Weed Dynamics Research Articles

Effect of Changing Temperature and CO2 Concentration on Weed Dynamics and Behaviour: A Review

Agriculture and climate change are interwoven with each other in various measures, as climate change is the main culprit of biotic and abiotic stresses, which has adverse impact on crops and weed flora and the effectiveness of weed management strategies. Indeed weed physiology and crop productivity has been greatly influenced by several means of climate variability. Climate change causes a shift in weed population dynamics by altering the physiological pathways with the changing temperature and CO2 conditions. Climate change can affect crop-weed interactions by favouring C4 weeds in increased temperature scenarios requiring adaptation and mitigation strategies. Weeds can also shift their range by invading into new areas and higher latitudes or altitudes due to climatic variability affecting weed diversity, establishment, and management. These factors helps in understanding the crop interactions, weed infestation and herbicide efficacy. This review paper summarizes the challenges that occur due to climate change in weed behaviour requiring more attention on sustainable agricultural production.

Effect of weed management practices on weed dynamics in sweet cherry cv. Regina

Effect of weed management practices on weed dynamics in sweet cherry cv. Regina

Weed dynamics, energetic, yields and economics as influenced by sequential application of herbicides for weed management in direct seeded rice

This study quantifies the crop yield loss by weeds and management of hardy and prominent weeds. Uncontrolled weeds reduced grain yield of DSR by 68%. Pendimethalin 1.0 kg ha−1 pre-emergence (PE) followed by (fb) bispirbac-sodium 30 g ha−1 at 25 DAS fb fenoxaprop-p-ethyl 60 g ha−1 at 30 DAS, and pendimethalin 1.0 kg ha−1 (PE) fb azimsulfuron 25 g ha−1+fenoxaprop-p-ethyl 60 g ha−1 at 30 DAS significantly reduced weed density and weed dry matter, and recorded higher grain yield in DSR than other treatments. The pendimethalin 1.0 kg ha−1 (PE) fb bispyribac-sodium 30 g ha−1 at 30 DAS was statistically similar to stale seed-bed fb bispyribac-sodium 30 g ha−1 at 30 DAS and gave higher weed control efficiency and energy index compared to unweeded control and bispyribac-sodium 30 g ha−1 at 30 DAS. Pendimethalin 1.0 kg ha−1 (PE) fb bispyribac-sodium 30 g ha−1 at 25 DAS fb fenoxaprop-p-ethyl 60 g ha−1 30 DAS showed more promising in controlling tough weeds like L. chinensis and D. aegyptium and predominant weeds (Echinochloa colona, broad-leaved weeds and Cyperus species) in DSR.

Interactive effect of nutrient and weed management in transplanted rice (Oryza sativa L.) for enhancing the productivity in Eastern India

A field experiment comprising three nutrient and six weed management practices was conducted in strip plot design with three replications during 2019 and 2020 at Odisha University of Agriculture & Technology (OUAT), Bhubaneswar, India to assess the effect of the treatments on weed dynamics, productivity and nutrient uptake by crop and weed. Averaged over both years, among nutrient management practices, the soil test based dose (STD: 100-40-40 N-P2O5-K2O kg ha-1) + green manuring (GM) of dhaincha recorded the minimum weed density of 45.3 and 64.2 number m-2 and weed biomass of 19.2 and 37.6 g m-2 at 30 and 60 days after transplanting (DAT), respectively and the minimum N, P and K uptake of 6.4, 2.0 and 6.8 kg ha-1 by weed and the maximum N, P and K uptake of 113.6, 23.2 and 122.6 kg ha-1 by the crop, respectively. Among weed management practices, bensulfuronmethyl + pretilachlor (PE) fb HW on 35 DAT produced the minimum weed density of 25.15 and 20.66 number m-2, the minimum weed biomass of 7.70 and 8.08 g m-2 at 30 and 60 DAT, respectively and the minimum N, P and K uptake of 2.4, 0.5 and 2.6 kg ha-1 by weed and the maximum N, P and K of 117.9, 25.3 and 263.7 kg ha-1 by crop, respectively. Among nutrient management practices, the STD + GM proved to be the best with the maximum grain yield of 5562 kg ha-1. whereas the application of bensulfuronmethyl + pretilachlor (PE) fb HW on 35 DAT excelled over other weed management practices with the maximum grain yield of 5907 kg ha-1 registering 17.71 and 47.64% higher grain yield compared to the STD and the weedy check, respectively.

