Development of Power Weeder for 3 Row-Planted Paddy

Weeds are the major reason for the significant yield reduction problems in rice cultivation of Sri Lanka. Power weeders have been introduced to rice cultivation as an alternative solution for the controversial herbicide application. The effectiveness of existing power weeders is also low due to the associated rotary mechanism. Besides, “Asakura wooden clog” has been identified as an appropriate weeding mechanism, which could be developed as a power weeder. Therefore, this research was aimed to introduce an appropriate lowland power weeder, especially for medium and large-scale rice farmers in Sri Lanka using the weeding mechanism of manual “Asakura wooden clog”. comprehensive design calculations, fabrications, series of performance tests and modifications were carried out to achieve this goal. Final version of prototype consists of power source, frame and separate mechanisms for power transmission, weed burying, turning/row changing, floating, manipulation and controlling which are facilitated to bare the activated load, burying the weeds, achieve the required tractive power, speed and machine control in road and field manipulation. Besides, it attained satisfactory field performances; 0.03 ha h-1 effective field capacity, 83.25% field efficiency, 80% weeding efficiency, 6.34% damaged plants, 580 performance index. Further, calculated cost for weeding, fuel consumption, labour and power requirement were 38.355 USD ha-1, 0.503 L h-1, 33 man-h ha-1 and 0.319 kW, respectively. Further, no ergonomic or mechanical defects were reported during the performance testing. Thus, this prototype has a potential to develop as an appropriate machinery for weeding processes in medium and large-scale, row planted rice cultivations in Sri Lanka