Weed Composition Research Articles

The Weeds in Sunflower Crops when Grown in Arid Conditions of The Steppe of Ukraine

In the arid conditions of the Steppe of Ukraine, the species composition of weeds characteristic of this soil-climatic zone develops. The correctly chosen method of basic soil tillage determines the effectiveness of weed suppression while simultaneously improving the growing conditions for sunflower varieties and hybrids. The purpose of the study was to identify the species composition of weeds in the steppe zone and establish the effectiveness the methods of basic tillage of soil in the technology of growing sunflower hybrids aimed at suppressing weeds and reducing the quantity of weeds in agrocenoses. Research has established that weeds of sunflower agrophytocenoses are represented by 78 species that belong to 2 classes, 18 orders, 27 families, 62 genera. In the agrophytocenosis of sunflower, the largest number of 93.5-96.3% is represented by dicotyledonous weeds (Magnoliopsida). The species composition is dominated by weeds of the Compositae family (Asteraceae) of the dicotyledonous class (Magnoliopsida), which leads to a significant decrease in the yield level. According to the species composition, 3 groups of weeds of the Asteraceae family (Asteraceae) were identified, of which 1 group of weeds is the most harmful and leads to the formation of a minimum yield of sunflower hybrids Yason and Daryi of 1.77-1.79 t/ha. The use of non-moldboard tillage leads to a percentage increase in the share of air dry mass of weeds of the Asteraceae family by 11.1-13.1%, while reducing the yield of sunflower hybrids by 0.13-0.21 t/ha. Thus, with the established species composition of weeds and the quantity of weeds, the use of plowing in sunflower cultivation technology makes it possible to form a maximum yield of 2.07-2.24 t/ha, providing more effective weed suppression in sunflower agrophytocenoses with a minimum percentage of air-dry mass of weeds of the Asteraceae family to the total number of weeds of 21.1-24.1%.

How do farming practices influence the richness and floristic composition of weeds in some Mexican maize fields?

The milpa is a historically successful Mesoamerican agroecosystem, consisting of a mixture of cultivated plants with associated vegetation that is partially managed. Conventional farming practices, like weeding and fertilization, have modified some ecological parameters of weeds, affecting their ecological, evolutionary, cultural, and productive roles. This study explores these changes from various perspectives: field experiments in fields with different management histories, contrasting treatments within these fields, farmer interviews and field walks, in San Bartolo del Llano, Ixtlahuaca, Mexico. A field experiment in milpas with different histories of farming practices (traditional vs conventional) was conducted to understand (a) the effect of the history of farming practices on richness, composition, and biomass of aboveground weed vegetation and the seed bank, (b) the effect of contrasting weeding treatments within these fields on the biomass of weeds and maize, and (c) farmers’ traditional knowledge and use of these plants. Farming practices did not affect species richness (43 species) of the aboveground weed vegetation, but a history of herbicide use increased monocot biomass and reduced useful weeds. More introduced monocots were recorded in conventionally managed fields; manual weeding led to more species, including more monocots and dicots, a higher biomass of weeds, and more native and exotic species. The composition differed between plots with different farming practices and treatments. The seed bank contained more species (54) than the aboveground vegetation. Maize ears’ and total biomass were somewhat higher in conventionally treated fields, but no differences were found between treatments. We found a considerable species turnover, with some species disappearing or becoming rare, particularly useful ones, and others being introduced‚ particularly grasses. Traditional management can help farmers keep useful weeds and higher biodiversity, thus contributing to overall productivity. Though herbicides reduce labor requirements, improved management should combine the benefits of traditional farming with some modernization.

