Physiological Response of Operators during Power Tiller Use for Paddy Field Cultivation

Abstract

Power tillers (single axle, two-wheel hand tractors) are widely used for paddy field cultivation in Thailand. Currently, over one million power tillers are being used as they suit both the economical and physical conditions of paddy farming in developing countries. Controlling these hand tractors while walking behind is often hard work. Safety and health concerns associated with the use of these machines have not been well documented. This study was aimed at evaluating the physical response of operators during various operations by power tillers in paddy field. The most popular power tiller model in Thailand was used for this investigation. Field tests were conducted to determine the physical response of operators while using this machine. The response was assessed through measurement of operator heart rates during different operations. The comfort, working posture and the task were also evaluated. The physical work capacity was established with the help of a bicycle ergometer. The field operations carried out were first-plowing, second-plowing and harrowing. The tillage equipment used were moldboard plow, disc plow and peg tooth harrow. A statistical analysis was conducted to compare the effects of environmental factors and working intensity in each activity and results were compared with the standards. It was observed that the physical response during some of the operations exceeded the physical work capacity of the operators. It was noticed that the excessive physiological response was contributed by power tiller use as well as environmental factors. Working with power tiller in muddy paddy fields in a hot and humid climate also contributed to excessive workload. Surface conditions in the field also had a direct effect on physiological response of the operator. Energy cost during wetland operation was also due to unfavorable working conditions. Some ways to improve the design of the power tiller to make it more comfortable for the operator were suggested.