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Sustainable weed management in direct seeded rice culture: A review
Abstract
The weed-rice ecological relationship is very complex and dynamic. Weed distribution and successions are always affected by management and environmental factors. Weed spectrum and degree of infestation in rice field are often determined by rice ecosystems and establishment methods. Due to high weed pressure, weed management in direct seeded rice has been a huge challenge for the researchers and farmers as well. Integrated weed management approach based on critical period of crop weed competition, involving different direct and indirect control measures, has been developed and widely adopted by farmers to overcome weed problem in direct seeded rice in a sustainable way. Although a number of sulfonylurea herbicides, diquat, paraquat, glyphosate quinclorac, MCPA have been found to be suitable alternatives to the old herbicides like 2,4-D, a less herbicide-dependent weed management strategy must be developed to reduce the risk of developing herbicide resistance in weeds. Weed control methods must be sought that are friendlier to the environment and substantially reduce the cost of weed management to farmers. Weed-competitive and allelopathic rice varieties, seed priming for increased weed competitiveness, higher seeding density should be considered as a management strategy. In order to devise a sustainable weed management strategy for direct seeded rice, detailed studies need to be done on the biology and ecology of notorious rice weeds, particularly Oryza sativa L. (weedy rice), Echinochloa spp., Leptochloa chinensis (L.) Nees, Limnocharis flava (L.) Buch. Commelina benghalensis, Ipomoea aquatic, Cyperus iria and Fimbristylis miliacea.
... In the present paper we focus on weedy rice because it is considered as the worst agricultural weed in rice fields. There is an abundant academic literature on weedy rice, dealing with its origins (Ferrero 2003;Delouche et al. 2007;Grimm et al. 2013;Vigueira et al. 2013Vigueira et al. , 2019Burgos et al. 2014;Rathore et al. 2016), impacts (Labrada 2002;Zhang et al. 2014;Chakraborty et al. 2017;Durand-Morat et al. 2018;Durand-Morat and Nalley 2019), and management (Gealy et al. 2003;F.A.O. of the United Nations 2006; Gressel and Valverde 2009;Chauhan 2013;Juraimi 2013;Singh et al. 2013;Mahajan et al. 2014;Mispan et al. 2019), or any combination thereof. ...
... Weed management strategies are usually grouped in five categories: preventive, cultural, mechanical, biological, and chemical (Chauhan 2013;Juraimi 2013;Singh et al. 2013;Matloob et al. 2015). In the present section, we consider only three weed management strategies: cultural, mechanical and chemical. ...
... IWM involves the selection, integration and implementation of effective weed control means with due consideration of economics, sociological and environmental consequences. The latter means that a reduction of herbicide dependence is a central component of IWM (Juraimi 2013). In other words, IWM aims to provide sustainable weed control. ...
As a major staple, rice is at the center of attention given the current challenges related to food security and agriculture sustainability. From the last three decades, labor and water scarcity has led to a switch from traditional hand transplanting to direct seeding. While the latter presents some advantages, it also fosters weeds that are the major threat to rice production. Weedy rice is considered as the worst agricultural weed because it has a strong competitive ability, and as a congeneric of cultivated rice is very difficult to control. Despite its major adverse effects, weedy rice is thriving in all continents. Our aim is to identify some reasons that might explain the low effectiveness of the weed management strategies. For this purpose, we stress that the weedy rice problem is not unique and then, before designing the adequate weed management strategy, one should distinguish between the occurrence, dispersion, adaptation, and proliferation of weedy rice. In addition, the strategy – agronomical or biotechnological - should be adapted given the gene flow vector, either pollen or seeds.
... The academic literature on weedy rice is abundant and is about its origins (Ferrero, 2003;Grimm et al., 2013;Burgos et al., 2014;Rathore et al., 2016;Shrestha et al., 2018;Vigueira et al., 2013Vigueira et al., , 2019, impacts (Labrada, 2002;Zhang et al., 2014;Chakraborty et al., 2017;Durand-Morat et al., 2018;Durand-Morat and Nalley, 2019), and management (Gealy et al., 2003;FAO of the United Nations, 2006;Gressel and Valverde, 2009;Chauhan, 2013;Joshi et al., 2013;Juraimi et al., 2013;Mispan et al., 2019). ...
... Weeds are a major constraint to the success of DSR in general and to dry-DSR in particular. Changes in rice establishment method as well as water, tillage and weed management practices in DSR lead to changes in weed composition and diversity [Juraimi et al., (2013), pp.990-991]. Thus, the adoption of DSR has exacerbated weed problems, including grasses -such as weedy rice and Echinochloa spp. ...
... However, it is not; it is ineffective against weedy rice, may promote herbicideresistant weed species, and is not sustainable. Then several authors consider that a sustainable weed and weedy rice management strategy in DSR is an integrated weed management (IWM) [Ferrero, 2003;FAO of the United Nations, 2006;Chauhan, 2013;Juraimi et al., 2013;Singh et al., 2013;Mahajan et al., 2014;Matloob et al., (2015), p.320; Mispan et al., 2019). An IWM uses several methods -preventive, cultural, mechanical, biological, and chemical -that target different phases of the weedy rice cycle; such diversity is important because any weed management method that is continuously repeated provides heavy selection pressure for weed adaptation and resistance to that practice (Harker and O'Donovan, 2013). ...
... Direct seeding might be a strategic solution to save water, but sowing rice seeds into dry soil exposes the crop to many problems. One of the most prevalent problems is heavy weed infestation that impedes the success of the aerobic rice system (Juraimi et al. 2013). Mahajan et al. (2014) found that dry direct seeded rice is most heavily infested by grasses with sedges and broad-leaved weeds respectively being the next highest infestations. ...
... Farmers tend to increase the dosage of herbicides applied if the first attempt to kill the weeds failed. Repeated usages of similar chemicals cause the weeds to develop resistance (Juraimi et al. 2013). Herbicides induce toxicity for both soil and rice plants (Chauhan and Johnson 2011). ...
Eleusine indica is one of the most problematic weeds in aerobic rice systems in many countries. A pot study was conducted to evaluate the phytotoxic effect of urea fertiliser and pendimethalin on E. indica, while observing aerobic rice tolerance level and agronomic performance with the application rate. Four treatments were evaluated which were control (urea only without pendimethalin), and three rates of pendimethalin (0.25, 0.50, and 1 kg ai ha-1) in combination with optimum urea fertiliser (240 kg ha-1). Results demonstrated that banded application of urea and pendimethalin gave positive response in suppressing E. indica over control. A 0.50 kg ai ha-1 pendimethalin + 240 kg ha-1 urea and 1 kg ai ha-1 pendimethalin + 240 kg ha-1 urea gave significant suppression on the emergence and seedlings growth of E. indica with 60-90% inhibition relative to the control. The aerobic rice growth performance was highly stimulated and the grain yield production was higher for treatments of both 0.50 kg ai ha-1 and 1 kg ai ha-1 pendimethalin. These results imply that a lower application rate of 0.50 kg ai ha-1 pendimethalin + 240 kg ha-1 urea can be adopted to control E. indica effectively while enhancing the growth performance of aerobic rice plants since it is cost saving and reliable.
... Weed management strategies are usually grouped in five categories: preventive, cultural, mechanical, biological, and chemical [20,22,34,50]. However, weedy rice is difficult to control by any of these strategies because of its genetic, morphological, and phenological similarities with rice. ...
... IWM involves the selection, integration, and implementation of effective weed control means with due consideration of economics, sociological, and environmental consequences. The latter means that a reduction of herbicide dependence is a central component of IWM [50]. One might inappropriately conclude that IWM implementation means that herbicides should be avoided in preference for other weed management methods. ...
Weeds have always been a serious problem for farmers and especially nowadays given the current challenges related to food security and agriculture sustainability. During the last three decades, the increasing scarcity of labor, energy, and water has led to a switch of the rice establishment method from traditional hand transplanting to direct seeding. While the latter presents some advantages, it also fosters weeds among which weedy rice is considered the worst because it has a strong competitive ability, and as a congeneric of cultivated rice is very difficult to control. There are currently three main weed management strategies in rice: synthetic herbicides, herbicide-resistant rice varieties, and integrated weed management (IWM). However, all these strategies have low effectiveness and sustainability. Even though IWM is strongly recommended, its adoption remains very low owing to its complexity and the additional cost it induces. The use of crop rotation and cover crops is sustainable and consistent with the circularity principles, but this strategy presents the same drawbacks than those associated with IWM. We stress that other strategies used to control or suppress weedy rice are more efficient, sustainable, and consistent with the bioeconomy principles. They encompass the control of the pathways to weediness by ferality as well as the improvement of rice cultivars’ fitness based on allelopathic effects. Other non-chemical weed management strategies, such as the use of bioherbicides, are promising given the current transition towards bioeconomy and circular economy.
... All else equal, poor weeding can lead to lower yields or, in more serious cases, to the abandon of the plot. To overcome this obstacle, different weeding techniques, from the traditional (manual) to the mechanic and chemical are used (Pannacci et al. 2020;Juraimi et al. 2013). The traditional weeding technology in rice production is still more fastidious and requiring in terms of physical effort for hired labor because of the large rice areas, while mechanical and specifically chemical control with herbicides is the most practical, efficient and economically profitable method for a sustainable welfare of farmers (Antle 2015;Anwar et al. 2012;Roder and Phengchanh 1997). ...
... This has motivated the development of an integrated approach to weeding based on the identification of the critical period of competition with rice plants, which has been widely adopted by producers to overcome this constraint in a sustainable way. (Juraimi et al. 2013). ...
This article assesses the impact of the adoption of an herbicide as a new weeding technology on the sustainable welfare of rice producers in Cameroon. Weeding is one of the main technical constraints linked to the rice production in Cameroon. Using the stratified probability sampling technic, a sample of 553 rice producers was selected, based on the data from the survey carried out within the framework of the C2D-PAR-RIZ project, in three subdivisions in the West region of Cameroon, during the period going to May to July 2018. The main criteria that have guided the choice of these areas are essentially, the Socio-economic importance and the agricultural constraints of rice production and the organization of rice producers. The Probit model and propensity score matching (PSM) have been used to assess this impact. The results reveal that with a statistical difference of US $54.207, the adoption of the new weeding technology sustainably improve income of producer in Cameroon. Furthermore, rice productivity, the size of the rice plots, agricultural training, number of weedings per campaign and rice income are the main determinants of this adoption. To ensure the sustainable well-being of rice producers in Cameroon, it is therefore important that agricultural technology vulgarization policies such as weeding techniques implemented by the authorities be further amplified, taking into account the local conditions of producers.
... All else equal, poor weeding can lead to lower yields or, in more serious cases, to the abandon of the plot. To overcome this obstacle, different weeding techniques, from the traditional (manual) to the mechanic and chemical are used (Pannacci et al. 2020;Juraimi et al. 2013). The traditional weeding technology in rice production is still more fastidious and requiring in terms of physical effort for hired labor because of the large rice areas, while mechanical and specifically chemical control with herbicides is the most practical, efficient and economically profitable method for a sustainable welfare of farmers (Antle 2015;Anwar et al. 2012;Roder and Phengchanh 1997). ...
... This has motivated the development of an integrated approach to weeding based on the identification of the critical period of competition with rice plants, which has been widely adopted by producers to overcome this constraint in a sustainable way. (Juraimi et al. 2013). ...
Despite several studies on livelihood security, there is a dearth of studies on livelihood security in relation to gender among aquaculture fish farmers. Therefore, this study examined gender differentials in livelihood security among aquaculture fish farmers in southwest, Nigeria. This is important because of the relevance of aquaculture, livelihood security and gender issues to the Sustainable Development Goals (SDGs). The selection of 192 respondents was achieved using a multistage sampling procedure. Identified security pointers from the data were grouped under four security domains and standardised in line with the method used to measure life expectancy in reports of human development. Also, descriptive statistics and two-stage least squares regression were employed to analyse the data collected. The empirical findings revealed that male aquaculture fish farmers were more secure economically in terms of food, health and education than their female counterparts in the study area. Furthermore, the results of the analysis showed that, overall, the livelihood security status of female aquaculture fish farmers was poorer relative to their male counterparts. Moreover, the effect of economic security and educational security on overall livelihood security is greater among male aquaculture fish farmers than among their female counterparts. Therefore, there is a need to close the gap between men and women in terms of livelihood security through economic and educational empowerment programmes if sustainable development is to be achieved, especially for female aquaculture fish farmers in southwest Nigeria.
... All else equal, poor weeding can lead to lower yields or, in more serious cases, to the abandon of the plot. To overcome this obstacle, different weeding techniques, from the traditional (manual) to the mechanic and chemical are used (Pannacci et al. 2020;Juraimi et al. 2013). The traditional weeding technology in rice production is still more fastidious and requiring in terms of physical effort for hired labor because of the large rice areas, while mechanical and specifically chemical control with herbicides is the most practical, efficient and economically profitable method for a sustainable welfare of farmers (Antle 2015;Anwar et al. 2012;Roder and Phengchanh 1997). ...
... This has motivated the development of an integrated approach to weeding based on the identification of the critical period of competition with rice plants, which has been widely adopted by producers to overcome this constraint in a sustainable way. (Juraimi et al. 2013). ...
Prescribed yearly mid-dry season fire is generally used in the Guinean savanna (a humid savanna of West Africa) as a vegetation management tool. Despite this fire, bush encroachment can be observed due to climate change and high sapling recovery rates with increasing CO2 emissions. There is therefore a need to analyze other fire seasons. We analyzed fire behavior during a 5-year field fire in the Guinean savanna of Lamto reserve in Ivory Coast. Early (EDS), mid (MDS), and late (LDS) dry season fires were tested. Nine 0.5 ha plots were burnt annually to determine the rate of spread, fire intensity and the residence time above 60 °C. Fuel characteristics and weather conditions were measured to assess their impact on fire behavior. Recruitment from resprout to adult tree stage were assessed for an estimation of these fires’ severity. Understory grass height, fuel load, and moisture content had greater values in EDS than in MDS and LDS. The rate of spread and intensity of both MDS and of LDS were greater than those of EDS fires. The best predictors for fire behavior were fuel moisture content and air humidity. In dry conditions, fires were faster and more intense. With climate change predicting increasingly longer and drier periods, we expect more and more intense fires. A longer time of exposure to lethal temperatures (>60 °C) and the phenological state of trees in the late dry season explains the higher severity of this fire (there was no recruitment to adult stage under LDS fire). In some years, LDS helped to reduce bush encroachment in the subject region. This data provides important insights into fire behavior and its severity in the Guinean savanna, informing fire management policies and procedures.
