Workplace Design of Selected Rice Transplanters for Farm-women Operators

Kerala, known for its lush greenery and extensive rice fields, has seen a decline in rice production since the 1980s. The reduction in rice land, from 0.85 million ha in 1980 to 0.093 million ha in 2021-22, poses challenges for farmers who are now turning to other crops, potentially impacting food security (Agriculture Statistics and Paddy Outlook, 2022). Also, Women agricultural workers, integral to the workforce, endure strenuous manual tasks, such as transplanting rice seedlings. This labor-intensive work puts them at risk of health issues and despite being essential, their efforts often go unpaid (Potdar et al., 2020; Tamilselvi and Anantha Krishnan, 2016). To alleviate their burden and enhance efficiency, providing farm women with increased access to rice transplanters is crucial. To address these issues, there is a growing reliance on advanced agricultural machines, including imports from other nations. However, the shift to modern equipment may overlook ergonomic considerations, affecting operation efficiency, operator safety and comfort (Sam, 2013; Kamendra et al., 2022). Efforts by ICAR institutes and various organizations aim to develop and implement improved paddy transplanters, specifically designed to relieve women from agricultural labor (Mohanty et al., 2012; Gayathri and Sam, 2017). However, research indicates that transplanters primarily designed for male workers may not be suitable for women operators, emphasizing the importance of ergonomic considerations (Dewangan, et al., 2010; Syuaib, 2015).
 
Incorporating human aspects into design improves operator efficiency, comfort and safety. Control, visualand spatial requirements are functional factors in operator workspace design. The operator’s anthropometric and biomechanical characteristics affect these factors. The operator’s workstation is designed using anthropometric data to meet visibility and clearance requirements (John et al., 2004). Anthropometric considerations in equipment design improve performance, efficiency, safety and comfort and prevent work-related injuries and accidents. Gender, race, ethnicity and age significantly impact anthropometric measures (Pheasant, 2003). Efforts are being made to collect anthropometric data in India by a few researchers and the dimensions included were specific to the Indian male agricultural workers (Dewangan et al., 2008; Gite and Majumder, 2007; Ratn et al., (2010); Agrawal et al., 2011, Vyavahare and Kallurkar, 2016). As far as the Indian female workers are concerned available information suggests that steps have been initiated only recently (Dixit and Namgial, 2012). In these studies, they conducted an anthropometric survey of India’s Western and Northeastern (NE) regions. However, there is a lack of anthropometric data on the female population of this southern-western region. A little work observed in this region, Sam, (2013) collected 29 body dimensions and 1 strength parameter from 120 female agricultural workers.

Given the aforementioned, the present study aimed to (1) collect anthropometric data of women agricultural workers in SW Kerala to design and modify their workplace and equipment. (2) establish important anthropometric measurements for selected rice transplanters and compare them to male and female agricultural employees. (3) comparing selected rice transplanters’ spatial and control requirements to IS and ISO redesign criteria based on anthropometric data and questionnaires.

The study, conducted in 2022 at Kelappaji College of Agricultural Engineering and Technology, KAU, Tavanur, involved collecting anthropometric data from 450 women agricultural workers aged 18-60 from the northern, central and southern zones of Kerala, following the recommendations of AICRP on ESA, Bhopal. A sample of 150 women from each zone was selected and 79 physical measurements were recorded to aid ergonomic agricultural machinery design, including age, weight and strength. Of these, 49 measurements were taken while standing, 8 height and 8 transverse measurements while seated and 14 measurements were obtained in both positions, following the NASA 1978 anthropometric handbook standards. Body dimensions and strength were measured using the Integrated Composite Anthropometer (ICA) (Tewari et al., 2007), weighing scales, dynamometers and pinch gauges. Precautions were taken to avoid errors during measurement. Data were analyzed in Microsoft Excel, with adjustments for any errors. Descriptive statistics, such as minimums, maximums, means, standard deviations, standard errors and percentiles, were determined for body dimensions and strength. An unpaired Student’s t-test compared body proportions between male and female transplanting agricultural workers.
 
Spatial and control requirements of selected rice transplanters
 
As demonstrated in Plate 1, this study used Yanmar, Redlands and Yanji self-propelled rice transplanters. These rice transplanters were ergonomically assessed with ten women subjects, based on age and anthropometric measurements that satisfied statistical standards from the study region’s database. The ten participants were examined for normal health using blood pressure, electrocardiogram and bio-clinical analyses.



Participants were equally trained in operating the selected rice transplanters. The ergonomic evaluation was carried out by Gayathri and Sam (2017). During the operation, the operator performs multiple tasks like steering, observing the operation and controlling various parts. The tasks and workplace determine the postures and loading patterns of the body structures. After the experiments, participants provided feedback through a questionnaire, which considered workplace dimensions, controls and operations, visual requirements and the working posture of the operator.
 

A statistical analysis was performed on 450 female anthropometric data from Kerala. Table 1 shows the minimum, maximum, mean, SD, SEM, CV and 5^th and 95^th percentiles of 76 body dimensions and ten strength metrics, including age and body weight. The analysis is important to ensure equipment is designed with utmost precision due to significant variation in body dimensions among participants. Female individuals ranged in height from 136 to 183.3 cm, averaging 152.4 cm. Certain bodily measurements exhibit higher SEM and CV%, indicating increased variability among individuals. This variability can be advantageous while designing agricultural equipment, as it allows for the consideration of the 5^th and 95^th percentiles.



