Modified weeding machine effects to rice growth, yield, and competition to weeds in an organic farming, Northeastern of Japan

Modified weeding machine effects to rice growth, yield, and competition to weeds in an organic farming, Northeastern of Japan | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Modified weeding machine effects to rice growth, yield, and competition to weeds in an organic farming, Northeastern of Japan Margi Asih Maimunah, Andara Ayu Dyati, Yabe Manami, Jean Yves Dukuruzuemyi, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8574081/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The development of weeding methods is important to support organic rice farming success. Most of organic rice farmer in Japan choose mechanical rotary weeder to remove weeds. Moreover, intra row-weeds remains a big problem in rice fields. The idea was attaching chain in a rotary weeder machine, to remove intra row-weeds during weeding time. This study aims to examine the effects of chained-machine weeding to the growth of weeds and rice yield in the harvest time. Hypothetically, more weeds would be removed, and rice yield would increase. To test the hypothesis, a field experiment was carried out in one organic rice plot in Yamagata, Japan. The treatment was non weeding plot as control/non-weeding (NW); machine weeding (M); and chained-machine weeding (M + C) with four replications each treatment. The result showed us that the addition of chain on the weeding machine not significantly performed higher yield compared to machine weeding. Both M + C and M treatments significantly suppressed weeds biomass and density compared to non-weeding. The decrement for weeds density was up to 90% for both treatments, while M + C suppressed 10% more weeds biomass compared to M. Our study concluded, the addition of chain in the machine weeding remove intra-row weeds but was not affect significantly to the rice yield. Mechanical weeding intra row weeds organic rice rice yield paddy field Figures Figure 1 Figure 2 Figure 3 Figure 4 1. Introduction Intensive agriculture production was started mainly during 1960s, the massive production was involving government intervention (Dethier and Alexander 2012). In the late 1960s, new technologies such as high-yielding varieties, mechanization, and the use of chemicals in the field were applied massively. This revolution which was called “green revolution” had increased the crop yield significantly. However, not only did drastic increase in crop yield but also sharp decline of environmental quality the revolution has left. Such an intensive use on herbicide was not only declining environmental quality, but also causing the evolution of resistant weeds (Nagargade et al 2024 ). Related to environmental quality decrement, strategies have been developing around the world to maintain earth sustainability. United Nation decided to intensify the 17 SDGs (Sustainable Development Goals) to improve people life quality and environment sustainability. Furthermore, Ministry of Agriculture, Forestry, and Fisheries (MAFF) of Japan arrange a strategy called “MeaDRI” for enhancing engagement of stakeholders at each stage of food supply chains and promoting innovation to reduce environmental load (MAFF 2023). To foster sustainability, Japan's rice farming should lower the use of synthetic fertilizers and pesticides (Tran and Kubo 2025 ). Aims mentioned in the MEADRI strategies to achieve by 2050 were 50% reduction in risk-weighted use of chemical pesticides, 30% reduction in chemical fertilizer use, increase in organic farming to 1 Mha, and several more points related to increase sustainable food production. Those aims will be enabled only through greening of MAFF’s policy tools and development and dissemination of innovative technologies. Moreover, agriculture must meet the twin challenge of feeding a growing population, with rising demand for meat and high-calorie diets, while simultaneously minimizing its global environmental impacts (Seufert et al, 2012 ). Organic farming is one fast-growing system developing surround the world. This system aimed at producing food with minimum harm to ecosystems, animals or humans is often proposed as a solution (La de Cruz et al 2023 and Seufert et al 2012 ). Without any chemical addition, organic rice fields owing to the diversified consumer needs, preference for pesticide-free product, and need to reduce the environmental load (Sori et al 2018 ). Thus, organic farming could support both of human and environmental health. Field managed organically face major problems such as minimum nutrient source, weeds, and pest interference. Those obstacles may lead to crop yield-loss. Weed control is a world-wide problem in paddy field (Jiao et al 2022 ). Between weeds, animal pests, and pathogens, weeds had the highest loss potential (32%), whereas animal pests and pathogens had 18% and 15% of yield losses potential, respectively (Oerke and Dehne 2004 ). The yield losses potentially higher in organic farming, compared to conventional farming (Korsaeth 2008 ). Weeding technology has evolved from a simple hoe to sophisticated weeding robots to control weeds interference in crop field. As mentioned by Pinke et al ( 2025 ), weeding is one important variable affected weeds growth and weeds species composition in organic rice fields. Many studies proved that weeding would boost rice growth and production. More intensive weeding