Ergonomic Refinement of Manual Multi-Row Seed Planter from Pull to Push Type: A Postural and Physiological Assessment

Manual multi-row seed planters are commonly used by marginal farmers, but amongst them, pull-type models often cause operator discomfort and reduced efficiency, mainly due to the single handle and backward movement. This study aimed to redesign and improve the seed planter into a push-type configuration and evaluate its effects on operator physiology, posture, and field performance. The push-type planter was improved using anthropometric data and ergonomic guidelines to eliminate the need for walking backward, minimise physical strain, and enhance handling efficiency. The push-type design maintained moderate work severity, whereas the pull-type exceeded ergonomic thresholds with moderate to heavy severity. Physiological workload (heart rate and energy expenditure) and postural risk were evaluated in twelve farm workers (n = 12) to ergonomically refine a conventional manual multi-row seed planter from a pull-type to a push-type configuration. The participants represented a typical adult farming population, with ages ranging from 23 to 54 years and diverse body dimensions relevant to manual planter operation. Lower mean heart rate (108 vs. 117 beats min^-1), decreased energy expenditure (15.0 vs. 17.0 kJ min^-1), and improved posture based on Rapid Entire Body Assessment (REBA) scores (6.4 vs. 8.3) were observed with the improved push-type design vs. the existing pull-type design. Forward-facing operation and improved balance enhance user control and safety, reducing the risk of slips or falls, unlike backward movement in pull-type models. Additionally, the push-type planter achieved better field performance, with a higher capacity (0.088 ha h^-1) and reduced labour requirement (11 man-h ha^-1) compared to the pull-type. Overall, the ergonomic transformation to a push-type design led to significant improvements in comfort, safety, and efficiency, contributing a more sustainable and inclusive solution for small-scale farm mechanization.