SCIENTISTS at the Zonal Research Centreat the College of AgriculturalEngineering (CAE) in Coi-mbatore havedeveloped a motorised machine forweed extraction in fields and orchards.The device claims to bring down thecost of weeding a hectare of cultivatedland by 70 per cent from Rs 2,200 formanual weeding, down to Rs 600 withthe motorised implement.
The machine, which resembles thefront half of a bicycle with a motorrigged above the wheel, is drivenbetween crop rows to uproot the weeds.The machine is suitable for weedingfields of crops like turmeric, tomato,tapioca, cotton, maize, soyabean,groundnut and pulses, as well asfor orchards, coconut and areca nutplantations (Invention Intelligence,Vol 30, No 1).
Says R Karunanithi, head Of CAE whoinitiated work on the research project todevelop the machine, "Weeds destroyabout Rs 420 crore worth of crop annually in India, and weed control is one ofthe most expensive operations in cropproduction. About one-third of the costof cultivation is spent on weeding alonewhen carried out manually."
Karunanithi advocates mechanicalweeding over chemical weeding asweedicides are expensive and selectiveand are often harmful to humans andcrops. Weedicide application alsorequires large quantities of water.
The CAE weeding machine is capableof weeding upto 0.05 ha of land perhour, or one acre in an 8 hour day. Itworks at a depth of 4-5 cm and consurnes I litre of kerosene per hour offield operations.
Says Karunanithi's associate ATaiuddin, "The weeding machine isoperated by a 1.1 kilowatt (1.5 horse-power) engine that requires petrol tostart and kerosene to run. The enginepower is transmitted to a 450 nim diameter wheel through sprockets and chainsin 2 steps so as to have the walking speedof 2.5 km per hour."
A replaceable sweep blade is fixed atthe back of the machine. Sweep bladesof width ranging from 150 to 250 mincan be fitted depending on the row-to-row spacing required. A 150 mm diameter iron wheel with pegs had been provided in front of the sweep blade to disturb the soil and for maintaining thedepth of the blade.
The development of the weedingmachine was financed by the TamilNadu State Council for Science andTechnology. The machine is priced atRs 9,500, and efforts are on to bringdown its cost.