practice applied in early periods of rice growth was found to suppressed weeds biomass while boosted up rice biomass and N uptake (Maimunah et al 2021 ). Furthermore, the increase of rice N concentration and N uptake over weeds after weeding application was a prove that weeding supported rice to increase its competitiveness to weeds, which is urgently needed by organic rice farming to optimize the yield (Maimunah et al 2025 ). The use of weeding machine is world widely recognized. Liu et al ( 2023 ) recommended the use of autonomous weeding machines as one alternative to herbicide use that found to appropriate with the need of environmentally safe technologies on the field. This research started with a simple idea to modify a rotary machine weeder (which was a method that has been used for over 20 years) by adding a set of chain to support intra-row weeding more intensively. Hypothetically, the chained-machine weeding would remove more weeds that affected to increase rice growth and production. A field experiment was done to study organic rice yield and weeds response to modified machine weeding by adding chain compared to usual rotary machine weeding. 2. Materials and methods 2.1 Experimental site A field experiment was conducted at one plot of organic rice field (30 x 100 m2) at Yamagata University Farm in Takasaka, Yamagata (38° 42’ N 139° 49’ E). Based on the Japan Meteorological Agency database of the Tsuruoka Meteorological Observatory ( http://www.data.jma.go.jp/obd/stats/etrn/index.php ), the seasonal data for total precipitation, temperature average, and total sunshine was 538.5 mm, 23.63°C, and 776.7 hours, respectively (FigS1). The field was flooded using irrigation system and the output water was flow to the river. The rice growing period was from May 24th to September 22nd, 2022. A consistent field management was applied since 2007. Farmer has been planting rice (cv. Sasanishiki) without any fertilizer and chemical application. To control weeds growth, mechanical weeding was done between 8 to 60 DAT (Days After Transplanting). A mechanical rotary weeder was operated by one person and gasoline was needed to operate the machine. 2.2 Treatments This experiment induced treatments of two different mechanical weeding and one non-weeding plot as control which were labelled as M (machine weeding), M + C (chained-machine weeding), and NW (Non-weeding). Weeding treatments applied on same day, with same intervals (six times of weeding) (Table 1 ). The design of plot is depicted in Fig. 1 . Table 1 Schedule of weeding between 0 to 60 DAT Date - Day After Transplanting (DAT) Activity 24-May-22 0 Transplanting day 9-Jun-22 14 1st Weeding 16-Jun-22 21 2nd 23-Jun-22 28 3rd 29-Jun-22 34 4th 7-Jul-22 59 5th 14-Jul-22 60 6th 22-Sep-22 120 Harvest 2.3 Sampling and analysis Plant sampling was conducted twice to determine the growth of rice and weeds. The first sampling was July 21st, 2022 and the second sampling was on September 22nd, 2022, during the harvest time. Rice and weeds were collected randomly using a metal frame sampler (30 x 15 cm) from each treatment plots. The plant sample was first cleaned by tap water and then parameters such as tiller number and weeds number was determined. The biomass data was gained by 70°C oven-drying process to a constant weight. The biomass of roots, stems + leaves, and ears of rice were measured separately while each weeds were measured based on the weeds group without separating plant parts. During harvesting day, nine hills of rice plants (3x3 plants) were collected by cutting the above ground to measure rice yield parameters. Data from nine hills per treatment were averaged. Harvested rice was separated into grains and straw, then air-dried for one month and weighed to determine total yield (Cheng et al. 2009 ). 2.4 Statistical analysis All data were subjected to ANOVA to examine the direct effects of weeding frequencies on rice yield, yield components, weeds density, and weeds biomass. Significant differences among means for the different treatments were compared using Tukey’s HSD test at P < 0.05 (unless specified otherwise). The data were analysed using SPSS 20 software (SPSS Inc., Chicago, Il, USA). 3. Results 3.1 Rice yield parameters Several rice yield parameters were examined in this study to assess the effect of adding chains to machine weeding on rice yield (Fig. 2 ). When the weeds grew freely in non-weeding plot (NW), the grain yield was the lowest. In this study, uncontrolled weeds lowered the rice grain yield around 60%, compared to M and M + C plots. Chained-machine weeding did not increase rice yield significantly, compared to machine weeding alone. Significant differences were found in parameter of grain yield, panicle number, and individual grain yield. Those parameters showed similar trends each other that non-weeding (NW) performed significantly lowest amounts compared to other treatments and no significant difference between M and M + C plots. 3.2 Weeds growth The information of weeds growth is described by weeds density (Fig. 3 ) and weeds biomass (Fig. 4 ). A significant decrease in weeds density and biomass performed by both weeding treatments. An increase of weeds biomass was recorded for all treatment in September. Meanwhile weeds density was decreased in September. Compared to non-weeding (NW) plots, machine weeding suppressed weeds density and weeds biomass up to 92% and 69% in July; 93% and 70% in September, respectively. For chained machine weeding the reduction of weeds density and biomass was 93% and 84% in July; 93% and 83% in September, respectively. 