Driving out weeds
SCIENTISTS at the Zonal Research Centre
at the College of Agricultural
Engineering (CAE) in Coi-mbatore have
developed a motorised machine for
weed extraction in fields and orchards.
The device claims to bring down the
cost of weeding a hectare of cultivated
land by 70 per cent from Rs 2,200 for
manual weeding, down to Rs 600 with
the motorised implement.
The machine, which resembles the
front half of a bicycle with a motor
rigged above the wheel, is driven
between crop rows to uproot the weeds.
The machine is suitable for weeding
fields of crops like turmeric, tomato,
tapioca, cotton, maize, soyabean,
groundnut and pulses, as well as
for orchards, coconut and areca nut
plantations (Invention Intelligence,
Vol 30, No 1).
Says R Karunanithi, head Of CAE who
initiated work on the research project to
develop the machine, "Weeds destroy
about Rs 420 crore worth of crop annually in India, and weed control is one of
the most expensive operations in crop
production. About one-third of the cost
of cultivation is spent on weeding alone
when carried out manually."
Karunanithi advocates mechanical
weeding over chemical weeding as
weedicides are expensive and selective
and are often harmful to humans and
crops. Weedicide application also
requires large quantities of water.
The CAE weeding machine is capable
of weeding upto 0.05 ha of land per
hour, or one acre in an 8 hour day. It
works at a depth of 4-5 cm and consurnes I litre of kerosene per hour of
Says Karunanithi's associate A
Taiuddin, "The weeding machine is
operated by a 1.1 kilowatt (1.5 horse-power) engine that requires petrol to
start and kerosene to run. The engine
power is transmitted to a 450 nim diameter wheel through sprockets and chains
in 2 steps so as to have the walking speed
of 2.5 km per hour."
A replaceable sweep blade is fixed at
the back of the machine. Sweep blades
of width ranging from 150 to 250 min
can be fitted depending on the row-to-
row spacing required. A 150 mm diameter iron wheel with pegs had been pro
vided in front of the sweep blade to disturb the soil and for maintaining the
depth of the blade.
The development of the weeding
machine was financed by the Tamil
Nadu State Council for Science and
Technology. The machine is priced at
Rs 9,500, and efforts are on to bring
down its cost.