An ideal plant for soil and moisture conservation in Tea Plantations In India.

 P Haridas

Tata Tea Limited 

Few resource problems are so important and so little publicized, as the disappearance of soil from our land. Each year millions of tons are washed away to the rivers and sea by erosion. There is no way we can replace this soil. If we wait for the natural processes to do the job, it would take centuries, if not millennia. Yet, because it is a silent problem, few give it the attention it deserves. It is not an issue that excites public opinion. Soil erosion is a quiet crisis, largely man made disaster that is unfolding gradually. The changes it brings are chronic and irreversible : lost land, reduced productivity of farms, plantations and forests, silted rivers, reservoirs, canals and irrigation works, washed out roads, bridges and destroyed agricultural land where myriad valuable micro-organisms would normally breed and prosper. Soil erosion is getting worse in warmer parts of the world. Here the swelling population, poor land management, vulnerable soils and hostile climates add up to lethal combination that fosters erosion bringing with it environmental degradation, rising deforestation and erratic water supplies. The world’s forests are disappearing 30 times faster than they are being planted. Such immediate and far reaching consequences have led to its recognition in almost all countries as one of the most serious agricultural problems of the world. Suffice to say, soil erosion is literally costing the earth. It is with this scenario in mind that many people around the world who were concerned about the environmental problem became intrigued by the ideas of a couple of world Bank Agriculturists, Richard Grimshaw and John Greenfield. These two had an entrancing vision: a little known grass called Vetiver, they proposed , could provide the answer to soil erosion - and it could do so in a way that would appeal to millions of farmers, land owners, politicians and administrators.

There are many soil conservation measures but the most outstanding of these is the use of vegetative soil and moisture conservation measures that are cheap, replicable, sustainable and fully effective in stopping erosive degradation and increasing crop yield. The use of vegetation as a bio-engineering tool for erosion control and slope stabilization has been implemented for centuries but its popularity has increased in the last few years. Many studies all over the world have shown that Vetiver as a hedge is the ideal plant to conserve soil and rehabilitate eroded land. This grass has been used for soil and water conservation in agricultural lands for many years but its related impact on land stabilization, soil erosion and sediment control only started in the late 1980s following its promotion by the World Bank.

During the heavy rains nothing strikes a traveler in the hilly tracts of Western ghats more than the scouring of the fields by the run off and enormous loss of best portion of the top soil. If only the surface drainage was controlled this loss of fertile soil would stop and time would be given for the water to soak into the soil. The remorseless ecological degradation of the Brahmaputra valley over the past many years is a national disgrace. In spite of numerous conferences, committees and formulation of action plans the riverbanks have become sand traps and soon the river will be biologically dead.

The problem of soil erosion in Tea plantations in South India and North East India is getting worse over the years. Considerable expenditure is being incurred by estates in these regions due to works on water management and soil erosion. Although specimens of Vetiver grass and its sporadic use could be seen in some tea gardens its commercial use as soil and moisture conservation grass is yet to be fully recognised. To line it out across the hill slopes in tea plantations in South India and along the periphery of tea fields adjacent to river banks, streams and drains in North East India will be a new and innovative concept. It is heartening to see that estates in High Range in South India have taken initiative in adopting Vetiver Grass Technology (VGT) for soil and moisture conservation in tea plantations. There in the next 3-4 years, the Vetiver system of soil and moisture conservation will demonstrate its effects sufficiently to leave no doubts that this is the system of future. It is cheap to install, replicable, and sustainable. Thus as a planter/farmer based technology it is not difficult to introduce it at a wider scale for an extended range of applications in tea gardens.

In their struggle for survival, certain plants and animals have evolved fantastic, sometimes unbelievable, adaptations. Vetiver grass is one such plant. It is a climax plant capable of growing over an extremely wide range of soils and climate. It meets all the criteria of a vegetative soil conservation plant. Vetiver grass is not just another grass, it is a special grass – like bamboo is a special grass. When people think of grass, they think of their lawns, fodder grass or as useless as grass! But none of these match up to Vetiver for persistence and freedom from problems.

The Plant : Vetiver, belongs to the same part of grass family, Gramineae as rice, maize, sugarcane and lemon grass. Its botanic name is Vetiveria zizanioides. The generic name comes from "Vetiver" its name in Tamil meaning "root that is dug up". The specific name "zizanioides" means ‘riverside’ which reflects the fact that in the remote past the plant was commonly found in the riverbanks along the waterways in India. The plant is native to India where it is known as Vetiver, Vetivert, Khus or Khus Khus. Its common names in other languages are Ilamichamver, Vettiver(Tamil), Ramacham(Malayalam), Vattiveeru(Kannada) Birina(Assamese)Khas-Khas(Bengalee), Bala, Bena, Khas, Panni(Hindi). It has been used in our country since ancient times and is recorded as a medicinal plant in the Ayurvedic science. For several centuries Vetiver has been commercially cultivated for the scented oil that is distilled from its roots. In North India villagers weave these roots into mats, baskets, fans and ornaments. They also weave them into window coverings that freshen the air of village homes with a severe and penetrating scent. The roots and oil are known to repel insects. People in India and elsewhere have long used Vetiver roots among their clothes to keep insects away.