4. Discussion 4.1 Effect of modified machine weeding on organic rice yield Organic rice yield was increased 2.5 times when the weeds were controlled by both weeding methods. Since weeding was done during early periods of rice growth, weeds development was disturbed. This condition supported rice in growing optimally and achieving higher yield, because weeds presence during early growth periods inhibits rice vegetative growth and lowered yield component. In other words, the decrease of rice-weed competition during critical rice-growth periods provide suitable environment that optimize nutrition absorption of rice (Song et al 2021 ; Jiao et al 2022 ). Mechanical weeding found to be beneficial in improving seed-setting rate that increasing number of grains per panicle, panicle number, and thousand-grain weight, thereby maintaining high yield (Shi et al 2023 ). Moreover, our study found greater increases in spikelets per panicle and individual grain weight, that strengthen the statement of Shi et al ( 2023 ) and Jiao et al ( 2022 ). Previous studies mentioned that 18–76% of crop yields were reduced due to intra-row weeds interference (Alba et al. 2020 ; Chandel et al. 2015 ; Gharde et al. 2018 ). However, chain addition to the weeding machine did not give significant changes or increase to rice yield in our study. This study concluded clearly that mechanical weeding use rotary machine weeder is proved to be beneficial in increasing grain yield and several other yield parameters such as; panicle number, spikelets per panicle, and individual grain weight. 4.1 Weeds response to modified machine weeding Weeds response to weeding treatment was very clear, significant reduction of weeds density and biomass was observed in M and M + C plots, compared to NW plot. These results showed how mechanical weeding in our organic rice field performed effectively to remove weeds. Moreover, when chain was added to the machine, more weeds located in intra-row were removed. Barberi (2001) stated that crop:weed interactions in organic agriculture would be impacted more slowly compared to conventional agriculture. However our results suggest that mechanical weeding gives direct impact to weeds growth and would effects weeds density and biomass effectively due to execute weeding during early growth periods. According to Singh et al ( 2017 ) and Juraimi et al ( 2009 ), critical period of weed competition was started since 15–20 DAS (days after sowing). Weeding practices at this period would effectively suppress weeds growth. Even though our study started weeding at 14 DAT, it still suppressed more than 50% of weeds biomass and density. This result proves that years of mechanical weeding practice in our organic rice field is appropriate. In addition, our organic rice plot is a flooded rice field which makes it less suitable for some types of weeds. Both weeding treatments decreased around 93% of weeds density than NW plot. Previous studies accounted weeding machine efficiency in other crop fields and found that a rotary power weeder performed weeding efficiency more than 94% in vegetable crops (Chandel et al 2015 ); and a mechanical weeder with adjustable elastic rod resulted in 80.65% of weeding rate in organic rice field (Jiao et al 2024 ). Basically, our weeding machine works by disturbing soil surface and uprooting the inter row weeds. During the first stage of rice growth, many rice plants collapsed due to high disturbance of rotary weeder. However, rice is stronger than weeds in tillering period, when the roots are deeper than weeds, due to the weeding applied in the weeds zone. By disturbing weeds growth -with six times of weeding- in early periods, weeds density and biomass drastically suppressed in the later periods. 4. Conclusions This study demonstrated that mechanical weeding using a rotary machine weeder significantly improves grain yield and key yield components, including panicle number, spikelets per panicle, and individual grain weight. The addition of chain did not improve grain yield significantly compared to the use of weeding machine alone. However, regarding weed control in the organic rice cultivation system, the chained-machine weeding treatment (M + C) exhibited superior weed suppression efficacy relative to the sole use of the rotary machine weeder (M). Notably, both mechanical weeding interventions (M and M + C) induced a statistically significant reduction in weed biomass and density compared to the non-weeded control (NW), underscoring their operational effectiveness in weed management. Declarations Author Contribution Conceptualization: [Weiguo Cheng], [Keitaro Tawaraya]; Methodology: [Weiguo Cheng], [Margi Asih Maimunah]; Formal analysis and investigation: [Margi Asih Maimunah], [Weiguo Cheng], [Andara Ayu Dyati], [Yabe Manami], [Jean Yves Dukuruzuemyi], [Nukurunziza Christian]; Writing - original draft preparation: [Margi Asih Maimunah]; Writing - review and editing: [Margi Asih Maimunah], [Weiguo Cheng]; Funding acquisition: [Weiguo Cheng]; Resources: [Weiguo Cheng]; Supervision: [Weiguo Cheng]. Acknowledgement The first author, Margi Asih Maimunah, acknowledged the Japanese Government (Monbukagakusho) Scholarship for supporting her studies in Japan. The authors give special thanks to all members of the Soil Science and Plant Nutrition Laboratory, Faculty of Agriculture, Yamagata University, for the assistance and support. References Alba OS, Syrovy LD, Duddu HSN, Shirtliffe S J (2020) Increased seeding rate and multiple methods of mechanical weed control reduce weed biomass in a poorly competitive organic crop. Field Crops Res. 245:107648. https://doi.org/10.1016/j.fcr.2019.107648 Chandel NS, Tripathi H, Tewari VK (2015) Evaluation and Adoption Scope of Rotary Power Weeder for Weed Management in Vegetable Crops. International Journal of Bio-Resource and Stress Management. 