Species composition of weeds in soybean Glycine max crops in the Belgorod region

The weed species were studied based on monitoring data in soybean crops in the Belgorod region. A total of 37 species of weed plants were found, most of which belong to the families of Compositae, Gramineae, and Cruciferae. The significance of each species in soybean crops was evaluated on its partial activity, which was determined based on both its occurrence and projective cover. Chenopodium album, Echinochloa crusgalli, Amaranthus retroflexus, Fallopia convolvulus and two Setaria species (S. viridis and S. pumila) demonstrated the highest scores of partial activities. Cirsium incanum, Persicaria hydropiper, Convolvulus arvensis, Solanum nigrum, Polygonum aviculare s. str., Xanthium strumarium were shown to have rather high scores of partial activities. About a third of species (13) are low-active: Cyclachaena xanthiifolia, Sonchus arvensis, Euphorbia virgata, Descurainia sophia, Stachys annua, Artemisia vulgaris, Tripleurospermum inodorum, Lactuca serriola, Consolida regalis, Artemisia absinthium, Sonchus asper, Centaurea cyanus, S. italica. Twelve weed species were rated as inactive in soybean crops of the Belgorod region. The results of the study may be used to develop a regional strategy for protecting soybean crops from weeds in the Belgorod region.

Composition and Potential Values of Species in the Agricultural Area of Kupang Indonesia

This research was conducted to investigate the composition and potential value of weeds species in an agricultural area of Kupang, Indonesia. Two sites (dry and wet site) were selected subjectively. In each site, three stands (100 m x 100 m) were placed subjectively and in each stand 25 plots (1 m x 1 m) were placed randomly (∑150 plots). In each plot, all weed present were recorded and their density and percentage cover calculated. Each species was grouped into broad-leaves, sedges, and grasses. To determine the potential value of the weeds, all weeds were grouped into whether they medicinal plants, animal feed or food ingredients. For each species, the number of individuals, dominance, frequency, and Importance Value Index (IVI) were calculated. Species diversity was also calculated using the Shannon-Wienner Diversity Index (H'). Overall, 46 weed species were found. The weeds with the highest IVI (>5.00%) were Panicum repens L (IVI 14.80%), Bolboschoenus maritimus L. Palla (IVI 10.32%), Alternanthera sessilis L (IVI 7.47%), Cyperus rotundus L, (IVI 6.97%), Digitaria ciliaris (IVI 6.69%), Cyperus elatus L (IVI 6.63%), and Ischaemum timorense Kunth (IVI 5.02%). In general, the composition of weeds between the dry and the wet sites were relatively different. Based on the number of species and diversity index, the weed community in the wet site was relatively higher than that in the dry site. Based on the IVI, the dry site tended to be dominated by grasses and broad leaves while the wet site tended to be dominated by sedges. Based on IVI, 42.80% of all the weed species present had the potential to be used as medicinal plants, 39.81% as animal feed, and 17.39% as human food. Overall, most weed species studied had the potential to be used as medicinal plants, animal feed, and food ingredients. The potential of this weed needs to be studied more deeply in the future, including their use as an alternative source of medicine and food, especially as demand increases in the future.

Ecology and Management of Sedges in Direct-seeded Rice: A Review

Sedges, resilient weeds from the Cyperaceae family, pose a significant threat to direct-seeded rice cultivation due to their perennial nature and robust propagules, which endure harsh conditions. Their emergence, growth and seed production during fallow periods contribute significantly to seed banks, making their management challenging compared to other weed types. Water levels in paddy fields dictate weed composition, favouring sedges and grasses under saturated conditions but shifting to grass weeds during cropping seasons, influenced by factors like soil conditions and rainfall. Managing sedges requires a multifaceted approach due to their perennial hydrophilic and pro-alkaline nature with extensive propagules. Sedges possessing strong root system with morphological similarities necessitate continuous weed control throughout the cropping season during the critical period ranging from 15 to 60 days after sowing for wet and dry direct-seeded rice. Effective weed management practices proved crucial for minimizing yield losses caused by infestation of Cyperus difformis, Fimbristylis miliacea and Schoenoplectus juncoides by many researchers. Various methods, including cultural practices like stale seedbeds, physical methods like summer tillage, biological approaches such as integrating poultry and chemical interventions like herbicide application, are utilized for sedge management in rice fields. Higher efficacy of ethoxysulfuron for management of majority of sedge weeds in rice has been reported by many workers. However, relying on a single strategy is insufficient to keep sedge populations below the threshold, necessitating a comprehensive and adaptable approach to weed control in rice cultivation.

