Weed Survey Research Articles

Remote Coastal Weed Infestation Management Using Bayesian Networks

The increasing prevalence of species that are detrimental to biodiversity is a major concern, particularly for managers of national parks. To develop effective programmes for controlling weeds, it is essential to have a thorough understanding of the extent and severity of infestations, as well as the contributing factors such as temperature, rainfall, and disturbance. Predicting these factors on a regional scale requires models that can incorporate a wide range of variables in a quantifiable manner, while also assisting with on-ground operations. In this study, we present two Bayesian Network models specifically designed for six significant weed species found along the southern coast of Australia. Our models are based on empirical data collected during a coastal weed survey conducted in 2015 and repeated in 2016. We applied these models to the coastal national parks in the isolated and pristine East Gippsland region. Importantly, the prediction models were developed at two different spatial scales that directly corresponded to the scale of the observations. Our findings indicate that coastal habitats, with their vulnerable environments and prevalence of open dune systems, are particularly susceptible to weed infestations. Moreover, adjacent regions also have the potential for colonization if these infestations are not effectively controlled. Climate-related factors play a role in moderating the potential for colonization, which is a significant concern for weed control efforts in the context of global climate change.

The impact of herbicide-resistant canola systems on the weed community dynamics in the Canadian Prairies

Increased adoption of no-till and extensive cultivation of herbicide-resistant (HR) crops in low diversity rotations are some transformations that occurred during the 1970s–2000s in western Canada. Historical data analysis of weed survey data (Saskatchewan, Manitoba, and Alberta) in canola crops and a canola rotation field experiment were used to understand how tillage, herbicide-resistant cropping systems, and the temporal frequency of canola in the rotation can impact weed abundance, composition, and diversity in the Canadian prairies. Weed survey data revealed that the spatial frequency of many weed species declined in years after 1995 compared with before 1995, the year HR cultivars were introduced. False cleavers ( Galeum spurium L .) and volunteer wheat ( Triticum aestivum L.) were the only species showing a continuous increase in frequency throughout the surveyed years. Species richness showed no trajectories but varied depending on climatic conditions. Roundup-Ready (RR) systems were associated with green foxtail ( Setaria viridis L.) irrespective of their frequency in the rotation. Continuous canola systems had an obvious association with chickweed ( Stellaria media L.) regardless of herbicide systems. Wild oats ( Avena fatua L.) were predominant in the longer rotations with glufosinate and imidazolinone-resistant canola. In the field study, weeds associated before in crop herbicide application were relatively controlled after herbicides were applied, except for foxtail barley ( Hordeum Jubatum L.), which was not controlled in most HR systems. Overall, both weed survey data and field experiment data revealed greater control of most weed species due to the adoption of HR canola cultivars and the associated cultural practices.

Detection of Sedge Weeds Infestation in Wetland Rice Cultivation Using Hyperspectral Images and Artificial Intelligence: A Review

Sedge is one type of weed that can infest the rice field, as well as broadleaf and grasses. If sedges are not appropriately controlled, severe yield loss will occur due to increased competition with cultivated rice for light, space, nutrients, and water. Both sedges and grasses are monocots and have similar narrowed leaf characteristics, but most sedge stems have triangular prismatic shapes in cross sections, which differ them from grasses. Event sedges and grasses differ in morphology, but differentiating them in rice fields is challenging due to the large rice field area and high green color similarity. In addition, climate change makes it more challenging as the distribution of sedge weed infestation is influenced by surrounding abiotic factors, which lead to changes in weed control management. With advanced drone technology, agriculture officers or scientists can save time and labor in distributing weed surveys in rice fields. Using hyperspectral sensors on drones can increase classification accuracy and differentiation between weed species. The spectral signature of sedge weed species captured by the hyperspectral drone can generate weed maps in rice fields to give the sedge percentage distribution and location of sedge patch growth. Researchers can propose proper countermeasures to control the sedge weed problem with this information. This review summarizes the advances in our understanding of the hyperspectral reflectance of weedy sedges in rice fields. It also discusses how they interact with climate change and phenological stages to predict sedge invasions.