Table 2 shows significant differences in body dimensions between male and female agricultural workers in Kerala, India, except for waist, hip, sitting acromion, thigh clearance and elbow rest height. Rice transplanters must be designed for both genders to reduce discomfort for female workers. Lee (2000), Dewangan (2008) and others compared female agricultural workers’ body measurements from North-East India and eight other countries. They found that Colombian and US women have similar physical measurements. However, Indian farm-workers need to adapt foreign tools and machinery, as they are designed based on foreign worker body measurements.



Participants were asked about the needs of rice transplanters after trials. Yanmar was comfortable and adjustable, but its platform was harder to access in muddy fields. Women operating Yanji and Redlands complained about seat and backrest dimensions. The backrest should support the upper lumbar area (Mehta, 2000), but had no vertical adjustment and was too short. However, hand and foot controls were within reach due to longitudinal seat adjustment and operating all controls required little force. The visibility criteria were met by upright sitting with simple head and upper body motions from front to side in chosen transplanters. The Yanmar transplanter’s rear-view mirrors showed the backside transplanting region. Redlands and Yanji transplanters feature assistance on both sides and provide rear-view information. The display was likewise close to the operator’s view, requiring minimal eye movements. Yanji and Redlands transplanters made greater noise and vibration, according to subjects. Working with chosen transplanters was more uncomfortable after 11 AM than before 9 AM (Gayathri and Sam, 2017). Each transplanter’s workspace dimensions were measured from the operator seat index point to the machine controls. Table 3 and 4 display spatial dimensions for the operator seat index (SIP) and seat reference point (SRP) of selected rice transplanters, as described in ISO-5353(1984).

Table 3 shows, Yanmar self-propelled transplanter has a standard backrest width of 40 cm (bottom) and 25 cm (top). This falls within the 5th-95th percentile for female agricultural workers in study region. Seat pan width is 44 cm which is wider than the 95^th percentile hip breadth of 41.5 cm. The adjustable seat makes it comfortable for all operators to sit and ride the transplanter. Transplanter’s footrest-to-seat pan distance was 35 cm. Sitting women agricultural workers had 5^th percentile popliteal height of 35.4 cm. Thus, Yanmar transplanter operators found the seat height (from footrest to seat pan) comfortable. The steering wheel rim diameter was 3.5 cm, within the acceptable range for the 5^th (3.3 cm) and 95^th (5.7 cm) percentiles. Operator steering distance was 50 cm, meeting limitations for female agricultural workers. The steering height from the footrest was 55 cm, comfortable and within range (5^th percentile seated knee height, including elbow rest, was 57 cm).



The acceleration pedal was toe-triggered, with the 95^th percentile toe length of agricultural workers used for its construction. The minimal toe length was calculated as the difference between the 95^th percentile foot length (25.1 cm) and instep length (20.3 cm), resulting in a 4.8 cm minimal toe length for women agricultural workers. The Yanmar rice transplanter’s accelerator pedal length was 20 cm, exceeding the required toe length and the 5 cm pedal width was narrower than the recommended 95^th percentile foot breadth. The pedal should be raised to provide stable heel support, prevent engine speed fluctuations and reduce foot and pedal vibrations when driving over obstacles. Hand and foot controls should be easy to operate while seated. Seat adjustments (15 cm fore-and-aft, 10 cm vertical) enhance mobility for larger operators. The Yanmar transplanter’s step height was too high at 72 cm for women to reach easily in muddy fields. The footstep height should be adjusted to 40±7.6 cm, in line with AIS 122/D2 (2015) standards, to prevent operator discomfort.

Table 4 shows, a comparison of Redlands and Yanji transplanter’s part measurements to women farm workers’ anthropometric dimensions. The dimensions of Redlands and Yanji rice transplanters were similar. Yanji and Redlands transplanters have 15 cm of fore-and-aft seat adjustments for bigger workers. Both 5^th and 95^th percentile operators can use all foot and hand controls. Table 5 shows non-anthropometric seats for Redlands and Yanji rice transplanters. A new seat design is proposed, based on female agricultural workers’ measurements and workplace facilities.




 
Application of anthropometry in design of seats for Yanji and Redlands transplanters
 
Operator comfort depends on machine’s seat. Anthropometric data is used to determine the appropriate width, depth and height. Transplanter seat is designed for all rice transplanter women operators. See Table 5 for recommended main operator and helper seat dimensions and also shown in Plate 2 as per BIS and ISO.

The study developed an anthropometric database of 450 women agricultural workers from southwest India, including 79 physical characteristics such as age, weight and strength, to aid in the design or modification of agricultural equipment. Significant variation was found in the physical measurements of both male and female workers. Comparing the dimensions and clearances of selected rice transplanters with the database showed that the seats were too large for women. Recommended seat dimensions are: 39 cm backrest height, 38 cm width, 27.5 cm top width, 18 cm open area, 40 ± 3.4 cm length, 43 cm width, 10 cm cushion height and 8 cm backrest cushion height. A 35 cm round seat is suggested for assistants. These findings may help design rice transplanters that reduce discomfort for both men and women in agriculture.

Thanks to the Kerala State Council for Science, Technologyand Environment for their financial support. Also, appreciation to F S R S, Sadananda Puram research engineers for their assistance throughout the project.

The authors declare that there are no conflicts of interest regarding the publication of this article. No funding or sponsorship influenced the design of the study, data collection, analysis, decision to publish, or preparation of the manuscript.