Species composition of weeds in various crop rotations of the Mari El Republic

The article presents the results of long-term experiments to determine the species composition of weed vegetation, the dynamics of weeds on crops in various crop rotations is established. In order to develop rational measures to control weeds, their species and quantitative composition were studied. The experiment was carried out on the field of the Mari Research Institute of Agricultural Sciences, a branch of the Federal State Budgetary Educational Institution of the North–East, founded in 1996 and 1998. The duration is four rotations of six–field crop rotations. The soil is sod–podzolic medium loamy. The purpose of the work is to determine the species composition of weeds in crop rotations, to identify the influence of crop rotations, to trace the dynamics of crop contamination. The share of juvenile weeds accounts for 26 species, perennial – 10. The minimum amount of weed vegetation was noted in the III fruit–bearing crop rotation (average over the years – 49.55 pcs/m2), the maximum – in the grassy (61.15 pcs/m2). According to factor B, in all years of research on juvenile weeds, the lowest

Characteristics of several soybean varieties (Glycine max L.) and weed management systems in an effort to increase productivity in low land rice

Soybean productivity in paddy fields is influenced by variety selection and grass management practices. This study aimed to assess several soybean varieties and evaluate the impact of soil processing and weed control on Summed Dominance Ratio (SDR), as well as growth and yield of soybean seeds. Conducted in Sungai Kakap, Kubu Raya, West Kalimantan, during 2021, the research employed a Randomized Block Design with 15 treatments and 3 replications. Treatments included various combinations of tillage methods, weed control techniques, and mulching. The study identified four soybean varieties Detap-1, Derap-1, Devon-1, and Dena-2 with large seed sizes and high yields. These varieties also exhibited resistance to common pests such as Etiella zinkenella, Riptortus linearis, and Spodoptera litura. Weed composition analysis revealed O. sativa and Ageratum conyzoides as dominant species. Weed dry weight was lowest in the perfect tillage + pre-emergence herbicide treatment and highest in the minimum tillage + weeds are not controlled treatment. The highest plant growth and seed yield were observed in the minimum tillage + pre-emergence herbicide and perfect tillage + pre-emergence herbicide treatments. Plant height, number of pods per plant, number of seeds per plant, and dry seed yield were significantly higher in these treatments compared to others. In conclusion, varieties Detap-1, Derap-1, Devon-1, and Dena-2 possess suitable physical characteristics for cultivation in Indonesia. The most effective grass management models identified were minimum tillage + pre-emergence herbicide and perfect tillage + pre-emergence herbicide. These findings contribute to optimizing soybean cultivation practices, emphasizing varietal selection and weed control strategies for improved crop performance.

Impact of weed control methods and staking on the growth, yield, and weed response of cucumber (Cucumis sativus L.) in Kano, Sudan Savanna, Nigeria

Cucumber growing is becoming increasingly popular in Nigeria's Sudan savanna region due to its health benefits and minimal impact on the soil. However, weed infestation is a major challenge that can significantly reduce yields, by up to 45-95%. In view of this, two trials were conducted at the Teaching and Research farm of the Faculty of Agriculture and the net house of the Centre for Dryland Agriculture of the Bayero University Kano to examine the effects of weed control and staking on cucumbers during the 2021 dry season. The trial consisted of eight weed control treatments and two staking methods which were arranged in a split plot design with three replicates, with staking assigned to the main plot while weed control was assigned to the sub plots. The study analyzed data on growth and yield, using Genstat (17th edition) and significantly different means were separated using the Student Newman-Keuls Test (SNK) at a 5% level of probability. Results showed a higher composition of grass and broadleaf weeds in open fields compared to controlled net house environments. Weed Control Efficiency (WCE) was greater in weed-free plots, but Butachlor and metolachlor significantly outperformed other treatments, providing higher WCE. The herbicidal treated plots significantly resulted in longer days to 50% emergence than other treatments, while it also resulted in a shorter number of days to 50% flowering and fruiting than weedy check. The vine length, number of leaves, leaf area, and chlorophyll content were highly significant (p<0.01) in weed free, butachlor at 1.5 + Imazethapyr 1.5 kg a.i.ha-1 post emergence ( POE) and metolachlor at 1.5 + Imazethapyr 1.5 kg a.i.ha-1 POE. Similarly, yield and yield attributes followed the same pattern as obtained in growth components. Staking of vines on the other hand significantly resulted in greater growth and yield of cucumber. Based on these findings, farmers in the study area are advised to grow cucumber staked with the application of Butachlor at 1.5 + Imazethapyr 1.5 kg a.i.ha-1 POE and metolachlor at 1.5 + Imazethapyr 1.5 kg a.i.ha-1 POE for sustainable weed management.

