Performance Evaluation of Knapsack Type Roto Paddy Weeder

Abstract

Weeding is the more tedious task of all the labor stages in the farming cycle. To reduce the cost, work stress and drudgery, considering portability, easy handling and small field size of Konkan region, a knapsack type roto paddy weeder was developed. It consists of engine, flexible and rigid shaft, worm gear box, rotor with blade, frame, handle, rotor shaft, throttle lever, mud flap and backpack frame. Weeds cause most yield loss within the first 20–50 days after crop establishment. Hence the developed power weeder was tested after 30 days after of transplantation using the three types of rotors, viz. rotor with 4 L shape blade, rotor with 6 L shape blades and rotor with serrated-flat blades. Its performance was studied for weeding efficiency, plant damage, field capacity and fuel consumption. Its performance was also studied ergonomically. The highest weeding efficiency of 88.24% was found with rotor having serrated-flat blade which was 7.25% and 11.69% higher than rotor with 6 L shape blades and 4 L shape blade, respectively. The rotor with 4 L shape blade had resulted fuel consumption of 0.63 l/h which was 10.79% and 22.59% less over rotor with 6 L shape blade and serrated-flat blade, respectively. The maximum field capacity of 0.034 ha/h was found with rotor with 4-L shape. Considering weeding is the major function of power weeder, the rotor with serrated-flat blades was found to be better over rotor having 4-L shape blade and 6-L shape blade which gives highest weeding efficiency. The developed machine was also tested ergonomically. Six subjects of similar age group and posture were selected during the ergonomic evaluation of developed sprayer. The maximum heart rate of the group was in the range of 180–192 bpm with the corresponding maximum aerobic capacity in the range of 2.36–3.08 l/min. The mean HR max and mean VO2 max value for the subject were 188 (±4.68) bpm and 2.64 (±0.24) l/min, respectively. The average working heart rate (WHR) value of the subjects found in the range between 111.8 and 129.45 bpm with mean 122.45 (±7.03) bpm. The average working OCR ranged from 1.03 to 1.68 l/min with mean of 1.28 (±0.23) l/min. The EER for all the subjects was found to be in the range of 21.51–35.08 J/min with mean of 26.69 ± 4.87 kJ/min. Thus the energy grade of work of found to be of ‘heavy’ category. The work rest cycle was determined as 30-min rest after 30-min work.