Abstract
In Japan, walking-type machines are widely used for fertilizer application in tea cultivation. The work strain of an operator using such a machine is high because the operator is required to walk along each hedge. Therefore, we have developed a walking-type fertilizer applicator equipped with 2 boom-type blow heads and 4 wheels. The decrease in the work strain was assessed by using the increase in heart rate as an index. While operating this fertilizer applicator, the operator walks between hedges, and air flowing through the boom-type blow heads causes release of fertilizer simultaneously onto the 2 rows. In order to assess the performance of the newly developed applicator, we determined the effective operating capacity, the increase in heart rate, and the relationship between the operating speed and the increase in heart rate with the developed, the conventional pushcart-type, and the conventional power fertilizer applicators. The results revealed that the effective operating capacity of the developed fertilizer applicator was 0.89 ha/h, which was higher than the operating capacities of the conventional fertilizer applicators. The increase in the heart rate of 6 operators using the developed fertilizer applicator was 20-52% less than that of operators using the conventional fertilizer applicators. At equal operating speeds of the fertilizer applicators, the increase in the heart rate of operators using the developed fertilizer applicator was approximately equal to that of operators using the conventional pushcart-type fertilizer applicator. Operators using the conventional power fertilizer applicator exhibited a significantly higher increase in heart rate than operators using other fertilizer applicators. At equal operating capacities, the increase in the heart rate of operators using the developed fertilizer applicator was significantly lower than that of operators using the conventional fertilizer applicators. On the basis of these results we can conclude that the use of the developed fertilizer applicator can considerably reduce the work strain of operators.
