Ergonomic assessment and design consideration of manual weeders for Indian agricultural workers

Introduction

Agriculture is a major sector of India's economy, employing about 54.6% of the population and contributing significantly to food security and raw material supply. Among various agricultural operations, weeding is essential for maintaining crop productivity as weeds compete with crops for nutrients, water, light, and space. In India, where small and fragmented land holdings dominate, manual weeding using traditional tools such as khurpi, hoes, sickles, and spades is still widely practiced. However, these operations are labourintensive and are often performed in ergonomically unsuitable postures, leading to fatigue, physical strain, and musculoskeletal disorders among workers. Weeding accounts for nearly 25% of the total labour requirement (900-1200 man-hours ha⁻¹) during a cultivation season (Nag & Dutta, 1979) [35] . Hand weeding alone may require 400-600 man-hours ha⁻¹, depending on weed infestation. Delay in weeding operations can reduce crop yield by 30-60% (Singh, 1988). In India, about ₹4.2 billion is spent annually on weed control and approximately 40 million tonnes of food grains are lost each year due to weeds (Singh & Sahay, 2001). Yield reductions ranging from 5-60% have been reported due to weed competition, with several problematic weeds such as Cyperus rotundus, Cynodon dactylon, Phalaris minor, and Parthenium hysterophorus infesting large areas of the country (Biswas et al., 1999). Although several improved manual weeders such as wheel hoes and triangular blade hoes have been developed, their adoption remains limited due to factors such as tool weight, lack of awareness, and incompatibility with small farms (Kumar, 1983). Mechanical weed control helps remove weeds between rows while improving soil aeration and water infiltration (Biswas, 1990). Studies have also shown that ergonomically designed weeders can significantly reduce workload and fatigue. For example, a wheel hoe developed with ergonomic considerations required 60-110 man-hours ha⁻¹ in heavy soil and about 25 man-hours ha⁻¹ in light soil (Singh, 1992). Further ergonomic evaluations indicated that a push-pull force of about 60 N during weeder operation resulted in minimum fatigue and better human-machine interaction (Kumar et al., 2000). The need for ergonomically optimized manually operated weeders is therefore evident. Modifications such as adjustable handle angles (45-65°), lightweight frames, and optimized cutter blades have been introduced to reduce physiological stress and body discomfort during operation. Ergonomics, defined as the science of designing work systems and tools to suit human capabilities (Pheasant, 1991) [42] , plays an important role in improving agricultural tool efficiency and safety. The adoption of ergonomic principles in the design and testing of farm tools has also been recommended by FAO (1994). Considering the shortage of agricultural labour (Raut et al., 2013) [43] and the importance of effective human-machine interaction (Singh et al., 2019a), ergonomically improved manual weeders can help reduce drudgery, enhance operator comfort, and improve overall productivity in smallholder farming systems. As such, this review paper aims to provide a comprehensive overview of the current status of weed management systems in India, Weeding is a crucial agricultural operation but remains highly labour-intensive, time-consuming, and physically demanding, especially in smallholder farming systems. Traditional hand tools often cause operator fatigue, discomfort, and reduced efficiency due to poor ergonomic design. Ergonomically improved manually operated weeders can significantly reduce drudgery, physiological stress, and labour requirements while improving work efficiency. Therefore, incorporating ergonomic principles in the design and modification of weeding tools is essential to enhance operator comfort, productivity, and overall agricultural sustainability.

Scope And Structure

This section begins with an overview of manual weed control equipment and highlights the importance of effective weeding management in agriculture. It discusses the current practices followed in manual weeding and the major challenges associated with labour intensity, time consumption, and operator discomfort. Further, the classification of manual weeders based on their design and mode of operation is presented. Next, the ergonomic principles involved in agricultural tool design are explained, focusing on aspects such as gender considerations, power requirements, and working positions of operators. The section also describes the methods used for ergonomic evaluation of manual weeding tools, including physiological and postural parameters. Finally, a comparative analysis of ergonomically developed manual weeders is presented to understand their efficiency, operator comfort, and suitability for agricultural operations.

Current status and challenges in India

Manual weeding is still widely practiced in India, especially by small and marginal farmers, using traditional tools such as khurpi, hoes, and spades due to small and fragmented land holdings. However, this method is highly labour-intensive and accounts for nearly 25% of the total labour requirement in crop production (Nag and Dutta, 1979) [35] . Although improved manually operated weeders have been developed, their adoption remains limited due to lack of awareness, limited availability in local markets, and higher initial cost. Labour shortages and increasing wage rates further increase the difficulty of timely weeding operations. In addition, many existing tools lack proper ergonomic design and are not suitable for female workers, who constitute a large portion of the agricultural workforce. These constraints highlight the need for ergonomically designed, affordable, and easily accessible manual weeders to improve efficiency and reduce drudgery.

