In crop ecosystems, the primary challenge in establishing a long-term weed management strategy arise from a lack of understanding regarding the nature of weediness and the factors that contribute to species dominance. To address this, farmers and researchers often rely on quick and efficient, yet temporary weed control methods, which can lead to long-term issues. To develop a more effective and sustainable weed management approach, it is crucial to gain a comprehensive understanding of both the biological characteristics and ecological behaviours of weeds. This can be achieved by incorporating preventive techniques, scientific knowledge and management skills, with the goal of enhancing crop production and benefiting farmers. While further information is needed in all aspects of weed management, the primary objective of weed science is to increase our knowledge of weed biology and ecology, thus fostering a better understanding of weediness. This understanding will facilitate the adoption of appropriate management strategies instead of relying solely on short-term solutions that may create or exacerbate long-term problems. The successful growth and reproduction of any species depend on a variety of conditions. In a given ecosystem, the species that can thrive more efficiently under the specific set of environmental conditions will produce the most viable offspring and become the most abundant organisms. Weed ecology, which examines the adaptive mechanisms that enable weeds to thrive in highly disturbed soil conditions, provides essential insights into the distribution and abundance of weeds in both natural and managed systems. The occurrence of a weed in a particular area is influenced by multiple factors, with climatic, soil-related (edaphic) and biotic factors being the most significant among them.

Weed Ecology: Insights for Successful Management Strategies: A Review

In India the highest yield loss (34%) is caused by weeds, followed by insects (29%), pathogens (22%), storage pests (7%) and others (8%). Weeds compete with the crop for both above and below ground resources. Weed infestation is a serious challenge for maize growers in our country. Maize is sensitive to weeds especially during early stages of development and thus weed infestation from germination to 45 DAS causes maximum reduction in yield. Herbicides are efficient tools for checking weed infestation and its usage is increasing throughout the globe due to increasing labour cost and quick weed control in various situations. Continuous non-judicious use of herbicides for weed management leads to loss of biodiversity, environmental pollution and also develops herbicide resistance in weeds. Weed persistence is more in organic farming due to the extensive usage of organic manures, which act as weed seed reservoirs. 
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Ecological Weed Management Practices in Maize (Zea mays L.): A Review

<div>Background: Weeds are the major threat to direct seeded rice and a single strategy of weed control may not be effective for season-long weed control. Intending to accomplish the long-term and sustainable weed management of direct seeded rice, the integration approach of weed management strategies seems a better alternative. The current field study was aimed to evaluate the impact of integration of different weed control methods on direct seeded rice under irrigated ecosystem on weed growth and rice yield.</div>

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Methods: The experiment was laid out in randomized block design with three replications and twelve treatments during 2017 at G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India. The twelve treatments included the combination of cultural, mechanical, physical and chemical weed management methods.</div>

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Result: Combination of stale seedbed technique integrated with pre-emergence application of pendimethalin with mechanical weeding at 25 DAS followed by 1 hand weeding at 45 DAS, Sesbania (line sowing) fb application of pendimethalin (PE) fb 1 mechanical weeding at 25 DAS fb 1 hand weeding at 45 DAS, stale seedbed with application of pendimethalin (PE) with Sesbania brown manuring supplemented with mechanical weeding (25 DAS) fb hand weeding at 45 DAS, mulching with wheat straw mulch along with post-emergence application of penoxsulam (20 DAS) fb 1 hand weeding at 45 DAS and application of pendimethalin (PE) fb penoxsulum (PoE) at 20 DAS fb 1 hand weeding at 45 DAS with a row spacing of 25 cm found to be similar in the suppression of weed population and weed density at 40 and 60 DAS and crop yields (4.3, 4.1, 4.2, 4.0 and 4.2 t/ha, respectively) were on par with weed free plot i.e. 4.4t/ha. Application of pendimethalin (PE) fb penoxsulum (PoE) at 20 DAS fb 1 hand weeding at 45 DAS with row spacing of 25cm recorded 93.7%, 90.6% and 4.5% weed control efficiency, weed control index and weed index respectively, which was similar with above integrated weed management treatments. A negative correlation of the weed density and dry matter with the yield of rice was recorded.</div>

