Every year lakhs of public money have been spent to protect soil erosion by using conventional methods like bolder pitching, sand bags, brick – built walls etc. With the increasing number of natural calamity like flood, recurrent public expenditure has been increasing which restrains Govt. to utilize that very fund to create new infrastructure to meet the growing need of our state. Had there been any alternative way to cause for less expenditure to protect the enormous length of river embankments, the fund utilized for them over the years may be used for other purpose.
The problem can be solved in an eco-friendly, indigenous and low cost way. Yes, by using “Vetiver”.
“VETIVER” which is scientifically known as “Chrysopogon zizanioides” (from Tamil வெட்டிவேர்), is a perennial grass of the Poaceae family, native to India. In western and northern India, it is popularly known as “ khus”. In West Bengal it is known as “Khas Khas”. Vetiver can grow up to 1.5 metres high and form clumps as wide. The stems are tall and the leaves are long, thin, and rather rigid; the flowers are brownish purple. Unlike most grasses, which form horizontally spreading mat-like root systems, Vetiver's roots grow downward, 2–4 metres in depth. Though it originates in India, Vetiver is widely cultivated in the tropical regions of the world. The world's major producers include Haiti, India, Java etc. Because Vetiver propagates itself by small offsets instead of underground stolons, it is non-invasive and can easily be controlled by cultivation of the soil at the boundary of the hedge. The Vetiver System, a technology of soil conservation and water quality management, is based on the use of the Vetiver plant. Several aspects of Vetiver make it an excellent erosion control plant in warmer climates. Unlike most grasses, Vetiver does not form a horizontal mat of roots; rather, the roots grow almost exclusively downward, 2–4 meters, which is deeper than some tree roots. This makes Vetiver an excellent stabilizing hedge for stream banks, and protects soil from sheet erosion. The roots bind to the soil. The close-growing culms also help to block the runoff of surface water. It slows water's flow velocity and thus increases the amount absorbed by the soil (infiltration). It can withstand a flow velocity up to 5 metres per second (16 ft/s) approximately. Further Vetiver mulch increases water infiltration and reduces evaporation, thus protects soil moisture under hot and dry conditions. The mulch also protects against splash erosion.
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| Vetiver Plantation |
Besides the above, it is used as medicine, fuel cleaning from soil, aroma and cattle feed. Many a country in the world have been successfully using as a tool to combat soil erosion from the river embankment or from the hills. Once the grass is grown at a certain level, the more the cattle eat the more it grows since swab of cattle contain Lipase which helps Vetiver to grow up faster. In Assam in the downstream of Bramhaputra river, its plantation reportedly seems to be a grand success.
The cost of the vetiver system depends on the design and the site condition. The cost of Vetiver plant is around Rs.1.50 each. In 1 Sq mt some 17+1 = 18 plants are necessary. Experts say that about 170- 200 plants can be planted in one working day. However, more days are required for dressing the slope, fertilizing and maintenance. Also sometimes plants need to be pouched before transplanting in the field. But by all means the cost of planting Vetiver is almost 1/10 lesser to the the conventional guard wall method by using concrete etc.
Khanakul being the worst hit of recurrent flood attacks, the Hooghly district administration headed by the District Collector Sripria Rengarajan, IAS approves first in the history of this state to use Vetiver as a preventive for soil erosion from the river embankments. With this vision, Arindam Niyogi, WBCS(Exe), Sub-divisional Magistrate of Arambagh inspired Suprabhat Chatterjee, WBCS(Exe), a dedicated Block Development Officer of Khanakul-1 Block to exercise the technique on the embankment of the river “Mundeswari.”
Now on the 22 November 2011, the implementation process like dressing of soil and slope making will be taken place with an aim to plant the grass actually within the next 15 days on the embankment of the said river for the first time ever since, at minority prevailed UDNA village of Tantishal Gram Panchayat.
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