THE EFFECT OF TILLAGE TECHNOLOGY ON THE AMOUNT OF WEEDS AND THE YIELD OF POTATOES

Weeds deprive agricultural plants of life factors and deteriorate their productivity and quality indicators. Therefore, agricultural experts try to reduce the amount of weeds to minimize the damage caused by it. First of all, it is important to know their biological characteristics, extent of spread, species composition, which is reflected in the article, in order to carry out the measures against weeds correctly. It is known from the species composition of weeds spread in potato crops that it is possible to eliminate the damage caused by applying the correct soil cultivation technology. In the research work, when the intermediate plant (field pea + oat mixture) planted under rotation conditions is disked and mixed with the soil and plowed as a result of soil cultivation measures, the reduction of the amount of weeds significantly increases the productivity. Here, the yield increase was 58.5 q/ha or 37.55% compared to the variant that was left fallow after wheat, plowed 25-30 cm and sprayed with herbicide. This suggests that it is possible to significantly increase productivity while minimizing the use of herbicides by applying the correct tillage technology in potato crops.

ECOLOGICAL ATTRIBUTES OF WEEDS AS INDICATORS OF SUSTAINABILITY IN AGROECOSYSTEMS OF THE SOUTHEASTERN REGION OF MEXICO CITY

<p><strong>Background:</strong> Pre-Hispanic agroecosystems in Mexico City have changed the kind of crops, management practices, tools, and inputs, seriously impacting their biocultural value and sustainability. Previous studies have demonstrated these changes' economic, cultural, and political consequences. However, their effects on biodiversity have not been considered. The present study characterized the management carried out in three agroecosystems in the southeastern area of Mexico City and its possible relationship with agrobiodiversity. <strong>Objective</strong>: To evaluate the contribution of diversity, abundance, and composition of weeds as components of the sustainability of agroecosystems in Milpa Alta, Tláhuac, and Xochimilco municipalities. <strong>Methodology: </strong>179 interviews were conducted with campesinos. Weeds sampling in 30 plots, recording the abundance and frequency of each species. These data were used to estimate different ecological parameters. Information on management practices was transformed to develop an “agroecosystem sustainability index.” A multivariate analysis was applied to compare weed attributes between agroecosystems and spaces and to detect possible relationships between the index and ecological parameters. <strong>Results:</strong> 156 species were recorded. The <em>slope</em> had the highest diversity, and <em>ciénega</em> had the lowest. More than half of the weeds were native, and the <em>slope</em> exhibited the highest number. The Importance Value indicated no dominant species on the <em>slope, </em>opposite to<em> chinampa and ciénega</em>. Species composition also differed between the three agroecosystems. <em>Chinampa</em> was impacted the most, whereas the <em>slope</em> was least affected. <strong>Implications:</strong> The displacement of traditional crops and agricultural practices and the incorporation of technological practices have modified the ecological attributes of weeds, like their abundance and composition. <strong>Conclusion:</strong> Starting from the argument that ecological attributes of weeds can be used as an indicator of sustainability, the <em>slope</em> resulted in the agroecosystem being most sustainable and should be used as a model to recover the agrobiodiversity of <em>ciénegas</em> and <em>chinampas</em>. </p>

Do rotation and fertilization practices shape weed communities and affect rice yield in low input rainfed agroecosystems in the Malagasy highlands?