​Effect of Integrated Weed Management on Weed and Yield of Direct Seeded Rice

<div>Background: Weeds are the major biotic constraint to reduce the rice productivity in direct wet seeded rice. Weed infestation and competition are severe in direct wet seeded rice as compared to transplanted rice, because of the simultaneous growth of both crops and weeds. The yield loss due to weeds varies from 40 to 100 per cent in direct seeded rice. Use of herbicides either singly or in combination with manual or mechanical weeding in puddled direct seeded rice has been highlighted by several workers. Use of alternative herbicides with wide spectrum control of the weeds in direct seeded puddled rice is the need of the present time. The present study aimed to evaluate different weed management practices in direct wet seeded rice under sodic soil. 
 
Methods: A field experiment was conducted during Samba season (Rabi) 2016-17. to evaluate the weed management practices in direct wet seeded rice under sodic soil. The treatments comprised of different combination of weed management practices viz., pre emergence, early post emergence herbicides, mechanical weeding and hand weeding twice were tested. Total weed density and weed dry weight, weed control efficiency, yield parameters and yield of rice were recorded.&nbsp; 
 
Result: Among the different weed management practices, the lowest total weed density, total weed dry weight and higher WCE, yield attributes, grain and straw yields were registered under application of PE pyrazosulfuron ethyl 25 g/ha fb EPOE bispyribac sodium 25 g/ha. This was followed by application of PE pretilachlor 0.75 kg/ha fb EPOE bispyribac sodium 25 g/ha.&nbsp;</div>

<div>Weed Dynamics and Productivity of Direct Wet Seeded Rice under Different Weed Management Practices</div>

Background: Maize is the third most important cereal in India after rice and wheat which contributes nearly 9% in national food basket. Weed infestation is a major problem in maize, primarily at initial growth stages and due to wider spacing, hence weed control is essential to reduce the competition with maize crop. In maize row to row spacing is more so maximum number of weeds appears and compete with main crop. 
 
Methods: A field experiment was conducted in the University Agricultural Farm under the Department of Agronomy in kharif 2019. The soil of the experimental field was sandy loam in texture having pH 6.87 and electrical conductivity 0.32 mmhos/cm. The experiment was comprised of eight treatments and laid out in randomized block design with three replications T0 (Control), T1 (Hand weeding at 20 DAS, 40 DAS), T2 (Atrazine 1 kg/ha after 3 days of sowing), T3 (Metribuzin 1 kg/ha after 3 days of sowing), T4 (Alachlor 1.5 kg/ha after 3 days of sowing), T5 (Atrazine + hand weeding 1 kg/ha (after 3 days and 30 days after sowing), T6 (Metribuzin + hand weeding 1 kg/ha (after 3 days and 30 days after sowing), T7 (Alachlor + hand weeding 1.5 kg/ha (after 3 days and 30 days after sowing). The texture of the experimental field soil was sandy loam having pH-6.87, EC-0.32 mmhos/cm.&nbsp; 
 
Result:&nbsp;The weed species recorded at the experimental site were mainly comprised with grasses, sedges and broadleaf weeds. The dominant weed species infested in the experimental field were: Cynodon dactylon (doob grass), Cyperus rotundus, Amaranthus viridis, Anagallis arvensis, Argemone mexicana, Chenopodium album, Parthenium hysterophorus and Trianthema prolacastrum. Significant reduction in the weed density was recorded in manual weeding. The highest plant height, stem girth, number of leaves, flag leaf length, chlorophyll content, leaf area index, grain yield and stover yield was recorded highest with hand weeding which was followed by T7 (Alachlor + hand weeding 1.5 kg/ha (after 3 days and 30 days after sowing).

Effect of Integrated Weed Management Practices on Weed Dynamics and Performance of Maize Crop

<div>Background: Maize (Zea mays L.) is the most versatile and emerging food crop of global importance. Weeds are ubiquitous but their presence in wide spaced and initially slow growing crop like maize acts as an obstacle for plentiful harvest. Nutrient uptake by weeds during the first thirty days of maize growth was 59 kg N, 10 kg P2O5 and 59 kg K2O per ha, which was 7-10 times higher than the nutrient uptake by maize. 
 