6:513–516. https://ojs.pphouse.org/index.php/IJBSM/article/view/744 Cheng W, Sakai H, Yagi K, Hasegawa T (2009) Interactions of Elevated [CO 2 ] and Night Temperature on Rice Growth and Yield. 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In: Yoshizumi, M., Arata, M., Miyaguchi, T. (eds) Navigating Local Sustainability in Food, Community, and Innovation. Springer, Singapore. https://doi.org/10.1007/978-981-96-8963-7_11 Additional Declarations No competing interests reported. Supplementary Files supplementarymaterialMvs.MC.pdf Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8574081","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":585922989,"identity":"3da3614d-e946-47f9-8ef2-11f3ce4f1e15","order_by":0,"name":"Margi Asih Maimunah","email":"","orcid":"","institution":"Iwate University","correspondingAuthor":false,"prefix":"","firstName":"Margi","middleName":"Asih","lastName":"Maimunah","suffix":""},{"id":585922990,"identity":"376dd92c-c3ae-4095-9700-a7c5bce4b2f9","order_by":1,"name":"Andara Ayu Dyati","email":"","orcid":"","institution":"Gadjah Mada University","correspondingAuthor":false,"prefix":"","firstName":"Andara","middleName":"Ayu","lastName":"Dyati","suffix":""},{"id":585922991,"identity":"1274ace5-15bf-4d22-ad71-0a564ee4e66c","order_by":2,"name":"Yabe Manami","email":"","orcid":"","institution":"Yamagata University","correspondingAuthor":false,"prefix":"","firstName":"Yabe","middleName":"","lastName":"Manami","suffix":""},{"id":585922992,"identity":"99e39c19-7626-4255-972a-cd88f26778f2","order_by":3,"name":"Jean Yves Dukuruzuemyi","email":"","orcid":"","institution":"Yamagata University","correspondingAuthor":false,"prefix":"","firstName":"Jean","middleName":"Yves","lastName":"Dukuruzuemyi","suffix":""},{"id":585922993,"identity":"689ed1a5-d045-40df-8bb6-c35b6073965e","order_by":4,"name":"Christian Nkurunziza","email":"","orcid":"","institution":"Iwate University","correspondingAuthor":false,"prefix":"","firstName":"Christian","middleName":"","lastName":"Nkurunziza","suffix":""},{"id":585922994,"identity":"1754dea0-bb35-4aae-91f9-6ddf51016efa","order_by":5,"name":"Keitaro Tawaraya","email":"","orcid":"","institution":"Yamagata University","correspondingAuthor":false,"prefix":"","firstName":"Keitaro","middleName":"","lastName":"Tawaraya","suffix":""},{"id":585922995,"identity":"aa6f245e-fb54-42c5-89cf-771fe0784341","order_by":6,"name":"Weiguo Cheng","email":"data:image/png;base64,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","orcid":"","institution":"Yamagata University","correspondingAuthor":true,"prefix":"","firstName":"Weiguo","middleName":"","lastName":"Cheng","suffix":""}],"badges":[],"createdAt":"2026-01-11 14:23:13","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8574081/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8574081/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":102295189,"identity":"4b49a9de-9853-40bd-bd34-b16d6dfda210","added_by":"auto","created_at":"2026-02-10 10:09:41","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":88331,"visible":true,"origin":"","legend":"\u003cp\u003eDesign of weeding treatment in the organic rice plot with NW = non-weeding; M = machine weeding; MC = chained-machine weeding.\u003c/p\u003e\n\u003cp\u003ev\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8574081/v1/8203622a7d5343c57ab2dc40.jpeg"},{"id":101991166,"identity":"f9084934-de38-4e2b-84d0-815ff4e06843","added_by":"auto","created_at":"2026-02-05 20:04:27","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":269817,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of weeding methods on yield parameter (grain yield, filled spikelets, panicles, spikelets per panicle, and individual grain weight). Values are given as mean ± standard derviation. M, M+C, and NW refer to the treatment of Machine, Machine+Chain, and No weeding, respectively.\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8574081/v1/5979e225c0debae108682f31.jpeg"},{"id":102295251,"identity":"efe2ae42-2607-494e-bcc7-68dae6993ce7","added_by":"auto","created_at":"2026-02-10 10:10:18","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":166162,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of weeding methods on weeds density. Values are given as mean ± standard deviation. M, M+C, and NW refer to the treatment of Machine, Machine+Chain, and No weeding, respectively.\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8574081/v1/5fba6c161cdde50963e46b0b.jpeg"},{"id":101991169,"identity":"623b1302-4abb-4373-970d-22bc240afbe8","added_by":"auto","created_at":"2026-02-05 20:04:28","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":16930,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of weeding methods on weeds biomass. Values are given as mean ± standard deviation. M, M+C, and NW refer to the treatment of Machine, Machine+Chain, and No weeding, respectively.