... All else equal, poor weeding can lead to lower yields or, in more serious cases, to the abandon of the plot. To overcome this obstacle, different weeding techniques, from the traditional (manual) to the mechanic and chemical are used (Pannacci et al. 2020;Juraimi et al. 2013). The traditional weeding technology in rice production is still more fastidious and requiring in terms of physical effort for hired labor because of the large rice areas, while mechanical and specifically chemical control with herbicides is the most practical, efficient and economically profitable method for a sustainable welfare of farmers (Antle 2015;Anwar et al. 2012;Roder and Phengchanh 1997). ...
... This has motivated the development of an integrated approach to weeding based on the identification of the critical period of competition with rice plants, which has been widely adopted by producers to overcome this constraint in a sustainable way. (Juraimi et al. 2013). ...
Universities are often seen as drivers of change in their regions of operation through research, teaching, engagement and enterprise activities. This is significant in Africa where several universities are state owned, rely on government subsidies, and possess a mission to promote the sustainable development of the nation. Whilest the UN sustainable development goals provide an opportunity for Africa to achieve its development targets, we examined the role of the university. More specifically, we considered the significance of Indigenous knowledge to a university’s mission towards development. This is pivotal, as Africans and their institutions provide leadership to the transformation of their nations, not just in terms of knowledge production but also integration. We adopted a multiple case-study design that recruited participants from Zambia (N = 50) and The Gambia (N = 40) comprising academics, university managers and community members. Participants took part in relational dialogues that address the intersection between Indigenous knowledge, the university’s mission and sustainable development. Findings from a comprehensive data analysis posit the need for the university in Africa to re-envision its teaching and research architectures for sustainable development. The chapter underscores that Indigenous knowledge holders should be provided space to contribute to the curricula if the teaching mission of the university would result in graduates who are suited to contribute to the continent’s development with sustainable outcomes. Similarly, it is argued that Indigenous people can be co-researchers, who can identify and provide indigenised methodological insights into the investigation of complex development challenges faced by their communities.
... All else equal, poor weeding can lead to lower yields or, in more serious cases, to the abandon of the plot. To overcome this obstacle, different weeding techniques, from the traditional (manual) to the mechanic and chemical are used (Pannacci et al. 2020;Juraimi et al. 2013). The traditional weeding technology in rice production is still more fastidious and requiring in terms of physical effort for hired labor because of the large rice areas, while mechanical and specifically chemical control with herbicides is the most practical, efficient and economically profitable method for a sustainable welfare of farmers (Antle 2015;Anwar et al. 2012;Roder and Phengchanh 1997). ...
... This has motivated the development of an integrated approach to weeding based on the identification of the critical period of competition with rice plants, which has been widely adopted by producers to overcome this constraint in a sustainable way. (Juraimi et al. 2013). ...
The current population dynamics is projected to increase yearly, and expected to challenge the Sustainable Development Goals, especially in relation to food and nutrition security. While the demand for agricultural food products is increasing, the availability of cultivable land is either stable or decreasing due to various environmental factors such as drought, floods and climate change effects. Considering that sustainability can only be achieved when a system is resource conserving, socio-culturally supportive, commercially competitive, and environmentally friendly, urban and peri-urban snail (Achatina fulica or Archachatina marginata) farming systems could represent viable sources of essential dietary nutrients and income for many families in Africa. Snail farming is profitable, with minimal capital and land demands, and limited risks. Snails are handpicked in the forest and easily farmed in gardens, backyards, basins, or cages. They are omnivores and environmentally friendly without odorous wastes (unlike pigs and poultry). Snails have high protein content, low in fat and cholesterol, and they are cheaper than other meat products. In addition, their by-products are inputs for other industries such as cosmetics and medicines. However, the current rate of snail farming in Cameroon barely satisfies 25% of the national demand. Hence, this study aims to encourage snail farming by evaluating the profitability of snail business as a valuable urban and peri-urban livestock alternative for sustainable development in Cameroon. Data were collected between March–May 2018 with the use of questionnaires administered to 60 urban and peri-urban snail farming households in the Buea Municipality, South West Region of Cameroon. Farm budgeting analysis enabled investigations of performance from farmers while semi-log functions enabled the evaluation of factors affecting the level of snail production in the study area. The descriptive statistics and gross margin results from farm budgeting and profit revealed a total production costs of only US2 per kg of snail sold. Considering the environmental friendliness, profitability of snail business, and health value of snails in relation to food and nutrition security, urban and peri-urban snail farming is highly recommended within the scope of sustainable development in Cameroon.
... Weeds are a major constraint on the success of DSR in general and on dry DSR in particular. Changes in rice establishment methods as well as water, tillage and weed management practices in DSR lead to changes in weed composition and diversity (Juraimi et al., 2013). Thus, the adoption of DSR has exacerbated the weed problem, including grasses-such as weedy rice (Oryza sativa f. spontanea) and Echinochloa spp. ...
... Weeds of rice are difficult to control because of their genetic (for weedy rice), morphological and phenological similarities with rice. Thus, what seems an effective strategy against weeds in DSR is integrated weed management, i.e. using several methods-preventive, cultural, mechanical, biological and chemical-that target different phases of the weedy rice cycle (Labrada, 2002;Ferrero, 2003;FAO, 2006;Chauhan, 2013;Juraimi et al., 2013;Singh et al., 2013;Mahajan, 2014;Matloob et al., 2015;Mispan et Delouche et al. (2007) al., 2019). Using a diversity of weed management methods is more important than striving to exclude any single method (Harker and O'Donovan, 2013). ...
On the Sustainability of Direct-Seeded Rice
February 16, 2020
Serge Svizzero
Faculté de Droit et d’Economie, Université de La Réunion.
15 Avenue René Cassin, CS 9003, 97400 Saint Denis, France.
Serge.svizzero@univ-reunion.fr
ORCID – 0000-0003-3895-7273.
Abstract
The most widespread recommendation for the improvement of rice cultivation sustainability is a technological switch from hand transplanting rice to direct-seeding. In the short term direct-seeding presents social, economic and ecological advantages. It allows cropping intensification, reduces labor cost and avoids drudgery of hand-transplanting; it is consistent with reduced tillage, reducing cost and carbon emission. Water is used more efficiently, and by avoiding anaerobic conditions, methane emissions are drastically reduced. However in the longer term direct-seeded rice induces a major problem, the proliferation of weeds. Weeds lower grain yield and quality, and therefore farmers’ income. Their control induces additional cost and has a low effectiveness. In addition the weed management methods imply in the long term important economic and ecological costs that impede the sustainability of rice cultivation.
Keywords: direct-seeded rice, hand transplanting rice, crop yield, water management, labor cost, methane emissions, weeds, weedy rice, integrated weed management.
Citation: S. Svizzero (2020), On the sustainability of direct-seeded rice, in Agro-Based Bioeconomy: Reintegrating Trans-disciplinary Research and Sustainable Development Goals, edited by C. Keswani, CRC Press, USA, pp 93-108.
... The data revealed that weed density was significantly influenced by seeding methods and weed management practices. Among the seeding methods at initial crop growth stage i.e. 20 DAS significantly more weed density was observed in the line sowing (S2) (6.19) than the broadcasting (S1) (5.68) which might be due to the higher plant density and intraspecific competition for resources (Juraimi at al., 2013) [5] . However, at these stages (40, 60 DAS and at harvest) significantly lower weed density was observed in the line sowing than the broadcasting. ...
... It might be due to fact that these weed management practices proved their capacity for better control of weeds with the application of pre and post emergence herbicides action. Azimsulfuron was found to be effective against Cyperus species (sedge) and broad leaf weeds as it was completely eliminated from treated plot (Singh, V.P et al. 2010) [5] . Further, the findings of the present investigation at 60 DAS and at harvest shown best results in the treatment T9 as hand weeding (at 20, 40 and 60 DAS) recorded the lowest weed density and it was followed by T6 which was on par with T5, T7 and T8. ...
A field experiment was conducted at College Farm, College of Agriculture, Professor Jayashankar Telangana State Agricultural University (PJTSAU), Rajendranagar, Hyderabad, during kharif, 2014. The soil of the experimental field was sandy loam in texture with pH of 7.6. The experiment was laid out in factorial randomized block design with two factors. Pretilachlor as pre-emergence herbicide, is not effective against grasses and sedges while azimsulfuron was the new selective, post-emergence herbicide was found to be most efficient against sedges and broadleaf weeds & less effective against grassy weeds. However, sequential application of herbicides along with one hand weeding was reported to be more effective than application of herbicides alone, hence the present investigation was undertaken to study the efficacy of sequential application of pre and post emergence herbicides. Herbicidal treatments significantly influenced the dry matter production of weeds as well as grain yield. Lowest weed dry matter (10.5) as well as higher WCE (95.5) was recorded with hand weeding thrice at 60 DAS. Which was at par with T6-(Pretilachlor 50%EC @ 0.75 kg ai /ha as PE fb Azimsulfuron 50%W.P@ 35g.ai/ha+ cyhalofop butyl 10% EC@ 75 g. ai/ha as PoE 15-20 DAS fb HW at 50 DAS) with regard to WCE (95.3 %) and grain yield (3218.3 kg/ha) indicating that weeds are controlled efficiently with sequential application of herbicides resulted in Higher grain yield.
... To kill or reduce weeds population, numerous numbers of predators, microbes, and competitors of weeds have been utilized. Many scientists have done remarkable work to explore this environmentally friendly, safe, and economical approach and have declared it as the best option in integration with other techniques in conservation agriculture (Charudattan, 2001;Juraimi et al., 2013;Müller-Schärer et al., 2000). Charudattan (2001) examined the significance and usefulness of several microbial agents as biocontrol agents of lethal weeds. ...
... These are successful in flooded lowland rice but not as effective in aerobic conditions as they are directly linked with standing water (Ismail et al., 2012). In Indonesia, the rice-fish farming system offered proper management of sedges like Fimbristylis miliacea (L.) Vahl and Cyperus iria (L.) (Juraimi et al., 2013). Fungal based (Exserohilum monocerus and Cocholiobolus lunatas) bio-herbicides proved to be highly effective against Echinochloa crus-galli (L.) P. Beauv in rice. ...
Climate change, environmental pollution and depletion of natural resources are among the prominent
potential challenges for sustainable crop production and environment management in modern agriculture.
Rice production systems have threatened with insect pests and weeds that significantly contribute
to yield losses. Although control of insects, pests and weeds has remained the major effective plant protection
tool, yet hazards to environmental safety urge the scientific community to propose alternative
pest management strategies. Apprehensions about conventional agriculture sustainability have impelled
the extensive introduction of integrated pest management (IPM). Bio-based IPM is one of the important
component for controlling insect-pests, and weeds in rice, as it is environmentally benign, effective, and
economically viable. In the present article, we analysed several studies to highlight the: (1) description of
practices related to IPM in rice, (2) progress regarding the bio-based integrated insect pests and weed
management with possible implications and scope, (3) allelopathy effectiveness for weed management
in rice, and (4) present dilemmas and proposed future research directions. Briefly, this article explores
the opportunities for the scientists and rice farmers to maximize the utilization of diverse natural control
agents as a partial or total substitute for synthetic pesticides.
... To kill or reduce weeds population, numerous numbers of predators, microbes, and competitors of weeds have been utilized. Many scientists have done remarkable work to explore this environmentally friendly, safe, and economical approach and have declared it as the best option in integration with other techniques in conservation agriculture (Charudattan, 2001;Juraimi et al., 2013;Müller-Schärer et al., 2000). Charudattan (2001) examined the significance and usefulness of several microbial agents as biocontrol agents of lethal weeds. ...
... These are successful in flooded lowland rice but not as effective in aerobic conditions as they are directly linked with standing water (Ismail et al., 2012). In Indonesia, the rice-fish farming system offered proper management of sedges like Fimbristylis miliacea (L.) Vahl and Cyperus iria (L.) (Juraimi et al., 2013). Fungal based (Exserohilum monocerus and Cocholiobolus lunatas) bio-herbicides proved to be highly effective against Echinochloa crus-galli (L.) P. Beauv in rice. ...
Climate change, environmental pollution and depletion of natural resources are among the prominent potential challenges for sustainable crop production and environment management in modern agriculture. Rice production systems have threatened with insect pests and weeds that significantly contribute to yield losses. Although control of insects, pests and weeds has remained the major effective plant protection tool, yet hazards to environmental safety urge the scientific community to propose alternative pest management strategies. Apprehensions about conventional agriculture sustainability have impelled the extensive introduction of integrated pest management (IPM). Bio-based IPM is one of the important
component for controlling insect-pests, and weeds in rice, as it is environmentally benign, effective, and economically viable. In the present article, we analysed several studies to highlight the: (1) description of practices related to IPM in rice, (2) progress regarding the bio-based integrated insect pests and weed management with possible implications and scope, (3) allelopathy effectiveness for weed management in rice, and (4) present dilemmas and proposed future research directions. Briefly, this article explores the opportunities for the scientists and rice farmers to maximize the utilization of diverse natural control agents as a partial or total substitute for synthetic pesticides.
... The preemptive competition is the most important competition for a plant species to emerge and grow among seedling of another competitive species (Rao et al., 2007). Weed are the major burden for rice growing farmer, weed management is a huge challenge both for the researcher and farmers (Juraimi et al., 2013). A variation in rainfall pattern due to unpredictable drought and due to the rising temperature intensifies the crop weed competition pressure (Ramesh et al., 2017). ...