The first record of milk thistle (Silybum marianum, Asteraceae) as an alien invasive weed species in Addis Ababa City, Ethiopia.

Abstract Since 2020, milk thistle Silybum marianum, an invasive weed species, has been widely observed in urban green spaces and roadsides in Addis Ababa city, Ethiopia. To plan future management activities, this study aimed to determine the current distribution status of the weed in urban green areas of Addis Ababa city. Weed surveys were conducted across 42 urban green sites located in Yeka, Lemi Kura, Bole, Nifas Silk-Lafto, Kolfie Keraniyo, Akaky Kality, and Gullele sub-cities during the main rainy season from June to September 2023. Urban green areas were selected using purposive sampling techniques. Field observations confirmed that Silybum marianum can invade and colonize a wide range of habitats and is highly competitive, posing a threat to important native plant species. High weed density rates and dense stands of weeds were recorded in the 34 urban green areas surveyed. The survey results strongly suggest implementing fast integrated weed management options such as mowing/tilling, weeding before the plant goes to seed, cutting (stems and/or seed heads), and burning (collected plant parts and/or seed heads) into a prepared burrow to minimize the spread of the weed and its ecological impacts. The purpose of this survey study is to provide information about Silybum marianum to minimize or avoid its distribution and associated impacts by following sustainable invasive weed management programs in the city before spreading to other cities in the country.

Aerial survey and glyphosate-resistant weeds control before soybean seeding

Interference from herbicide-resistant weeds is one of the biggest impediments in soybean crops. The aim was to evaluate the spatial dynamics and weed control under glyphosate and glufosinate combinations before soybean seeding. The experiment was conducted in a striped arrangement with thirteen treatments and seven replicates. The treatments consisted in no-treatment, glyphosate, glyphosate + fomesafen, glyphosate + saflufenacil, glyphosate + diclosulam, glyphosate + imazetapir, glyphosate + flumioxazine, glyphosate + carfentrazone-ethyl, glyphosate + imazetapyr + flumioxazine, glyphosate + glufosinate, glyphosate + flumioxazine + carfentrazone, glufosinate + saflufenacil, glufosinate + flumioxazine. The weed spatial dynamic was analyzed for geostatistics methods, while weed control by conventional and UAV (Unmanned Aerial Vehicle) methods. We identified twenty weed species, representing eighteen different genera and fourteen botanical families. It's worth noting that eudicotyledonous species were the dominant group, primarily characterized by an annual life cycle and sexual reproduction. The utilization of precision agricultural methods proved highly effective in conducting weed surveys before soybean seeding. Using glyphosate alone is not recommended in fields with a history of reactive management with this herbicide. Alternatively, combining glyphosate and glufosinate with Protox-inhibitors showed outstanding control efficacy against glyphosate-resistant or glyphosate-tolerant weeds, Cenchrus echinatus, Spermacoce verticillata and Turnera subulata

PREVALENCE AND ALLELOPATHIC EFFECT OF PARTHENIUM HYSTEROPHORUS ON CROPS IN SOUTHWEST REGIONS OF BANGLADESH

Periodical weed surveys were conducted during 2020-21in Jashore, Jhenaidah, Chuadanga, Meherpur and Khustia districts of Bangladesh to observethe severity and allelopathic effect of Parthenium hysterophorus on field crops. Parthenium infected the crops differently as observed in rice ( 8.75), maize (11.45%), lentil (12.45%), chickpea (32.40%), field pea (57.63%), jute (57.63%), cotton (13.45%), mustard (63.85%), sesame (17.50%), groundnut (28.35%), pointed gourd(11.50%), pumpkin (8.45%),onion (30.47%), garlic(26.25%), turmeric (17.50%), potato (38.75%), banana(24.33%), sugarcane (60.25%), napiergrass (55.00%) and marigold (11.25%).Allelopathic effect was examinedusing 5% aqueousleaf extract of P. hysterophorus ingermination test and results showedcomplete failure of germination in seeds of sesame, jute, pumpkin, red amaranth, chili, radish and tomato. Seeds of other crops germinated poorly in aqueous solution of parthenium with reduced radicle and plumule growth. Among the different crops, wheat had the highest reduction in radicle (96%) and plumule (94%) length compared to their control.

