winter wheat fields, including information on post-dispersal seed losses by vertebrate and invertebrate seed predators. For agroecosystems with highly effective weed control measures (e.g. chemical and mechanical weed control), model simulations showed that seed losses via seed predation need to reach at least 78% at peak seed shedding to suppress population growth of A. myosuroides. The field experiment showed that vertebrates were most important for seed predation in July, at peak seed shedding. In August, after crop harvest, invertebrates were responsible for almost all seed predation. The model indicated that weed seed predation was much more important for weed regulation when it occurred before crop harvest in July. Vertebrates most strongly reduced population growth of A. myosuroides, although both vertebrates and invertebrates were needed to prevent it entirely. Synthesis and applications. We showed that weed seed predation by vertebrate and invertebrate seed predators is key for reducing the population growth of winter annual weeds like A. myosuroides in intensively managed agroecosystems. Therefore, protection of weed seed predators is essential for making management of unwanted vegetation less dependent on chemical and mechanical measures.
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| 3. |
- Jäck, Ortrud, et al.
(author)
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Chlorophyll Fluorescence Measurement: A New Method to Test the Effect of Two Adjuvants on the Efficacy of Topramezone on Weeds
- 2019
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In: IFIP Advances in Information and Communication Technology. - Cham : Springer International Publishing. - 1868-4238. ; 545, s. 206-216
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Conference paper (peer-reviewed)abstract
- To test the effect of adjuvant on the efficacy of herbicides in a fast and non-destructive way is very helpful for selecting a right spray adjuvant for herbicide, which is an important strategy to enhance the efficacy of herbicides, reduce application dose, and enhance environmental safety. Experiments were conducted in the laboratory and greenhouse to study the effect of 2 adjuvants - Methylated seed oil (MSO) and organosilicone on the efficacy of topramezone on grass weed giant foxtail (Setaria faberi Herrm.) and broadleaved weed velvetleaf (Abutilon theophrasti Medik.) using weed leaves chlorophyll fluorescence measurement and whole plant biomass test. The results indicated that the top leaf maximum quantum efficiency (Fv/Fm) of two weeds treated by herbicide mixed with MSO adjuvant was significantly lower than that of treated by herbicide alone from the 2-3 days after treatment, while the difference between treatments of herbicide mixed with organosilicone adjuvant and herbicide applied alone was not significant. Results of the whole-plant pot tests showed biomass of the treatment of topramezone mixed with MSO was significantly lower than that of herbicide applied alone. This is similar to the result of chlorophyll fluorescence test. Chlorophyll fluorescence measurement has proven to be an attractive tool for studying the effect of the adjuvants on the efficacy of herbicide.
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| 4. |
- Jäck, Ortrud, et al.
(author)
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Winter wheat yield loss in response to Avena fatua competition and effect of reduced herbicide dose rates on seed production of this species
- 2017
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In: Journal of Plant Diseases and Protection. - : Springer Science and Business Media LLC. - 1861-3829 .- 1861-3837. ; 124, s. 371-382
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Journal article (peer-reviewed)abstract
- Avena fatua is one of the most abundant and competitive grass weed species in cereal cropping systems worldwide. Despite its main occurrence in summer annual cereals, A. fatua is suspected to cause significant yield losses in winter wheat as well. Five yield loss experiments were conducted over the course of five years to investigate the impact of A. fatua on winter wheat yield. Two additional field studies were conducted to assess the efficacy of two ALS-inhibiting herbicides as well as of two ACC-aseinhibiting herbicides at variable dose rates on A. fatua seed production. Avena fatua caused significant winter wheat yield losses of up to 40% at densities of approximately 250 plants m(-2). Winter wheat yield losses did not differ between years and sites. Relative A. fatua biomass was a better predictor for winter wheat yield loss as A. fatua density and biomass. Three out of four herbicides showed high efficacy against A. fatua, even at reduced dose rates, but A. fatua seed production was not directly related to herbicide efficacy. Seed production was rather influenced by the mode of action and the competitiveness of the winter wheat stand. The results showed that A. fatua can be a serious threat for winter wheat production in the local conditions, leading to high yield losses if not controlled. We did not find a general potential for reducing herbicide dose rates for the control of A. fatua in winter wheat due to variable effects on A. fatua seed production. The potential is highly dependent on the winter wheat competitiveness and herbicide mode of action.
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| 5. |
- Lagerquist, Elsa, et al.
