Surging success

Twin gains: saving both water< (Credit: The Hindu)AN IRRIGATION system that reduces water
consumption, increases yield and eliminates dependency on rainfall, is nothing
short of a boon for farmers. A novel
method of crop irrigation - surge irrigation - incorporating these features,
is currently under trial on the experimental farms of Tamil Nadu University
of Agriculture in Coimbatore.

What makes this new system worth
a mention is its promise to reduce agricultural water consumption by more
than 50 per cent, while boosting up the
crop yield by nearly 15 per cent. The system, reportedly, has the potential of saving 40 per cent of the present water supply during summer, and upto 60 per
cent during the rainy season.

Sigr@ificarttly, 70 per cent of the net
sown area in India still depends on rainfall for cultivation. The problem is compounded by the fact that rains occur in
heavy showers for short periods and a
large proportion of it goes waste as runoff. The method of surge irrigation,
apart from saving water, also ensures
that minimum land is wasted as irrigation channels. Under the present 'basin
farroV system of irrigation, upto 20 per
cent of the land houses water channels
and hence, goes waste. In surge irrigation, the fields are first levelled
to avoid water stagnation in
depressions. The c*op is then
planted in single or double rows
between furrows that are 60 cm
apart in the former case, and
120 cm apart in the latter. A
water supply channel that runs
at right angles to the furrows
bears a bund that is pierced at
regular intervals by short inlet
pipes. Each pipe is capped on
the channel side to cut off the
water flow when desired.

To operate the system, water is let
out of the source - a tank or a well -
into the supply channel. Starting from'
one end, 'a fixed number of inlet pipes
are uncapped for a fixed time period.
Water gurgles through the pipes and
rushes down the length of the furrow.
The pipes are recapped after the furrows
are adequately filled with water. Studies
indicate that this intermittent water
supply reduces water run-off and deep
percolation losses. Successfully tried out
for sunflower cultivation, the tests are
currently being conducted on maize.

Surge irrigation is, however, ruled
out for closely-planted crops like rice
which requires standing water. It is ideal
for crops like maize, cotton, tomato and
brinjal. With trials of all major crops on
the anvil, researchers are now looking
into means of perfecting the system.