Changes in the weed flora of cotton fields in the Eastern Mediterranean region of Turkiye

Cotton is the most dominant field crop, especially in higher soil saline parts of the Eastern Mediterranean region of Türkiye. This study aims to determine the current statues of weed flora of cotton fields in the East Mediterranean region, to compare it with weed flora in 1991-1992 and to understand whether a weed flora shift has occurred in these fields. Eighty-two cotton fields were surveyed during the growing season (July and August) in 2018, and thirty-seven weed species distributed in 17 families were found in the survey fields, where 18, 23, 17, and 33 of them were recorded in the Kahramanmaraş, Hatay, Mersin, and Adana provinces, respectively. Canonical correspondence analysis revealed that the phytosociological composition of the cotton fields was significantly related to the P content of the soil, average temperature, and cumulative rainfall. The current weed survey also indicated that these fields were under the threat of some invasive alien plant species that had not been found in previous surveys, such as Ipomoea triloba L., Amaranthus palmeri L., and Cucumis melo var. agrestis Naudin. Although cotton fields in the region were reduced by two-thirds in 2018 compared to 1991-1992, weed richness increased. Weed flora shifts were influenced by crop, crop rotation, herbicide use, irrigation, and landscape factors of cotton fields in the East Mediterranean Region of Türkiye.

Traits of weed species present in maize respond to tillage and cropping systems

IntroductionArable weeds adapt to any changes in disturbance and management. On arable fields, tilling disturbs the soil, while cropping practices like rotation, pesticide use, fertilizer use, and the use of subsidiary crops characterize the management of the field. On a species level, weeds adapt in their abundance and composition. The species have certain traits to use the on-site resources best. Our objective was to investigate if traits beyond just species describe the adaptation of weeds to tillage and cropping systems. Therefore, we present a use case of weeds on fields cropped with maize in Germany.Material and methodsOver 2 years, we conducted a nationwide weed survey on 577 maize fields. On each field, the abundance of each weed species was counted on 10 randomly sampled square plots of 0.1 m² not treated with herbicides at the fourth to eighth leaf stages of the maize. Weed species frequent on at least 5% of the fields were assigned traits. Traits were taken from published updated databases. We interviewed all farmers about the management practices of their fields.ResultsThe management practice data identified three management clusters of tillage and cropping sequence on maize fields. The standard system so far is a management system characterized by inversion tillage and maize cropped in rotations (“Traditional”). The two transformation systems are maize cropped in rotations but with non-inversion tillage as the method of soil disturbance (“Conservational”) and maize cropped continuously regardless of the tillage system (“Monoculture”). Ordination techniques showed that both weed species and traits are assigned to these management systems. Traditional disfavored weed species with a greater plant height. Conservational selected dicot weed species with a high seed weight and a long flowering duration. Monoculture mainly filtered monocot weed species and favored weeds that germinate in spring.DiscussionOur study describes weed responses on transformations of maize cropping in tillage and cropping systems on both the species and the trait level. This application expresses the importance and value of collecting weed surveys with field management data on a geographically widespread and repeated timescale.