Weeds are a major threat in tropical regions where climate conditions favor their growth and development. This is particularly true in low-input rice-based cropping systems in the Malagasy highlands, where weed management is mainly done by manual removal. Crop rotation is often promoted as an efficient way to control weed infestations, while the role of fertilization is more controversial. In this study, we compared rice monoculture to three rainfed rice-based two-year rotations: rice followed by groundnut, rice followed by sorghum-cowpea mixture, and rice followed by a velvet-bean crotalaria mixture. Each rotation was tested with two levels of fertilization (5 t DM ha−1 organic manure, sole or in combination with mineral fertilizer - 400 kg ha−1 NPK + 200 kg ha−1 urea). We assessed the effect of rotation and fertilization on weed composition, diversity, biomass and rice yield. Additionally, the farmers’ perception of weed harmfulness and the relation between their assessment of weed harmfulness and rice production was tested. Our results showed that weed biomass significantly decreased rice yield but only under the low fertilization level. The rotation of rice with the velvet bean-crotalaria mixture was efficient in reducing weed biomass, modified weed community composition and allowed to achieve the highest rice yield. A significant negative relationship was found between weed community harmfulness index and weed species richness. Yet, the lowest rice yield was observed under rice monoculture despite a higher species richness over years and under high fertilization level. The lack of significant correlation between the harmfulness index and the actual rice yield is probably because our index is partly based on farmer’s perception, and only on major weeds. More studies on tropical weed harmfulness are needed to support the design of ecologically intensified cropping systems.

Assessment of weed species composition of Cabbage family plants (Brassicaceae) of ruderal and segetal habitats of the Ussuriysk urban district of the Primorsky Territory

The data on the species composition of weeds from the Cabbage family (Brassicaceae) that grow stably in the territory of the Ussuriysk urban district of the Primorsky Territory and dominate in agrocenoses are given in the article. Objectives of the study are: to summarize data on the most widespread (background) plant species of natural and adventive flora of the Cabbage family of ruderal and segetal habitats of the Ussuriysk urban district of the Primorsky Territory; to note the species listed in the "Black Book of Flora of the Far East" and growing within the limits of the urban district; to cite the species composition of herbaceous plants of the Cabbage family found in the Ussuriysky Nature Reserve. Field studies were conducted using the traditional route-reconnaissance method in 2010–2023. Phenological observations, geobotanical descriptions of identified habitats, collection, identification of herbarium material and photographing of objects from growing sites were carried out. Of the 23 species of Brassicaceae cited in the paper, ten are invasive in the ecosystems of the Far Eastern Federal District: Armoracia rusticana Gaertn., Mey. et Scherb., Berteroa incana (L.) DC., Brassica juncea (L.) Czern., Bunias orientalis L., Capsella bursa-pastoris (L.) Medik., Hesperis matronalis L., Lepidium densiflorum Schrad., Thlaspi arvense L., Turritis glabra L., Velarum officinale (L.) Reichenb. Most of them, with the exception of B. juncea, C. bursa-pastoris and Th. arvense, are classified as plants that do not cause significant damage at this stage of development. Ruderal habitats are also sites of biodiversity conservation. In the V.L. Komarov Ussuriysky Nature Reserve, 16 species of Cabbage, of which Barbarea orthoceras, B. incana, and Th. arvense are segetal, were identified on the territory of the Ussuriysk Urban District.

Crop rotation as a biological factor of weed control in spring barley crop in the Sonkovsky district of the Tver region

Spring barley is widely used for fodder and food purposes. Modern farming systems involve the use of short crop rotations, which leads to a deterioration in the phytosanitary condition of the fields, so improving the structure of the fields is a priority. The potential of the crop will not be fully exploited if local resources are used irrationally. Weed components, in turn, inhibit crop growth and reduce the amount of product obtained. Successful weed control is based on a systematic approach involving agrotechnical, biological and chemical measures. The pursuit of yield without the optimization of technological processes leads to low profitability of agricultural production, so a properly selected predecessor is the key to profit for agricultural producers. The aim of the study is to regulate barley weeds in the Tver region using biological methods. Crop rotation is the cheapest method without material costs. Predecessors have a different effect on the species and quantitative composition of weeds. The maximum clogging in the sum of weed vegetation, including biological groups, was found for the oat predecessor (62 pcs/m2 of juvenile weeds and 53 pcs/m2 of perennial weeds). The best predecessor for spring barley in the experiment is corn for silage, after which the number of Erysimum cheiranthoides decreased to 3 pcs/m2, which caused an increase in the yield of the studied crop from 4.5 to 7.4 t/ha.

