Agriculture Reference
In-Depth Information
Fig. 3.7
Stone wall fence
this type of fence will depend upon the availability of stones and the average distance
of their transportation. Sometimes stones may have to be quarried or pried off the
ground using the crowbar, in which case the cost may go up.
A ditch-cum-bund fence is an appropriate choice where soil depth is not less than
1 m. Soil should be medium to heavy and not very light or sandy, in which case neither
the section of the ditch nor that of the bund will remain stable. If gravel or friable soft
rock is encountered at lower depth and is available in adequate depth, it constitutes
the most stable ditch fence. Ditch fence is not suitable in areas with excessive and
irregular ground slopes. Flow of water will erode certain sections of the ditch and
fill others with earth; consequently, the fence will be rendered ineffective. In case
of saline soils prone to waterlogging, care should be taken to make provision for
drainage of surface water. Being labour-intensive work, this type of fence generates
a lot of employment, and is often easy to maintain. Sections of a ditch fence may vary,
but it is better to adopt one of the standard sections and then adhere to it throughout
the programme.
A barbed-wire (BW) fence is recommended for sandy soils, where none of the
fences discussed earlier will be feasible. Since varying number of wire strands and
posts of different materials and sizes can be used in its design, this type of fence
has the advantage of being flexible in size and specifications. The disadvantages of a
BW fence are that it can be costlier and that it does not generate local employment.
It is also not eco-friendly because the large amount of steel used—if not carefully
removed later—can be a long term pollutant. In some cases wild animals like the blue
bull (
Boselaphus tragocamelus
) pose such a great risk to plantations that stone wall
and ditch-fence either will not be effective or will be prohibitively costly (if very large
sections are used). In such special cases, a BW fence of higher specifications may be
used. In areas prone to vandalism this type of fence will not be successful since it is
vulnerable to theft, pilferage, and wilful damage. The economics of a BW fence can
be made comparable to that of the other two fences if the fencing material—namely,
the angle-iron posts and the barbed wire—is carefully removed and re-used after
establishment of the plantation. At least three cycles of re-use may be considered
practically useful, thus enhancing the overall utility of the costly material.
Electric fence (energized fence) can be considered in areas where wild animals,
rather than humans and livestock, are the main threat to plants. Electric current is
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