Purpose Agricultural tractors generate various types of noise, with engine noise being the most significant. However, with advancements in engine design, transmission gear noise has emerged as an increasingly prominent issue. Despite this, limited research has been conducted on the evaluation and analysis of transmission gear noise in agricultural tractors. This study focuses on the assessment of tractor noise levels and their impact on the physiological health of the operator and bystanders. Methods Field experiments were conducted at the Pulse Research Station, SKUAST-K, Srinagar, under controlled weather conditions. A tractor with a 55 hp engine was hitched with a disc plough, rotavator, and cultivator to evaluate noise at the operator's ear level and at the bystander's position, 7.5 m away from the tractor. Noise measurements were recorded using a Larson Davis Sound Meter with a frequency range of 6.3 Hz to 20,000 Hz. The study also evaluated the physiological impact on operators by measuring heart rate and blood pressure using a Polar Watch RS 400sd and an Automatic Blood Pressure Monitor, respectively. Energy expenditure was estimated using metabolic equivalents (METs), with 4.0 METs applied to tractor driving during tillage operations. Data were collected under various conditions: implement types (disc plough, rotavator, and cultivator), engine speeds (1000, 1500, 2000 rpm), and depths of operation (no-load, 5–10 cm, 10–15 cm). Statistical analyses were performed to evaluate the relationship between tractor noise and operator physiological responses. Results Noise levels were highest for the Rotavator at 2000 rpm and 14 cm tillage depth, with dominant peak frequencies between 63 and 100 Hz, and a secondary rise observed near 1,000 Hz. Heart rate and blood pressure increased with engine speed and tillage depth, with the Rotavator causing the highest increases. Noise protection devices, especially ear muffs, effectively reduced noise exposure and physiological responses, with ear muffs reducing heart rate by 37.38% and blood pressure by 7.8%. These findings underscore the significance of noise control measures in mitigating operator stress. Conclusion The study demonstrates that tractor-hitched implements produce noise levels exceeding the 85 dB(A) limit, impacting both operators and bystanders. Ear protection devices significantly alleviated the physiological stress on operators, with ear muffs proving most effective in reducing heart rate and blood pressure. The use of ear muffs, ear plugs, and moist cotton all resulted in notable reductions in physiological responses and noise exposure. These interventions can help mitigate discomfort, reduce health risks, and improve working efficiency in agricultural operations.

Occupational Health Impacts of Tractor Noise and its Attenuation Through Ergonomic Interventions

期刊论文
发表日期：

2025年4月17日

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Sheikh Aadil Mushtaq,
Aqib Gul,
Jagvir Dixit

摘要

Purpose

Agricultural tractors generate various types of noise, with engine noise being the most significant. However, with advancements in engine design, transmission gear noise has emerged as an increasingly prominent issue. Despite this, limited research has been conducted on the evaluation and analysis of transmission gear noise in agricultural tractors. This study focuses on the assessment of tractor noise levels and their impact on the physiological health of the operator and bystanders.

Methods

Field experiments were conducted at the Pulse Research Station, SKUAST-K, Srinagar, under controlled weather conditions. A tractor with a 55 hp engine was hitched with a disc plough, rotavator, and cultivator to evaluate noise at the operator's ear level and at the bystander's position, 7.5 m away from the tractor. Noise measurements were recorded using a Larson Davis Sound Meter with a frequency range of 6.3 Hz to 20,000 Hz. The study also evaluated the physiological impact on operators by measuring heart rate and blood pressure using a Polar Watch RS 400sd and an Automatic Blood Pressure Monitor, respectively. Energy expenditure was estimated using metabolic equivalents (METs), with 4.0 METs applied to tractor driving during tillage operations. Data were collected under various conditions: implement types (disc plough, rotavator, and cultivator), engine speeds (1000, 1500, 2000 rpm), and depths of operation (no-load, 5–10 cm, 10–15 cm). Statistical analyses were performed to evaluate the relationship between tractor noise and operator physiological responses.

Results

Noise levels were highest for the Rotavator at 2000 rpm and 14 cm tillage depth, with dominant peak frequencies between 63 and 100 Hz, and a secondary rise observed near 1,000 Hz. Heart rate and blood pressure increased with engine speed and tillage depth, with the Rotavator causing the highest increases. Noise protection devices, especially ear muffs, effectively reduced noise exposure and physiological responses, with ear muffs reducing heart rate by 37.38% and blood pressure by 7.8%. These findings underscore the significance of noise control measures in mitigating operator stress.

Conclusion

The study demonstrates that tractor-hitched implements produce noise levels exceeding the 85 dB(A) limit, impacting both operators and bystanders. Ear protection devices significantly alleviated the physiological stress on operators, with ear muffs proving most effective in reducing heart rate and blood pressure. The use of ear muffs, ear plugs, and moist cotton all resulted in notable reductions in physiological responses and noise exposure. These interventions can help mitigate discomfort, reduce health risks, and improve working efficiency in agricultural operations.