Methodology

This review synthesises peer-reviewed journal articles, conference papers, government reports, and technical publications related to manual weeders and ergonomic assessment in agriculture published between 1990 and 2025. Relevant literature was collected from databases such as Google Scholar, ScienceDirect, SpringerLink, and Indian agricultural research repositories (ICAR and CIAE). A total of more than 60 publications were reviewed, with particular emphasis on studies conducted under Indian farming conditions and smallholder systems. Selected studies focused on design improvements, ergonomic interventions, and performance evaluation of traditional and improved weeders. Data extraction was carried out based on parameters such as weeding efficiency, field capacity, heart rate, energy expenditure, postural stress, and tool design characteristics. Both qualitative and quantitative findings were analysed to evaluate the relationship between tool design, operator comfort, and work efficiency. The review also incorporates different ergonomic evaluation methods, including subjective assessment (RPE, VAS), observational techniques (RULA, REBA, OWAS), and physiological measurements (heart rate and energy expenditure), to provide a comprehensive understanding of workload and drudgery in manual weeding operations.

Overview of manual weed control equipment

Weed management is essential for maintaining crop productivity and ensuring food security, as weeds compete with crops for light, water, nutrients, and space, and may also harbor pests and diseases. If not controlled, weeds can cause severe yield losses, sometimes up to 100% depending on crop type and weed density (Oerke, 2006). In India, average yield losses due to weeds have been reported as 36% in peanut, 31% in soybean, 25% in maize, and 19% in wheat, highlighting the importance of effective weed management strategies (Gharde et al., 2018). Weed control methods include manual, mechanical, chemical, cultural, and integrated approaches. Manual weeding using simple hand tools such as hoes and sickles is still widely practiced in smallholder farming systems. Mechanical weeders and power-operated tools are gradually being adopted to reduce labour dependency, while herbicides are commonly used due to their quick and economical action. However, excessive herbicide use has led to the development of herbicide-resistant weed species worldwide (Heap, 2019). Therefore, Integrated Weed Management (IWM), which combines multiple control methods, is increasingly recommended as a sustainable approach (Chauhan et al., 2017). Despite its effectiveness, manual weeding is labourintensive, time-consuming, and accounts for about 25% of the total labour requirement in crop production (Nag and Dutta, 1979) [35] . Labour shortages, rising wages, and migration of rural workers further limit its feasibility. In addition, the use of traditional tools and prolonged bending postures can cause physical strain, fatigue, and musculoskeletal disorders among workers (Singh, 1988). Delayed weeding due to these constraints may reduce crop yield by 30-60%, emphasizing the need for improved ergonomic tools and efficient weed management practices.

Classification of Manual Weeder

Manual weeding refers to the removal of weeds by human effort using hands or simple hand-operated tools. It is widely practiced in smallholder farming systems, especially in developing countries. Manual weeding can be classified based on the method used, based on power source, type of tool, and mode of operation. Recent research highlights the importance of incorporating gender-specific ergonomic principles in the design of agricultural tools to reduce drudgery and improve work efficiency among women farm workers. Anthropometric compatibility is a key factor, as tools must be designed according to the body dimensions, grip strength, and reach characteristics of the actual users. Studies show that women generally have smaller hand breadth, shorter reach, and lower upper-body strength than men; therefore, tools designed only using male anthropometric data often become oversized and difficult for women to operate effectively. Research on modified wheel hoes and other manual tools demonstrates that designing equipment based on female anthropometric measurements significantly reduces energy expenditure, improves comfort, and increases productivity during operations such as weeding and transplanting (Sinha, Singh, & Kumar, 2023; Negi, Singh, & Singh, 2025) [51,36] . [32] . Similarly, ergonomic evaluation of manual weeding tools has shown that improved designs can significantly lower cardiac cost of work and reduce drudgery among women farm workers (Anusha, Mehta, & Sharma, 2021).