Effect of the tillage system on the floristic composition and the emergence of weeds in Allium sativum

In fragile environments, no-tillage (0T) instead of conventional tillage (CT) is desirable to prevent agroecosystem degradation, but there is little information on its implementation in horticulture. This study aimed to investigate the effects of replacing CT with 0T on floristic composition and weed emergence dynamics in a garlic crop, under the hypothesis that the implementation of a 0T system alters the weed community during the initial stage of the transition. Two experiments were carried out following a randomized complete block design with two treatments (garlic crop grown under 0T and CT). In two subsampling per plot, biweekly destructive weed surveys were carried out. Although both tillage systems presented a similar diversity between systems, these weed communities varied by 36% in their species identity, and it was recorded a higher total weed density under CT (P>0.05). Under 0T, anemophilous Asteraceae, such as Conyza bonariensis and Sonchus oleraceus, tended to increase their presence. Under CT, there was a greater amount of indehiscent fruiting Brassicaceae such as Raphanus sativus and Rapistrum rugosum. The implementation of Vicia villosa as a predecessor crop led to many births due to its capacity for natural reseeding. It is concluded that there are important changes in the species composition and weed emergence patterns immediately after the implementation of 0T compared to CT, suggesting that the filtering pressures exerted by each tillage system favor certain weed species over others. By understanding weed community shifts and critical stages of weed emergence, farmers can improve herbicide application, thereby reducing the excessive use of chemicals and minimizing environmental impact. In addition, this information can help to schedule labor and machinery more efficiently, saving time and production costs.

Fifth survey on weed flora in spring cereals in Finland

Regular weed surveys provide information on changes in weed communities. The composition of weed flora in spring cereal fields was investigated in southern and central Finland during 2020–2022. The survey was conducted in 16 regions, 226 farms and 549 fields. The occurrence of weeds was assessed in the second half of July from 90 organically cropped and 459 conventionally cropped fields. The weed flora was dominated by broad-leaved species, representing 81% of the total number of 138 identified species. The average species number per field was 21 in organic fields and 12 in conventional fields. The most frequent weed species in organic fields were Chenopodium album 99%, Erysimum cheiranthoides 84%, Viola arvensis 83% and Stellaria media 82%. In conventionally cropped fields, the most frequent species were Viola arvensis 83%, Stellaria media 65%, Galeopsis spp. 59% and Galium spurium 59%. The two most common grass species in both production systems were Poa annua and Elymus repens. The frequency and density of Poa annua had increased substantially in conventional cropping since the previous survey in 2007–2009. The average density of weeds was 384 plants m-2 in organic fields and 147 plants m-2 in sprayed conventional fields. The average air-dry biomass of weeds was 678 kg ha-1 and 151 kg ha-1, respectively. Elymus repens produced almost a quarter of the total weed biomass in both production systems. Changes in weed flora were minor in terms of frequency and density of the most common broad-leaved weed species. Increased infestation of Poa annua in conventional cropping calls for special attention. The dominance of Elymus repens decreased in both production systems since the previous survey.

Effect of Environmental, Soil and Management Factors on Weed Flora of Field Pea in South-East Hungary

Pea is a widely cultivated leguminous plant which also contributes to soil enrichment through nitrogen fixation and benefits crop rotations. However, large weed populations are a challenge for pea production, requiring effective management strategies. It is essential to highlight the influence of soil parameters, factors affecting the environment, and management practices on weed populations to develop effective weed control and maximize pea yield and ease of harvesting. In our study, a total of 31 pea fields were surveyed prior to harvest to determine the coverage of each weed species, with the aim of identifying the typical weeds in the study area. In addition, environmental, soil, and management factors were recorded for each field. Based on our hypotheses, these factors influence the weed composition, and these effects can be described by the dominance of weed species. In our study, summer annuals and geophytic perennials were common, with Echinochloa crus-galli and Convolvulus arvensis being most dominant. The analysis revealed that the year of data record, soil type, and farming system most significantly influenced weed composition. Weed species were observed to have varying responses to soil texture, salt concentration, and phosphorus content. The survey period, geographical factors, farming system, and tillage practices also played a role in determining weed flora. The findings suggest strong correlations between soil parameters and weed composition, highlighting the importance of soil management in weed control. The year of data collection had the greatest influence on weed infestation. Soil-related variables, such as soil type, also played a significant role. Farming systems had a smaller effect on weed composition. Comparing our results with previous country level weed surveys in Hungary, our results identified some unique characteristics in the weed flora of South-East Hungary.