Efficacy of Pre and Post Emergence Herbicides against Complex Weed Flora, Yield and Economics of Blackgram under High Hills Wet Temperate Zone of Himachal Pradesh

Background: Implementing integrated strategies for weed management is essential in maximizing blackgram yield. Unchecked weed proliferation leads to substantial decrease in crop productivity. Methods: The current field experiment was conducted at Salooni, Himachal Pradesh, to evaluate the efficacy of different integrated weed management practices during Kharif 2022 and 2023. Eleven treatments targeting weed control were evaluated both at pre and post - emergence stages. Result: The predominant weeds were Echinochloa colona, Galinsoga parviflora, Cyperus species and other broad leaf weeds were Plantago lanceolata, Trifolium repens, Trianthema species, Ageratum conyzoides. Data on weed dynamics revealed that; after weed-free treatment, the application of Imazethapyr 75 g/ha as PE fb HW at 30 DAS; Pendimethalin 1.0 kg/ha as PE fb HW at 30 DAS and Pendimethalin 1.0 kg/ha + imazethapyr 75 g/ha (PE) recorded a significantly lower total weed count as compared to other treatments. Parameters related to blackgram growth and yield, including plant height, number of branches per plant, pods per plant, grain yield and haulm yield were significantly higher with weed-free treatment followed by application of imazethapyr 75 g/ha as PE fb HW at 30 DAS, remaining at par with application of pendimethalin 1.0 kg/ha + imazethapyr 75 g/ha (PE) and pendimethalin 1.0 kg/ha as PE fb HW at 30 DAS. The most economically efficient weed control method was the combination of pendimethalin 1.0 kg/ha + imazethapyr 75 g/ha (PE), as it resulted in the highest net returns and marginal benefit-cost ratio.

The Relationship between the Density of Winter Canola Stand and Weed Vegetation

Canola (Brassica napus L.) is an important oilseed crop that provides essential vegetable oil but faces significant competition from weeds that are influenced by various agronomic practices and environmental conditions. This study examines the complex interactions between canola stand density and weed intensity over three growing seasons, identifying a total of 27 weed species. It is important to establish a connection between the density of winter canola stands, the intensity of weeding and the response of individual weed species in real conditions. The case study was executed on plots located in the Přerov district (Olomouc region, Czech Republic). The assessment was carried out during two periods—autumn in October and spring in April. Canola plants (plant density) were counted in each evaluated area, weed species were identified, and the number of plants for each weed species was determined. Half of the plots were covered with foil before herbicide application to prevent these areas from being treated with herbicides. We used redundancy analysis (RDA) to evaluate the relationships between canola density and weed dynamics, both with and without herbicide treatment. The results show the ability of canola to compete with weeds; however, that is factored by the density of the canola stand. In dense stands (over 60 plants/m²), canola is able to suppress Galium aparine L., Geranium pusillum L., Lamium purpureum L., Papaver rhoeas L. and Chamomilla suaveolens (Pursh) Rydb. Nevertheless, there are weed species that grow well even in dense canola stands (Echinochloa crus-galli (L.) P. Beauv., Phragmites australis (Cav.) Steud., Tripleurospermum inodorum (L.) Sch. Bip. and Triticum aestivum L.). These findings highlight the potential for using canola stand density as a strategic component of integrated weed management to reduce herbicide reliance and address the growing challenge of herbicide-resistant weed populations. This research contributes significantly to our understanding of the dynamics of weed competition in canola systems and informs sustainable agricultural practices for improved crop yield and environmental stewardship.

Geographical Distribution and Abundance of Species of the Pycreus Genus in Rice Production Regions in Rio Grande do Sul

Theoretical Reference: Identifying, tracking, and analyzing weed infestation levels in rice crops are essential for developing more effective control strategies, ultimately enhancing efficiency, reducing costs, and minimizing environmental impact. This study focuses on the geographic distribution and abundance of species within the Pycreus genus (family Cyperaceae) in rice fields in Rio Grande do Sul (RS), Brazil. Method: During the 2005/06 growing season, collections and abundance assessments of Pycreus species were conducted across three irrigated rice fields located in three municipalities within five major rice production regions of RS. Plants were collected during vegetative or reproductive stages, dried, and identified using specialized literature. Specimens were then deposited as vouchers in the PEL Herbarium at the Department of Botany, Federal University of Pelotas. Results and Conclusion: The study revealed the presence of Pycreus species in rice fields across RS, with P. polystachyos (Rottb.) P. Beauv. being the most abundant and frequently observed species. P. macrostachyos (Lam.) J. Raynal and P. lanceolatus (Poir.) C.B. Clarke were also identified, though less commonly. The highest abundance of Pycreus species was recorded in the coastal physiographic region, particularly within the Internal Coastal Plain of Lagoa dos Patos and southern rice production areas. Implications of Research: These findings emphasize the need for targeted weed management strategies in rice cultivation, particularly in regions where Pycreus species are most prevalent, to enhance crop productivity and sustainability. Originality/Value: This study provides valuable insights into the distribution and abundance of Pycreus species in RS rice fields, contributing to the understanding of weed dynamics in rice production and offering a basis for the development of more effective control measures.

