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.

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

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 style="text-align: justify;">Worldwide yield losses in maize due to weeds are estimated to be around 37%. Weeds reduce crop yield by competing for light, water, nutrients and CO2, interfere with harvesting and increase the cost of cultivation. The predominant weed flora were Echinochloa crusgalli L. and Cynodon dactylon L. among monocots; Cyperus rotundus L. among sedges; and Amaranthus viridis L., Digera arvensis L., Portulaca oleracea L., Alternenthara sessili L. and Trianthema spp. among dicots in India. The infestation of these weeds is increasing day by day in the maize growing belt of the state especially where the farmers are using atrazine year after year. New herbicides with broad spectrum of weed control are highly essential for effective control of grasses, sedges and broad leaved weeds. So, in order to widen the weed control spectrum, it is desirable to use tank mix combinations of two herbicides having different mode of action and integrated weed management practices for better weed control.</div>

Studies on integrated weed management practices in maize- A review

<div style="text-align:justify">Background: Among pulse crops, pigeon pea [Cajanus cajan (L.) Millsp] is one of the most important pulse crops of India after chick pea. Among various biotic factors limiting pigeon pea yield, weeds are of prime importance which can causes seed yield losses up to 80 per cent. Therefore, weed management is an important key factor for enhancing the productivity of pigeon pea. Imazethapyr, an herbicide of imidazolinones group has been registered for soybean, groundnut and other legumes. Various trials in different regions were conducted to study the effects of imazethapyr alone or in combination for controlling the weeds in different crops but in pigeon pea limited research were conducted. Therefore, current study aimed to study the effect of imidazolinones alone and in combination on weed dry matter accumulation in pigeon pea (Cajanus cajan L.). Methods: Pre and post emergence application of imidazolinones alone and in combination was done and dry matter accumulation by different types of weeds i.e. grassy, broad leaf and sedges in pigeon pea crop were worked out at different interval of crop span.&nbsp; Result: Among all weed controls treatments, two hoeing at 40 and 70 DAS found most effective to control all kind of weeds. Alone application of pendimethalin was not effective to control sedges. PRE application of imidazolinones was comparatively more effective than POE application. Application of imidazolinones in combination with pendimethalin improves its efficacy to control total weeds than alone application of it. Therefore, PRE application of pendimethalin + imazethapyr @ 1000 + 75 g ha-1 proved to be an effective and a profitable alternative to the existing recommendation (two hoeing at 25 and 45 DAS) of weed control in pigeon pea in Haryana locality.</div>

<div style="text-align: justify;">Effect of Imidazolinones Alone and in Combination on Weed Dry Matter Accumulation in Pigeon Pea (Cajanus cajan L.)</div>

Background: The River Brahmaputra is one of the largest braided rivers in the world, where the island and bars (&ldquo;Chapories&rdquo;) are formed almost annually by erosion and deposition, which are good agricultural lands, as most of the depositions are extremely fertile and possess ready water source in close proximity.&nbsp; With an aim to depict the weed vegetation pattern in upland direct seeded rice ecosystem in such an ecotone zone, Chapories of Majuli district were surveyed during 2021 and 2022. 
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Methods: One square meter quadrates were plotted in between 20 to 65 days after sowing (before flowering) of rice to study the weed status in the critical period of crop weed competition in four locations.&nbsp; 
 
Result: Study recorded altogether 55 species of weedy nature in four locations with as many as 39 broadleaved species belonging to 25 families, 3 sedges and 13 grasses, which represented a great diversity with several unusual species unique to chapori areas. Isolation of location - 4 by water channel has contributed in increasing dissimilarity with respect to weed flora, though river water might have had great role in distribution of weeds especially the stubble borne perennial species. The cumulative IVI of grass species was also 30.4 per cent higher in this isolated location than the non-grass species, unlike the locations that had land connectivity with shore areas.&nbsp;

Weed Flora Composition in Upland Direct Seeded Rice in Brahmaputra River Ecotones and Edges in Majuli District, Assam

<div>Wheat is India&rsquo;s second-largest staple food crop grown in different agro climatic zones within different crop sequences, as a result of which a diversity of weeds infests to this crop. Diversity of weeds including grassy, broadleaf weeds and sedges are mainly infested to the crop. Phalaris minor (grassy) and Rumex dentatus (broadleaf) are the most dominant weeds in northern region of country. For receiving fast results, use of herbicides is most popular method of weed control and used all over the world. But over reliance on herbicides has created several complications such as environmental quality deterioration, shifting in weed flora and development of herbicide resistant weeds. These problems can be abridged to a great extent by decreasing reliance on chemical method which can be done by integration of various cultural and mechanical methods to the weed management program. Various cultural practices such as nutrient management, seeding rate, spacing, cropping sequence, water management, sowing methods, sowing time and competitive varieties should be followed in such a way that crop plants utilize much more resources in comparison to weed plants. As a mechanical measure, furrow irrigated raised bed (FIRB) method and stale seed bed technique are recommended for effective weed management. Timely application of herbicides with recommended doses with the help of efficient spray technology improves the efficacy of herbicides. So with the help of integrated weed management (IWM) i.e integration of various cultural, mechanical and chemical methods, we can efficiently managed the diverse weed flora in wheat crop.</div>

Weed Management Practices in Wheat (Triticum aestivum L.): A Review

Background: Weeds are the key pest, which reduce crop productivity. Direct-seeded rice is very prone to early-stage weed infestation during initial crop development. Cultural and mechanical methods are difficult due to unavailability of labour and poor work efficiency. Hence, use of herbicides is an effective method for timely weed control. However, the efficacy of agrochemicals depends on the efficiency of spraying equipment. Conventional knapsack sprayers are used most often to spray herbicides but they are highly time-consuming, labour intensive and labour drudgery practices. Hence, the current experiment was aimed to study the efficiency of unmanned aerial vehicles (UAVs) on weed management.&nbsp; 
 
Methods: A field experiment was conducted at Tamil Nadu Agricultural University, Coimbatore during summer, 2022 to evaluate the efficacy of UAV-based herbicide application in direct-seeded rice. The study comprised of five weed management treatments such as pre emergence application of pretilachlor with safener and pyrazosulfuron through both UAV and knapsack sprayer and unweeded check as control. The experimental plot was laid out in a randomized block design with four replications. 
 