Results of weed surveys in greening plants

Greening crops play an essential role in Hungary's agriculture. Weeds can also cause many problems during the development of greening plants. Our research aimed to evaluate the weed control properties of greening crops sown with different germination rates. Analysis of the effect of crop rotations on weed density. Comparison of weed growth in control, fertilised and greened areas. In October of 2021, a weed survey was carried out in lupin (Lupinus albus L.), common vetch (Vicia sativa L.), oil radish (Raphanus sativus var. oleiferus L.) and buckwheat (Fagopyrum eculentum Moench). During the weed survey, we determined the different weed species and their abundance. In terms of seed rates, the higher seed rates for lupin, oil radish, and buckwheat may be worth choosing for weed suppression. Plots in rotation III had the lowest weed incidence of all greening crops. The probable reason for this finding is that there was no prior greening in rotation III. For greening, the choice of buckwheat and oil radish will result in higher weed pressure. The most important weeds were the cereals sown before the greening crop. Fertilised plots had minimally fewer weeds than control plots. Research results show the difficulties of weed control in herbicide-free greening crops.

IDENTIFICATION OF BROADLEAF WEEDS IN MATURE COCONUT PLANTATIONS IN TIAL VILLAGE, CENTRAL MALUKU REGENCY, MALUKU PROVINCE, INDONESIA

Coconut (Cocos nucifera L.) is a species to be cultivated in Mollucas. Recently, the population of coconut plants has to be decreased as a result of broad leaf weeds that impede the growth of coconut, especially in the nursery phases. The identification of broad leaf weeds is the first step in controlling weeds. However, until now, there has been no research on the influence of broad leaves weed species is important as the base of accurate weed control. This research on broad leaf weed composition in the coconut planting area is important as the base of accuracy is based on Summed Dominance Ratio (SDR) at the production plant in Tial Village, Village Central Mollucas District. This research uses the weed survey method type quadrat method with a sample plot size of 1 m x 1m. The result shows that 13 species of broad leaves weed, 12 families in the areal coconut planting in Tial village

Weed Survey on Wheat in the Northern State, Sudan

A weed survey was conducted in seven locations in Dongolaarea during the winter season of 2008/2009 to determine the mostprevalent weed species associated with wheat (Triticum aestivum L.). Astratified random sampling procedure was adopted and each location wasdivided into fields, of which 10 were randomly selected. Number ofindividual weed species was determined in 10 quadrates, each 1 m 2 . Thefield density, field frequency, field uniformity, relative field density,relative field frequency, relative field uniformity and relative abundanceof the species were determined. The data revealed the presence of 29species of annual and perennial weeds belonging to 15 families. Thehighest number of species occurred in Elmasakeen and Sheikh Shareef,while the lowest was recorded in Selaim basin. Sinapis arvensis, Cynodondactylon, Malva palviflora, Convolvulus arvensis, Chenopodium albumand Sorghum arundinaceum occurred at high relative abundance. Specieswith moderate relative abundance were Cyperus rotundus, Trigonellahamosa, Eruca sativa, Chenopodium murale and Sinapis alba. The otherspecies occurred in few locations and exhibited low to very low relativeabundance