Effects of occasional tillage on soil physical and chemical properties and weed infestation in a 10-year no-till system

Few studies have investigated how one-time targeted tillage of long-term no-till fields impacts topsoil properties and weed dynamics. An on-farm trial was implemented in 2020 to test the effects of occasional tillage (OT) in Morocco with a long-term no-tillage (NT) system and rainfed field crops: durum wheat (Triticum durum), faba bean (Vicia faba minor), and chickpea (Cicer arietinum). Four treatments were established, namely, continuous NT with crop residues maintained (“NT + residue”); continuous NT with crop residues not maintained (“NT-residue”); shallow inversion tillage (“shallow OT”); and deep non-inversion tillage (“deep OT”). We assessed the effect of these treatments on soil physical and chemical properties in 0–10 and 10–20 cm soil depths after crop harvest of the 2020–2021 (year 1) and 2021–2022 (year 2) growing seasons corresponding to 1 and 2 years after OT, respectively. In addition, we evaluated the effect of the treatments on weed populations and the effect of the legume crop rotated with wheat on soil nitrogen (N) and weed density. In year 1, deep OT reduced the water content at field capacity and available water capacity at 0–10 cm compared to continuous NT; the cation-exchange capacity (CEC) under deep OT was lower than in NT-residue and NT + residue at 0–10 cm and 10–20 cm, respectively. Furthermore, deep OT increased ammonium-N (NH4-N) at 0–10 and 10–20 cm compared to NT + residue but reduced exchangeable potassium (K) at 10–20 cm depth compared to NT-residue. In year 2, shallow OT had lower total porosity at 10–20 cm than NT + residue, while shallow and deep OT recorded higher water-stable aggregates at 0–10 cm than NT + residue; at 10–20 cm, deep OT recorded lower CEC than NT + residue. However, deep OT had higher nitrate-N (NO3-N) and available sulfur (S) than NT-residue at 10–20 cm. Occasional tillage did not significantly affect 10 out of 19 of the soil properties evaluated, including soil organic matter (SOM), in all the years and did not help reduce the stratification of soil nutrients in NT. In year 1, 50 days after OT, deep OT reduced the weed density by 46% compared to NT + residue, while in year 2, 406 days after OT, shallow OT reduced weed density by 53% compared to NT-residue. Regarding the effect of the legume rotated with wheat, faba bean appeared to be the better preceding or following wheat crop as it resulted in higher residual soil mineral N and lower weed infestation than chickpea.

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

Pre-emergence herbicide selection for successful cultivation of black seed (Nigella sativa L.), psyllium (Plantago ovata Forsk), and quinoa (Chenopodium quinoa Willd.)

Weed control in black seed, psyllium, and quinoa is of huge importance for successfully cultivating and adapting these medicinal and nutritious crops. The recent study was designed to evaluate the pre-emergence herbicides (S-metolachlor and pendimethalin) for their possible application in these crops. The study consisted of three experiments on each crop for two years (2020-21, 2021-22). In each experiment, herbicides and their incremental doses (0, 25, 50, 75, and 100% of recommended label dose) were applied under a randomized complete block design under the factorial arrangement. Data on weed dynamics, crop agronomic, and yield attributes were collected. Results revealed that the weed control efficiency of both herbicides ranged from ~60 to 80%. Crops, on the other hand, varied in their tolerance to both herbicides. Pendimethalin proved to be more detrimental for all the crops. Dose-response curves showed the crop tolerance to pendimethalin and can be ranked as black seed>psyllium and quinoa. Contrastingly, all the crops showed tolerance to the incremental dose of S-metolachlor. Crops tolerance to S-metolachlor can be ranked as black seed>quinoa>psyllium as per their respective Ed50 values. The study concluded that pendimethalin use in these crops should be avoided. However, S-metolachlor can be employed as a pre-emergence herbicide in the cultivation of black seed, psyllium, and quinoa at the recommended label dose.