Rice (Oryza sativa L.) is the most important crop in Nepal, despite having significant contribution to food security and agricultural economy, its production is being affected greatly by weed infestation. A field experiment was conducted during the spring season of 2022 to evaluate the different weed management practices in transplanted spring rice at Radhapur, Banke, Nepal. Seven weed management treatments were laid in Randomized Complete Block Design (RCBD) with three replications. The treatments were pre-emergence application of Pendimethalin 50% EC, 1 kg a.i./ha, at 3 DAT, post-emergence application of Bispyribac Na 10% SC, 25 g a.i./ha, at 28 DAT, pre-emergence application of Pendimethalin followed by post-emergence Bispyribac Na, Pre-emergence application of Pendimethalin followed by one hand weeding at 40 DAT and Farmer’s practice i.e. one hand weeding at 40 DAT along with two controls (weedy free and weedy check). The rice variety Hardinath-1 was used in the experiment. Data regarding the weed flora, weed density, weed dry weight, rice growth, yield attributes and yield was recorded and analyzed. Weed flora in the experimental plot comprised of 11 weed species viz. five were broadleaf weeds belonging to four families, four grasses belonging to Poaceae family whereas three sedges belonging to Cyperaceae family. Sedges weeds were dominant as compared to broadleaf and grasses. The highest number of effective tillers per m2 (413) and number of grains per panicle (101.33) were obtained in Pendimethalin followed by Bispyribac Na treated plot. The plot treated with combination of pre-emergence followed by post emergence recorded significantly the lowest weed density (9.67 weeds/m2) at 60 DAT. This treatment significantly gave higher grain (4780 kg/ha), straw yield (4318 kg/ha) yield, harvest index (52.55%), other traits like sterility (22.19%) was recorded least and thousand grains weight was significantly higher (23.61g). The yield on weedy check plot produced the lowest yield as compared to weed free plot. Sedges weeds such as Cyperus difformis, Cyperus iria and Fimbristylismiliaceae were dominant as compared to dicots such as Amaranthus spinosus, Chenopodium album and grasses such as Echinochloa crus-galli, Echinochloa colonum at the experimental field. The ultimate overall analysis revealed that the application of pre-emergence followed by post-emergence herbicide was the best treatment so far as compared to other weed management treatments considering various data regarding variables.
... One of the most crucial requirements for ensuring a sufficient production of rice is thought to be effective weed control (Juraimi 2013). In direct seeded rice, high weed pressure reduces the yield and, in the worst situations, makes rice farming unprofitable. . ...
The production of rice is always important for the security of
food and everyday life. Rice cultivation has changed from
traditionally flooded transplanting to aerobic rice due to
expectations of increased water limitations under a changing
climate and growing manpower shortages in agriculture.
Because there is less standing water, aerobic rice becomes
more affected by weeds, which puts crop plants in
competition for the same resources. According to research, in
order to minimize crop losses, weeds should be managed 20–
60 days after seeding.Aerobic rice may become widely used if
integrated weed management strategies, namely,i.e. cultural,
mechanical, chemical, and preventive, are adopted globally.
Key words : aerobic rice,weed management,prevention
... Paddy (Oryza sativa) or rice is the most important staple crop in Asia and a significant source of food for nearly half of the world's population [1]. In many countries, including Bangladesh, India, and China rice consumption accounts for more than 50 % of the daily caloric intake of the population. ...
Seed viability is essential to have a homogeneous plant population. The seed industry cannot adopt traditional procedures for seed viability evaluation since they are destructive, time-consuming, and need chemicals. This study aimed to investigate the potential of combining hyperspectral and color image features to differentiate viable and non-viable paddy seeds. The hyperspectral and color image of the 355 paddy seeds was captured and later used to exam their viability. An image processing algorithm was developed to extract features from color images of paddy seeds and investigated significant differences in the retrieved feature data using variance analysis. The spectra were extracted from the selected region of interest (ROI) of the hyperspectral paddy seed image and averaged. In the next step, the partial least square discrimination analysis (PLS-DA) model was developed to distinguish viable and non-viable paddy seeds. Initially, the PLS-DA model was developed using spectral data with different pre-processing techniques, and the result obtained an accuracy of 88.9 % in the calibration set and 86.1% in the prediction set using Savitzky-Golay 2nd derivative pre-processed spectra. With the fusion of spectral and significant color image features, the model’s accuracy improved to 93.3% and 90.9% in the calibration and prediction sets, respectively. Results also showed that the fusion of selected color image features with Savitzky-Golay 2nd derivative pre-processed spectra could achieve higher F1-score, recall, and precision values. The visualization map for the viable and non-viable paddy seeds was also developed utilizing the most effective predictive model. The results demonstrate the possibility of using the fusion of the hyperspectral and color image features to sort seeds according to viability, which may be applied in developing an online seed sorting method.
... Weed and nematode infestation are major problems, which can cause large yield losses in DSR (Joshi et al., 2013). Weed management is a fundamental practice, failure of which may result in severe losses in terms of yield and economic return (Juraimi et al., 2013). In the absence of continuous flooding, weeds can proliferate more easily. ...
The abstract of direct-seeded rice (DSR) in sustainability perspective highlights its potential to address key challenges facing modern agriculture. DSR, involving the direct sowing of rice seeds, offers water efficiency, reduced labor demands, climate resilience, and contributions to global food security. By optimizing water use through practices like alternate wetting and drying (AWD), DSR conserves water resources, aligning with sustainable water management goals. The reduced need for manual labor in DSR addresses labor shortages and enhances rural livelihoods, promoting social sustainability. DSR's adaptability to changing climates and mitigation of methane emissions contribute to its climate resilience and align with climate change goals. Furthermore, DSR's increased rice yield potential within limited land resources supports food security, a crucial aspect of sustainability. While challenges persist, such as weed management and knowledge dissemination, ongoing research, technology advancement, and supportive policies are essential to fully harness DSR's sustainability prospects, making it a promising approach for resilient and sustainable rice production.
... Weed and nematode infestation are major problems, which can cause large yield losses in DSR (Joshi et al., 2013). Weed management is a fundamental practice, failure of which may result in severe losses in terms of yield and economic return (Juraimi et al., 2013). In the absence of continuous flooding, weeds can proliferate more easily. ...
... One study categorized rice land ecosystems into four types: irrigated, rainfed lowland, upland, and deep-water (Khush, 1997). With higher area coverage, irrigated rice is the primary technique farmers use and has higher production than other rice areas (Anwar et al., 2011;Juraimi et al., 2013). Approximately 57% of rice production in Peninsular Malaysia is obtained from ten granary areas with extensive irrigation and drainage facilities (Dilipkumar et al., 2020). ...
Sedge is one type of weed that can infest the rice field, as well as broadleaf and grasses. If sedges are not appropriately controlled, severe yield loss will occur due to increased competition with cultivated rice for light, space, nutrients, and water. Both sedges and grasses are monocots and have similar narrowed leaf characteristics, but most sedge stems have triangular prismatic shapes in cross sections, which differ them from grasses. Event sedges and grasses differ in morphology, but differentiating them in rice fields is challenging due to the large rice field area and high green color similarity. In addition, climate change makes it more challenging as the distribution of sedge weed infestation is influenced by surrounding abiotic factors, which lead to changes in weed control management. With advanced drone technology, agriculture officers or scientists can save time and labor in distributing weed surveys in rice fields. Using hyperspectral sensors on drones can increase classification accuracy and differentiation between weed species. The spectral signature of sedge weed species captured by the hyperspectral drone can generate weed maps in rice fields to give the sedge percentage distribution and location of sedge patch growth. Researchers can propose proper countermeasures to control the sedge weed problem with this information. This review summarizes the advances in our understanding of the hyperspectral reflectance of weedy sedges in rice fields. It also discusses how they interact with climate change and phenological stages to predict sedge invasions.
... Determining the critical period of weed competition might help decide whether to apply weed management and if it's cost-effective (Juraimi et al., 2013). The critical period of weed competition is the key information for weed control. ...
Weeds limit sugar cane production. A field experiment employing cultivar NCO334 and Randomized Complete Block Design (RCBD) was done to assess weed competition crucial period. After planting, experimental plots were either weed-free or weedy (0, 25, 50, 75, 100, 125, and 150 DAP). Weed density, weed dry weight, sugarcane sprout, tiller number, cane height, millable cane number, girth, weight, and predicted cane and sugar production traits were evaluated. For different periods, weed competition affects tiller number, cane height, girth, weight, millable cane number, and cane and sugar yield. Tiller production, cane height, girth, weight, millable canes, and cane and sugar output rose with more extended weed-free periods. Weeds in sugarcane caused 90. 5% and 94.6% cane and sugar yield losses, respectively. Cane girth, height, weight, tiller number, cane, and sugar production correlated positively and negatively with weed density and dry weight. weed crop competition begins between 17 and 131 DAP. To limit the impact of weeds on sugar cane yield, weed management measures should be implemented in sugarcane plantations during this important period.
... Rice (Oryza sativa L.) is the leading cereal of the world (Juraimi et al., 2013) and two third of the Asian peoples receive their daily calories from rice. Rice is a principal and extensively grown crop of India. ...
Field experiments were conducted during Rabi 2014, at Paddy Breeding Station, Tamil Nadu Agricultural University, Coimbatore to study the effect of pre-emergence / early post emergence herbicides along with hand weeding options on weed control in transplanted rice. The soil of the experimental field was clay loam in texture with pH 8.23. The performance of different pre-emergence application of butachlor 50% EC 1.5 kg a.i. ha-1, flucetosulfuron 10% WG in two doses at 20 g a.i ha-1 and 25 g a.i ha-1, pyrazosulfuron-ethyl 10% WB 75 g a.i ha-1, early post emergence application of penoxsulam + cyhalofop-butyl in two doses at 120 g a.i ha-1 and 135 g a.i. ha-1, bispyribac sodium 10% SC 35 g a.i ha-1 were evaluated along with pre-emergence application of pretilachlor 50% EC 1.0 kg a.i ha-1 + HW at 45 DAT, butachlor 50% EC 1.0 kg a.i ha-1 + HW at 45 DAT in comparison with hand weeding twice at 20 and 40 DAT, unweeded control and weed free check. The test variety used in this experiment was Co (R) 50. The experimental results revealed that weed free check had 100% weed control efficiency (WCE) in all the stages of crop growth. Among the various treatments tested, At 90 DAT, weed control efficiency (WCE) was maximum with early post emergence application of penoxsulam + cyhalofop-butyl135 g a.i. ha-1 (T5) recorded the maximum weed control efficiency of 85.78%. The number of productive tillers m-2 recorded ranged between 441 in T5 and 295 in unweeded control (T11). Grain yield ranged between 7717 kg ha-1 in weed free check (T12) and 5194 kg ha-1 in unweeded control (T11). The maximum straw yield of 9277 kg ha-1 was recorded in weed free check (T12). This was on par with early post emergence application of penoxsulam+ cyhalofop-butyl 135 g a.i. ha-1 (T5) and hand weeding twice at 20 and 40 DAT (T10) with 9206 kg ha-1 and 9019 kg ha-1.
... In Uganda few studies have attempted to establish the most effective and economical integrated weed management options in upland rice ecosystems and research on row direction in rice is limited. It was reported [18] that any weed management approach should be aimed at controlling weeds only during the critical period of weed competition for a more cost effective and eco-friendly weed management. The critical period of weed control is defined as the time period in the crop growth cycle, during which weeds must be controlled to prevent unacceptable yield loss [19,20], observed the critical period for NERICA rice to be 14-42 days after sowing and weed control before or after that period had negligible effect on rice grain yield. ...
A study determined the effects of row direction and integrated weed management on the growth, productivity and economics of upland rice at Ikulwe Research Station using a completely randomized block design, replicated thrice with NAMCHE 5 upland rice in Uganda (2021b & 2022b). 12 treatments with 6 weeding regimes namely Pre- emergence Butanil (PREB) + 1hand hoeing (HH), 2HH, 3HH, PREB + Post emergence Butanil (POEB), weekly weeding (42 days) and control (EW & NS orientation) were adopted. Nitrogen (100 kg) Phosphorus (60 kg) and Potash (40 kg) were applied ha-1. Collected data on plant height, tillers, leaves, panicles; and grains were subjected to ANOVA (13th edition Genstat). Higher growth and yield parameters were in EW than NS direction. Leaves (27-28 leaves), height (65-70 cm), tillers (5-6 tillers and panicles (4-5 panicles) plant-1 were high under 2HH, PREB +1HH, PREB + POEB and 3HH (EW) compared to similar treatments in NS direction during 2021b and 2022b. Grain yield (2.34 t ha-1; HH), (2.26 t ha-1; PREB + 1 HH), (2.01 t ha-1; PREB + POEB), (1.89 t ha-1; 3HH) was significantly high in 2021b. During 2022b increased panicles (4-5 panicles), panicle length (21 cm), grains panicle-1 (110-117 grains) and grain yield (3.8 - 4.4 t ha-1) were recorded relative to 2021b. Weekly weeding (EW) developed high grains panicle-1 (102 grains) and grain yield (3.0 t ha-1) in 2022b relative to reduced tillers (4.5 tillers), filled panicles (3.6 panicles) and grain yield (1.9 t ha-1) in 2021b. Row directions had no effect on leaf width and grass biomass was numerically higher under EW than NS direction. Benefit Cost Ratios and Marginal Rate of Returns were optimum under 2HH and PREB + 1HH (EW). 2HH and PREB + 1HH (EW) may be recommended in Uganda having been the most economic technologies.