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8574081/v1/6064085574eb1b959a7af060.png"},{"id":103804509,"identity":"785f2c8d-3c43-4a51-a460-44d83a05792c","added_by":"auto","created_at":"2026-03-03 06:56:35","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1035725,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8574081/v1/d8db9f3b-d65b-486f-8364-664886e6f92b.pdf"},{"id":101991168,"identity":"02396a07-b8a3-4d28-880d-0d20f2773b72","added_by":"auto","created_at":"2026-02-05 20:04:27","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":346403,"visible":true,"origin":"","legend":"","description":"","filename":"supplementarymaterialMvs.MC.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8574081/v1/cbcdc9aa6417dc0e071dc6e0.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Modified weeding machine effects to rice growth, yield, and competition to weeds in an organic farming, Northeastern of Japan","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eIntensive agriculture production was started mainly during 1960s, the massive production was involving government intervention (Dethier and Alexander 2012). In the late 1960s, new technologies such as high-yielding varieties, mechanization, and the use of chemicals in the field were applied massively. This revolution which was called \u0026ldquo;green revolution\u0026rdquo; had increased the crop yield significantly. However, not only did drastic increase in crop yield but also sharp decline of environmental quality the revolution has left. Such an intensive use on herbicide was not only declining environmental quality, but also causing the evolution of resistant weeds (Nagargade et al \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eRelated to environmental quality decrement, strategies have been developing around the world to maintain earth sustainability. United Nation decided to intensify the 17 SDGs (Sustainable Development Goals) to improve people life quality and environment sustainability. Furthermore, Ministry of Agriculture, Forestry, and Fisheries (MAFF) of Japan arrange a strategy called \u0026ldquo;MeaDRI\u0026rdquo; for enhancing engagement of stakeholders at each stage of food supply chains and promoting innovation to reduce environmental load (MAFF 2023). To foster sustainability, Japan's rice farming should lower the use of synthetic fertilizers and pesticides (Tran and Kubo \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). Aims mentioned in the MEADRI strategies to achieve by 2050 were 50% reduction in risk-weighted use of chemical pesticides, 30% reduction in chemical fertilizer use, increase in organic farming to 1 Mha, and several more points related to increase sustainable food production. Those aims will be enabled only through greening of MAFF\u0026rsquo;s policy tools and development and dissemination of innovative technologies. Moreover, agriculture must meet the twin challenge of feeding a growing population, with rising demand for meat and high-calorie diets, while simultaneously minimizing its global environmental impacts (Seufert et al, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2012\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eOrganic farming is one fast-growing system developing surround the world. This system aimed at producing food with minimum harm to ecosystems, animals or humans is often proposed as a solution (La de Cruz et al \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2023\u003c/span\u003e and Seufert et al \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Without any chemical addition, organic rice fields owing to the diversified consumer needs, preference for pesticide-free product, and need to reduce the environmental load (Sori et al \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Thus, organic farming could support both of human and environmental health. Field managed organically face major problems such as minimum nutrient source, weeds, and pest interference. Those obstacles may lead to crop yield-loss. Weed control is a world-wide problem in paddy field (Jiao et al \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Between weeds, animal pests, and pathogens, weeds had the highest loss potential (32%), whereas animal pests and pathogens had 18% and 15% of yield losses potential, respectively (Oerke and Dehne \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). The yield losses potentially higher in organic farming, compared to conventional farming (Korsaeth \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2008\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eWeeding technology has evolved from a simple hoe to sophisticated weeding robots to control weeds interference in crop field. As mentioned by Pinke et al (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2025\u003c/span\u003e), weeding is one important variable affected weeds growth and weeds species composition in organic rice fields. Many studies proved that weeding would boost rice growth and production. More intensive weeding practice applied in early periods of rice growth was found to suppressed weeds biomass while boosted up rice biomass and N uptake (Maimunah et al \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Furthermore, the increase of rice N concentration and N uptake over weeds after weeding application was a prove that weeding supported rice to increase its competitiveness to weeds, which is urgently needed