In addition to anthropometric and strength considerations, weight optimization and task-specific design play a major role in ergonomic efficiency. Lightweight tools improve manoeuvrability and reduce strain on the wrists, shoulders, and lower back during repetitive agricultural tasks. [45] . Therefore, integrating ergonomic principles such as anthropometric compatibility, reduced force requirement, lightweight design, and task-specific modifications is essential for developing agricultural tools that are safe, efficient, and suitable for women agricultural workers. Power-based ergonomic principles emphasize matching the energy requirements of agricultural tools with the physiological capacity of the operator in order to minimize fatigue and improve work efficiency. Agricultural tools may be powered by human effort, animals, electric motors, batteries, or small engines, and the selected power source should ensure that the operator can perform tasks continuously without excessive physical strain. In manually operated agricultural tools, human power limitations are particularly important during the design stage. Ergonomic studies indicate that agricultural workers can sustain only a limited amount of mechanical power during prolonged work, and exceeding this capacity can lead to rapid fatigue and reduced productivity. Research on agricultural workers shows that physiological workload during farm operations should remain within about 35% of maximum aerobic capacity to maintain safe levels of physical strain (Behera, Swain, & Mohanty, 2007) [3] . Mechanical advantage is another essential aspect of ergonomic tool design. Proper leverage systems, optimized handle length, appropriate gear ratios, and efficient power transmission mechanisms help amplify human force and reduce the physical effort required during operations such as digging, cutting, and weeding. Modern agricultural engineering studies demonstrate that ergonomic redesign of manual tools-such as improved handle dimensions and blade configuration-can significantly reduce physiological workload, heart rate, and overall discomfort among farm workers (Sinha, Singh, & Kumar, 2023) [51] .

Power-Based Ergonomic Principles

In addition, vibration control, noise reduction, and energyefficient mechanical systems are critical in power-operated agricultural equipment. Excessive vibration and noise from engines or rotating components can increase operator discomfort and may lead to long-term health problems such as hand-arm vibration syndrome. Recent ergonomic research on agricultural machinery highlights that improved machine balance, vibration-damping materials, and lightweight structural design can significantly reduce physiological stress and improve operator comfort during field operations (Chaudhary et al., 2022) [7] .

Reducing static load and evaluating postural risk are also essential in ergonomic tool design. Prolonged bending during tasks such as weeding and harvesting increases spinal stress and fatigue, whereas ergonomic tools like longhandled weeders allow operators to work in a more upright posture and reduce drudgery. Studies indicate that improved tool designs can lower physical workload by 30-40% and enhance productivity (Gite, Agarwal, & Yadav, 2009) [14] . Postural risk in agricultural work is commonly evaluated using ergonomic assessment methods such as RULA, REBA, and OWAS, which analyze body posture, joint angles, and force exertion to identify potential musculoskeletal hazards (Hignett & McAtamney, 2000) [17] . Push and pull forces are another important ergonomic parameter, particularly for push-type tools such as weeders and seeders. Excessive push-pull force increases muscular strain, cardiovascular load, and the risk of low back pain. Ergonomic guidelines suggest that sustained push-pull forces should remain within 20-30% of the operator's maximum voluntary force capacity. Tool design should therefore consider factors such as wheel diameter, weight distribution, handle height, and mechanical advantage to reduce the required force. Considering gender differences in strength capacity is also essential to ensure safe and efficient operation for both men and women agricultural workers (Gite et al., 2009) [14] .

Ergonomic evaluation method on manual weeding

Ergonomic evaluation of manual weeding is essential to assess drudgery, physiological load, postural stress, and overall work efficiency. Since weeding is labor-intensive and often performed in bending or squatting postures, a systematic evaluation helps in tool improvement and worker safety. The major ergonomic evaluation methods are described below

Subjective Assessment Method (User Feedback)

The subjective assessment method is an ergonomic evaluation approach that relies on direct feedback from workers to assess discomfort, fatigue, pain intensity, and perceived physical exertion during manual weeding tasks. Instead of measuring physiological responses through instruments, this method captures the worker's personal experience of workload and strain, making it especially useful in field conditions. Common tools used in subjective assessment include the Rating of Perceived Exertion (RPE) scale developed by Gunnar Borg, which measures perceived physical effort; the Body Part Discomfort Scale, which identifies specific body regions experiencing pain; the Visual Analogue Scale (VAS), which quantifies pain intensity along a graded line; and the Nordic Musculoskeletal Questionnaire (NMQ), designed to record musculoskeletal symptoms in different body parts. These methods are simple, economical, and easy to administer in agricultural settings. They help identify discomfort-prone body regions during weeding operations and allow researchers to correlate tool design, posture, and workload with the worker's perception of strain, thereby supporting ergonomic improvements.