Weed Dynamics in Acid Saline Pokkali Ecosystem of Kerala

Background: Pokkali is a versatile rice- fish system of cultivation, producing naturally organic rice along the waterlogged coastal regions of Kerala. The weed flora of Pokkali rice fields is different from other rice ecosystems. Diverse weed flora appears in low saline phase, when rice is cultivated, but they dry up and decompose in high saline phase. With time, significant deviations have been reported in various climatic parameters and as a result, the weed spectrum has also undergone changes. Methods: Two level stratified surveys and anotomical studies were conducted during Kharif 2017 and 2018 to study the weed flora in five major Pokkali growing blocks of Kerala. Two panchayaths (political village units) from each block and two padasekharams (group farming units) in each panchayath were selected for surveying. To understand the adaptive mechanism of weeds in saline soil condition, anatomical studies were performed on individual weed species. Result: Cyperaceae family dominated in the ecosystem with more number of species. Diplachne fusca and Eleocharis dulcis were the major weeds. Echinochloa crus-galli, a dominant weed reported in earlier weed survey was found confined to very few locations and the frequency got reduced from 80% to 12.5%. In addition, Sphenoclea zeylanica was observed as an emerging weed with notable morphological adaptations. Floating ferns like Najas graminea and Hydrilla verticillata caused problems to aeration in the water in fields.

The utility of the 'Arable Weeds and Management in Europe' database: Challenges and opportunities of combining weed survey data at a European scale.

Over the last 30 years, many studies have surveyed weed vegetation on arable land. The 'Arable Weeds and Management in Europe' (AWME) database is a collection of 36 of these surveys and the associated management data. Here, we review the challenges associated with combining disparate datasets and explore some of the opportunities for future research that present themselves thanks to the AWME database. We present three case studies repeating previously published national scale analyses with data from a larger spatial extent. The case studies, originally done in France, Germany and the UK, explore various aspects of weed ecology (community composition, management and environmental effects and within-field distributions) and use a range of statistical techniques (canonical correspondence analysis, redundancy analysis and generalised linear mixed models) to demonstrate the utility and versatility of the AWME database. We demonstrate that (i) the standardisation of abundance data to a common measure, before the analysis of the combined dataset, has little impact on the outcome of the analyses, (ii) the increased extent of environmental or management gradients allows for greater confidence in conclusions and (iii) the main conclusions of analyses done at different spatial scales remain consistent. These case studies demonstrate the utility of a Europe-wide weed survey database, for clarifying or extending results obtained from studies at smaller scales. This Europe-wide data collection offers many more opportunities for analysis that could not be addressed in smaller datasets; including questions about the effects of climate change, macro-ecological and biogeographical issues related to weed diversity as well as the dominance or rarity of specific weeds in Europe.

Effects of Weed Control Treatments on Weed Composition and Yield Components of Winter Wheat (Triticum aestivum L.) and Winter Pea (Pisum sativum L.) Intercrops

Intercropping is an ancient and worldwide agricultural practice expected to become more prevalent in Hungary due to the accumulating impact of climate change. In this study, the plant association of pure winter wheat (Triticum aestivum L.) and pure winter pea (Pisum sativum L.) was analyzed without weed control and with applied herbicides at different intervals (pre-emergence, early and late post-emergence) and different active herbicide ingredients. Two growing seasons, 2018–2019 and 2019–2020 were examined to compare weed composition and weed cover to evaluate the effect of the applied herbicides at different timings. To determine weed control efficiency, weed surveys were conducted six times in each growing season. The effect of cultivation methods (pure and mixed plots) on the development of plants was also measured by yield production analysis. Findings from these investigations indicate that there were significantly more weed species and occurrences of weeds in pure wheat and pure pea plots compared to mixed plots. In addition to cultivation and weed control treatments, meteorological events significantly influenced the development of the plants, and thus the yield components.

Weed Types and Dynamics Associations with Catena Landscape Positions: Smallholder Farmers’ Knowledge and Perception in Zimbabwe

