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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.

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.

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.

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.

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 ACCase-inhibiting 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.

Weeds are causing significant yield losses in intensive winter wheat cropping systems worldwide. Prospective weed control strategies aim to reduce herbicide inputs in order to diminish the environmental, food safety and operator risks. The objective of this study is to make a long-term comparison of herbicide saving weed control strategies in intensive winter wheat cropping systems. The herbicide saving weed control strategies are compared with emphasis on herbicide input, crop yield, economic net return and weed population dynamics. The modelling approach is based on existing models for calculation of crop yield loss, herbicide dose-response, weed seed bank development and economic net return. The model is parametrised for wild oat in winter wheat. Field experiments were conducted for model parameter estimation. Three herbicide saving weed control strategies were compared, namely the economic threshold strategy as well as two reduced herbicide dose strategies. The two reduced dose strategies differed in their intensity of dose reduction and thus in their risk for potential efficacy failure. The modelling results could show that, depending on the risk level, reduced dose strategies can decrease herbicide inputs by 21% respectively 59%, compared to the economic threshold method. Differences between the three herbicide saving weed control strategies regarding yield and economic net return were negligible. From the consumer and environmental safety point of view, the high potential for herbicide input reduction makes the reduced herbicide dose methods favourable. However, the benefit for farmers is questionable due to the absence of an actual economic benefit and the enhanced risk of efficacy failure and herbicide resistance development.

Superficial short-wavelength ultraviolet (UV-C) treatment (1.2 kJ/m2) of fresh-cut endive was combined with conventional cold (4 °C, 120 s) and innovative warm (45 °C, 120 s) water washing prior to and after irradiation in order to improve its microbial and sensory quality including physiological properties. UV-C doses applied exerted only minor physiological stress on the plant tissue, irrespective of the washing procedure as indicated by largely unaltered headspace gas compositions, chlorophyll fluorescence maximum quantum yields (F v/F m), and retention of chlorophylls and β-carotene. Independent of the washing procedure applied, phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), and peroxidase (POD) activities were slightly inhibited by UV-C irradiation. As a result of UV-C irradiation, significantly improved microbiological and sensory quality was retained during the entire storage period, particularly, when applied after washing. Being applicable in organic fresh-cut production, UV-C represents a valuable alternative to chlorine application to washing water. The most efficient decontamination (2.1 log10 units) of fresh-cut endive was achieved by combining warm water washing with subsequent UV-C irradiation. Furthermore, when UV-C lamps were integrated into the water tank of a continuous industrial washing machine, the microbial loads of the process water were also significantly lowered. Accordingly, in-line UV-C decontamination of process water may be instrumental in minimizing both fresh water consumption and the risk of cross-contamination.

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 propoxycarbazone. 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.

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 °C, 120 s; 45 °C, 60 s) reduced PAL activities, while Fv/Fm remained widely unaffected and visual quality was only partially improved. However, warm water washing at elevated temperatures (45 °C, 120 s; 50 °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.

The sustainable management of unwanted vegetation in agricultural fields through integrated weed control strategies requires detailed knowledge about the maternal formation of primary seed dormancy, to support the prediction of seedling emergence dynamics. This knowledge is decisive for the timing of crop sowing and nonchemical weed control measures. Studies in controlled environments have already demonstrated that thermal conditions and, to some extent, water availability during seed set and maturation has an impact on the level of dormancy. However, it is still unclear if this applies also under field conditions, where environmental stressors and their timing are more variable. We address this question for Alopecurus myosuroides in south‐western Sweden. We quantified the effects of cumulated temperature and precipitation as well as soil water potential during the reproductive growth phase of A myosuroides on primary seed dormancy under field conditions. Empirical models differing in focal time intervals and, in case of soil water potential, focal soil depths were compared regarding their predictive power. The highest predictive power for the level of primary dormancy of A. myosuroides seeds was found for a two‐factorial linear model containing air temperature sum between 0 and 7 days before peak seed shedding as well as the number of days with soil water potential below field capacity between 7 and 35 days before peak seed shedding. For soil water potential, it was found that only the top 10 cm soil layer is of relevance, which is in line with the shallow root architecture of A. myosuroides. We conclude that for this species the level of dormancy depends on the magnitude and timing of temperature and water availability during the reproductive growth phase. Water availability appears to be more important during maternal environmental perception and temperature during zygotic environmental perception.