How the Management and Environmental Conditions Affect the Weed Vegetation in Canary Grass (Phalaris canariensis L.) Fields

Canary grass (Phalaris canariensis L.) is a versatile crop with global significance; it is primarily cultivated for its small elliptical seeds, which are used as bird feed and for human consumption. This crop is adapted to various climates and soils, so it can be grown successfully in Hungary. However, challenges such as weed control, climate change impacts, and soil factors require strategic management for sustained success in canary grass cultivation. Our study investigated the impact of management and environmental (as seasonal and soil) factors on pre-harvest weed vegetation in canary grass fields in Southeast Hungary between 2017 and 2020. In addition to showing the weed vegetation of the canary grass, the aim of our work was to promote more effective weed management of canary grass by revealing correlations between soil, seasonality, and management variables, influencing weed diversity and coverage. Using the analysis of covariance (ANCOVA) and correlation tests, we tested significant variables, providing insights into the complex interactions affecting weed composition. A redundancy analysis (RDA) further unveiled the relationships between explanatory variables and weed species’ composition. The findings offer valuable information for effective weed management strategies in canary grass cultivation. Our comprehensive study on canary grass fields in Southeast Hungary sheds light on significant factors influencing weed composition and abundance. The average weed coverage was 10.8%, with summer annuals and creeping perennials being the most prevalent life forms. Echinochloa crus-galli, Cirsium arvense, Xanthium italicum, and Setaria viridis were among the dominant species. ANCOVAs revealed the impact of soil, management, and seasonal factors on weed cover, species richness, diversity, and yield levels. Soil properties like texture, pH, and nitrogen content showed varying effects on weed parameters. The vintage effect, tillage systems, and farming practices also played crucial roles. The redundancy analysis highlighted the influence of the year, soil sulfur content, and winter preceding crops on weed composition. In conclusion, the herbaceous vegetation in the studied area is dominated by summer germinating and creeping perennial species. Despite slight differences in average coverage and occurrence, a well-defined set of significant species is evident. Multicollinearity among variables suggests limitations to further increase the number of variables that can be included in the analysis. The ANCOVAs showed that the soil, seasonal, and farming variables significantly influence overall weed vegetation and crop yield, with a lesser impact on species richness and diversity. The reduced RDA model highlights the strong influence of the year on species’ composition, emphasizing the inherent factors during canary grass cultivation that are challenging to modify through farming practices.

Tezcalera, a traditional agricultural system that promotes native wild and agrestal germplasm conservation

Background: Traditional agricultural systems in Mesoamerica are adaptations of ancient farmers to the complex and varied environments. Tezcalera represents one of them. Questions: How is the environmental context under which the tezcalera develop? Which management practices are followed in tezcalera? How do these management practices affect weeds' richness, composition, and abundance? How do these management practices contribute to the resilience of the agricultural system, the tropical dry forests, and to the maintenance of subsistence resources? Studied species: Weeds growing in tezcaleras with different management. Study site and dates: Zumpahuacán, State of México, 2020-2021 Methods: Twenty-four collaborators were interviewed about the environmental, technological, and cultural aspects of tezcalera. We recorded weeds' richness, composition, and abundance in seven plots with different management histories. Results: Tezcaleras originate from the slash-burn process and follow different paths: tlacolol-milsol-shallow plot, potrero, and recently, Agave crop. We recorded 161 morphospecies from 45 botanical families; 95 % were native to tropical dry forests. Twenty-five species are endemic to the Balsas region, and thirty-four are at risk. Richness and abundance varied between tezcaleras, where tlacolol plots exhibited the highest values. Plant composition was similar; 65 % had intangible or tangible values. Conclusions: Tezcalera is a biocultural unit and a resilient agroecosystem. Traditional practices remain and positively impact the richness and composition of native weeds. The uncontrolled use of herbicides and the introduction of Agave crop are displacing traditional crops and modifying traditional practices, risking local agrobiodiversity.

Morpho-physiological adaptations to weed competition impair green bean (Phaseolus vulgaris) ability to overcome moderate salt stress.