Weed infestation is considered as one of the major biotic stresses of dryland crop production. Weed species occurrence, abundance, and densities differ due to spatial soil fertility variability, and management practices by farmers. Weed surveys are therefore vital for tracking such changes and in turn developing appropriate weed management strategies for farmers. A weed survey was carried out in Wedza, eastern Zimbabwe to assess farmer knowledge and perceptions of major weeds in maize fields across catena landscape positions. A multistage sampling procedure was used, involving random sampling of six villages within a 20 km radius, divided according to the catena position and economic status of the farmer. Two hundred and forty-nine (249) households were interviewed using a structured questionnaire. The data were coded and processed using the CSPro software package, and then analysed using the SPSS program. Factors that predicted the spatial distribution of weeds were determined using a binary logistic model. From the survey, 52.8% and 42.3% of farms are on the upper catena and lower catena, respectively, and only 4.8% are on the middle catena. Thirty-one weed species belonging to 15 families were listed by respondents and identified by enumerators in the study area and were categorised into three main groups (broadleaf, grasses, and sedges). Acanthospermum hispidum and Striga asiatica were considered as problem weeds in maize fields on the upper and lower catena, respectively. Xanthium strumarium was perceived as a new invasive weed in low-lying arable fields. The binary logistic model predicted farm location on the landscape and fertiliser use as the main factors affecting weed types, distribution, and abundance. Moreover, farms on lower catena had more Striga infestations compared to upper catena. The results suggested an integrated weed management approach to control A. hispidum, Striga species, and the invasive fast-spreading X. strumarium in the area.

Weed suppression capacity of camelina (Camelina sativa) against winter weeds: The example of corn-poppy (Papaver rhoeas)

Crop rotation is one of the most relevant tools for Integrated Weed Management (IWM). In semiarid Mediterranean areas, the crop rotation is limited by climatic conditions. Camelina (Camelina sativa (L.) Crantz) is an interesting option to introduce due to its tolerance to cold and drought and because of its short life cycle, which allows a flexible management for weed control. In this study, the capacity of camelina to reduce the growth and seed rain of corn poppy (Papaver rhoeas L.) was studied. The experiment was carried out at the University of Lleida during three seasons (2018–19, 2019–20 and 2020–21). In each season, three camelina varieties (GP204, Sonny and Joelle) and barley were sown on two sowing dates (SD) (between November and February) in 1.5 m wide × 10 m long plots with three replications. Three 0.5 × 0.5 m2 quadrates were established, where five P. rhoeas plants from a natural population were allowed to grow in each SD. Additionally, every season in March, weed surveys were performed to observe the effect of the SD in the weed flora. Results show that delaying the SD effectively controlled winter weeds, including P. rhoeas, which could not establish in the second SD plots. The growth of P. rhoeas in the first SD was reduced similarly in the presence of the crops in 2018–19, but camelina competed better against it in 2020–21, while barley competed better in 2019–20. Due to the short life cycle of camelina and its earlier harvest date, the potential seed production of P. rhoeas was reduced by 34% in 2018–19, 52% in 2019–20% and 70% in 2020–21, while this reduction was of 23% in 2018–19% and 56% in 2020–21 in barley. The capacity of camelina to reduce the presence of corn poppy and its seed production in semiarid conditions should be considered as a tool for IWM.

Weed response in winter wheat fields on a gradient of glyphosate use in the recent past

In the discussion about glyphosate-based herbicides, the question of how repeated applications affect biodiversity has become prominent. However, approaches are lacking to assess direct glyphosate effects under real, on-farm field conditions. This paper focuses the effect of post-harvest and / or pre-sowing glyphosate use on weed density, richness, diversity and composition in arable cropping systems. An on-farm monitoring was conducted in Northeast Germany over the period 2014–2016. The pre-harvest weed survey took place on a total of 97 winter wheat fields. Farmers´ records of field management were obtained for the surveyed fields for the year in which a field was visited and also the nine previous years. A total of 66 species over the three survey years were identified shortly before harvest. Overall, the highest number of specimens were found for the species Viola arvensis Murray, Fallopia convolvulus (L.) Á. Löve and Polygonum aviculare L. This study provided evidence that intensive glyphosate use in the recent past significantly sinks species richness by 31% and the true diversity by 40%. In contrast, weed density and weed community composition were not affected by past glyphosate use intensity. Indeed, we found that glyphosate-based or inversion tillage-based cropping systems induce different weed community patterns. The results of this study provide one more piece in the puzzle for the assessment of the impact of glyphosate use on the environment.