... Original research included 12 laboratory experiments (Ansara-Ross et al., 2008;Botelho et al., 2012;Bouétard et al., 2013;Chusaksri et al., 2010;Cousin et al., 2013;De Solla et al., 2012;Kim et al., 2009;Li et al., 2015Li et al., , 2017Marvá et al., 2010;Nsibande and Forbes, 2016;Oh et al., 2014;Thaimuangphol and Kasamesiri, 2015); 11 sampling studies in situ (de Queiroz et al., 2018;Donald et al., 2018;Ismail et al., 2011;Kathiresan and Deivasigamani, 2015;Leboulanger et al., 2011;Love et al., 2011;Messing et al., 2011;Mottes et al., 2017;Siemering et al., 2008;Wast et al., 2016;Yarpuz-Bozdogan, 2016); 1 clinical study on humans (Konthonbut et al., 2018); 1 epidemiologic study (Gatto et al., 2009); and 2 articles were computer model risk assessment (Dabrowski et al., 2014;Henning-De Jong et al., 2008); 1 one case study (Tsai, 2013b). Review articles included 7 reviews (Fenner et al., 2013;Gebrehanna et al., 2014;Juraimi et al., 2013;Roberts et al., 2012;Sartori and Vidrio, 2018;Singh and Singh, 2016;Tsai, 2013a) and 1 systematic review on the impact of pesticides on human health (Freire and Koifman, 2012). Aquatic environments from locations around the world ranged from drinking water, well water, surface water, ditches, reservoirs, ponds, wetlands, lakes, catchment areas, large watersheds, and coastal ecosystems. ...
Pesticides used in agriculture are widely considered to be the most cost-effective way to reduce undesirable plants and animal pests and increase crop yields. However, these economic benefits should be evaluated against any deleterious impacts on the natural environment and human health. While a great deal of attention is paid to the impact of agricultural runoff, more studies are needed on the impacts of pesticides on local waterways. The aim of this study was to: (i) develop a methodology to determine which pesticides were being used in local agriculture in the Byron Shire, Australia, and (ii) search the literature for evidence of the impact of these chemicals on local waterways. After a comprehensive search involving multiple government databases, three herbicides with potentially high toxicity on the aquatic ecosystems and humans, which are used for the treatment of crops cultivated on the agricultural land in the Byron Shire, Australia, were selected for this review: bromoxynil, diquat and paraquat. In the systematic scoping review, two databases were searched (Scopus and Web of Science) for publications between January 2008 and April 2019. From 160 articles identified, 36 papers were selected for inclusion. The evidence of harmful effects at realistic field concentrations (concentrations that are within the recommended safety range for use in the environment) was found for all selected herbicides, but not on all organisms. In aquatic environments, diquat was found to be toxic to snails and bromoxynil to microalgae. The clearest and most consistent evidence was found for paraquat. At realistic field concentrations, paraquat: (i) severely inhibited healthy bacterial growth (E. coli), (ii) distorted tropical freshwater plankton communities, and (iii) increased fish kills (common carp) three times more than the weed (water hyacinth) that it was employed to control. Of particular concern is that paraquat has been banned from sale in the European Union and many countries around the world but remains available in Australia and is likely in use in the Byron Shire. While there are existing Australian government regulations restricting the use of paraquat in agriculture, further work is required to scope the extent of its use, the effectiveness of these regulations and the amount of paraquat entering the environment. This study provides a methodology that can be used to identify pesticides that are likely to be in local use and to identify evidence of any negative impacts on the health of local waterways.
... Rosenzweig and Hillel (1995) reported that high temperature accelerated physiological development, resulting in hastened maturation and reduced yield. Dry tillage, aerobic soil condition along with lack of head start make this waterwise rice production system highly vulnerable to weeds, and therefore weed management is always a huge challenge in DDSR (Juraimi et al., 2013). Since primed seed exhibits increased, faster and synchronized germination along with better crop growth (Basra et al., 2005;Farooq et al., 2009), increased weed competitiveness (Anwar et al., 2012) and ultimately increased yield (Du and Tuong, 2002;Kaur et al., 2005), it was therefore hypothesized that seed priming may counteract those problems faced by DDSR. ...
Seed priming is a pre-sowing hydration technique which leads to a physiological condition triggering germination and enhancing uniform seedling emergence. It is a promising tool for enhancing drought tolerance in plants which is essential for promoting economic development by coping up with the adverse effects of climate change on crop productivity. So, a better understanding of seed priming efficacy is required. Therefore an experiment was conducted with a view to investigating the effect of seed priming agent on the weed growth and yield performance of high yielding rice variety BRRI dhan29 sown on different dates following dry direct seeded condition in boro season. Two sowing dates viz., 20th January (early or optimum sowing as control) and 20th February (late sowing as high temperature stress during reproductive stage) and seed priming agents included NaCl (20000 and 30000 ppm), KCl (20000 and 30000 ppm), CaCl2 (20000 and 30000 ppm), CuSO4 (50 and 75 ppm), ZnSO4 (10000 and 15000 ppm), Na2MoO4 (2 and 3 ppm) and PEG (100 and 150 ppm) were used. Plant height and tillers of BRRI dhan29 were significantly enhanced when seeds were sown early (20th January) and due to seed priming at early stage and at harvest. Among the yield parameters grains panicle-1, grain yield, and straw yield were produced more by early sowing (20th January). Grains panicle-1, 1000-grain weight, and grain yield were positively influenced due to seed priming. Considering the growth and yield parameters and yield of rice, early sowing and seed priming with KCl or CaCl2 were found as the best. Seed priming produced no significant effect on the weed growth. There was no significant effect of interaction between sowing date and priming agent on crop characters and yield parameters. Therefore, seed priming with 20000 ppm KCl or 20000 ppm CaCl2 and early sowing is recommended for increasing the yield of dry direct seeded boro rice (BRRI dhan29). If somehow early sowing is not possible, seed priming with 20000 ppm KCl or 20000 ppm CaCl2 is highly recommended or mitigating temperature stress during reproductive stage and enhancing yield of BRRI dhan29 under dry direct seeded, late sowncondition.
... However, this method has its disadvantages: it is a slow, tedious, and time-consuming process, which may also induce damage to rice seedlings and mistaken removal of rice seedlings. It has been estimated that 150 to 200 labor days/ha are required to keep rice crops free of weeds, and then its economic profitability directly depends on the labor cost [101]. ...
Rice (Oryza sativa L.) is the staple food of more than 50% of the world’s population. Manual puddled transplanted rice (PTR) system is still the predominant method of rice establishment. However, due to declining water tables, increasing water scarcity, water, labor- and energy-intensive nature of PTR, high labor wages, adverse effects of puddling on soil health and succeeding crops, and high methane emissions, this production system is becoming less profitable. These factors trigger the need for an alternative crop establishment method. The direct-seeded rice (DSR) technique is gaining popularity because of its low input demand compared to PTR. It is done by sowing pre-germinated seeds in puddled soil (wet-DSR), standing water (water seeding), or dry seeding on a prepared seedbed (dry-DSR). DSR requires less water and labor (12–35%), reduces methane emissions (10–90%), improves soil physical properties, involves less drudgery and production cost (US$9–125 per hectare), and gives comparable yields. Upgraded short-duration and high-yielding varieties and efficient nutrient, weed, and resource management techniques encouraged the farmers to switch to DSR culture. However, several constraints are associated with this shift: more weeds, the emergence of weedy rice, herbicide resistance, nitrous oxide emissions, nutrient disorders, primarily N and micro-nutrients, and an increase in soil-borne pathogens lodging etc. These issues can be overcome if proper weed, water, and fertilizer management strategies are adopted. Techniques like stale bed technique, mulching, crop rotation, Sesbania co-culture, seed priming, pre-emergence and post-emergence spray, and a systematic weed monitoring program will help reduce weeds. Chemical to biotechnological methods like herbicide-resistant rice varieties and more competitive allelopathic varieties will be required for sustainable rice production. In addition, strategies like nitrification inhibitors and deep urea placement can be used to reduce N2O emissions. Developing site and soil-specific integrated packages will help in the broader adoption of DSR and reduce the environmental footprint of PTR. The present paper aims to identify the gaps and develop the best-bet agronomic practices and develop an integrated package of technologies for DSR, keeping in mind the advantages and constraints associated with DSR, and suggest some prospects. Eco-friendly, cost-effective DSR package offers sustainable rice production systems with fewer resources and low emissions.
Graphical abstract
... and thus is not an economical for the farmers (Juraimi et al., 2013). Mechanical weeding using hand pushed weeders is feasible only where rice is planted in rows; however, weeds emerging within rows are difficult to remove with these weeders (Chauhan, 2012b). ...
Rice (Oryza sativa) is a staple food of more than half of the population of the world and provides food security and livelihoods for millions of population. Direct seeding of rice (DSR) refers to the process of direct sowing the seeds in the field rather than by transplanting seedlings from the nursery. Direct seeded rice is an age old practice and before the introduction of green revolution in India. Rainfed rice was often broadcasted into moist soil and crops were highly prone to weed competition resulted into low yield. Rice ecosystems and establishment methods determined the weed spectrum and degree of infestation in rice field (DSR). Weeds are considered as a major biological constraint in direct seeded rice. In direct seeded rice, weed management depend on weed flora, critical period of weed control, availability of water and method to be adopted. Integrated weed management (IWM) is essential to achieve the long term, sustainable and economic management of weeds in direct seeded rice. The literature regarding the direct seeded rice, critical period of crop weed competition, different types of weed flora and different methods for the effective and sustainable management of weeds in direct seeded rice are reviewed in this paper.
... Overall, weeds cause significant losses in crop yield more than other pests [4]. The losses in crop yields caused by weeds depend on various factors such as crop type, weed species, and density [5]. In Iraq, according to some studies, the weeds can cause losses in Wheat yield ranging from 13 to 43% [6]. ...
The experiment was implemented by CRD design with three replications and lasted for 40 days, from 5 October until 15 November 2020. Four extract concentrations of D. graveolens 0, 2, 6, and 10% were used. The concentration of 0% was considered as control. The allelopathic effect has been studied on five weed species; Amaranthus retroflexus L., Portulaca oleracea L., Lolium multiflorum Lam., Sorghum halepense L., and Cuscuta campestris Yunck. The research also aimed to determine the effect of Stinkwort extract on the growth of tomato seedlings. All concentrations affected seed germination for all studied weeds. The concentration of 10% was more influential in growth-related indicators compared to other concentrations. The seeds of L. multiflorum and rhizomes of S. halepense were more tolerant to D. graveolens allelochemicals in germination rate than A. retroflexus, P. oleracea, and C. campestris. All concentrations led to a reduction in the weed heights and the wet and dry weights compared with the controls. The effect of the extract with various concentrations was catalytic for the growth of tomato seedlings, as the average height of tomato seedlings was in direct proportion to the concentration.
... For example, the water managements of wet direct-seeded and transplanted rice are comparable, but the transplanted rice has a shorter reproductive period and therefore required less irrigation than wet direct-seeded rice (Jin et al., 2021;Ashraf et al., 2018). In transplanting systems where seedlings are planted in flooded and submerged soils, creates anaerobic conditions that limit the growth of weeds (Juraimi et al., 2013). More weeds have been reported to develop in direct-seeding than in transplanted rice . ...
Increasing energy output and improving energy production efficiency is essential to ensure the long-term sustainability of rice production systems in China. Present study assessed the energy input/output and its production efficiency for manual transplanted rice with manual broadcasting fertilizer (TR-MBF), mechanical pot-seedling transplanted rice synchronized with deep fertilization (MPST-DF), and mechanical hill direct-seeding rice synchronized with deep fertilization (MHDS-DF) in a three-year field experiment. Two rice cultivars i.e., Yux-iangyouzhan (YXYZ, inbred rice) and Wufengyou615 (WFY615, hybrid rice) were used to determine the energy input/output and production efficiency of each system. Results depicted that the MHDS-DF and MPST-DF treatment substantially improved the grain yield by 20.9% and 32.3% for WFY615 and YXYZ owing to enhanced total above-ground biomass (TAB) and leaf area index (LAI), respectively. Means across years and cultivars for energy input in the TR-MBF, MPST-DF, and MHDS-DF were remained 31918.0, 35267.1 and 36036.7 MJ ha − 1 , respectively. The energy consumed by diesel and fertilizer for energy inputs in the production system exceeds 70% of the total energy input. Moreover, the three rice production systems were highly dependent on non-renewable energy. The highest output energy and net energy were obtained for MHDS-DF and MPST-DF treatments with 221517.2 and 185670.0 MJ ha-1 , respectively. Among the three rice production systems , the highest energy use efficiency, energy productivity efficiency, energy profitability efficiency was found in MPST-DF, which was slightly higher than MHDS-DF. However, the human energy profitability efficiency of MHDS-DF treatment was significantly higher than other treatments. Therefore, MHDS-DF and MPST-DF could be best alternative technologies than conventional rice production systems with improved energy input and energy production efficiency in South China. Furthermore, both MHDS-DF and MPST-DF would also be suitable in the regions with lack of labor force for rice production.
... applied at 10 DAS followed by manual weeding at 30 DAS or pretilachlor + cinosulfuron (at 0.35 + 0.0075 kg ha-1 a.i.) applied at 4 DAS followed by manual weeding at 30 DAS or a combination of molinate + bensulfuron (at 3.0 +0.03 kg ha-1 a.i.) applied at 10 DAS. Integrated weed management practices for managing weeds including E. crus-galli were summarized (Karim et al., 2004;Azmi & Baki, 2006;Juraimi et al., 2013). ...
Echinochloa crus-galli (L.) P. Beauv., a C4 annual grass, is locally known
in Malaysia as Rumput Sambau and in English as Barnyardgrass. E. crus�galli was included in the Global Compendium of Weeds and is considered
one of the world’s worst weeds (Randall, 2017) in rice and earlier it was
also listed as a weed in at least 36 other crops in 61 countries throughout
tropical and temperate regions of the world (Holm et al., 1991). E. crus�galli is also considered an environmental weed that has become invasive
in natural grasslands, coastal forests and disturbed sites in Asia, Africa,
Australia, Europe and America (FAO, 2014; USDA-ARS, 2014). In
Malaysia, it was detected in 1925 (NWGIAS, 2014) and suspected to be
introduced unintentionally through contaminated seeds (Moody, 1989).
Since then, the weed has spread and becomes the most important weed
in all rice growing areas. In this paper synthesized information
is included on the ecology, current scenario of infestation, losses caused
and management of E. crus-galli in Malaysia.
