Jua Kali Intermediate Technology

How to Improve Your Spraying Techniques PDF Print E-mail

Using simply made accessories


Most small scale farmers use chemicals for insect and pest control on crops but seldom have experience of chemicals for weed control.

Poor weed control is responsible for major reduction in crop yield potential due to their competition with the crop for moisture light and nutrients. Various hand weeding tools are traditionally used by women and, for any given area, the weeds germinate at the same time so the amount of labour for their control is high and costly or frequently not available.

Weeding is slow with the available tools so that before they are controlled at the end of each plot they have grown large and affected the final yield of the crop.

Chemical weed control has long been used with success by large scale farmers where large areas of the same crop are grown but at the small scale level crops are often on small areas and intercropped with crops susceptible to the chemical.

Farmers often use insecticides and fungicides but seldom use herbicides so have little experience of applying them.

To obtain good results more care is needed to apply herbicides and this information is limited to some additional equipment for herbicide application which can be made cheaply using locally available parts.

The Sprayer
Most backpack sprayers use only one nozzle or jet and this makes covering a large area slow and erratic unless careful marking out with string is used. Spray booms with more than one nozzle may be available but are often very costly so the information given below is for the local manufacture of either a two or three nozzle boom.

A locally made three nozzle boom – Note use of protective clothing


A two nozzle boom showing the spray patterns meeting above the ground


This simple two or three nozzle boom has been made from pvc components normally used for water distribution.

To fit the nozzle a GI ½” cap is drilled and filed to accept the nozzle. A rubber seal or tap washer reduced in size is used to prevent leaks.

The sprayer pump must have sufficient capacity to pressurize more than one nozzle so the spray droplets from the nozzles merge to provide good coverage.

The Sprayer Shield

This simple shield allows weed control between rows but prevents contact by chemicals which would affect the growing crop.

A simple sprayer shield

FileDescriptionFile size
Download this file (Sprayer Shield  Sections D 2.pdf)Sprayer Shield Sections D 2.pdfSprayer shield (2)13 Kb
Download this file (Sprayer Shield D 1.pdf)Sprayer Shield D 1.pdfSprayer shield (1)11 Kb
Download this file (Sprayer Shield Sections D 3.pdf)Sprayer Shield Sections D 3.pdfSprayer shield (3)8 Kb
Download this file (Three Nozzle Boom D 4.pdf)Three Nozzle Boom D 4.pdfThree nozzle boom19 Kb
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