Result: The experimental findings showed that the application of pre-emergence pretilachlor significantly reduced the density and dry weight of grasses, sedges and broad leaved weeds in knapsack application. Moreover, it was found on par with UAV application of same herbicide without any phytotoxicity to rice seedlings. From the experiment, the application of pre-emergence pretilachlor through UAV is found to be more effective for timely weed control during early stages in direct-seeded rice, which reduce the labour intensity and drudgery than knapsack application.

UAV-based Herbicide Application for Efficient Weed Management in Direct-seeded Rice

Background: The water requirements for Oryza sativa L. need to be known to support its growth. Furthermore, water conditions in rice plantations can affect weed growth. Cyperus rotundus L. is an important weed of rice, so it needs to be controlled so as not to disrupt rice growth. 
 
Methods: This research aims to obtain irrigation intensity that is effective in suppressing the growth of Cyperus rotundus L. and identify its density of it, which can reduce rice yields. The research was conducted in a greenhouse at the field laboratory of the faculty of agriculture, Sebelas Maret University, from December 2022 to March 2023 using a factorial randomized block design using two factors. The first factor is irrigation intensity with three levels (daily irrigation, irrigation every 4 days and irrigation every 8 days), while the second factor is the weed density of Cyperus rotundus L. with four levels (without weeds, 1 weed, 2 weeds and 3 weeds), each repeated three times. The data obtained were analyzed using a variance test and if significant differences were found, then a 5% duncan multiple range test was carried out. 
 
Result: The results showed that daily irrigation with a density of 2 weeds increased the height of rice plants and the number of rice panicles. However, a density of 1 or 2 weeds reduced the number of tillers by 18.2% in rice plants. A density of 3 sedge weeds resulted in a more significant reduction of tillers by 45.96% and a decrease in the dry grain weight per clump by 34.97%.

Growth and Yield of Rice under Different Irrigation Intensity and Purple Nutsedge (Cyperus rotundus L.) Density

Background: Black rice a special type of rice species known in multiple ways through its beneficial nutrients and health needs and are in need to be cultivated to its outmost potential. Cultivation of weed suppressible variety along with integrated weed management can be considered for high outcome of yield.&nbsp;&nbsp;&nbsp; 
&nbsp; 
Methods: A farm trial during kharif season of 2021 and 2022 was laid out in split plot design (SPD) on the experimental field of School of Agricultural Sciences (SAS), Nagaland University, Nagaland consisting of four integrated weed management in the main plot while sub-plot consisting of four cultivars respectively. 
&nbsp; 
Result: Grasses, sedges and broad-leaved weeds with a total of 11 species were identified and recorded dominant. Lowest depletion of nutrients by weed was observed with hand weeding at 15 and 30 DAS with cultivar Chakhao Poireiton and was followed with application of pretilachlor @ 1.0 kg ha-1&nbsp;(PE) fb HW at 40 DAS. Hand weeding at 15 and 30 DAS along with cultivar Chakhao Poireiton exhibited highest plant height, LAI and biological yield and was closely followed with application of pretilachlor @ 1.0 kg ha-1&nbsp;(PE) fb HW at 40 DAS with Chakhao Poireiton, while similar results were also observed with the phenological studies. Further, weedy check recorded lowest plant height and LAI. However, plant population showed no significant variation with context to integrated weed management and different cultivars in both the years. Additionally, correlation studies revealed a strong negative correlation between plant height and nutrient depletion by weeds. 
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Evaluation of Growth, Phenology, Yield and Weed Dynamics as Influenced by Integrated Weed Management in Black Rice Cultivars under Nagaland Condition

<div>Pulses are the important crop after cereals and is the cheapest source of dietary protein. After the Green revolution, the production of pulses in India remain stagnant over the years due to various biotic and abiotic stresses. Among the various biotic stresses, weeds are the major one which causes severe yield loss in pulses. Due to initial slow growth of pulses, weeds emerge first and gain competitive advantage over the crop and exhibit smothering effect on crop. Moreover, major area of pulses (84 per cent) are under rainfed condition and grown in combination with non-legume crop. As a result, pulses are subjected to various types of biotic and abiotic stresses. Weeds besides causing direct loss in yield also hinder farm activities and serve as alternate host to many pests. Weed management in pulses is essential to bring the weeds below the threshold level to maximize the seed yield and quality. The literature regarding the importance of weed management in pulses, weed flora, critical period of crop weed competition and different weed management methods of weed control are collected and presented in this paper.Weeds are the predominant biological constraint in pulse production due to the slow initial growth of the crop. Strategies&rsquo; of weed management depends on the weed competition, types of weeds present and weed control method adopted. In general, critical period of weed competition for short duration pulses is up to 30 days and for long duration pulse crops it is up to 60 days. The major three types of weeds viz., grasses, broad leaved weeds and sedges were found in association with pulses. Intensity of weed infestation varies with agroecological conditions and crop management practices followed. A system approach is necessary to maintain the weed population below the economic threshold level thereby reducing the yield loss. Integrated weed management (IWM) which has been proved to be more effective than any single method in alleviating the buildup of weeds in pulse crop.</div>