by organic rice farming to optimize the yield (Maimunah et al \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). The use of weeding machine is world widely recognized. Liu et al (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) recommended the use of autonomous weeding machines as one alternative to herbicide use that found to appropriate with the need of environmentally safe technologies on the field. This research started with a simple idea to modify a rotary machine weeder (which was a method that has been used for over 20 years) by adding a set of chain to support intra-row weeding more intensively. Hypothetically, the chained-machine weeding would remove more weeds that affected to increase rice growth and production. A field experiment was done to study organic rice yield and weeds response to modified machine weeding by adding chain compared to usual rotary machine weeding.\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Experimental site\u003c/h2\u003e \u003cp\u003eA field experiment was conducted at one plot of organic rice field (30 x 100 m2) at Yamagata University Farm in Takasaka, Yamagata (38\u0026deg; 42\u0026rsquo; N 139\u0026deg; 49\u0026rsquo; E). Based on the Japan Meteorological Agency database of the Tsuruoka Meteorological Observatory (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.data.jma.go.jp/obd/stats/etrn/index.php\u003c/span\u003e\u003cspan address=\"http://www.data.jma.go.jp/obd/stats/etrn/index.php\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e), the seasonal data for total precipitation, temperature average, and total sunshine was 538.5 mm, 23.63\u0026deg;C, and 776.7 hours, respectively (FigS1). The field was flooded using irrigation system and the output water was flow to the river. The rice growing period was from May 24th to September 22nd, 2022. A consistent field management was applied since 2007. Farmer has been planting rice (cv. Sasanishiki) without any fertilizer and chemical application. To control weeds growth, mechanical weeding was done between 8 to 60 DAT (Days After Transplanting). A mechanical rotary weeder was operated by one person and gasoline was needed to operate the machine.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Treatments\u003c/h2\u003e \u003cp\u003eThis experiment induced treatments of two different mechanical weeding and one non-weeding plot as control which were labelled as M (machine weeding), M\u0026thinsp;+\u0026thinsp;C (chained-machine weeding), and NW (Non-weeding). Weeding treatments applied on same day, with same intervals (six times of weeding) (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The design of plot is depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSchedule of weeding between 0 to 60 DAT\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e- Day After Transplanting (DAT)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003eActivity\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24-May-22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003eTransplanting day\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e9-Jun-22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1st\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"5\" rowspan=\"6\"\u003e \u003cp\u003eWeeding\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e16-Jun-22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2nd\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e23-Jun-22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3rd\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e29-Jun-22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4th\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7-Jul-22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e59\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5th\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e14-Jul-22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6th\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e22-Sep-22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e120\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003eHarvest\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Sampling and analysis\u003c/h2\u003e \u003cp\u003ePlant sampling was conducted twice to determine the growth of rice and weeds. The first sampling was July 21st, 2022 and the second sampling was on September 22nd, 2022, during the harvest time. Rice and weeds were collected randomly using a metal frame sampler (30 x 15 cm) from each treatment plots. The plant sample was first cleaned by tap water and then parameters such as tiller number and weeds number was determined. The biomass data was gained by 70\u0026deg;C oven-drying process to a constant weight. The biomass of roots, stems\u0026thinsp;+\u0026thinsp;leaves, and ears of rice were measured separately while each weeds were measured based on the weeds group without separating plant parts. During harvesting day, nine hills of rice plants (3x3 plants) were collected by cutting the above ground to measure rice yield parameters. Data from nine hills per treatment were averaged. Harvested rice was separated into grains and straw, then air-dried for one month and weighed to determine total yield (Cheng et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2009\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Statistical analysis\u003c/h2\u003e \u003cp\u003eAll data were subjected to ANOVA to examine the direct effects of weeding frequencies on rice yield, yield components, weeds density, and weeds biomass. Significant differences among means for the different treatments were compared using Tukey\u0026rsquo;s HSD test at P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 (unless specified otherwise). The data were analysed using SPSS 20 software (SPSS Inc., Chicago, Il, USA).