Japanese bindweed was found to be one of the most abundant and most difficult-to-control weed species during a 2-yr weed survey in more than 100 winter wheat fields in the North China Plain region. Multivariate data analysis showed that Japanese bindweed is most abundant at sites with comparative low nitrogen (N) fertilization intensities and low crop densities. To gain deeper insights into the biology of Japanese bindweed under various N fertilization intensities, winter wheat seeding rates, herbicide treatments, and their interactions, a 2-yr field experiment was performed. In nonfertilized plots, a herbicide efficacy (based on density reduction) of 22% for 2,4-D, and of 25% for tribenuron-methyl was found. The maximum herbicide efficacy in Nmin-fertilized plots (target N value based on expected crop yield minus soil mineral nitrogen content,) was 32% for 2,4-D and 34% for tribenuron-methyl. In plots fertilized according to the farmer's practices, a maximum herbicide efficacy of 72% for 2,4-D and of 64% for tribenuron-methyl could be observed. Furthermore, medium and high seeding rates improved the herbicide efficacy by at least 39% for tribenuron-methyl and 44% for 2,4-D compared to the low seeding rate. Winter wheat yield was not significantly affected by seeding rate itself, whereas at low and medium seeding rates, Nminfertilization was decreasing winter wheat yield significantly compared to the farmer's usual fertilization practice. At the highest seeding rate, Nminfertilization resulted in equal yields compared to the farmer's practices of fertilization.

Summary Due to the steadily increasing number of putative herbicide-resistant weed populations, the demand for rapid in-season tests is rising. In this study, we introduce a new quantitative herbicide-resistance test system based on chlorophyll fluorescence imaging analysis of photosynthesis-related parameters. Susceptible and herbicide-resistant populations of Alopecurus myosuroides (black-grass) were cultivated in multiwell tissue culture plates containing nutrient agar and different dosages of fenoxaprop-P-ethyl and mesosulfuron+iodosulfuron. The maximum quantum efficiency of the PSII was measured 3 h after transplanting (HAT) and then for seven days every 24 h. Data of maximum quantum efficiency of the PSII were compared with standard whole-plant pot tests and molecular tests for target-site mutations. It was possible to fit dose-response curves and calculate corresponding resistance factors for ED90 for all populations tested using the chlorophyll fluorescence imaging. It was possible to distinguish between resistant and susceptible populations. The results of the chlorophyll fluorescence imaging corresponded well with the standard whole-plant pot tests in the glasshouse. However, populations with proved target-site mutations did not differ from other herbicide-resistant populations in the maximum quantum efficiency values of the PSII. We conclude that the chlorophyll fluorescence imaging provides reliable data on herbicide resistance for both modes of action tested in a shorter time and using less space, compared with standard whole-plant pot tests in the glasshouse.

Methylated seed oil (MSO) is a recommended adjuvant for the newly registered herbicide topramezone in China and also in other countries of the world, but the mechanism of MSO enhancing topramezone efficacy is still not clear. Greenhouse and laboratory experiments were conducted to determine the effects of MSO on efficacy, solution property, droplet spread and evaporation, active ingredient deposition, foliar absorption and translocation of topramezone applied to giant foxtail (Setaria faberi Herrm.) and velvetleaf (Abutilon theophrasti Medic.). Experimental results showed that 0.3% MSO enhanced the efficacy of topramezone by 1.5-fold on giant foxtail and by 1.0-fold on velvetleaf. When this herbicide was mixed with MSO, its solution surface tension and leaf contact angle decreased significantly, its spread areas on weed leaf surfaces increased significantly, its wetting time was shortened on giant foxtail but not changed on velvetleaf, and less of its active ingredient crystal was observed on the treated weed leaf surfaces. MSO increased the absorption of topramezone by 68.9% for giant foxtail and by 45.9% for velvetleaf 24 hours after treatment. It also apparently promoted the translocation of this herbicide in these two weeds.