Shiraz University Iran Agricultural Research 1013-9885 44 1 2025 04 01 Effects of some functional parameters on noise pollution of John Deere 3350 and New Holland 155 tractors تاثیر برخی پارامترهای عملکردی بر آلودگی صوتی تراکتورهای جان دیر 3350 و نیوهلند 155 33 41 8073 10.22099/iar.2025.51391.1639 EN Babak Moradvand Department of Mechanical Biosystems Engineering, Faculty of Agriculture, College of Agriculture and Natural Science, Razi University, Kermanshah, I. R. Iran Leila Naderloo Department of Mechanical Biosystems Engineering, Faculty of Agriculture, College of Agriculture and Natural Science, Razi University, Kermanshah, I. R. Iran Hossein Javadikia Department of Mechanical Biosystems Engineering, Faculty of Agriculture, College of Agriculture and Natural Science, Razi University, Kermanshah, I. R. Iran Kamran Kheiralipour Department of Mechanical Biosystems Engineering, Faculty of Agriculture, College of Agriculture and Natural Science, Ilam University, Ilam, I. R. Iran Journal Article 2024 10 09 In this study, noise pollution from the John Deere 3350 and New Holland 155 tractors was measured at three operator-related positions: 10 cm from the driver’s ear and at distances of 7.5 and 20 m from the tractor centerline, as they traveled over asphalt and soil surfaces. Measurements were conducted under three engine speeds (1000, 1500, and 2000 rpm) and three gear settings (gears 1, 2, and 3), with three replications for each condition. Data were analyzed using a factorial test within a completely randomized design. Results indicated that noise levels increased with higher engine speeds and gear settings on both surfaces. The main factors had a statistically significant effect on noise emission levels in both tractors at the 1% probability level. For the John Deere 3350, noise levels at the driver’s ear position exceeded the standard limit of 85 dB (A) at all gear and speed combinations on asphalt, except for 1st gear at 1000 rpm. The New Holland 155 exhibited lower noise levels at the driver’s ear compared to the John Deere 3350, likely due to the presence of an enclosed cab. https://iar.shirazu.ac.ir/article_8073_e61a076d00854f0d8340f29c97bc7889.pdf