Observational Methods

Ergonomic evaluation of manual weeding is essential to assess drudgery, physiological workload, postural stress, and work efficiency, as these operations are typically performed in prolonged bending or squatting postures that increase the risk of musculoskeletal disorders. Evaluation methods generally include subjective assessment and observational techniques. [5,29,14] . Observational ergonomic methods are widely used to evaluate working posture and biomechanical risk during manual weeding. [31,17] . These tools frequently reveal high-risk conditions in weeding operations, including excessive trunk flexion (>20-30°), prolonged squatting, knee overloading, and wrist deviation during tool use. [11, 23] . By identifying biomechanical risk factors and integrating modern digital evaluation techniques, ergonomic assessment supports the redesign of improved weeders such as long-handle tools, adjustable handles, and optimized grips thereby reducing drudgery, improving working posture, and enhancing occupational safety and productivity among agricultural workers.

Physiological and Biological Methods

Physiological and biological methods are objective approaches used to evaluate the internal body responses of workers during manual weeding operations. These methods measure how the cardiovascular, respiratory, and muscular systems respond to physical workload, providing a scientific basis for assessing task intensity and worker fatigue. [2,26,14] . Modern ergonomic studies increasingly integrate portable metabolic analyzers, wearable heart-rate monitors, and wireless EMG systems to obtain real-time physiological data in field conditions, enabling more accurate assessment of tool performance and supporting the development of improved ergonomic weeding tools that reduce worker fatigue and enhance productivity (Karwowski, 2021; Joshi et al., 2023) [23] . [2,23,30] . Work performance and efficiency metrics are also important for evaluating the effectiveness of weeding tools and their impact on worker productivity. [14,39,27] .

Direct Measurement Techniques

Design consideration and improvement

Design consideration is essential in manual weeders to ensure efficient performance, operator safety, and reduced physical strain. Traditional tools often cause fatigue and musculoskeletal problems due to poor design and improper working posture. By incorporating ergonomic principles such as proper handle height, grip size, tool weight, and blade geometry, the weeder can be made more comfortable and easier to use. Good design helps in maintaining a better working posture, reducing drudgery, improving work efficiency, and increasing productivity, especially for smallholder and women farmers. [41] . One common modification is the adjustable or telescopic handle, which allows the handle height to be adjusted according to the operator's body height. This design helps maintain a more upright posture and reduces excessive trunk bending and lower back strain during prolonged work. Studies on modified wheel hoes have shown that adjustable handles significantly reduce physiological workload and discomfort among agricultural workers (Sinha et al., 2023) [51] . Another important improvement is the angled or bent handle design, typically inclined between 45° and 65°, which helps maintain neutral wrist alignment and reduces forearm muscle strain. Experimental evaluations of modified weeders have demonstrated that optimized handle angles reduce heart rate, oxygen consumption, and energy expenditure during weeding operations (Singh et al., 2025) [50] . Anthropometric-based handle design is also widely recommended in ergonomic tool development. Research indicates that grip diameters of 30-40 mm and handle lengths of approximately 110-120 mm are suitable for most adult agricultural workers and help improve grip strength while reducing localized pressure on the palm (Chakrabarti, 1997; Kumar & Narayan, 1995) [28] . In addition, redesigned handles for women agricultural workers, including modified grip width and diameter, have been shown to reduce physiological strain and improve work efficiency (Sinha et al., 2023) [51] . Improvements in handle materials, such as cushioned and non-slip grips, also enhance comfort and reduce muscular fatigue by distributing pressure more evenly across the palm (Moroney et al., 1988) [33] .

Tool Geometry

Tool geometry, including blade shape, width, cutting angle, and operating depth, plays a crucial role in determining the performance and ergonomic efficiency of manual weeding tools. Proper geometric configuration reduces soil resistance, improves soil penetration, and minimizes the muscular effort required for manual operation. In contrast, poorly designed tools increase draft force, operator fatigue, and the possibility of crop damage. According to Hu et al. (2024), the geometric parameters of weeding blades such as blade width, thickness, and cutting angle significantly influence the cutting efficiency and energy requirement of manual weeding implements. Optimized blade geometry allows efficient slicing of weeds while maintaining minimal disturbance to surrounding crops. Blade shape is particularly important in determining how the tool interacts with soil and weed roots. Sweep-shaped and V-shaped blades are widely used in manual weeders because they provide effective horizontal slicing action and reduce soil resistance. These blade shapes promote cutting rather than lifting of soil, thereby reducing the draft force required for operation. Experimental studies have shown that optimized blade shapes can significantly improve weeding efficiency and field capacity while maintaining acceptable physiological workload for the operator (Chethan et al., 2018; Hu et al., 2024) [8,18] . Blade width must also be selected according to crop row spacing to prevent crop injury while ensuring efficient weed removal. Studies on improved weeders indicate that blade widths between 120 and 200 mm are suitable for most row crops and help achieve higher field efficiency without increasing operator workload (Yadav & Pund, 2007; Chethan et al., 2018) [52,8] . The cutting angle of the blade also plays a significant role in determining tool performance. A proper cutting angle improves soil penetration and reduces draft force during operation. Research on mechanical weeding tools indicates that cutting angles between 15° and 30° provide effective slicing action and reduce energy consumption during weed removal (Hu et al., 2024; Shirwal, 2020) [18,47] . Similarly, maintaining an appropriate operating depth of 2-5 cm is sufficient to remove shallow-rooted weeds while minimizing soil disturbance and resistance. In push-pull weeders equipped with wheels, wheel diameter also influences tool performance. Larger wheels, typically 200-300 mm in diameter, reduce rolling resistance, improve tool stability, and help the operator maintain a comfortable working posture during field operation (Panigrahi et al., 2025) [40] . These geometric optimizations contribute significantly to improving operational efficiency and reducing drudgery in manual weeding tasks.