... They are grasses, sedges and broad leaved weeds [28], and Table 1 shows a compilation of the primary weeds usually found in paddy fields. The environmental relationship between weed and rice is very complicated and complex [29]. The weed management system needs improvement to control the spreading of weeds. ...
This paper reviewed the weed problems in agriculture and how remote sensing techniques can detect weeds in rice fields. The comparison of weed detection between traditional practices and automated detection using remote sensing platforms is discussed. The ideal stage for controlling weeds in rice fields was highlighted, and the types of weeds usually found in paddy fields were listed. This paper will discuss weed detection using remote sensing techniques, and algorithms commonly used to differentiate them from crops are deliberated. However, weed detection in rice fields using remote sensing platforms is still in its early stages; weed detection in other crops is also discussed. Results show that machine learning (ML) and deep learning (DL) remote sensing techniques have successfully produced a high accuracy map for detecting weeds in crops using RS platforms. Therefore, this technology positively impacts weed management in many aspects, especially in terms of the economic perspective. The implementation of this technology into agricultural development could be extended further.
... Overall, weeds cause significant losses in crop yield more than other pests [4]. The losses in crop yields caused by weeds depend on various factors such as crop type, weed species, and density [5]. In Iraq, according to some studies, the weeds can cause losses in Wheat yield ranging from 13 to 43% [6]. ...
The experiment was implemented by CRD design with three replications and lasted for 40 days, from 5 October until 15 November 2020. Four extract concentrations of D. graveolens 0, 2, 6, and 10% were used. The concentration of 0% was considered as control. The allelopathic effect has been studied on five weed species; Amaranthus retroflexus L., Portulaca oleracea L., Lolium multiflorum Lam., Sorghum halepense L., and Cuscuta campestris Yunck. The research also aimed to determine the effect of Stinkwort extract on the growth of tomato seedlings. All concentrations affected seed germination for all studied weeds. The concentration of 10% was more influential in growth-related indicators compared to other concentrations. The seeds of L. multiflorum and rhizomes of S. halepense were more tolerant to D. graveolens allelochemicals in germination rate than A. retroflexus, P. oleracea, and C. campestris. All concentrations led to a reduction in the weed heights and the wet and dry weights compared with the controls. The effect of the extract with various concentrations was catalytic for the growth of tomato seedlings, as the average height of tomato seedlings was in direct proportion to the concentration.
... Only 1.74% of the farmers controlled their weeds manually in paddy fields, where it is is a labour-intensive effort. Therefore, the most cost-effective and practical option for controlling weeds is the application of herbicides (Juraimi et al., 2013). Some of the weeds featured in this study are being controlled solely using herbicides without any input of manual labor. ...
Rice is an important crop and a staple food in Malaysia. Herbicides are used extensively to control weeds, which represent a major constraint to yield production. Although the introduction of Imidazolinone-resistant Rice with its management system (IRPS) has greatly improved both yields and weed control, the system is designed to be used for only a short term before transitioning to local varieties. Thus, a survey was conducted among 115 farmers to obtain information on their general knowledge on weed control and IRPS. The results showed that the majority of the farmers use herbicides to control all types of weed presented, with a small minority still using manual control. The majority of farmers using IRPS were applying the herbicide imidazolinone when soil condition were right, and only once per season, which is the recommendation. Most of the farmers still utilized imidazolinone to control weedy rice but would not use it on other weeds. However, many of the farmers perceived imidazolinone as becoming more ineffective and expensive and were willing to change to other herbicides if there was a viable alternative. Although herbicide is the main method employed in controlling weeds when using IRPS, farmers still regard imidazolinone as an ineffective herbicide. The reason IRPS is still in use is due to the high yields provided. This study shows a better understanding of knowledge on weeds and IRPS among farmers. Nonetheless, the IRPS will become a redundant system due to the ineffectiveness of imidazolinone and a new system should be introduced to replace it.
... These factors warrant integrated approaches to manage weeds while reducing the environmental hazards associated with herbicides, and high costs associated with manual weeding Juraimi et al. 2013). Estimates indicate that farmers spend about US$100 to 300 ha -1 , which is about 10% to 20% of total production cost for controlling weeds in rice fields (Hasanuzzaman et al. 2008;Islam et al. 2017). ...
In Bangladesh, weeds in transplanted rice are largely controlled by labor-intensive and costly manual weeding, resulting in inadequate and untimely weed control. Labor scarcity coupled with intensive rice production has triggered increased use of herbicides. These factors warrant a cost-effective and strategic integrated weed management (IWM) approaches. On-farm trials with transplanted rice were conducted during monsoon (‘ Aman ’) season in 2016 and 2017 and winter (‘ Boro ’) season in 2016 to 2017 in agroecological zones 11 and 12 with ten treatments - seven herbicide-based IWM options, one mechanical weed control-based option, and two checks – farmers’ current weed control practice and weed-free, to assess effects on weed control, grain yield, labor use, and profitability. Compared to farmers’ practice, herbicide-based IWM options with mefenacet+bensulfuron-methyl as preemergence (PRE) followed by ( fb ) either bispyribac-sodium or penoxsulam as postemergence (POST) fb one hand-weeding (HW) were most profitable alternatives, with reductions in labor requirement by 11 to 25 persons-day ha ⁻¹ and total weed control cost by USD 44 to 94 ha ⁻¹ , resulting in net returns increases by USD 54 to 77 ha ⁻¹ without compromising on grain yield. In contrast, IWM options with bispyrbac-sodium or penoxsulam as POST application fb one HW reduced yields by 12 to 13% and profits by USD 71 to 190 ha ⁻¹ . Non-chemical option with mechanical weeding fb one HW performed similarly to farmers’ practice on yield and profitability. We suggest additional research to develop feasible herbicide-free approaches to weed management in transplanted rice that can offer competitive advantages to current practices.
... These weeds need to be dealt with quickly especially in the early stages to prevent paddy loss (Dangwal et al., 2012). In Malaysia, researches are focused on improving the farmers' weed control management such as developing a better breed of rice paddy and enhancing the current herbicides (Abdul Shukor et al., 2013;Rahman et al. 2012). However, these methods are appropriate only if farmers recognize the type of weeds found in their fields and apply the right herbicides. ...
Paddy weed appears to be one of the many visible threats to paddy crop production and subsequently farmers’ income. It is for this reason that the growth of paddy weeds in paddy fields should be controlled as it results in a significant decrease of paddy yields. However, farmers might have limited knowledge on weed types, and are thus unable to identify and determine the right prevention methods. This paper presents classification methods for paddy weeds through the leaf shape extraction and applies neuro-fuzzy methods for recognizing the types of weeds. The types being focussed are the Sphenoclea zeylanica, Ludwigia hyssopifolia and Echinochloa crus-galli. The developed e-prototype methods would be able to classify paddy weeds with 83.78% accuracy. Hopefully, the findings in this study would assist farmers and researchers in increasing their paddy yields and eliminating weed growth respectively. The production of paddy in Malaysia would eventually be improved with the proposed methods, which can be considered as a technology advancement in the field of paddy production.
... They compete with crop plants in the field and negatively influence the crop yield quality and quantity along with survival of the plants. Weed control using herbicides is the most popular method among farmers and it allows economically viable weed control providing costeffective method in the production of agricultural crops (Juraimi et al., 2013). In this context, herbicide-resistant rice has the potential to improve the efficiency of weed management. ...
Productivity of rice is influenced by a number of biotic and abiotic factors. Among these, weed accounts as a major constraint for rice production. It competes with the associated crops for water, soil nutrients, space, and light resulting in drastic reduction in crop yield. Manual and mechanical weeding incurs huge cost and often becomes impracticable, especially in areas with heavy weed infestation. However, non-selective herbicide particularly glyphosate proved to be a feasible solution to eradicate weed infestation, but it's off target movement to rice negatively influences plant growth, survival and seed yield. Therefore, development of herbicide resistance in rice turns to be the major focus in rice breeding. In the present study, the authors presented a detailed review of the weed management along with mode of action, weed resistance, genetic basis of glyphosate resistance, scope for exploring natural resistance, screening methodology and possible ways for development of glyphosate resistance in rice to confer selectivity and enhance crop safety and production.
... Direct seeded rice (DSR) produces a 5.33% higher yield and 25-50% low water use compared to the conventional method (Liu et al., 2015). Moreover, a significant reduction in paddy yield is often recorded due to greater operating costs in transplanting rice (Javed, Afzal, & Mauro, 2021;Juraimi et al., 2013). DSR is considered the optimal choice for higher rice yield with a lower cost of production . ...
A field experiment was conducted in 2016 to find out the sequential
use of different herbicides with adjuvants (a substance which enhances
pesticides efficiency) towards improved rice production and weed
management in direct-seeded rice crop. The early postemergence
herbicides (Kelion 50 WG, Ryzelan 240 SC, and Nominee 100
SC were applied at full or 75% of the full dose with and without
adjuvants i.e. 2% solution of ammonium sulfate (AS) and alkyl ether
sulfate (AES) at 14 days after sowing (DAS), followed by late postemergence herbicides i.e. Puma super (7.5 EW) and Sunstar 60
WG at 28 DAS. Application of herbicides with and without adjuvant
substantially suppressed weed with weed dry weight at 40 and 60 DAS
and improved rice yield attributes over a weedy check. It was found
that a combination of 75% of Nominee 100 SC along with adjuvant
i.e. AS (2% v/v) resulted in higher biological yield (9.16 t/ha), harvest
index (30.65%), more grains per panicle (98.13), 1000 grain weight
(21.32 g) with improved seed yield (3.86 t/ha). Also, abortive kernel
(5.33), chalky kernels (5.66), opaque kernels (5.00), normal kernel
(70.66), water absorptive ratio (4.28), and kernel length (10.13).
... The increased incidences of weed community in rice fields are much higher after the introduction of direct seeding rice cultures. According to Juraimi et al. (2013), the factors in determining the degree of infestation and weed types encountered in rice often depended on rice ecosystems and establishment methods. Bhagat et al. (1996) and Matloob et al. (2015b) also explained that factors such as cultural practices (fertilizer and type of rice cultivar), rice cultaviation practice (irrigated, rainfed lowland, upland, deep water, or tidal wetlands), moisture regime (irrigated or rainfed), crop establishment (transplanted or direct seeded), and land preparation (lowland, upland, tillage, or no-till) influence the types of weed and severity of weed infestation in rice fields. ...
... The effectiveness of evaluated herbicides on barnyardgrass has been well documented (Akkari et al. 1986;Balyan et al. 1996;Juraimi et al. 2013;Kirkwood and Fletcher 1984;Ryang 1998;Shaner 2014;Ushiguchi et al. 2014;Wilson et al. 2014). Soilapplied PRE herbicides need to be applied prior to weed emergence to maximize weed control (Shaner 2014 annual weed species, barnyardgrass may have several peaks of seed germination during the rice production season (Kennedy et al. 2010). ...
Resistance to penoxsulam among barnyardgrass populations is prevalent in rice fields in China. Seeds of penoxsulam-resistant (AXXZ-2) and -susceptible (JLGY-3) barnyardgrass populations, as well as the seeds of two rice varieties including Wuyungeng32 (WY) and Liangyou669 (LY) were planted in plastic pots and then treated with a rate titration of acetochlor, anilofos, butachlor, clomazone, oxadiazon, pendimethalin, pretilachlor, pyraclonil, or thiobencarb. The two barnyardgrass populations exhibited similar susceptibility to acetochlor, anilofos, butachlor, oxadiazon, pretilachlor, or pyraclonil. However, the susceptibility differed between the barnyardgrass populations in response to clomazone, pendimethalin, and thiobencarb. For AXXZ-2, herbicide rates that caused 50% reduction in shoot biomass from the nontreated control (GR 50 ) were 179, >800, and 1798 g ha ⁻¹ for clomazone, pendimethalin, and thiobencarb, respectively; while JLGY-3 GR 50 values were 61, 166, and 552 g ha ⁻¹ , respectively. Both rice varieties demonstrated excellent tolerance to acetochlor, butachlor, oxadiazon, pretilachlor, and thiobencarb. However, substantial rice damage was observed with anilofos and clomazone. Anilofos at 352 g ha ⁻¹ and clomazone at 448 g ha ⁻¹ reduced rice shoot biomass by 41 and 50% from the nontreated, respectively. Averaged across herbicide rates, clomazone reduced rice shoot biomass from the nontreated control by 52 and 34% for WY and LY, respectively; and pendimethalin reduced rice shoot biomass from the nontreated control by 25 and 9% for WY and LY, respectively.
... Worldwide numerous reports have been published on salinity stress and weed management in rice [2]. In addition to salinity stress, the weed management of rice in coastal areas is one of the most potent challenges in all rice-producing countries such as Malaysia [12]. The composition weed species in saline areas is different from flood plain areas [13]. ...
To mitigate environmental pollution and food contamination caused by inappropriate and excessive herbicide usage, most potent herbicides should be screened to control rice weeds. A research trial was executed for assessing the comparative efficacy of different herbicides to control rice field weeds and to evaluate the toxicity on rice under normal (distilled water) as well as different salinity levels (4 and 8 dS m−1). The study was designed to select the most potent herbicide and its appropriate dose for weed control of rice crop in coastal areas. Fourteen herbicidal treatments were included weed free crop, Pretilachlor (0.25, 0.50, 0.375 and 0.75 kg a.i. ha−1), Propanil + Thiobencarb (0.6 + 1.2, 0.9 + 1.8, 1.2 + 2.4 and 1.8 + 3.6 kg a.i. ha−1), Bensulfuron + MCPA (0.03 + 0.05, 0.045 + 0.075, 0.06 + 0.1 and 0.09 + 0.15 kg a.i. ha−1) and weedy check (control). The results revealed that all tested herbicides in higher than recommended doses for non-saline rice fields were effective in controlling Cyperus iria, Echinochloa colona (salt-tolerant) and Jussiaea linifolia but showed in light injury in rice plants grown in non-saline soils. These higher doses of herbicides recorded severe crop injury under saline conditions indicating their differential efficacy from normal non-saline conditions. Treatments including Pretilachlor (0.375kg a.i. ha−1), Propanil + Thiobencarb (0.9 + 1.8 kg ai/ha), Bensulfuron + MCPA (0.06 + 0.1 kg a.i. ha−1) and Pretilachlor (0.50 kg a.i. ha−1) remained superior in terms of weed control and grain yield production under all salinitylevels at TanjungKarang, Malaysia. It is concluded that herbicides respond differently under saline conditions and optimization of their doses potentially prevent herbicidal injury in rice plants.
