Physiological Work Load and Subjective Assessment of Micro Tillers for Homestead Farming

The cardio respiratory performance of men operators was studied in two models of micro tillers for homestead farming in Kerala. Psychophysical measurement technique was used to quantify the overall discomfort as well as body part discomfort. The mean heart rate of operator was 109 beats min-1 for model I while it was 111 beats min-1 for model II. The work pulse of the micro tillers are 38 beats min-1 and 40 beats min-1 respectively for models I and II which was well within the limit of continuous performance of 40 beats min-1. The predicted oxygen consumption rate was 0.9589 l min-1 that is 47% of maximum aerobic capacity (VO2 max) for model I while it was 0.99 l min-1 that is 48% of their aerobic capacity for model II which was above the acceptable limit of 35% of VO2 max indicating that the micro tillers were could not be operated continuously for 8 hours without frequent rest-pauses. It is suggested that two operators may be engaged in shift for a day long work with micro tillers. The performance of the second model was better than I model and the operation was graded as moderately heavy for both models. The first model was best suited to sandy loam soil however the second model was suited to both sandy loam soil and laterite soil. The weeding index was found to be 79% and the area covered by the first model was 0.5acre/day while the weeding index was found to be 85% and the field capacity was 0.75acre/day for the second model. Mean overall discomfort rating on a 10 point visual analogue discomfort scale ( 0- no discomfort, 10- extreme discomfort ) was 2.0 and scaled as and quot; light discomfort and quot; during weeding for model I while it was 4.0 and scaled as and quot; more than light discomfort and quot; for second model. Micro tillers are mainly used for weeding as well as tilling the soil and it can be also used for making furrows/ channels and models would be selected based on the type of soil.