Methods: The present field experiment was conducted during Rabi, 2018-19 under irrigated conditions at wetland farm of S.V. Agricultural College, Tirupati andhra Pradesh, with ten treatments and three replications in a randomized block design. 
 
Result: Lower density and dry weight of weeds with higher weed control efficiency, lower nutrient uptake by weeds and higher nutrient up take by maize at 80 DAS, kernel and stover yield was recorded with hand weeding twice at 15 and 30 DAS, which was statistically at par with atrazine 1.0 kg ha-1 as PE fb topramezone 30 g ha-1 or tembotrione 120 g ha-1 as PoE or atrazine 1.0 kg ha-1 as PE fb HW at 30 DAS, while these were lowest with weedy check. Higher benefit cost ratio of maize was noticed with both atrazine 1.0 kg ha-1 as PE fb topramezone 30 g ha-1 as PoE (T3), which was in parity with atrazine 1.0 kg ha-1 as PE fb tembotrione 120 g ha-1 as PoE (T2) and hand weeding twice at 15 and 30 DAS (T9). From the present study it may be concluded that atrazine 1.0 kg ha-1 as PE fb topramezone 30 g ha-1 or tembotrione 120 g ha-1 as PoE were considered to be the most effective and economic weed management practices to increase the productivity of Rabi maize at times of labour scarcity.</div>

<div>Weed Dynamics and Nutrient Uptake of Maize as Influenced by Different Weed Management Practices</div>

<div>The present study was conducted in kharif seasons of 2015, 2016 and 2017 at experimental farm of Rajasthan Agricultural Research Institute, Durgapura, Jaipur (Rajasthan) to study efficacy of different weed management practices in clusterbean. Three years result shows that compared to weedy check (6.82 m-2) application of Pendimethalin @ 0.75 kg a.i. ha-1 as PE fb one hand weeding recorded lowest weed density (3.58 m-2). Among herbicidal treatments, Pendimethalin @ 0.75kg a.i/ha as PE fb one hand weeding at 25 DAS (83.7%) and Pendimethalin @ 0.75 kg a.i./ha as PE+ Imazathapyr+ Imazamox @ 40g a.i./ha PoE (74.0%) recorded highest weed control efficiency. Likewise, application of Pendimethalin @ 0.75kg a.i/ha as PE fb one hand weeding at 25 DAS and Pendimethalin 0.75kg/ha at PE fb Imazathapyr + Imazamox @ 40g a.i. ha-1 recorded significantly higher seed (1136 kg ha-1 and 1009 kg ha-1), haulm (3304 kg ha-1 and 2943 kg ha-1) and biological yield (4440 kg ha-1 and 3953 kg ha-1), respectively over other herbicidal treatments. Economic evaluation indicated that application of Pendimethalin @ 0.75kg a.i/ha as PE fb one hand weeding at 25 and which was followed by with Pendimethalin @ 0.75 kg a.i./ha as PE+ Imazathapyr+ Imazamox@ 40g a.i./ha recorded, gross return (INR 55352 ha-1 and INR 49189 ha-1) net returns (INR 38852 ha-1 and INR 34289 ha-1) and B:C ratio (2.35 and 2.20), respectively. Whereas, minimum cost of cultivation (INR 10000 ha-1) and gross returns (INR 25632 ha-1), net returns (INR 15632 ha-1) and B:C ratio (1.56) were recorded under weed check. So looking to the laborious pressure of hand weeding, cost effectiveness ease of application of chemical herbicides, application of Pendimethalin 0.75 kg ha-1 fb one hand weeding can be an effective weed control option in cluster bean crop with higher seed and haulm yield under Semi-arid and Arid regions of Rajasthan.</div>

<div>Effect of Different Weed Management Practices on Weed Dynamics, Productivity and Farm Profitability of Cluster Bean</div>