... Harrowing has been found effective in DSR, especially when the crop plants are larger than weeds. Hand weeding is very easy and environment-friendly but tedious and highly labor intensive and thus is not an economical for the farmers (Juraimi et al., 2013). Mechanical weeding using hand pushed weeders is feasible only where rice is planted in rows; however, weeds emerging within rows are difficult to remove with these weeders (Chauhan, 2012). ...
... Chauhan and Johnson (2011) also reported similar results in relation to weed control efficiency due to less dry matter production and population of weeds. Juraimi et al. (2013) reported higher selectivity of bispyribac-Na between rice and barnyard grass when applied at 2 to 4 leaf stage. In this study, application of post bispyribac-Na pendimethalin evidenced higher WCE by reducing total weed pressure at early growth stages of crop and later due to bispyribac-Na at standard rates. ...
Aim: To identify the best sequence of pre- and post-emergence herbicides for achieving better weed control efficiency in aerobic rice. Methodology: A field experiment was conducted in Randomized Block Design with eleven treatment combinations, replicated thrice.? The dominant weeds in field were C. dactylon, E. colona and E. crusgalli among grasses, C. rotundus, C. difformis and F. maliaceae among sedges and C. axillaris and P. niruri among broad-leaf weeds. Treatments consisting sequential application of two pre-emergence application [Pendimethalin (30 EC) @ 1.00 kg a.i. ha-1; Butachlor (50 EC) @ 1.5 kg a.i. ha-1] followed by three post emergence herbicides [Bispyribac-Na (10% SC) @ 35 g a.i. ha-1; 2, 4-D Na salt (80 WP) @ 0.06 kg a.i. ha-1; Almix (CME + MSM ) (20 WP) @ 40 g a.i. ha-1] and straw mulching @ 4 t ha-1;? Mechanical weeding at 20 and 45 DAS, weed free and unweeded check.? Results: Among herbicidal treatments, pre-emergence application of pendimethalin at 3-4 DAS fb Bispyribac-Na at 15-20 DAS as post-emergence was most effective in minimizing weed density (4.81 m-2), biomass (6.20 g m-2), weed index (1.11%) and in enhancing the weed control efficiency (84.50%), grain yield (3.68 t ha-1) and straw yield (4.87 t ha-1) over rest of the treatments. Interpretation: Sequential application of pendimethalin at 3-4 DAS fb bispyribac-Na at 15-20 DAS is prominent in enhancing herbicide efficacy and reducing weed flora abundance resulting in higher weed control efficiency and grain yield due to their broad spectrum weed control.
54 (8 خاص): (عدد) 1 88-8 1 8 , 4815 و شاطي الزيادي 881 ومبيدات البذار معدالت تأثير األدغال الورقية المساحة دليل في ا في الجافة المادة اكم وتر لرز شاطي كريم ريسان الزي الرحيم عبد حاتم صدام ادي مساعد مدرس أستاذ الحقلية المحاصيل قسم-كلية اعة الزر-جامعة بغداد المستخلص ال محافظة المشخاب/ في الرز ابحاث محطة في حقلية تجربة فذت ُ ن سنتي خالل االشرف نجف 4888 و 4882 معدالت تأثير اسة در بهدف (البذار 148 و 158 و 168 و 188 كغم.هـ-1 ومبيدات) األدغال (المعاملة ومب المدغلة يد Oxadiazon ومبيد Propanil غياب ومعاملة األدغال) في الورقية المساحة دليل الجافة المادة اكم وتر مدد خالل نمو مختلفة (08 و 84 و 188 و 114 اعة) الزر من يوم (صنف للرز ياسمين). ا األ بترتيب المعشاة الكاملة القطاعات تصميم ستخدام ات. مكرر بأربعة المنشقة اح لو معدل تفوق النتائج بينت بذار 188 كغم.هـ-1 جميعها المدد في المعامالت بقية على في إ عطاء أعلى معدل في الجافة المادة اكم تر للنبات بلغ
This study was carried out in containers which were placed outdoor to evaluate the efficacy of different herbicides with different mixtures on weed growth suppression in rice and their effects on rice grain yield under saturated soil water regime in two consecutive seasons (cropping season and off season) at the Universiti Putra Malaysia Farm, Serdang, Selangor, Malaysia during 2016 to 2017. Eight combinations of different herbicides, viz. T1, T2, T3, T4, T5, T6, T7 and T8 along with weed free and non-weeded treatments were used in the study following a RCBD. Weed composition in the experimental containers and their summed dominant ratio (SDR) at 60 days after planting were recorded from non-treated containers. Naturally grown eleven weed species mainly under the families of Poaceae, Cyperaceae and Pontederiaceae were found in the experimental containers. Based on the SDR values the dominant weed species were Monochoria vaginalis, Echinochloa crus-galli, and Fimbristylis miliacea in both the seasons. Results revealed that four herbicide treatments viz. Pretilachor fb Bentazon/MCPA (T1), Pretilachor+Pyribenzoxim fb Bentazon/MCPA (T2). Bispyribac-sodium fb Bentazon/MCPA (T2), Fenoxaprop+Ethoxysulfuron (T3), fb Bentazon/MCPA (T7) were superior in their effectiveness for weed control in both seasons and gave better rice grain yield with high economic return. Bangladesh J. Bot. 52(1): 37-44, 2023 (March)
A field experiment was conducted during the kharif season of 2018 at the experimental farm of Agronomy, NU:SASRD, Medziphema campus, Nagaland, to study the effect of non-chemical weed management techniques for direct seeded rice. The experiment was laid out in randomized block design with 8 treatment combinations consisting of non-chemical weed management practices comprised of five treatments viz. Weedy check (W1), Hand weeding at 30 and 60 DAS (W2), Soil solarisation (W3), Brown manuring (W4), and Organic mulching (W5). Sowing methods comprised of three treatments viz. Broadcasting (S1), Line sowing at 20 cm (S2), and Hand dibbling (S3). Non-chemical weed management treatment hand weeding at 30 and 60 DAS significantly reduced weed density, and weed biomass and increased weed control efficiency, grain yield (35.05 q ha-1), and straw yield (80.93 q ha-1), whereas weedy check (W1) recorded the highest weed density, weed biomass and lowest weed control efficiency, grain yield (17.30 q ha-1), straw yield (69.77 q ha-1). Among the sowing methods S2-Line sowing recorded lower weed density, weed biomass, higher weed control efficiency, and highest grain yield (29.24 q ha-1).
Weed management practices are crucial for controlling weeds as they reduce yield, increase the production cost as well as deteriorate the grain quality. So, an experiment was conducted at Monirampur, Jashore, Bangladesh during July 2020 to June 2021 to find out the appropriate weed management practices in boro rice. BRRI dhan29 was selected as planting material to see the effect of seven different weed management practices such as no weeding, pre-emergence, post-emergence, pre-emergence followed by (fb) hand weeding (HW) at 40 DAT, post-emergence fb HW at 40 DAT, pre-emergence fb post-emergence and two HW at 20 and 40 DAT following single factor randomized complete block design (RCBD) with three replications. The study revealed that Poaceae and Cyperaceae contributed more weeds among 15 different families. Monochoria vaginalis, Fimbristylis miliacea, Echinochloa crus-galli, Cyperus rotundus and Alternanthera sessilis were more abundant among 34 weed species. The highest weed density (98.22 m −2) and dry weight (51.36 g m −2) were found in no weeding condition but that of the lowest value (weed density: 9.93 m −2 and dry weight: 3.59 g m −2) was observed in pre-emergence fb one HW at 40 DAT. The highest grain yield (6.52 t ha-1), net income (91571 Tk ha-1) and B:C ratio (1.9) were recorded in pre-emergence fb HW at 40 DAT followed by pre-emergence fb post-emergence treatment. The lowest value of grain yield (3.29 t ha-1), net income (12290 TK ha-1) and B:C ratio (1.14) were found in no weeding treatment. As per results, it can be concluded that pre-emergence fb HW at 40 DAT has been revealed as the best weed management practice for BRRI dhan29.
Weed management practices are crucial for controlling weeds as they reduce yield, increase the production cost as well as deteriorate the grain quality. So, an experiment was conducted at Monirampur, Jashore, Bangladesh during July 2020 to June 2021 to find out the appropriate weed management practices in boro rice. BRRI dhan29 was selected as planting material to see the effect of seven different weed management practices such as no weeding, pre-emergence, post-emergence, pre-emergence followed by (fb) hand weeding (HW) at 40 DAT, post-emergence fb HW at 40 DAT, pre-emergence fb post-emergence and two HW at 20 and 40 DAT following single factor randomized complete block design (RCBD) with three replications. The study revealed that Poaceae and Cyperaceae contributed more weeds among 15 different families. Monochoria vaginalis, Fimbristylis miliacea, Echinochloa crus-galli, Cyperus rotundus and Alternanthera sessilis were more abundant among 34 weed species. The highest weed density (98.22 m−2 ) and dry weight (51.36 g m−2 ) were found in no weeding condition but that of the lowest value (weed density: 9.93 m−2 and dry weight: 3.59 g m−2 ) was observed in pre-emergence fb one HW at 40 DAT. The highest grain yield (6.52 t ha-1 ), net income (91571 Tk ha-1 ) and B:C ratio (1.9) were recorded in pre-emergence fb HW at 40 DAT followed by pre-emergence fb post-emergence treatment. The lowest value of grain yield (3.29 t ha-1 ), net income (12290 TK ha-1 ) and B:C ratio (1.14) were found in no weeding treatment. As per results, it can be concluded that pre-emergence fb HW at 40 DAT has been revealed as the best weed management practice for BRRI dhan29.
In the era of rapid industrialization, there is increasing global concerns pertaining to anthropogenic activities mediated massive enhancement in atmospheric greenhouse gases like carbon dioxide, etc., thereby triggering global warming phenomenon. The global warming mediated climate change has been found to impose long-lasting detrimental impact on the environment. In contrast, adverse environment poses new unsightly challenges to agriculture sector like changes in precipitation pattern, temperature variations, pest infestation patterns and so on. Plant health management essentially contributes to socio-cultural sustainability, economic and environment sustainability as well as food security. The development of next-generation Integrated Pest Management programmes equipped with Artificial Intelligence, Bioinformatics and Biotechnology based tools would be a milestone for the protection of water, soil/land, wild species, environmental safety, improved plant productivity and profitability. This chapter provides an overview on the scientific approaches/strategies towards the prevention of climate change mediated impacts on agricultural plant/crop health and productivity with some notable eco-friendly pest management solutions. Overall, the better global treaties of coordination, cooperation and collaboration would lead to improved management of adverse environment and pests and plant/crop production can sustain the life on earth.
Dry Direct Seeded Rice (DDSR) is a promising technology to address environmental, water, labor and profitability issue that is constantly threatening the rice farming community around the world. Rice yield under DDSR is primarily limited due to weeds. There are instances of complete crop failure in DDSR owing to poorly managed weeds. More than 50 weeds species infest DDSR crop due to aerobic nature of soil confronting a major challenge in the wide spread adoption of dry direct seeding. Direct-seeded rice faces a potential threat from changes in the competing weed flora, with an increase in those species that are difficult to control. This review article presents the prospects of DDSR along with the available weed management strategies such as preventive, physical, chemical, cultural and biological methods and their judicious use. Over reliance on only one approach of managing weeds may be back firing as well. The use of chemical means are getting popular in an alarming rate for being cost effective, without calculating the environmental concerns which might lead to herbicidal resistance and negative consequences to environment and human health. Therefore, it is necessary to understand the environment while shifting from transplanted rice to dry direct seeding, identifying weeds flora and choosing or integrating the best weed management practices foreseeing the future consequences. The logical integration of available weed management options that is ecologically sound, economic and effective for season long weed control is the main essence that ensures the sustainability of rice production.
Plant-based bioherbicides could be an effective alternative to current chemical herbicides for sustainable agriculture. Therefore, this research evaluated the weed control efficacy and crop-weed selectivity of the new plant-derived bioherbicide WeedLock compared to commercial herbicides in glasshouse and field conditions. In the glasshouse, the herbicides applied were WeedLock (672.75, 1345.50, 2691.00 L ha−1), glyphosate isopropyl-amine, and glufosinate-ammonium (1, 2, 4 L ha−1), over the untreated (control) on six weeds and four crops. In the field trial, typical weeds were allowed to grow at a uniform density across plots (2.5 × 2.5 m), and WeedLock (1345.50, 2691.00 L ha−1), glyphosate isopropyl-amine, and glufosinate-ammonium (2, 4 L ha−1) were applied along with untreated plot (control). A randomized complete block design was set with four replications for glasshouse and field experiments. WeedLock at 1345.50 L ha−1 showed efficacy similar to glyphosate isopropyl-amine and glufosinate-ammonium at 2 L ha−1 for Ageratum conyzoides L. in the glasshouse. Applied herbicides killed all tested crops except Zea mays L. at 1345.50 L ha−1 (WeedLock). WeedLock showed more than 50% efficacy at 35 days after spray, while 65% was produced by glyphosate isopropyl-amine and glufosinate-ammonium compared to the untreated plot (control). WeedLock has excellent potential to control weeds in both glasshouse and field conditions and showed a non-selective character.
