Weeds and grasses pose a major problem to farmers. Similarly in maintaining lawns, the grasses are to be cut above the ground level. The commercially available machines for lawn mowing are costly and as such no machine is available for bush clearing.
A power tiller rotovator has been modified as bush cutting machine for cutting grass and clearing bushes. The machine requires only one operator to perform the operation.
Rotational speed
The sprockets and chain transmitting power to the rotovator shaft are replaced with belt and pulleys to increase the rotational speed of the rotary shaft for cutting the grass and bushes by impact.
The modified machine has 15 numbers of mild steel circular plates of 60 mm diameter welded at the end of 6 mm size mild steel chains of 150 mm length. Each chain is attached to the rotovator shaft after removing the rotovator blades.
Rough grounds
The outer edge of the circular plates are sharpened by smithy and grinding work. The machine can be used on rough ground, wherein the other types of mowers such as cutter bar mower, horizontal rotary disc mower or cylinder mower will not work.
When these mowers are used in rough terrain, the cutting elements will be damaged.
As the rotary shaft rotates, centrifugal force pushes the flails (chains) outward. When the flails encounter any obstacles in the field, it simply bounces off. This fact makes the flail mower best suited for rough areas.
The machine covers 0.10 ha/h (around 2.0 acre/day). The cost of modifying the power tiller rotovator as bush cutting machine comes to ` Rs. 7,000 (excluding the cost of power tiller rotavator).
The cost of clearing bushes using this machine has been calculated as Rs.1,800 per hectare whereas the cost of manual cutting of bushes and grasses is Rs. 4,000 per hectare.
Soil moisture
The equipment cuts weeds and grasses without opening the soil. This enhances soil moisture conservation. Besides, the cut weeds are scattered on the soil surface which act as crop residue mulch.
This machine is useful for orchards, oil palm plantations and to clear parthenium weeds. The equipment can easily be reverted back as power tiller rotovator when desired.
Prof. A. Tajuddin & B. Suthakar
Agricultural Engineering College & Research InstituteTNAU, Kumulur , Tiruchi
