Development and performance evaluation of narrow row spaced weeder

The weeds are undesirable, unwanted plants. Weeding is an important operation in crop production and labour-intensive agricultural operation. Weeding is generally done 15 - 20 days after sowing. Weeding is carried out at the initial stages of crop growth especially for controlling the weeds. After weeding operation, soil earthing-up provides favourable condition for crop growth. Weeding in narrow row spacing is difficult operation with less space between the two rows. In addition to that the soil compaction is the limiting factor due to the rotary motion of rotating blade in dry land weeder hence to avoid this, reciprocating motion type weeder was developed and performance was evaluated in narrow row spaced crop of 200 - 300 mm. The weeder consists of prime mover, ground wheel, power transmission unit, scotch yoke or spading mechanism, spading blade and earthing-up unit. Ground wheels were provided for the stability of the equipment. Scotch yoke mechanism consists of two turning pairs and two sliding pairs which were used for converting rotary motion into a reciprocating motion. The mechanism comprising of four links viz., fixed link or frame, rotating cam disc, connecting arm and spading arm. The inversion is obtained by fixing any one of the links namely as frame. Spading blade was mounted at the end of connecting arm. Earthing-up operation was done with ridger type blade which was provided at rear side of spacing mechanism. The maximum rotating speed of cam disc and forward speed of unit was measured as 125 rpm and 1.5 km h-1 respectively. The power required was calculated as 0.39 kW and bite length of cutting blade is 190 mm. The results for field evaluation of developed prototype weeder revealed that the weeding efficiency, plant damage, actual field capacity and performance index are 78.35 %, 5.1 %, 0.03 ha h-1 and 571.95 respectively. The cost of the developed prototype weeder was ₹35000. The cost of operation of the machine was ₹3871.66 ha-1 compared to ₹6152 ha-1 for hand weeding.