The two stresses of weed competition and salt salinity lead to crop yield losses and decline in the productivity of agricultural land. These constraints threaten the future of food production because weeds are more salt stress tolerant than most crops. Climate change will lead to an increase of soil salinity worldwide, and possibly exacerbate the competition between weeds and crops. This aspect has been scarcely investigated in the context of weed-crop competition. Therefore, we conducted a field experiment on green beans (Phaseolus vulgaris ) to investigate the combined impact of weed competition and salt stress on key morpho-physiological traits, and crop yield. We demonstrated that soil salinity shifted weed composition toward salt tolerant weed species (Portulaca oleracea and Cynodon dactylon ), while it reduced the presence of lower tolerance species. Weed competition activated adaptation responses in green bean such as reduced leaf mass per area and biomass allocation to the stem, unchanged stomatal density and instantaneous water use efficiency, which diverge from those that are typically observed as a consequence of salt stress. The morpho-physiological modifications caused by weeds is attributed to the alterations of light intensity and/or quality, further confirming the pivotal role of the light in crop response to weeds. We concluded that higher yield loss caused by combined salt stress and weed competition is due to impaired morpho-physiological responses, which highlights the negative interaction between salt stress and weed competition. This phenomenon will likely be more frequent in the future, and potentially reduce the efficacy of current weed control methods.

Effect of Zero Tillage and Different Weed Management Practices in Direct Seeded Rice (Oryza sativa L.) in Indo Gangetic Plains: A Review

Millions of rural and urban residents depend on the rice-wheat cropping system of the Indo-Gangetic plains (IGP) for their food security and means of subsistence. About 18 million hectares (m ha) of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) are rotated across Asia, of which 13.5 m ha are in the Indo-Gangetic Plains (IGP) of India. This agricultural system’s viability is currently in jeopardy due to static yields of both wheat and rice and a decline in total factor productivity. The North West IGP's high input crop culture has allowed weeds to dominate the weed flora, including P. minor in wheat and Echinochloa crus-galli L. in rice. Farmers in North West India have largely used zero tillage for growing wheat, and recently, farmers in the eastern IGP have done the same. Perennial weeds in the Eastern Indo-Gangetic Plain, such Cynodon dactylon L. and Cyperus rotundus L. can occasionally be a nuisance under zero tillage. As an alternative to puddled transplanted rice, the focus is currently on dry direct-seeded rice and machine transplanting of non-puddled rice. As a result of changes in tillage, crop establishment techniques, water use, and weed control brought on by the switch from transplanted rice to direct seeded rice, weed composition and diversity frequently vary. In nations where DSR is frequently used, weedy rice has become a significant concern. Using the Zero Tillage DSR system, certified seed, cultivars that are weed-competitive, stale seedbed procedures, living mulches, and chemical and biological weed control might change weed-crop competition in the crop's favour. However, more research on emergence characteristics and mulching effects of different crop residues on key weeds under zero tillage, cover cropping, and breeding crops for weed suppression will strengthen nonchemical weed management programs. In this review, we examine the extent of weed infestation, weed flora shift and the non-chemical alternative weed management in DSR.

Засоренность посевов яровой пшеницы при применении ресурсосберегающих технологий обработки почвы

The purpose of research is to study the influence of primary tillage systems on the weed infestation of spring wheat crops placed on green manure fallow in a five-field grain-fallow crop rotation. Objectives: to study the weed infestation of spring wheat crops; to establish the effectiveness of herbicide use; to determine the grain yield of spring wheat. The study was carried out in 2017–2022 in the conditions of the Krasnoyarsk forest-steppe on leached chernozem, which is characterized by an increased humus content (6.1–8.0 %) and a neutral reaction of the soil solution (pH – 6.1–7.0). The object of the study is spring wheat of the Novosibirskaya 15 variety. The research results showed that the bulk of weeds in the studied variants are represented by a group of young plants. Different tillage systems influenced the quantitative and species composition of weeds. When soil tillage is minimized, the number of weeds increases and their species composition changes. In spring wheat crops under the studied tillage options, the most numerous group of weeds were young ones. The most common species found in spring wheat crops were bedstraw (Galium aparine L.) and millet (Echinochloa crusgalli (L.). Their share in the total number of weeds in the variant with plowing was 71.4 %, without tillage – 81.4 %. There was a significant change in the share of biological groups of young and perennial weeds in the option without tillage during the study period. The share of young weeds in 2022 decreased compared to 2017 from 93.1 to 58.8 %, while the number of perennial weeds increased from 6.9 to 41.2 %.Over the years of the study (2017–2022), a change in the species composition of weeds was established. In the option without tillage, such species as yellow sow thistle, medicinal dandelion, hemlock, and small petal, which were absent in 2017, appear in spring wheat crops.

