Vetiver System for Erosion Control in India - a Home Grown Technology

Vetiver hedgerows have been used by some Indian farmers for generations for soil and water conservation, forage, structural strengthening and boundary delineation. Sadly most officials involved with soil conservation in India conveniently neglected these facts. Below is a short brief by two professionals who didn't! At that time (1980s) the World Bank for soil conservation in rainfed agriculture, promoted the replacement of traditional earthen bunds by Vetiveria zizanioides grass. Some observers in India were/are sceptical and most were under the impression that the technology is not known to Indian farmers. Subramanya and Ranganatha Sastry found that this was not the case. . Here are their findings.

"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 almost 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-year­old 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, Bangalore 560 001 India

K. N. Ranganatha Sastry, Visvesvaraya Centre, Dr. Ambedkar Road Bangalore 560 001 India"

Dick Grimshaw