Weight and Balance Considerations

The weight and balance of agricultural hand tools are critical factors affecting operator fatigue, energy expenditure, and overall work productivity. Tools that are excessively heavy increase muscular strain and cardiovascular workload during prolonged manual operations. Ergonomic studies recommend that manual weeding tools should ideally weigh between 4 and 8 kg, which allows efficient operation while minimizing physical stress on the operator (Singh et al., 2023). Maintaining tool weight within this range helps reduce physiological workload and improves operator endurance during repetitive field tasks. [40] . Recent technological advancements in agricultural tool design emphasize the use of lightweight and high-strength materials, such as aluminium alloys, hollow steel frames, and composite structures. These materials reduce the overall mass of the implement while maintaining structural durability and operational stability. According to Hu et al. (2024), improved structural design combined with lightweight materials can significantly reduce the physiological workload of operators and increase field efficiency during manual weeding operations. Such design improvements help reduce drudgery, improve ergonomic comfort, and enhance the overall productivity of small-scale farming systems.

Anthropometric Considerations (Indian Operators)

Anthropometric considerations are fundamental in the ergonomic design of agricultural tools, as they ensure compatibility between human body dimensions and the physical characteristics of the tool. Designing tools based on anthropometric data helps improve operator comfort, reduce physical strain, and enhance operational efficiency during manual agricultural activities. In agricultural ergonomics, it is generally recommended that tools should accommodate users within the 5th to 95th percentile of the target population, ensuring that both smaller and larger operators can perform tasks safely and effectively (Chakrabarti, 1997; Pheasant & Haslegrave, 2006) [41] . Failure to consider anthropometric variability often results in poor working posture, increased muscular effort, and a higher risk of musculoskeletal disorders among farm workers. Operator height is a key anthropometric parameter that influences tool design, particularly for implements such as manual weeders and hoes. The average stature of Indian agricultural workers generally ranges between 150 and 175 cm, and tools should therefore be designed to accommodate this range. Improper handle height forces workers to adopt excessive trunk bending or shoulder elevation, leading to discomfort and increased loading on the lumbar spine and shoulder muscles. Adjustable handle mechanisms are therefore recommended to allow operators to maintain a near-upright posture during work (Bridger, 2018; Sinha et al., 2023) [51] . Arm reach and shoulder breadth also play an important role in determining the appropriate handle length and spacing for bilateral agricultural tasks. If handle spacing does not match the operator's shoulder breadth, it may lead to overextension of the arms or asymmetric loading on the upper limbs. Studies on ergonomic agricultural tools indicate that proper alignment between handle spacing and shoulder width improves force transmission and reduces fatigue during repetitive push-pull operations (Kroemer & Grandjean, 1997; Singh et al., 2025) [26,50] . Hand dimensions are another critical factor in tool design, particularly in determining the appropriate grip diameter. Grip sizes that are too small or too large can significantly reduce grip strength and increase muscular activity in the forearm muscles. Research suggests that grip diameters between 30 and 40 mm are optimal for most adult users and allow maximum grip strength with minimal muscular effort (Chakrabarti, 1997; Kumar & Narayan, 1995) [28] . Properly designed grips increase the contact area between the hand and the handle, thereby reducing localized pressure and minimizing fatigue during prolonged manual operations. Anthropometric design must also consider the natural working posture of the operator. Agricultural tools should allow workers to maintain neutral or near-neutral positions of the trunk, arms, and wrists during operation. Excessive trunk flexion, lateral bending, or wrist deviation can increase mechanical stress on joints and soft tissues, contributing to musculoskeletal disorders. Ergonomic guidelines suggest that trunk flexion during manual agricultural work should ideally be limited to less than 20°, while elbow joint angles should remain within 90-120° to allow efficient force application without overloading the shoulder or forearm muscles (Bridger, 2018; David, 2005) [