(author)
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Temporal and Spatial Positioning of Service Crops in Cereals Affects Yield and Weed Control
- 2022
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In: Agriculture. - : MDPI AG. - 2077-0472. ; 12
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Journal article (peer-reviewed)abstract
- Leguminous service crops (SCs) can provide multiple services to cropping systems, reducing the reliance on external resources if sufficient biomass is produced. However, rapid light and temperature reductions limit post-harvest cultivation of SCs in Northern Europe. A novel practice of intercropping SCs in two consecutive crops (spring-winter cereal) to extend the period of SCs growth, and hence improve yield and reduce weeds, was tested. Three spatial and temporal arrangements of SCs and cash crops were investigated, as well as three SC mixtures, characterized by their longevity and frost sensitivity. Compared to no SC, the best performing mixture, frost-tolerant annuals, increased grain and N yield of winter wheat by 10% and 19%, respectively, and reduced weed biomass by 15% and 26% in oats and winter wheat, respectively. These effects were attributed to high biomass production and winter survival. However, this SC reduced oat yields by 15% compared to no SC. Furthermore, SC growth and service provision varied largely between experiments, driven by the weather conditions. Extending the SC's growth period by intercropping in two consecutive cereal crops has potential, but locally adapted species choices and establishment strategies are needed to ensure SC vitality until termination.
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| 6. |
- Menegat, Alexander
(author)
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Acetohydroxyacid synthase (AHAS) amino acid substitution Asp376Glu in Lolium perenne: effect on herbicide efficacy and plant growth
- 2016
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In: Journal of Plant Diseases and Protection. - : Springer Science and Business Media LLC. - 1861-3829 .- 1861-3837. ; 123, s. 145-153
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Journal article (peer-reviewed)abstract
- Recently, the acetohydroxyacid synthase (AHAS) amino acid substitution Asp376Glu was detected in a Lolium perenne population originating in France. This is the first documented occurrence of the Asp376Glu single-nucleotide polymorphism in a Lolium species. The effects on herbicide efficacy and plant fitness are presented. Separation of the original population into different genetic subgroups allowed the comparison of different L. perenne AHAS genotypes according to their susceptibility to AHAS-inhibiting herbicides. Root and shoot biomass accumulation as well as tiller production was analysed for resistant and sensitive populations. Genotype-specific AHAS activity and inhibition were studied in vitro, using recombinant Arabidopsis thaliana DNA. Plants expressing the AHAS Asp376Glu genotype were resistant against mesosulfuron + iodosulfuron, pyroxsulam and propoxy-carbazone. To imazamox, reduced susceptibility for dosages below 140 g a.i. ha(-1) was observed. In the absence of herbicide, no significant impact of the Asp376Glu genotype on shoot biomass and tiller accumulation could be observed, whereas root biomass of the Asp376Glu genotype was significantly reduced by 68 % compared to the AHAS genetic wild type. The AHAS enzyme study revealed reduced AHAS enzyme rate of 48 % for the Asp376Glu genotype compared to the AHAS genetic wild type. This study highlights the role of the amino acid exchange on resistance profile against the most relevant AHAS-inhibiting herbicides. First indications were found that fitness of the Asp376Glu genotype is hampered.
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| 7. |
- Menegat, Alexander
(author)
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An ecological future for weed science to sustain crop production and the environment. A review
- 2020
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In: Agronomy for Sustainable Development. - : Springer Science and Business Media LLC. - 1774-0746 .- 1773-0155. ; 40
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Research review (peer-reviewed)abstract
- Sustainable strategies for managing weeds are critical to meeting agriculture's potential to feed the world's population while conserving the ecosystems and biodiversity on which we depend. The dominant paradigm of weed management in developed countries is currently founded on the two principal tools of herbicides and tillage to remove weeds. However, evidence of negative environmental impacts from both tools is growing, and herbicide resistance is increasingly prevalent. These challenges emerge from a lack of attention to how weeds interact with and are regulated by the agroecosystem as a whole. Novel technological tools proposed for weed control, such as new herbicides, gene editing, and seed destructors, do not address these systemic challenges and thus are unlikely to provide truly sustainable solutions. Combining multiple tools and techniques in an Integrated Weed Management strategy is a step forward, but many integrated strategies still remain overly reliant on too few tools. In contrast, advances in weed ecology are revealing a wealth of options to manage weedsat the agroecosystem levelthat, rather than aiming to eradicate weeds, act to regulate populations to limit their negative impacts while conserving diversity. Here, we review the current state of knowledge in weed ecology and identify how this can be translated into practical weed management. The major points are the following: (1) the diversity and type of crops, management actions and limiting resources can be manipulated to limit weed competitiveness while promoting weed diversity; (2) in contrast to technological tools, ecological approaches to weed management tend to be synergistic with other agroecosystem functions; and (3) there are many existing practices compatible with this approach that could be integrated into current systems, alongside new options to explore. Overall, this review demonstrates that integrating systems-level ecological thinking into agronomic decision-making offers the best route to achieving sustainable weed management.