\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Rice yield parameters\u003c/h2\u003e \u003cp\u003eSeveral rice yield parameters were examined in this study to assess the effect of adding chains to machine weeding on rice yield (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). When the weeds grew freely in non-weeding plot (NW), the grain yield was the lowest. In this study, uncontrolled weeds lowered the rice grain yield around 60%, compared to M and M\u0026thinsp;+\u0026thinsp;C plots. Chained-machine weeding did not increase rice yield significantly, compared to machine weeding alone. Significant differences were found in parameter of grain yield, panicle number, and individual grain yield. Those parameters showed similar trends each other that non-weeding (NW) performed significantly lowest amounts compared to other treatments and no significant difference between M and M\u0026thinsp;+\u0026thinsp;C plots.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Weeds growth\u003c/h2\u003e \u003cp\u003eThe information of weeds growth is described by weeds density (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e) and weeds biomass (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). A significant decrease in weeds density and biomass performed by both weeding treatments. An increase of weeds biomass was recorded for all treatment in September. Meanwhile weeds density was decreased in September. Compared to non-weeding (NW) plots, machine weeding suppressed weeds density and weeds biomass up to 92% and 69% in July; 93% and 70% in September, respectively. For chained machine weeding the reduction of weeds density and biomass was 93% and 84% in July; 93% and 83% in September, respectively.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e4.1 Effect of modified machine weeding on organic rice yield\u003c/h2\u003e \u003cp\u003eOrganic rice yield was increased 2.5 times when the weeds were controlled by both weeding methods. Since weeding was done during early periods of rice growth, weeds development was disturbed. This condition supported rice in growing optimally and achieving higher yield, because weeds presence during early growth periods inhibits rice vegetative growth and lowered yield component. In other words, the decrease of rice-weed competition during critical rice-growth periods provide suitable environment that optimize nutrition absorption of rice (Song et al \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Jiao et al \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Mechanical weeding found to be beneficial in improving seed-setting rate that increasing number of grains per panicle, panicle number, and thousand-grain weight, thereby maintaining high yield (Shi et al \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eMoreover, our study found greater increases in spikelets per panicle and individual grain weight, that strengthen the statement of Shi et al (\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) and Jiao et al (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Previous studies mentioned that 18\u0026ndash;76% of crop yields were reduced due to intra-row weeds interference (Alba et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Chandel et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Gharde et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). However, chain addition to the weeding machine did not give significant changes or increase to rice yield in our study. This study concluded clearly that mechanical weeding use rotary machine weeder is proved to be beneficial in increasing grain yield and several other yield parameters such as; panicle number, spikelets per panicle, and individual grain weight.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e4.1 Weeds response to modified machine weeding\u003c/h2\u003e \u003cp\u003eWeeds response to weeding treatment was very clear, significant reduction of weeds density and biomass was observed in M and M\u0026thinsp;+\u0026thinsp;C plots, compared to NW plot. These results showed how mechanical weeding in our organic rice field performed effectively to remove weeds. Moreover, when chain was added to the machine, more weeds located in intra-row were removed. Barberi (2001) stated that crop:weed interactions in organic agriculture would be impacted more slowly compared to conventional agriculture. However our results suggest that mechanical weeding gives direct impact to weeds growth and would effects weeds density and biomass effectively due to execute weeding during early growth periods. According to Singh et al (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) and Juraimi et al (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2009\u003c/span\u003e), critical period of weed competition was started since 15\u0026ndash;20 DAS (days after sowing). Weeding practices at this period would effectively suppress weeds growth. Even though our study started weeding at 14 DAT, it still suppressed more than 50% of weeds biomass and density. This result proves that years of mechanical weeding practice in our organic rice field is appropriate. In addition, our organic rice plot is a flooded rice field which makes it less suitable for some types of weeds.