. In addition, prolonged squatting or kneeling postures are commonly associated with manual weeding operations and can lead to lower limb fatigue, reduced blood circulation, and increased discomfort. Modern ergonomic tool designs therefore aim to enable standing or semi-bent postures during weeding operations, which significantly reduce lower limb strain and improve work endurance (Panigrahi et al., 2025) [40] . Adjustable handles, optimized grip dimensions, and proper handle spacing are among the key design strategies used to accommodate anthropometric variability among agricultural workers. Incorporating these considerations into tool design helps reduce drudgery, improve operator safety, and enhance the overall efficiency of manual farming operations.

Safety & Usability of Equipment

Safety and usability are essential aspects of ergonomic agricultural tool design, as they directly influence operator protection, ease of operation, and long-term efficiency during manual farming tasks. Proper safety features help minimize the risk of injuries such as cuts, abrasions, and accidental contact with moving parts. For instance, tools should be designed without exposed sharp edges and should include guards for rotating components such as blades or wheels to protect the operator's hands and fingers during operation. Smooth finishing of the tool frame without projecting bolts or sharp corners also prevents skin abrasions and reduces the risk of clothing snagging. In addition, non-slip handle grips made from rubberized or textured materials improve control of the tool, especially under sweaty or wet conditions, thereby reducing the chances of slips or strain injuries. A stable wheel base is another important safety feature, as it helps maintain balance, prevents tipping, and ensures even load distribution during push-pull operations (Bridger, 2018; Kroemer & Grandjean, 1997) [26] . Usability features further enhance the practicality and efficiency of agricultural tools. Tools designed with modular components allow easy assembly, repair, and maintenance, reducing downtime during field operations. Simple blade replacement systems enable quick replacement of worn or damaged blades without requiring specialized tools, thereby improving operational efficiency. Low maintenance requirements, achieved through durable construction and corrosion-resistant materials, reduce maintenance costs and increase the service life of the implement. Clear operating instructions and ergonomic guidelines also play an important role in minimizing operator errors and ensuring safe and effective tool usage (Pheasant & Haslegrave, 2006) [41] . Recent design improvements in agricultural tools include the incorporation of protective blade covers, which protect users when the tool is not in operation or during transportation. Rounded frame edges are also recommended to reduce the risk of impact injuries during handling. In addition, anti-vibration systems and shock-absorbing grips are increasingly used to reduce hand-arm vibration and fatigue during prolonged use. Safety decals and warning labels are also commonly added to provide visual guidance and hazard awareness for operators. Together, these safety and usability improvements contribute to safer working conditions, reduced injury risk, and enhanced productivity in manual agricultural operations. [48] . Another important future direction is the application of artificial intelligence and machine learning for automated ergonomic evaluation. AI-based posture recognition systems using computer vision and deep learning algorithms can analyze workers' body movements and identify non-neutral postures during agricultural tasks. For example, recent research demonstrated that AI-enabled posture classification systems can automatically detect ergonomic risks in agricultural activities and help prevent musculoskeletal disorders among workers. Such intelligent systems can significantly enhance the accuracy and efficiency of ergonomic assessment and support the development of safer agricultural tools (Kapse, Wu, & Thamsuwan, 2024) [22] . Wearable technologies and motion-capture systems are also expected to play a major role in future ergonomic studies. Devices such as inertial measurement units (IMUs), smart wearable sensors, and physiological monitoring systems can record parameters such as body posture, movement patterns, fatigue levels, and energy expenditure in real time. These wearable systems enable predictive risk assessment and provide continuous feedback to operators and researchers, allowing early detection of ergonomic hazards during manual agricultural operations like weeding (Apicella & Tarabella, 2025) [1] . Furthermore, future ergonomic assessment may incorporate robotics, human robot interaction, and digital simulation technologies. Advances in agricultural robotics and intelligent machinery allow collaborative work between humans and machines, where robotic systems assist farmers in physically demanding operations while maintaining ergonomic safety. Human-robot interaction frameworks can dynamically monitor worker posture and adjust machine operations accordingly, thereby reducing operator workload and improving occupational safety in agricultural environments (Benos et al., 2023) [4] .