The establishment of the critical period of specifi c crop-weed interference is an important step in the development of effective and sustainable integrated weed management approach. Fimbristylis mil-iacea was allowed to compete with rice at different growth periods after rice emergence before removal by hand. In order to evaluate the onset of the critical period of weed removal, plots were left weedy for 14, 28, 42, 56 and 70 days after sowing , after which the weeds were removed and the pots maintained weed-free until harvest. To determine the end of the critical period, another set of pots were kept weed-free for 14, 28, 42, 56 and 70 days after sowing and subsequently weeds were allowed to grow until harvest. Full term weedy and weed-free treatments were included as controls for comparison. Grain yield reduction caused by increasing durations of F. miliacea competition was accompanied by high weed dry matter which simultaneously reduced rice straw biomass and number of productive tillers. Based on the predicted Logistic and Gompertz response curves, the critical period for controlling F. miliacea in direct -seeded rice was between 14-28 days after sowing.
Experiments were initiated at MARDI Bertam Rice Research Station in Penang in the dry season of 2004 and main season 2004/2005 to study the effect of different water regimes on diversity of weed species. Plots receiving continuous flooded treatment (T1) and flooding up to panicle initiation (T2) significantly suppressed weed population to approximately 18 - 58% and reduced weed biomass to 14 - 57% as compared to the highest values in continuous field capacity treatment (T5) at all sampling dates (30, 60 and 90 DAS) in both planting seasons. Across water regime treatments the weed composition comprised of 11 weed species in the dry season and 10 weed species in the main season. Broadleaved weeds, especially Monochoria vaginalis and Limnocharis flava were the most dominant weeds in most water regime treatments. The SDR values of broadleaved weeds in the dry season were 48.7, 46.4, 44.2, 40.7 and 35.8% for T2, T1, T3 (flooding for the first month), T5 and T4 (continuous saturation), respectively. In the main season, the SDR values for the broadleaved weeds increased to 79.5, 68.2, 62.4, 62.2, and 50.57% for T2, T1, T3, T4 and T5, respectively. Fimbristylis miliacea and Cyperus iria were dominant in the dry season with SDR values of more than 34% in all water regime treatments, but decreased to less than 23% in the main season. For grasses, comprising of mostly Echinochloa crus-galli, Echinochloa colona and Leptochloa chinensis, SDR values of more than 20% were recorded in T4 and T5 in the dry season, while in the main season SDR values of between 21 - 34% were observed in treatments T1, T3 and T5.
Field experiment was conducted at the Malaysian Agriculture Research and Development Institute (MARDI) station, Seberang Perai, Penang in off-season 2005 and main season 2005/2006, to determine the critical period of weed competition in saturated and flooded conditions. The experiment consisted of different seasons, namely weed free and no weeding periods. Sum Dominance Ratio showed that the weed compositions were different in the saturated condition, as compared to the flooded condition for both seasons. The dominance ranking of weed groups in the off- season in 2005 in saturated condition was sedges, followed by grasses and broadleaved, while during the main season of 2005/2006, grassy weeds were the most dominant, followed by sedges and broadleaved weeds. In the flooded condition, the dominance rankings of weed groups (such as broadleaved>grass>sedges) were the same in both seasons. The number of tillers, along with rice grains yield, was significantly affected by the weed competition in both saturated and flooded conditions. Yield loss due to weed competition was higher in the saturated condition (54.5%) than in the flooded condition (35.2%). Based on the 5% level of yield loss, the critical period in the off-season of 2005 was between 2-71 days, after sowing (DAS) in saturated condition, and 15-73 DAS in flooded condition. Meanwhile in the main season of 2005/2006, the critical period was between 0-72 DAS in the saturated condition and 2-98 DAS in the flooded condition.
High weed pressure is amongst the major constraints to the extensive adoption of aerobic rice system as a water-wise technique. Towards developing a sustainable weed management strategy, seeding method and rate may substantially contribute to weed suppression and reduce herbicide use and weeding cost. A trough experiment was established at the Plant House of Universiti Putra Malaysia with two seeding methods, namely conventional broadcast seeding (CBS) and line seeding with east-west row orientation (REW). Three seeding rates were established at 200 (SR200), 300 (SR300) and 400 seeds m -2 (SR400); and two weed control levels were established as weedy (W) and weed free (F) in a factorial RCBD with four replications. Twenty (20) weed species comprising eleven broadleaved, five grasses and four sedges were identified. Broadleaved weeds contributed more than 50% of the total dry matter. Weed density and dry weight decreased gradually with increased seeding rate, but were independent of methods. REW produced significantly higher grain yield compared with CBS. Among the seeding rates, SR300 produced the highest grain yield followed by SR200 and SR400. Weed free treatment performed better with a yield advantage of 23% over weedy treatment. Weed inflicted relative yield loss did not vary due to seeding methods or rates. Therefore, increasing seeding rate up to 300 seeds m -2 may be worthwhile to reduce weed pressure without sacrificing rice yield.
ABSTRACT
Studies for weed management in transplanted rice were carried out at the experimental farm of Rice Research Institute,
Kala Shah Kaku, Lahore during the Kharif seasons of 2004 and 2005 to find out the best strategy for weed control in
transplanted rice (Oryza sativa L.). The experiment was laid out in randomized complete block design and replicated
thrice with a net plot size of 10X5 m2. During both the years newly released rice variety Basmati-2000 was used as an
experimental material. The nursery was transplanted during second week of July. Six herbicides applied at 4th day of
transplanting were compared with weedy check in which no weeds were eradicated as well as with manual hand
weeding at 22 DAT. Highest weed control ( (93.03%) was recorded in case of sunstar during first year, while during the
second year the maximum control of weeds was 94.67 % in case of hand weeding. Regarding number of tillers/plant,
hand weeding resulted into 21.4 and 20.8 for the year 2004 and 2005 in comparison to 15.3 and 16.6 for control (weedy
check) for first and second year of the experiment, respectively. Where as the highest number of grains / panicle was
recorded 132.56 during first year (2004) and 135.50 during the second year (2005). All of the herbicidal treatments did
not differ significantly from hand weeding during both the years for this character. In terms of paddy yield, hand
weeding gave the highest grain yield but remained statistically at par with certain herbicides. Welchlore and declore gave
lower yield for the year 2004 and 2005, respectively. Control (weedy check) produced the lowest yield during both the
years.
Key words: Herbicides, Oryza sativa L. Weeds.
Aerobic rice systems, wherein the crop is established via direct seeding in non-puddled, non-flooded fields, are among the most promising approaches for saving water and labor. However, aerobic systems are subject to much higher weed pressure than conventionally puddled transplanted rice (CPTR). Experiments were conducted for two years to develop effective and economical methods for managing weeds in aerobic rice grown by direct seeding rather than by conventional transplanting method. The proportion of mean grass-weed dry matter was 28.3% more in aerobic direct-seeded rice (ADSR) as compared to CPTR. Both weed density and dry weight were negatively correlated with rice grain yield. ADSR treatment produced yield similar to CPTR treatment when weeds were controlled effectively. Post-emergence application of bispyribac Na 25 g/ha and penoxsulam 25 g/ha could effectively control all the weeds in ADSR. Irrigation water productivity remained statistically the same in both ADSR and CPTR under the weed-free situation or when bispyribac Na herbicide was applied as post-emergence because of effective weed control in ADSR. The variation in net profitability between the ADSR and CPTR decreased with herbicide treatments, viz., Bispyribac Na, followed by penoxsulam and sequential application of pretilachlor and metsulfuron.
Aerobic rice is a potential water-wise rice production system, but high weed infestation has threatened its sustainability, which demands an efficient and cost-effective weed management technique. Eight commercial herbicide products were applied singly or as tank-mix or in sequence to evaluate their efficacy, rice selectivity and cost-effectiveness in aerobic rice. The study was conducted under field conditions in Malaysia during 2010/2011 following a randomized complete block design. Most of the herbicide treatments provided excellent weed control, and produced much higher net benefit than weedy or weed-free check. None of the herbicides caused significant phytotoxicity to rice plants. Among the herbicide treatments, sequential application of Cyhalofop-butyl+Bensulfuron at early growth stage followed by Bentazon/MCPA at mid growth stage provided the highest weed control efficiency, productivity and net benefit. Application of Bispyribac-sodium at early growth stage followed by Bentazon/MCPA at mid growth stage performed very close to the above-mentioned treatments. Sequential application of Pretilachlor/safener just after seeding followed by Propanil/Thiobencarb at early growth stage also provided satisfactory results in terms of efficacy and economic return. Since manual weeding was not economic, herbicide rotation using the above chemicals may be recommended for effective weed management in aerobic rice.
The allelopathic effect of rice (Oryza sativa L.) on lettuce (Lactuca sativa L.) and ducksalad [Heteranthera limosa (Sw.) Willd.] was investigated with water soluble extracts. Ducksalad is a major weed in southern USA rice fields. 'P1312777' and 'Rexmont', which are suppressive and nonsuppressive to ducksalad in the field, were used to establish the bioassay of allelopathic activity in rice. Water soluble compounds, which were extracted from rice seedlings and adult plants, were applied to lettuce seeds. Leaf extract of P1312777 inhibited the root growth of lettuce more strongly than those of Rexmont. Extracts from the leaves of rice seedlings at the six-leaf stage inhibited the growth of ducksalad and lettuce, and a close relationship existed between the inhibitory effect and the two test plants. A wide range of variation in allelopathic activity among rice cultivars was assessed using water soluble extracts from their leaves and lettuce as a test plant.
Increasing concerns about pesticide use and a steadily increasing conversion to organic farming have been major factors driving research in physical and cultural weed control methods in Europe. This article reviews some of the major results achieved with nonchemical methods and strategies, especially adapted for row crops (e.g., corn, sugar beet, onion, leek, and carrot) and small-grain cereals (e.g., barley and wheat). In row crops, intrarow weeds constitute a major challenge, and research has mainly aimed at replacing laborious hand-weeding with mechanization. A number of investigations have focused on optimizing the use of thermal and mechanical weeding methods against intrarow weeds, such as flaming, harrowing, brush weeding, hoeing, torsion weeding, and finger weeding. And new methods are now under investigation such as robotic weeding for row crops with abundant spacing between individual plants and band-steaming for row crops developing dense crop stands. The strategic use of mechanical weed control methods in small-grain cereals has been another area of considerable interest. Weed harrowing and interrow hoeing provide promising results when they are part of a strategy that also involves cultural methods such as fertilizer placement, seed vigor, seed rate, and competitive varieties. Although research in preventive, cultural, and physical methods have improved weed control in row crops and small-grain cereals, effective long-term weed management in low external input and organic systems can only be achieved by tackling the problem in a wider context, i.e., at the cropping system level. Basic principles of this approach, examples of cover crop and intercropping use for weed suppression, and an application in a 2-yr rotation are presented and discussed. Nomenclature: Barley, Hordeum vulgare L.; carrot, Daucus carota L.; corn, Zea mays L.; leek, Allium porrum L.; onion, Allium cepa L.; sugar beet, Beta vulgaris L.; wheat, Triticum aestivum L.
In field experiments conducted in 2001 and 2002, the optimum timing for weed control in maize was investigated. Both experiments were designed according to randomized complete blocks, and Cyperus rotundus L., Amaranthus retroflexus L., Portulaca oleracea L. and Chenopodium album L. were naturally infested on experimental plots in both years. The study in 2001 was conducted to determine the critical period for weed control for maize. With this aim plots were maintained weed-free or weedy for different periods based on crop growth stage. The relationships between grain yield and different weedy or weed-free periods were determined via regression analyses in 2001. The results of this study suggested that a weed-free period between 3- and 10-leaf stages of maize was enough to provide acceptable grain yield. In the following year weed control was carried out during the critical period that was determined in 2001. Weed removal from plots was started at the 3-leaf stage of maize and plots were kept weed-free for different periods until the 5-, 7- and 10-leaf stages. Whole season weedy and weed-free plots were included in the experiment for yield comparison. The highest grain yield was obtained from plots kept weed-free between the 3- and 7-10-leaf stages. Results from both years suggest that weed control should be carried out between the 3- and 7-10-leaf stages of maize to provide maximum grain yield. Thus, it is possible to optimize the timing of weed control, which can serve to reduce the costs and side effects of intensive weed control.
glycine), and trifluralin (a,a,a-trifluoro-2,6-Dinitro-N, N-dipropyl-p-toluidine) are prone to leaving the site of The economic and environmental costs of weed management in application through surface runoff, potentially adversely soybean (Glycine max (L.) Merr.) have led to interest in developing weed suppressive soybean varieties to enhance traditional herbicide affecting water quality (USDA/NRCS, 1998). Besides and tillage-based approaches. We evaluated 104 inbred progeny from herbicides, growers rely on cultivation as a weed man- three crosses among elite soybean lines to determine optimal selection agement tool. Cultivation, however, disturbs the soil, criteria for weed suppressive ability (WSA). We grew the lines in aggravating erosion losses and increasing the sediment 1996 and 1997 at Becker, MN, an irrigated sandy site, and Rosemount, load of surface waters. These costs bring together farm- MN, a rainfed silt loam site, in a split-plot, with and without white ers and environmentalists in calling for more diverse, mustard (Brassica hirta Moench). We measured soybean height 7 wk ecologically sound options to manage weeds (Liebman after emergence (WAE), light interception 5 and 7 WAE, specific and Dyck, 1993). Diverse options may be even more leaf area 7 WAE, and date of full bloom. We harvested aboveground important if over-emphasis on a few management meth- mustard biomass 8 WAE and calculated each soybean line's WSA as ods leads to shifts in weed species or evolution within the difference between mustard biomass when grown in competition with that line and the overall mean mustard biomass. We estimated weed populations toward resistance to these methods, genetic correlations between soybean morphological traits, WSA, and reducing their efficiency (Jordan and Jannink, 1997). the agronomic traits lodging, maturity date, and yield. Soybean early Two traits inherent to the crop genotype contribute height's heritability (h 2
Dry seeding of rice (Oryza sativa L.) involves a major change in the production practices for attaining optimal plant density and high water productivity in the water- deficit areas of Pakistan. Weeds pose serious threat to sustainability and viability of direct seeded rice system. Information on weed management in dry seeding rice in Pakistan is lacking. A field experiment was conducted to identify appropriate, effective, and economical methods of managing weeds in dry-seeded rice. The major weeds associated with dry-seeded rice were Echinochloa crus- galli, Cyperus iria, C. difformis, Paspalum distichum, Eclipta prostrata, and Trianthema portulacastrum. Pendimethalin 750 g a.i. ha-1, ethoxysulfuron at 18 g a.i. ha-1, and 2,4-D (ester) at 500 g a.i. ha-1, were equally effective in realizing higher rice grain yields by controlling broad leaf weeds and sedges. Among these, 2,4-D (ester) at 18 g a.i. ha-1 was found to be least expensive but effective for controlling broad leaf weeds. Effective and economical weed control methods include pre- and post-em herbicides along with one hand weeding was found effective in controlling weeds and producing higher paddy yield.
