For soil
conservation in rainfed agriculture, the World Bank is promoting the replacement
of traditional
earthen bunds
by Vetiveria zizanioides grass. Some observers in India are sceptical and most
are under the
impression
that it is not known to Indian farmers. Subramanya and Ranganatha Sastry found
that this was
not the
case.
S. Subramanya and
K.N. Ranganatha Sastry
As implementing
officers of the khus-based vegetative barrier system for soil conservation, we
were also
sceptical at
first, as the technology has not been tested by researchers. Some questions
which arise are: Can
the grass adapt
to our conditions? What if it spreads like a weed? What if it gets diseased?
What if it is
browsed? Can it
endure for many years? A glance through the flora of South India (Gamble,
1928;
Sambasiva Rao,
1964) revealed that V. zizanioides grows wild in many parts of Karnataka
State. The only
economic uses
stated were extraction of perfumery oil from the roots and using the leaves as
fodder. The
claim has been
made that this plant was never used in India for soil conservation (Anon.,
1988). In July
1988, we happened
to find farmers in some villages of Gundlupet
Taluka of Mysore District using V.
zizanioides
(khus) grass for soil conservation. Inquiries revealed that Vetiver vegetative bunds had already
been farmer
practice for decades. This evidence erased most of our doubts about the
capabilities of the plant
and made us think
there might be more farmers practising this system independently as part of the
natural
innovative
process. We then toured the State, visiting farmers, and made the following
findings.
Independent
selection
The local names
of the plant differ widely between districts, suggesting its independent
adoption. The
farmers in
Maddur, Channagiri, Halalkere, Tumkur and Kadur appear to have innovated on
their own,
seeking ways of
conserving their soils, and eventually selected V. zizanioides. As one example:
the plant is
called "ramancha"
by farmers using it in villages of Gundlupet
Taluka of Mysore District. Even the oldest
farmers (over 80
years) say they used it in their fields since they were young, just as their
fathers did. Where
irrigation and
intensive land shaping were adopted, khus appeared less important for soil and
water
conservation but
it is still used in the drylands. It has been planted in all vulnerable areas
where rills and
gullies would
otherwise have formed. Even on al most flat fields, some farmers plant khus to
mark boundary
lines, as it is a
perennial plant. These lines have remained for several decades. The farmers also
use khus to
protect
waste-weirs and to stabilize drop structures. The farmers regard the fodder
value of khus as an
additional merit.
They said that 3-4 cuttings can be obtained at an interval of 45 days, mainly
during and
shortly after the
monsoon, yielding enough green fodder for two animals for 6 months in a
year.
Farmers'
practices
The farmers have
developed their own ways of multiplying and propagating khus. On sloped land,
they form
small section
bunds across the slope and plant 2-3 slips per rill 20-30 cm apart on the
upstream side. In flat
fields, the slips
are simply planted in the plough furrow. In either case, they chop off the top
of the plant and
avoid planting
inflorescence axles. Khus establishes well if planted after the first monsoon
shower. Even
without
irrigation, the lines form hedges in about a year. The slips for further
planting are taken from 3-year-
old bunds. When
waste-weirs or drop structures are to be treated, even clumps of khus are taken
and placed
at appropriate
locations. During field visits, we noticed a sole case of diseased khus. The
plants had been
affected by
Ustilago raysiae, a smut disease without serious consequence. None of the
farmers regarded khus
as a weed or as
a host for pests and diseases. A few farmers in Tumkur District said that
growing khus
prevented the
occurrence of striga, a root parasite. Khus has long been used by Indian
farmers, but most
scientists are
still unaware of this. The indigenous knowledge of Indian farmers has not been
appreciated.
The knowledge
they have gained in dealing with khus-based soil conservation systems needs to
be
documented and
the other uses of khus, e.g. for fodder, should be studied.
S.
Subramanya
Gavt. af
Karnataka
Vidhanasaudha
Building