Development and Ergonomic Evaluation of Manual Weeder

To increase the productivity per unit area of small land holdings and considering the economic condition of Indian farmers, it is quite necessary to have suitable agricultural implements which farmers can use and also allow them to use for custom hiring. Weeding is an important agricultural unit operation. Delay and negligence in weeding operation affect the crop yield up to 30 to 60 per cent. With regard this, a manually operated weeder was developed and tested ergonomically. Various parameters such as speed of travel, time of operation, field capacity, weeding efficiency and horse power requirement were considered during the testing. The ground wheel of weeder (390 mm Ф) was fabricated from mild steel flat of 52 x 3 mm. The weeding blades were made from steel flat to impart enough strength to sustain the prevailing forces acting on it. V-shape support made of mild steel was directly welded to the handle to join the ground wheel with the main frame. The arrangement was also made to adjust the height and angle of the handle as per the need and posture of the operator. The weeding efficiency of the developed weeder was satisfactory and it was easy to operate. The developed weeder could work up to 30 mm depth with field capacity of 0.048 ha/hr and higher weeding efficiency was obtained up to 92.5 %. During weeding operation, the peak heart rate of the subjects was found to range from 142 to 150 beats per min. In case of heavy work and dense grass infested field, the rest pause of 14 min was required by the subjects to come to the normal heart rate. The overall performance of the weeder was promising