Tef [Eragrostis tef (Zucc.) Trotter] is an annual C4 grass crop that originated in Ethiopia. The average grain yield of this crop is low; averaging < 0.8 Mg ha-1 in farmer's fields of the semi arid conditions. Productivity can be increased to a considerate extent through the improvement of management practices alone, particularly sowing time with appropriate weed control. The objective of this study was to identify the growth and yield performance of tef as affected by cultural manipulation of date of sowing and weed removal time at semi arid region in Alem tena in Ethiopia. Tef was planted at three sowing dates, recommended sowing date, 7 and 15 days delay after the recommended date. The five weed removal time were included as weedy check (W1), weeded two weeks (W2), four weeks (W3), six weeks (W4) after crop emergence and weed-free check (W5). All data were subjected to analysis by ANOVA, principal component analysis (PCA) and correlation/regression analysis. Weed removal time played a minor role compared to sowing time. Irrespective of weeding dates, delayed tef sowing time was very critical. Plant height reduced by 23 to 32%, panicle length by 45.51 and 55.11% crop biomass by 34.39 and 35.53% and grain yield 60 to 68%, when sowing was delayed for 7 and 15 days, respectively. The relationship between plant height and grain yield and crop biomass and grain yield of tef was very strong and quadratic, whereby, as the plant height as well as crop biomass increased, the yield also increased. All these relationships clearly indicate the high competitive ability of tef against nutsedge. Nutsedge competition during the first 6 weeks after crop emergence reduced tef biomass by more than 30%. Keeping the tef field free of weeds for at least six weeks for early and late sown tef is essential to give the crop advantage of growing faster to enhance crop yields.
Yield of both superior hybrid and inbred lines developed by the Chinese plant breeders has been stagnant even with the standard rice-growing practices; thus raising the need for suitable modifications in these practices. Nitrogen uptake, yield attributes and yield response of two rice cultivars under the varying plant densities and nitrogen application rates has been investigated in these studied. Two management systems including conventional practices or standard rice management (SRM), and new rice management or the system of rice intensification (SRI) have been investigated in a two year trial. Significantly higher grain yields (15%) and higher N uptake rates (24.8 kg ha -1) were recorded for SRI compared with SRM during both years of experimentation. In this study, yield optimization under SRI was achieved with substantially lower plant densities than typically planted with super-rice under SRM. According to these experimental results, applications of N fertilizer can also be effectively reduced with concomitant increases in yield. Increasing plant densities associated with SRM were found to decrease the crop performance as increase in yield per unit of input (seeds, water, N fertilizer) were negative at the margin. Although in the SRM experiments, N uptake was enhanced by higher N application and by greater plant density, the uptake of N ha -1 with SRI was greater with lower plant density, and it was not affected in a linear manner by N applications. Compared to SRM, N productivity was higher at all levels of application with SRI. It appears that not only agronomic benefits but also economic and environmental benefits may be accrued from these two methods of rice management, especially with the super-rice varieties developed in China. Trial results indicate that modification in the management practices can positively influence the rice crop outputs. Key words: Standard rice management (SRM), the system of rice intensification (SRI), super-rice, hybrid rice (Oryza sativa L.), grain yield, nitrogen uptake.
Continuous rice (Oryza sativa L.) cropping in Latin America and the Caribbean has resulted in serious weed problems and herbicide overuse. Competitive rice cultivars could help reduce herbicide dependence. A study was conducted during 1994 and 1995 at Palmira, Colombia, to (i) assess the competitiveness of semidwarf irrigated rice plant types adapted to Latin America and the Caribbean's direct-seeding systems, (ii) identify plant traits responsible for such competitiveness, and (iii) detect adverse effects of competitiveness on rice yield potential. Pregerminated seed of 10 and 14 semidwarf rice cultivars was sown on drained puddled soil in 1994 and 1995, respectively. Cultivars were grown weed-free or with junglerice [Echinochloa colona (L.) Link] (40 viable seeds m -1, broadcast immediately after seeding rice), and were intermittently irrigated to keep the soil near saturation. Rice and junglerice biomass, leaf area index, tiller number, and height were recorded at 20, 40, 60, 90, and 120 days after emergence (DAE). Rice cultivars differed in their competitiveness against junglerice. Average yield losses ranged from 27 to 62% under saturating junglerice infestations of up to 5.9 Mg DM ha -1. Leaf area index, tiller number, and canopy light interception recorded in competition, and not much before 40 DAE, correlated positively with rice competitiveness. Competitive semidwarf cultivars can substantially reduce the number of herbicide applications in systems where suboptimal water control does not allow weed suppression by flooding. Breeding to enhance rice competitiveness appears as a valid objective, since competitive and also highly productive cultivars were identified in this study.
When savannas in Latin America are brought into cultivation, rice (Oryza sativa L.) can be sown with the perennial grasses palisadegrass [Brachiaria brizantha (Hochst. ex A. Rich) Stapf] and signalgrass (B. decumbens Stapf) to harvest a grain crop while establishing a pasture to suppress weeds and provide grazing in subsequent years. However, these Brachiaria spp. can reduce upland rice yields. Rice cultivars need to be competitive with Brachiaria spp. to maintain yields but must allow Brachiaria spp. sufficient growth for pasture establishment. Field studies were conducted during 1994 and 1995 on a Typic Haplustox oxisol soil in the Eastern Plains of Colombia to evaluate the competitiveness of upland rice cultivars and to identify rice traits for competitiveness. Ten (1994) and 14 (1995) upland rice cultivars were grown with and without signalgrass in 1994 and palisadegrass in 1995. Rice cultivars differed substantially in their competitiveness. Rice yield losses ranged from 18 to 55%, and Brachiaria aboveground biomass ranged from 1.4 to 3.2 Mg ha-1 dry mass. Competition for light was critical; rice photon flux density interception, leaf area index [≥45 d after emergence (DAE)], and number of tillers (≥60 DAE) were correlated with competitiveness. No tradeoff between high yield potential and competitiveness was detected in these upland rice cultivars. Early maturity of rice is a desired characteristic for the rice-Brachiaria spp. association. The development of more-competitive cultivars appears to be a viable approach for reducing herbicide dependency and improving profitability of Latin American rice-pasture intercropping systems.
This study was conducted to evaluate the effects of intercropping Sesbania with dry-seeded rice up to its vegetative phase (Sesbania), mulching with wheat residue (mulch) and herbicides for managing weeds and optimising the yield of dry-seeded rice. The density of grass weeds was lower with the mulch at all stages of crop growth. Though the dry weight of grass weeds at 30 days after seeding (DAS) was lower with Sesbania than with mulch, they were similar at later stages. A lower broadleaved weed density and dry weight were observed with Sesbania than with the mulch. It is concluded that application of wheat residue mulch at 4 t ha–1 and Sesbania intercropping for 30 days were equally effective in controlling weeds associated with dry-seeded rice. However, pendimethalin (1000 g a.i. ha–1) or pretilachlor with safener (500 g a.i. ha–1) as pre-emergence applications followed by one hand-weeding were effective in controlling weeds, increasing grain yield of dry-seeded rice, and resulting in higher net returns than the weed-free treatment.
Aerobic rice systems, wherein the crop is established via direct-seeding in non-puddled, non-flooded fields, are among the most promising approaches for saving water and labour. However, aerobic systems are subject to much higher weed pressure than conventionally puddled transplanted rice (CPTR). Experiments were conducted for 2 years to develop effective and economical methods for managing weeds in aerobic rice grown by direct-seeding or transplanting on flat land or furrow-irrigated raised-bed systems (FIRBS).
Total weed dry weight and weed density were lower with CPTR and highest with aerobic direct-seeded rice on a FIRBS (ADSB), followed by aerobic direct-seeded rice (ADSR). In terms of weight grassy weed constituted 78–96% of total weed weight in all systems of rice establishment. Loss of grain yield of rice due to weed competition ranged from 38% to 92%, being the highest in ADSB. Both weed density and dry weight were negatively correlated with rice grain yield. ADSR treatment produced yield and net economic returns similar to CPTR treatment when weeds were controlled. Pretilachlor with safener at 500 g a.i. ha�1 applied 3 days after sowing (DAS)/ days after transplanting (DAT) followed by chlorimuron+metsulfuron at 4 g a.i. ha�1 applied 21 DAS/DAT followed by hand-weeding at 35 DAS/ DAT could effectively control all the weeds. The next best treatment was cyhalofop-butyl at 120 g a.i. ha�1 applied 14 DAS/DAT followed by chlorimuron+metsulfuron at 4 g a.i. ha�1 applied 21 DAS/DAT followed by hand-weeding at 35 DAS/DAT. The ADSR was as effective as conventionally puddle-transplanted rice in attaining higher rice grain yield and net returns when weeds were kept under control.
The effects of pre-sowing seed treatments on the germination and emergence of fine rice and on reducing, non-reducing and total sugars and α-amylase activity were studied. Fine rice seeds were either soaked in tap water by a traditional method, hardened for 18 or 24 h (two cycles)
or osmoconditioned (−1.1 MPa KNO3) for 24 or 48 h. Seed hardening (24 h) and the traditional soaking treatments resulted in a higher germination percentage, germination index and energy of germination and lower mean germination time and mean emergence time. Performance was
slightly better in seeds subjected to hardening for 24 h than the traditional soaking because of lower T50 and non-reducing sugars and higher reducing and total sugars and α-amylase activity. In seeds subjected to osmoconditioning for 48 h seed performance was impaired possibly
because of KNO3 toxicity.
Weed control is seen as the most significant management practice to improve upland rice yields, the most important rice field weeds on a worldwide basis being Dactyloctenium aegyptium, Digitaria spp., Echinochloa colona, Eleusine indica, Imperata cylindrica and Rottboellia cochinchinensis. These and others are discussed with respect to the critical period of weed competition, and possible control measures such as burning, cultivation and land preparation, cultivar use, nitrogen fertilization, manual weeding, inter-row cultivation, herbicides, intercropping, alley cropping and ground cover crops. -J.W.Cooper
Conservation tillage systems leave crop residues in the soil which provide sustenance for weeds. These eventually become resistant to the herbicides which are used to control them. The paper reviews the factors controlling the spread of weeds, the soil-herbicide-tillage interactions and considers future weed control technology but the trend towards increased herbicide resistance and tolerance in weeds appears inevitable and is occurring very quickly. -R.H.Johnson
To manage the weeds in direct seeded rice, four weedicides were tested and compared their efficacy with handweeding. Among the weedicides Nominee 100SC (bispyribac sodium) and Sunstar Gold 60WG (Ethoxy sulfuron) proved as the best weedicides with 90.5 and 87.19% weed control respectively. The paddy yield in both the weedicide treatments was also comparatively higher than other weedicides. The highest net benefit was obtained by the application of nominee 100sc followed by Sunstar Gold 60 wG treatment while the lowest net benefit was provided by control (weedy check). No doubt, the results of hand weeding are significantly better but as it is time consuming and laborious hence cannot be recommended at large scale.
A field experiment was conducted during 2004-05 and 2005-06 on clay-loam soil at Jabalpur in Madhya Pradesh to find out the effect of integrated weed-management practices on weeds and yield of zero-till direct-seeded rice (Oryza sativa L). Different methods of crop establishment were evaluated for getting higher productivity and profitability of irrigated rice-wheat cropping system. For rice there were four methods, viz. direct seeding by zero-till drill, direct drilling in friable soil by seed drill, direct seeding of sprouted seeds in puddled soil, and transplanting; and for the succeeding wheat (Triticum aestivum L. emend. Fiori & Paol.) there were two methods, viz. sowing with zero-till drill and conventional sowing. Echinochloa colona and Commelina spp. were the major weeds in zero-till, direct-seeded rice, which reduced the grain yield by 27.4%. Pre-emergence application of pretilachlor at 750 g/ha or pendimethalin at 1.0 kg/ha each, followed by one hand-weeding at 30 days after sowing was on a par with hand-weeding twice, giving significantly higher grain yield (5.20 and 3.50 t/ha) compared with the weedy check (3.98 and 2.25 t/ha). Zero-till, direct-seeded rice with proper weed management resulted in significantly higher yield than transplanted rice. In the succeeding wheat crop, population of dominant weeds, viz. Chenopodium album and Medicago hispida, was found to be reduced when wheat was grown after zero-till, direct-seeded rice compared with other methods of rice establishment. The wheat sown after zero-till, direct-seeded rice yielded significantly higher (3.76 and 3.61 t/ha) than when sown after other methods of rice establishment. Zero tillage in direct-seeded rice-wheat system reduced the weed problem and increased the system productivity as well as profitability.
The effect of two commonly used herbicides (atrazine and atrazine + metolachlor) on non-target soil microflora was investigated over a period of 8 weeks. One kilogram soil samples each from maize farm were treated with the herbicides separately at company recommended and one and half (X1.5) recommended rates. Effects of the herbicides on soil pH and percentage organic matter were also investigated. Significant changes in soil pH and percentage organic matter were observed only in atrazine treated soils (P < 0.05). Herbicide treatments at both recommended and X1.5 recommended rates resulted in decreases in microbial counts. Higher concentrations of herbicides treatments resulted in much lower microbial counts compared to soils treated with recommended herbicide does. Herbicide treatments also resulted in the elimination of some microbial species. Pseudomonas sp. and Bacillus sp. were the most frequently isolated bacteria from herbicide treated soils. While A. niger, A. Flavus, Penicillium sp and Trichoderma sp were the most frequently isolated fungi from herbicide treated soils.