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| 8. |
- Menegat, Alexander
(author)
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Chlorophyll Fluorescence Imaging for Monitoring the Effects of Minimal Processing and Warm Water Treatments on Physiological Properties and Quality Attributes of Fresh-Cut Salads
- 2016
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In: Food and Bioprocess Technology. - : Springer Science and Business Media LLC. - 1935-5130 .- 1935-5149. ; 9, s. 650-663
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Journal article (peer-reviewed)abstract
- In this study, chlorophyll fluorescence imaging (CFI) was used to monitor plant stress induced by cutting of mini romaine lettuce (Lactuca sativa L. var. longifolia) and by cutting and washing of endive (Cichorium endivia L.) during storage. Regarding the more detailed study of endive fresh-cut salads, we additionally monitored respiratory activity, phenylalanine ammonia lyase (PAL) activity, contents of plant pigments, and cut edge browning. Determination of maximum quantum efficiency F (v)/F (m) was feasible through sealed consumer-sized film bags, thus, enabling the non-invasive monitoring of both fresh-cut salad types in the corresponding modified atmosphere during storage. Cutting of romaine lettuce provoked a partially reversible drop of F (v)/F (m) during the first 24 h. Subsequently, F (v)/F (m) of cut romaine strongly decreased with elapsing shelf life, whereas intact leaves exhibited only a slight decline. Regarding minimally processed endive, warm water washing progressively reduced F (v)/F (m) with increasing heat exposure, while respiratory activities and the content of accessory pigments remained unaffected. The heat-dependent decrease of F (v)/F (m) was correlated to the inhibition of the PAL activity. Mildly warm washing (40 A degrees C, 120 s; 45 A degrees C, 60 s) reduced PAL activities, while F-v/F-m remained widely unaffected and visual quality was only partially improved. However, warm water washing at elevated temperatures (45 A degrees C, 120 s; 50 A degrees C, 30-60 s) enabled maximum visual quality retention, accompanied by a significant decrease of F (v)/F (m). CFI may represent a useful tool to monitor the stress conditions due to cutting and warm water treatments, hence, allowing the systematic improvement of fresh-cut produce.
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| 9. |
- Menegat, Alexander, et al.
(author)
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Interaction of Preventive, Cultural, and Direct Methods for Integrated Weed Management in Winter Wheat
- 2019
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In: Agronomy. - : MDPI AG. - 2073-4395. ; 9
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Journal article (peer-reviewed)abstract
- Crop rotations dominated by winter annual crops and relying on the use of herbicides to control weeds have resulted in weed communities dominated by a few highly specialized species such as Alopecurus myosuroides. Integrated weed management (IWM) represents a sensible strategy to target such difficult weeds, through a combination of preventive, cultural, and direct means. In six field trials over three years, we tested the effect of stale seedbed preparation, winter wheat seed rate, and chemical weed control strategy on Alopecurus myosuroides control efficacy and variability in efficacy. The field experiments were carried out under reduced tillage practice and without pre-sowing use of glyphosate. Stale seedbed preparation alone reduced A. myosuroides infestation level by 25% on average. No clear effect was found of increasing winter wheat seed rate from 300 to 400 seeds m(-2). A combination of stale seedbed preparation and herbicide treatment in autumn and spring was found to be synergistic, improving weed control efficacy significantly and moreover reducing the variability in control efficacy and hence the risk for weed control failure.
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| 10. |
- Menegat, Alexander
(author)
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Minimal soil disturbance combined with spring cropping can halt soil seedbank accumulation of Alopecurus myosuroides
- 2023
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In: Weed Research. - : Wiley. - 0043-1737 .- 1365-3180. ; 63, s. 115-122
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Journal article (peer-reviewed)abstract
- The basic mechanism of soil inversion tillage for control of annual weeds is based on the vertical translocation of weed seeds from the soil surface to deeper soil layers. Buried weed seeds either remain dormant in the soil seedbank and are exposed to biological and chemical decay mechanisms, or they germinate but the seedlings cannot reach the soil surface (fatal germination). However, depending on the seed biology of the respective target species, frequent inversion tillage can lead to a build-up of the soil seedbank. For soil seedbank depletion based on available knowledge of the biology of Alopecurus myosuroides seeds, soil inversion tillage is suggested to be reduced to every third or fourth year with reduced or even no-tillage (direct seeding) in between (rotational inversion tillage systems). Including spring crops in the crop rotation could further help dampening the population growth and hence the seed return into the seedbank. This study investigated the effect of rotational inversion tillage in combination with reduced tillage or direct seeding on the soil seedbank and population development of A. myosuroides. In a long-term field trial, set up in 2012, these tillage strategies were compared with continuous inversion tillage in a 3-year crop rotation with two consecutive years of winter wheat (Triticum aestivum) followed by spring barley (Hordeum vulgare). The results showed a significant decline in the soil seedbank following the spring crop, irrespective of the tillage system. The continuous inversion tillage system and inversion tillage before spring cropping with reduced tillage (shallow tillage with a disc harrow) before winter wheat both led to accumulation of seeds in the soil seedbank. In contrast, inversion tillage before spring cropping with direct seeding of winter wheat depleted the soil seedbank significantly after only one crop rotation. Although only covering one intensively studied field site, these findings highlight the need for diversified cropping systems and indicate potential avenues for reducing soil tillage while controlling economically important weeds.
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