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< prev - next > Agriculture Irrigation KnO 100029_The A frame (Printable PDF)
The A Frame is an A shaped
structure made from wooden poles
or thin metal poles that can be
easily constructed and used to peg
flat or graded contours or water
drains. These contours are mostly
used as soil and water conservation
structures. Where rainfall runoff is
less, i.e. less than 600 mm of poorly
distributed rains it is advisable to
make flat contours whereas where
there are chances of water-logging it
is advisable to slightly grade the
contour to allow water drainage.
The justification
There are a number of reasons why
one could choose to use the A
Frame for pegging compared to
pegging with a machine i.e. a kern
level, an automatic level or a
The main advantage of the a frame
is that it can be constructed very
easily using local materials and
literacy is not essential for making
and using it. When farmers are
faced with a developing gully or
erosion in their field they often don’t
Figure 1: Silva Chauque has been using the ‘A’
frame for water harvesting to help improve his crops.
He lives in Tchalefu in the Chigubo District,
Mozambique. Photo: Practical Action /Emma Judge
just look while the soil is being
washed but rather improvise to save the situation. In that bid they often exacerbate the
situation by digging down the slope or make ditches that are very graded. The A Frame at least
assists the farmer to safely peg and construct contours that save the soil. In some countries
those mandated to peg may not have adequate resources like transport and equipment to
service farmers. It is extremely important that farmers know how to peg and dig contours
because contours are very important as they form the first line of defence against erosion and
they are the backbone for all other in field conservation works.
How to make the A Frame
Materials required
2 x 3 metre poles
1 rail (pole) 1.5 metre long
Stone weight or half brick
2.6 metre long string
3 x 5 cm nails or tying wire
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