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Current Category » Practicals on Weed Managemet

Types of Sprayers

A) Knapsac Sprayers:

Loaded on the back of worker during operations.  Tanks may be plastic or metal. Common Knapsack sprayers are

i) Hydraulic

ii) Manual pneumatic and

iii) Motorized pneumatic.

i) Hydraulic Knapsac Sprayers:

Manually operated, tank capacity is 15 liters, mechanical or hydraulic agitation, worked with a hand lever to maintain constant pressure, particularly used for spot treatment small holding farmer and hand treatment. Equipped with a boom. It is good for blanket application.


These sprayers are mounted on back of man. One hand to lever and other to lance with a lance, one sprays 0.4 ha/day and with a boom 0.8 ha/day. It is high volume spray but low volume nozzles can be fitted. Spray potential is 12 kg/cm2. It sprayed at 3 to 4 kg cm2 to prevent spray drift.

ii) Pneumatic or compressed system Knapsac:

Do not require pumping during operation / spraying. The tank is pressurized after filling the liquid to 2/3rd capacity with a built in hand pump. Undesirable for weedicide spray pressure lower after some time spraying resulting into uneven spray. Tank cleaning is difficult. Used limited to spray on weeds in paddy and jute.

iii) Motorised Pneumatic sprayers:

As a low volume sprayer suitable for spraying concentrated spray liquid. A blast of air flows through spraying jet of delivery hose and nozzle tube and ejects spray liquid in this blast. Air blast atomizes spray liquid in to fine droplets. Air acts as carrier. Faster the air is pressured, more the atomization. These sprayers are also used as blowers. Mist blower cause considerable loss of herbicide by winds. The main advantages of Knapsac blower are:
1. Low volume spray. Loss of time in refilling tanks.
2. Portable working.
3. Fast spraying. Suited to post emergence translocated type. Herbicides as low volume
Spraying is not so uniform with Knapsac blowers.
Liquid – 60 liters / ha swath 7 to 8 m.

B. Foot Sprayer / Pedal Pump Sprayers:

Popularly applied for pesticide application operated with foot. It has provision of 1 – 2 long delivery hoses. Fitted with either lance or 2-6 nozzle booms. Its potential spray pressure is 17 to 21 kg / cm2 output with lance is 1 ha/day. It can spray high volume spray and covers more area.

C. Traction Pneumatic Sprayer:

Indian Institute of Sugarcane Research, Luck now has developed bullock drawn sprayer with size nozzle boom that of powered from the wheels of the frame. It is efficient, easy to operate and simple in its construction. It uses two pneumatic pumps and develops maximum pressure of 2-8 cm2 which his suited to minimize spray drift. Area covered 2-3 ha/day equipment.

D. Tractor mounted sprayers:

With spray pressure of 1.4 to 2.8 kg cm2 and fitted with multi nozzle boom are very useful in herbicide application for large holding of farmers. Tractor mounted sprayer fitted with booms are used to spray road side vegetation. Tractor run sprayers have.

1. High uniformity of sprayers.

2. High working efficiency.

3. Full utilization of tractor during idle time.

E. Acrial sprayers:

Herbicide application from air is limited to treat aquatic weeds like water hyacnth, paddy fields, large sugarcane plantation. Presence of obstacles like trees and diversified farming in India are bottle necks in its use.

Current Category » Practicals on Weed Managemet