Recent ergonomic research increasingly Modelling and Simulation Techniques uses digital modelling and simulation tools to evaluate agricultural tool performance before field testing. These tools allow researchers to analyze operator posture, joint stress, and human-tool interaction in virtual environments, improving design accuracy and reducing ergonomic risks. According to Padhiary, Roy, and Kumar (2025), simulation software helps engineers optimize ergonomic parameters through virtual testing and AIassisted automation, reducing design errors and minimizing the need for extensive field trials. Similarly, studies reported in the journal Ergonomics indicate that simulation approaches are widely used to enhance agricultural machinery design and evaluate operator safety and comfort. Motion capture technologies and wearable sensors are increasingly used for ergonomic assessment of agricultural tasks. These systems monitor body posture, joint angles, and movement patterns during field operations. Apicella and Tarabella (2025) reported that wearable devices such as inertial measurement units (IMUs), smart glasses, and motion sensors can provide real-time data on worker posture, fatigue, and physical workload. Such technologies are particularly useful in labor-intensive operations like manual weeding, where continuous monitoring helps identify ergonomic risks and improve tool design.

Conclusion

Manual weeding remains a crucial but highly laborintensive operation in Indian agriculture, particularly among smallholder farmers who rely on traditional hand tools. These conventional tools often require prolonged bending and repetitive movements, leading to fatigue, musculoskeletal disorders, and reduced work efficiency. The application of ergonomic principles in the design of manual weeders such as optimized handle geometry, appropriate tool weight, anthropometric compatibility, and improved blade design-can significantly reduce physiological workload and enhance operator comfort. Ergonomic evaluation methods, including subjective assessment, observational techniques, and physiological measurements, play an important role in identifying risk factors and improving tool performance. Comparative studies of improved weeders demonstrate that ergonomic modifications can reduce drudgery, improve field capacity, and increase productivity. Furthermore, emerging technologies such as digital modelling, wearable sensors, artificial intelligence, and virtual reality offer new opportunities for advanced ergonomic assessment and tool optimization. Therefore, integrating ergonomic design principles with modern technologies will be essential for developing efficient, safe, and user-friendly manual weeders that support sustainable and productive agricultural systems in India.