\u003c/p\u003e \u003cp\u003eBoth weeding treatments decreased around 93% of weeds density than NW plot. Previous studies accounted weeding machine efficiency in other crop fields and found that a rotary power weeder performed weeding efficiency more than 94% in vegetable crops (Chandel et al \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2015\u003c/span\u003e); and a mechanical weeder with adjustable elastic rod resulted in 80.65% of weeding rate in organic rice field (Jiao et al \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Basically, our weeding machine works by disturbing soil surface and uprooting the inter row weeds. During the first stage of rice growth, many rice plants collapsed due to high disturbance of rotary weeder. However, rice is stronger than weeds in tillering period, when the roots are deeper than weeds, due to the weeding applied in the weeds zone. By disturbing weeds growth -with six times of weeding- in early periods, weeds density and biomass drastically suppressed in the later periods.\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eThis study demonstrated that mechanical weeding using a rotary machine weeder significantly improves grain yield and key yield components, including panicle number, spikelets per panicle, and individual grain weight. The addition of chain did not improve grain yield significantly compared to the use of weeding machine alone. However, regarding weed control in the organic rice cultivation system, the chained-machine weeding treatment (M\u0026thinsp;+\u0026thinsp;C) exhibited superior weed suppression efficacy relative to the sole use of the rotary machine weeder (M). Notably, both mechanical weeding interventions (M and M\u0026thinsp;+\u0026thinsp;C) induced a statistically significant reduction in weed biomass and density compared to the non-weeded control (NW), underscoring their operational effectiveness in weed management.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eConceptualization: [Weiguo Cheng], [Keitaro Tawaraya]; Methodology: [Weiguo Cheng], [Margi Asih Maimunah]; Formal analysis and investigation: [Margi Asih Maimunah], [Weiguo Cheng], [Andara Ayu Dyati], [Yabe Manami], [Jean Yves Dukuruzuemyi], [Nukurunziza Christian]; Writing - original draft preparation: [Margi Asih Maimunah]; Writing - review and editing: [Margi Asih Maimunah], [Weiguo Cheng]; Funding acquisition: [Weiguo Cheng]; Resources: [Weiguo Cheng]; Supervision: [Weiguo Cheng].\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe first author, Margi Asih Maimunah, acknowledged the Japanese Government (Monbukagakusho) Scholarship for supporting her studies in Japan. 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Springer, Singapore. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/978-981-96-8963-7_11\u003c/span\u003e\u003cspan address=\"10.1007/978-981-96-8963-7_11\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Mechanical weeding, intra row weeds, organic rice, rice yield, paddy field","lastPublishedDoi":"10.21203/rs.3.rs-8574081/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8574081/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe development of weeding methods is important to support organic rice farming success. Most of organic rice farmer in Japan choose mechanical rotary weeder to remove weeds. Moreover, intra row-weeds remains a big problem in rice fields. The idea was attaching chain in a rotary weeder machine, to remove intra row-weeds during weeding time. This study aims to examine the effects of chained-machine weeding to the growth of weeds and rice yield in the harvest time. Hypothetically, more weeds would be removed, and rice yield would increase. To test the hypothesis, a field experiment was carried out in one organic rice plot in Yamagata, Japan. The treatment was non weeding plot as control/non-weeding (NW); machine weeding (M); and chained-machine weeding (M\u0026thinsp;+\u0026thinsp;C) with four replications each treatment. The result showed us that the addition of chain on the weeding machine not significantly performed higher yield compared to machine weeding. Both M\u0026thinsp;+\u0026thinsp;C and M treatments significantly suppressed weeds biomass and density compared to non-weeding. The decrement for weeds density was up to 90% for both treatments, while M\u0026thinsp;+\u0026thinsp;C suppressed 10% more weeds biomass compared to M. Our study concluded, the addition of chain in the machine weeding remove intra-row weeds but was not affect significantly to the rice yield.\u003c/p\u003e","manuscriptTitle":"Modified weeding machine effects to rice growth, yield, and competition to weeds in an organic farming, Northeastern of Japan","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-05 20:04:22","doi":"10.21203/rs.3.rs-8574081/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"6cb8a0ae-b73f-4c5e-8c79-569dbe524e4b","owner":[],"postedDate":"February 5th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-03T06:55:16+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-05 20:04:22","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8574081","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8574081","identity":"rs-8574081","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}