The experiment was laid out in randomized block design with three replications and eight weed control treatments viz., weedy check, polythene mulching as pre emergence (PE), pendimethalin30EC (PE), chlorimuron ethyl 9g ha-1as post emergence (POE), quizalofop ethyl 50g ha-1 (POE), imazethapyr 100g ha-1 as early post emergence (EPOE), one hand weeding at 40 days after sowing (DAS) and two hand weeding at 20 and 40 DAS. The results showed that polythene mulching had the lowest weed dry matter due to effectively suppression of weed emergence. It was followed by twice hand weeding at 20 and 40 days after sowing. Weed index was found to be the highest with weedy check (42.10%) followed by the pre-emergence application of pendimethalin (19.09%). The effect of herbicide applied as pre-emergence was subdued at this belated stage, which may possibly be on account of longer period after application and restricted effective residual period. Plant height, number of pods per plant and grain yield of soybean was found to be highest in the treatments twice hand weeding at 20 and 40 DAS as well as polythene mulching. However, the net return and B:C ratio was lower in comparison to imazethapyr and quizalofop ethyl due to higher cost of labour and polythene material respectively. On an average, the application of imazethapyr as early post emergence (3.17) and quizalofop ethyl (3.02) gave significantly highest B:C ratio than the other treatments for soybean.

Effect of weed control practices on weed dynamics, yield and economics of soybean [Glycine max (L.) Merrill]

Background: India faces a critical shortage of farm labour. Out of basic farming operations, weeding operations are not fully mechanized in India. Traditional weed control methods are tedious, labour-intensive and costly. 
 
Methods: The objective of this study was to develop a prototype of an autonomous weeder for inter and intra-row weeding. The materials were used include a DC motor operating on electric rechargeable batteries, a camera for taking photographs of the intra-row space, an inter-and intra-row weeding tool assembly, a Raspberry Pi to deploy a machine learning object detection model to detect weeds and crops, to control a motor and to control an intra-row weeding tool through the pneumatic actuator. While the intensive image dataset was prepared from a cultivated spring onion farm on a test soil bin over the University campus, moreover the small-sized YOLOv8n model worked accurately on the Raspberry Pi. 
 
Result: YOLOv8n achieved a mean average precision (mAP) of 0.85 at the Intersection of the Union (IoU) threshold of 50%. The results indicated that the prototype removed both types of weeds with an overall weeding efficiency of 86%, crop damage of 4%, a field capacity of 0.023 hectares per hour and a performance index 1726.26 using 0.11 horsepower. It was concluded that the study contributed a spring onion-weed dataset and a Weeding Agrobot prototype to test the described concept, which would help farmers reduce labour dependency and the cost of cultivation. 
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Development of a Weeding Agrobot Prototype for Inter-row and Intra-row Weeding

Background: This study evaluates the impact of various tillage systems and weed management practices on maize (Zea mays L.) growth and yield under Punjab agro-ecological conditions. During the time of study three tillage methods, conventional, minimum and zero tillage were combined with chemical weed control treatments focusing on post-emergence herbicides. 
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Methods: Design of experiment used was Split Plot Design and total number of treatments were 21. 
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Result: The results show that, the combined mix application of mesotrione (70 g/ha) and atrazine (0.5 kg/ha) post-emergence under conventional tillage proved most effective in suppressing dominant weeds including Parthenium hysterophorus and Amaranthus viridis, resulting in the lowest total weed counts (8.26 no/m&sup2;) and total weed dry weight (9.18 g/m&sup2;). This treatment also produced superior crop growth parameters: highest plant height (217.09 cm), plant dry weight (153.81 g), cob length (15.20 cm), cob girth (13.31 cm), number of grai rows per cob (13.41), grain yield (4.39 t/ha) and stover yield (7.23 t/ha). While conventional tillage preserved soil health, conventional tillage combined with integrated chemical weed control maximized maize productivity by effectively reducing weed competition. The findings highlight that a balanced approach integrating optimal tillage and targeted herbicide application is vital for enhancing maize yield and sustainability in Punjab&rsquo;s maize cropping system. 
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