Weeds and Their Response to Changing Climate: A Review

Climate change is one of the most important parameters to cause alteration in weed composition, population growth, life processes, physiological development, and infestation pressure. A few of the weed species may become inactive, while the rest may become aggressive invaders. Weeds possess unique biological characteristics and ecological range that enable them to tolerate and successfully intrude in any ecosystem with varied environmental conditions. Rising carbon dioxide, will benefit C3 crops to expand their photosynthetic capacity, thus leading to increased biomass production and productivity, on the other hand increased temperatures will benefit the C4 crops. These differences in response of C3 and C4 crops to changing climate will influence crop-weed interaction, most likely at the expense of crop. Moisture is another important environmental factor which plays a major role in weed seed germination, thus the survival. Temperature and relative humidity influence the course of absorption, translocation, and metabolism of herbicides in plants, any change in their range leads to decreased herbicide efficacy and thus the weed control. Studies focussed on the performance of weeds under elevated environmental factors help to make strategic decisions on their management before having their impact on change in weed biological aspects, and foresee the future with elevated temperature and carbon dioxide conditions. Weeds such as Parthenium hysterophorus, Sphagneticola trilobata, Prosopis juliflora and Eichhornia crassipes, have been identified as potential future threats. Consequently, exploring the bioprospecting potential of these weeds is seen as an inevitable necessity.

Weediness of spring cereal ear crops depends on the forecrop, tillage, fertilizers and herbicides

Goal. To analyze the species composition of weeds, their dominant role and to determine the type and level of weediness of spring cereal ear crops depending on different forecrops, methods of basic tillage, fertilization systems and herbicides in the conditions of the Eastern Forest-Steppe of Ukraine.
 Methods. The investigations were conducted in field experiments of spring cereal crops (barley, wheat, triticale) in a stationary field, fixed nine-course-fallow-grain-row crop rotation by means of route surveys.
 results. According to the data of 2016—2018, during the cultivation of spring cereal ear crops in crop rotation after soybeans, corn for grain and sugar beets as forecrops, 38, 34 and 45 species of weeds were identified, respectively. In total, 52 species of weed plants were found in the crops, of which 27 species occurred after all forecrops. The largest number of weeds in agrocenoses was represented by early and late spring species (48.9—58.8%), and the second and third places were respectively occupied by wintering, winter and biennial (26.5—31.1%), and perennial (14.7—20.0%). The main species of weeds in cereal crops were: after soybean forecrop, Setaria glauсa, Echinochloa crus-galli, Chenopodium album, Ambrosia artemisiifolia, Cirsium arvense, Convolvulus arvensis; after corn for grain forecrop, S. glauсa, E. crus-galli, C. album, Amaranthus retroflexus, Solanum nigrum, A. artemisiifolia, Polygonum lapathifolium, C. arvense, C. arvensis; after sugar beets forecrop, S. glauсa, E. crus-galli, C. album, A. retroflexus, S. nigrum, A. artemisiifolia, P. lapathifolium, C. arvense, Sonchus arvensis, C. arvensis. The largest number of weeds (33 species each) was found after sugar beets forecrop in the control (plowing, without fertilizers) and after chisel tillage (manure, after effect 30 t/ha + N30P30K30). Herbicides and forecrops significantly influenced the dominant and subdominant positions of certain weed species. In the crops, the cereal annual-bicotyledonous-root-sprouting type of weediness predominated (44.2%). The type of weediness of the crops depended on the use of agricultural practices in the years of research.
 Conclusions. In the conditions of the Eastern Forest-Steppe of Ukraine, weediness of spring cereal ear crops depended significantly on the forecrop, the method of basic tillage, the fertilization system, and the use of herbicides.