Physiological cost and subjective assessment of walking and riding type power tillers

The physiological response of the subject while operating two power tillers with one as walking type (7.46 kW) and the other as riding type (8.95 kW) was investigated during rototilling in untilled and tilled fields and in transport mode on farm and bitumen roads. Psychophysical measurement technique was used to quantify the overall discomfort as well as body part discomfort. The energy cost was observed to be 17.64 kJ min-1 for walking type, whereas for riding type power tiller, energy cost was 14.31 kJ min-1 during rototilling. Energy expenditure was more in the rototilling operation than in transportation. Mean overall discomfort rating on a 10 point visual analogue discomfort scale varied from 4.0 to 5.2 with the operator's seat and from 4.6 to 7.0 without the operator's seat during rototilling. It was observed that the attachment of an operator's seat to power tiller reduced human energy expenditure by 19%. This study emphasizes the need to provide a seat while operating power tillers for reducing the drudgery and fatigue.