Effect of mulching and herbicides on weed dynamics and productivity of black gram

Effect of mulching and herbicides on weed dynamics and productivity of black gram

Effect of integrated weed management on weed dynamics in pearlmillet (Pennisetum glaucum L.)

Effect of integrated weed management on weed dynamics in pearlmillet (Pennisetum glaucum L.)

Effect of weed management practices on weed dynamics and soybean productivity under mid hill zone of Himachal Pradesh

Effect of weed management practices on weed dynamics and soybean productivity under mid hill zone of Himachal Pradesh

Effect of pre-emergence herbicides on weed dynamics and productivity of soybean [Glycine max (L.) Merill

Effect of pre-emergence herbicides on weed dynamics and productivity of soybean [Glycine max (L.) Merill

Influence of various weed management practices on weed dynamics of transplanted rice

Influence of various weed management practices on weed dynamics of transplanted rice

Impact of Weed Management Options on Weed Dynamics and Yield of Chickpea (Cicer arietinum L.): A Review

Impact of Weed Management Options on Weed Dynamics and Yield of Chickpea (Cicer arietinum L.): A Review

Weed phytosociology survey in a Brazilian native pineapple, variety Turiaçu

The native pineapple variety Turiaçu holds significant market value and substantial export potential in comparison to other traditional pineapple varieties. Despite its economic importance, there is limited research on weed management for pineapple Turiaçu. Weed interference poses a threat to various crops at different phenological stages. This study had two primary objectives: (1) to assess the dynamics of weeds in a Turiaçu pineapple orchard across different climatic seasons and (2) to determine the critical control phase for weed management. We conducted weed phytosociological surveys during the dry, transition, and rainy seasons. Conventional methods were employed in 20 samples per season, evaluating relative density, relative frequency, relative abundance, importance value index, and Soresen's similarity index. Our findings revealed the presence of 32 weed species, spanning 24 genera and 12 botanical families, predominantly eudicotyledonous (78%), with an annual life cycle (50%) and sexual reproduction (78%). Seasonal variations significantly influenced the weed community, with a 500% increase in the number of species during the rainy season compared to the dry season. Based on our observations, we recommend implementing soil cover methods for controlling the weed seed bank. This approach is crucial in all seasons, with particular emphasis on the transition season, characterized by a relatively short and latent weed community that is more easily manageable.

Influence of sowing dates and weed management practices on weed dynamics, productivity and profitability of direct seeded rice

This study evaluated the impact of differential sowing windows and improved weed management strategies on weed dynamics, productivity, and economic viability of direct drum seeded rice (Oryza sativa L.) in the temperate agro-ecosystem of Kashmir. A two-year field experiment was conducted utilizing a split-plot design with two sowing dates (May 10 and June 3) as main plots and six weed management practices as sub-plots. The earlier sowing date (May 10) resulted in significantly enhanced leaf area index, crop growth rate, relative growth rate, net assimilation rate, and grain and straw yields compared to the later sowing (June 3). Among weed management treatments, four mechanized conoweedings (equivalent to weed-free conditions) and sequential application of bensulfuron methyl + pretilachlor (60 and 600 g a.i. ha−1) as pre-emergence followed by 2,4-D (0.75 kg a.i. ha−1) as post-emergence demonstrated superior efficacy in weed suppression and augmentation of crop growth parameters and yield attributes. These treatments also exhibited the lowest weed index and highest benefit–cost ratio. The May 10 sowing, coupled with efficacious weed control measures, significantly reduced weed density and biomass while concomitantly improving nutrient uptake and economic returns. The results indicate that adopting a May 10 sowing date for direct seeded rice, in conjunction with either four conoweedings or the aforementioned sequential herbicide application, can optimize agronomic productivity and economic profitability under the temperate conditions of Kashmir. The study aided in choosing the best sowing window and efficient weed management strategy for attaining higher productivity and profitability of direct seeded rice in temperate conditions.

Effect of post-emergence herbicides on weed dynamics and yield of soybean [Glycine max (L.) Merrill]

Effect of post-emergence herbicides on weed dynamics and yield of soybean [Glycine max (L.) Merrill]

Effect of Organic Mulches on Weed Dynamics and Productivity of Super Napier Grass

Effect of Organic Mulches on Weed Dynamics and Productivity of Super Napier Grass