Monday 8 April 2013

Growing grass to clean a lake

Heard of grass keeping the water clean? In common parlance, this is like asking the wolf to mend the sheep. Water bodies are generally choked by weeds and grass and here the post is taking about grass to clean water and that too in a lake.
Well, this is an experiment being conducted by the Department of Horticulture, Karnataka.
The department hit upon the idea after it had to take up repeatedly the cleaning of the Lalbagh lake, which covers almost 40 acres pf the 240 acres Lalbagh Botanical Gardens.
The lake is not only a source of water for the garden but it also provides an ideal roosting place for several species of birds, some of them migratory.   
The department has already spent crores of rupees on cleaning up the lake which is situated near the Siddapura Gate. After cleaning the lake for the second time in six months, the department decided to take the natural way of keeping the water body clean.
It decided, for the first time in the State,  to make use of grass to keep the lake clean. Vetiveria zizanioides, popularly known as khus grass, was grown around the lake, and it is this grass that will help the authorities to keep the lake clean.
The roots of khus grass have a special characteristic of absorbing the toxins in water and purify it naturally. Since Khus grass is being grown in Lalbagh, the authorities did not need to spend anything on producing it.
The main source of pollution is from the thousands of visitors who come to Lalbagh and then end up throwing plastic, paper, bottles, eatables and even small articles into the water body.
The Vetiveria or Chrysopogon zizanioides, commonly known as vetiver from Tamil is a perennial grass of the Poaceae family, native to India.
It is popularly called Khus in west and north India and it can grow up to 1.5 metres high and form clumps as wide it is high. 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 roots grow downward to a depth of two to four metres. Vetiver is most closely related to Sorghum but shares many morphological characteristics with other fragrant grasses, such as lemon grass (Cymbopogon citratus),citronella, (cymbopogon nardus), and palmarosa (Cymbopogpn martini.
Though it is  a native of India, Vetiver is widely cultivated in the tropical regions of the world. The world's major producers include Haiti, India, China, Java and Reunion Islands.
The most commonly used commercial genotypes of Vetiver are sterile (do not produce fertile seeds), and because Vetiver propagates itself by small offsets instead of underground stolons, these genotypes are non-invasive and can easily be controlled by cultivation of the soil at the boundary of the hedge.
However, a few fertile genotypes of Vetiver have become invasive. They are vegetatively propagated and are used in perfumery, agriculture and bio-engineering.
Today, the Vetiver system, a technology of soil conservation and water quality management, is based on the use of the Vetiver grass.
Vetiver is mainly cultivated for the fragrant essential oil distilled from its roots. In perfumery, the older French spelling, Vetyver, is often used. Worldwide production is estimated at about 250 tons per annum. The reason for its use in perfumery is because of its excellent fixative properties. Therefore, it is present in 90 per cent of all perfumes produced, manufactured and distributed in the West.
Vetiver is a more common ingredient in fragrances for men; some notable examples being Dior Eau Sauvage, Guerlain Vetiver, Zizan by Ormonde Jayne and Vetiver by L'Occitane.
The Khus is also used as a flavoring agent, usually through khus syrup which is made by adding khus essence to sugar, water and citric acid syrup.
Khus Essence is a dark green thick syrup made from the roots of khus grass. It has a woodsy taste and a scent prominent to khus.
The syrup is used to flavor milkshakes and yogurt drinks like lassi, but can also be used in ice creams, mixed beverages like Shirley Temples and as a dessert topping. Khus syrup does not need to be refrigerated, although khus flavored products may need to be
The Department of Horticulture plans to grow the grass on ramps made of bamboo poles, which will float on the lake. The purpose is to keep the lake water clean and use it for irrigating the garden.
The cost of the project is just around Rs. 50,000.


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