References

1. Apicella A, Tarabella A. Wearable technologies in Agriculture 4.0: applications for worker safety and International Journal of Advanced Biochemistry Research https://www.biochemjournal.com ergonomic support. International Journal of Academic Research in Business and Social Sciences. 2025.
2. Astrand PO, Rodahl K. Textbook of work physiology. Human Kinetics; 2003.
3. Behera BK, Swain S, Mohanty SK. Ergonomic evaluation of push-pull type weeders with women operators. Journal of Agricultural Engineering. 2007;44(3).
4. Benos L, Moysiadis V, Kateris D, Tagarakis A, Busato P, Pearson S, et al. Human-robot interaction in agriculture: a systematic review. Sensors. 2023.
5. Borg G. Psychophysical bases of perceived exertion. Medicine and Science in Sports and Exercise. 1982.
6. Bridger RS. Introduction to ergonomics. 2003.
7. Chaudhary D, Singh S, Kumar M. Ergonomic evaluation of a walking type power-operated maize stalk harvester. Agricultural Science Digest. 2022.
8. Chethan CR, et al. Ergonomic evaluation of manually weeders for row crops. 2018.
9. Computers and Electronics in Agriculture. State-of-theart in real-time virtual interfaces for tractors and farm machines: a systematic review. 2025.
10. David GC. Ergonomic factors in manual work stresses. Occupational Medicine. 2005.
11. Dul J, Weerdmeester B. Ergonomics for beginners. CRC Press; 2008.
12. E3S Web of Conferences. Integration of artificial intelligence in ergonomic risk assessment for agricultural activities. 2024.
13. Food and Agriculture Organization. Agricultural equipment safety guidelines. 1992.
14. Gite LP, Agarwal N, Yadav BG. Ergonomics in agricultural and allied activities. ICAR; 2009.
15. Grandjean E. Fitting the task to the man. 1988.
16. Gregg ES, Colton J, Matin MA, Krupnik TJ. Efficient and participatory design of scale-appropriate agricultural machinery workshops in developing countries. Development Engineering. 2020.
17. Hignett S, McAtamney L. Rapid Entire Body Assessment (REBA). Applied Ergonomics. 2000;31(2):201-205.
18. Hu Y, Zhao Z, Lan Y, et al. Innovative blade and tine push weeder for enhancing weeding efficiency of small farmers. Sustainability. 2024.
19. Joshi D, Singh R, Patel P. Ergonomic evaluation of improved agricultural hand tools for reducing drudgery among farm workers. Journal of Agricultural Engineering. 2024;61(1):45-53.
20. Joshi P, et al. Ergonomic assessment of farm operations in sustainable farming systems. Frontiers in Sustainable Food Systems. 2024.
21. Kapse S, Wu R, Thamsuwan O. Addressing ergonomic challenges in agriculture through AI-enabled posture classification. Applied Sciences. 2024.
22. Karwowski W. International encyclopedia of ergonomics and human factors. 2021.
23. Kee D. Participatory ergonomic interventions for improving agricultural work environment: a case study in a farming organization. Applied Sciences. 2022.
24. Kroemer KHE, Grandjean E. Fitting the task to the human: a textbook of occupational ergonomics. 5th ed. London: Taylor & Francis; 1997.
25. Kumar A, Sharma V, Joshi D. Ergonomic and performance evaluation of improved agricultural tools. Biosystems Engineering. 2024.
26. Kumar S, Narayan Y. Hand tool design based on anthropometry and biomechanical principles. Applied Ergonomics. 1995.
27. Kuorinka I, et al. Standardised Nordic questionnaires for the analysis of musculoskeletal symptoms. Applied Ergonomics. 1987.
28. Li X, Wang Y, Chen Z. Wearable sensor-based ergonomic assessment for agricultural workers. Applied Ergonomics. 2022.
29. McAtamney L, Corlett EN. RULA: a survey method for the investigation of work-related upper limb disorders. Applied Ergonomics. 1993;24(2):91-99.
30. Mishra S, Bhagat D, Borah S. Ergonomic interventions for women agricultural workers. Research on World Agricultural Economy. 2024.
31. Moroney SR, et al. Biomechanics of grip force and contact area. 1988.
32. Nag PK, Gite LP. Human-centered agriculture: ergonomics and human factors applied. Springer; 2020.
33. Nag PK, Dutta P. Ergonomic studies on agricultural workers. Indian Journal of Agricultural Engineering. 1979;11(2):57-66.
34. Negi B, Singh J, Singh T. Anthropometric-based design of agricultural hand tools. Work Journal. 2025.
35. Ojha TP, Michael AM. Principles of agricultural engineering. Vol. 1. Hill Publications; 1992.
36. Padhiary M, Roy P, Kumar K. Simulation software in the design and AI-driven automation of all-terrain farm vehicles and implements for precision agriculture. Recent Progress in Science and Engineering. 2025.
37. Pandey S, Singh R, Patel P. Performance evaluation of battery-powered weeding equipment. Journal of Agricultural Engineering. 2023.
38. Panigrahi SR, Bhattacharyya N, Bhuyan B. Assessment of traditional weeding tools for safe ergonomic practices. Archives of Current Research International. 2025.
39. Pheasant S, Haslegrave CM. Bodyspace: anthropometry, ergonomics and the design of work. 2006.
40. Pheasant ST. Ergonomics, work and health. Basingstoke, Hants: MacMillan Academic and Professional Ltd; 1991.
41. Raut VD, Deshmukh BD, Dekate D. Various aspects of weeders for economical cultivation. International Journal of Modern Engineering Research (IJMER). 2013;3(5):3296-3299.
42. RNAM test codes for agricultural machinery. 1983.
43. Roy Burman R, et al. Ergonomic efficiency and drudgery reduction in millet farming systems. Frontiers in Sustainable Food Systems. 2025.
44. Sanders MS, McCormick EJ. Human factors in engineering and design. 7th ed. New York: McGrawHill; 1993.
45. Shirwal S. Optimization of geometrical parameters of weeding tool in soil bin using response surface methodology. 2020.
46. Siddharth K, Shristi, Pandey TK, Isaac RK. Smart technologies for sustainable agriculture using IoT and AI-based precision farming tools. 2025.
47. Singh SP, Singh MK, Solanki RC. Design and development of four-wheel weeder for wide row crops. Indian Journal of Agricultural Sciences. 2016.
48. Singh V, Kumar A, Prasad P. Ergonomic comparison of modified weeders for improved operator comfort. Current Agriculture Research Journal. 2025.
49. Sinha J, Singh JK, Kumar A. Ergonomic assessment of wheel hoe and design compliance for women farm workers. Indian Journal of Agricultural Sciences. 2023;88(3):447-452.
50. Yadav R, Pund S. Development and ergonomic evaluation of manual wseeder. Agricultural Engineering International: CIGR Journal. 2007.