The Vetiver Grass Technology(VGT),in its most common form, is simply the establishment of a narrow(less than 1 meter wide) live stiff grass barrier, in the form of a hedge, across the slope of the land as shown in diagrammatic sketch.(Fig.1) When applied correctly, the technology is effective on slopes from less than 1 to over 100%. A well established grass hedge will slow down rainfall run off, spreading it out evenly, and will trap runoff sediments to create natural terraces. Vertical intervals can be more accurately decided by observation. This is something the planter can do; if rills start to develop below or above the hedge- another barrier can be planted to intercept them. The system is very user friendly. All this is possible with out the use of complex hydrological data and design, and without the aid of high cost consultants and surveyors. In China its use has extended from agriculture to engineering and mechanical devices are being replaced. It has been used successfully to stabilize flood embankments, river and canal embankments in many countries. In the early part of last century the sugar industry had recognized the value of Vetiver grass for conservation purpose and it was used in the West Indies and South Africa for this purpose. Although The sugar industry has used Vetiver grass as a vegetative soil conservation measure in isolated parts of the world for the past 50 years, it has gone unnoticed by researchers, even in the same countries. It has been overlooked by lecturers and professors teaching soil conservation. Strangely, it has never been a subject of any research. Yet over 200 years, it has been used by farmers in India as a permanent hedge. It has been free of problems and dense enough to effectively filter silt out of runoff.

Thus Vetiver seems to combine several characteristics that make it special.

• When planted correctly, V.zizanioides will quickly form a dense, permanent hedge which will reduce water flow velocity.divert run out water and form a very effective filter.
• It has a strong fibrous root system that penetrates and binds the soil to a depth of 3 meters and can withstand the effects of tunneling and cracking.
• It is perennial and requires minimal maintenance.
• It is practically sterile and because it produces no stolon or rhizomes it will not become a weed. It will not compete with the crop plants it is used to protect.
• It has stiff and erect stems which can stand up to relatively deep water flow(0.6-0.8m.). As its crown is below the surface it protects the plant against fire and overgrazing.
• Its sharp leaves and aromatic roots repel rodents, snakes and similar pests.
• Its leaves and roots have demonstrated a resistance to most diseases.
• Once established ,it is generally unpalatable to livestock. The young leaves, however, are palatable.
• It is both xerophyte and hydrophyte and once established it can with stand drought, flood and long period of water logging.
• It is cheap and easy to establish as a hedge and to maintain as well as to remove if it is not wanted.
• It will grow in all types of soil regardless of fertility, pH or salinity. It is highly tolerant to toxic levels of aluminium, manganese, arsenic, cadmium, chromium, nickel, copper, mercury, lead, selenium and zinc.
• It will grow in a wide range of climates. It is known to grow in areas with average annual rainfall between 200 and 6000 millimeters and with temperatures ranging from 1to 45 degree C.
• It is a climax plant and therefore even when all surrounding plants are destroyed by drought, flood, pests, diseases, fire or other adversity, Vetiver will remain to protect the ground from the onslaught of the next rains.

Method of propagation and planting.

Vetiver in cultivation rarely produces seeds. In vetiver literature, several terms have been used, sometime indiscriminately, to designate the parts of the vetiver plant that can be used in propagation.

• Tiller : (1) A shoot growing from the base of the stem of a plant ; (2) A shoot, especially one that sprouts from the base of a grass : (3) A shoot sprouts from the base of the stem of a vetiver plant. Tiller is the most popular part of the vetiver plant used in propagation since it is available in large quantity, employs simple technique, and gives good result. (Fig.2)
• Slip: (1) A stem, root, twig, etc cut or broken of a plant and used for planting or grafting; cutting; scion; (2) A part of a plant cut or broken off for planting; a cutting; (3) A shoot cut off from a vetiver clump used for planting. Many people use this term synonymously with tiller. Some even erroneously call it a ‘root division’ (in Vetiver, the structure from which the slip grows is the base of the stem, not the root. The term ‘tiller’ is more appropriate to describe the planting material.

• Culm: (1) A stalk, stem; the jointed stem of various grasses, usually hollow; (2) The stem of the grass; (3) The above-ground part of the stem of a vetiver plant. The culm of the vetiver grass is strong, hard, and lignified, having prominent nodes with lateral buds that can form roots and shoots upon exposure to moist condition. Laying the cut pieces of culms on moist sand, or better under mist spray, results in the rapid formation of roots and shoots at each node.

• Cutting: (1) A slip or shoot cut away from a plant for rooting or grafitng; (2) A part of stem removed from a plant to propagate new plants, as through rooting; (3) Vetiver culm cut into sections with at least one node each used to propagate new plant. Although commonly used as propagating material in horticultural crops, cutting’ is rarely used in vetiver. This term is probably synonymous with cut culm or culm-cutting.

• Clump: (1) A cluster, as of shrubs or trees; (2) A thick grouping, as of trees or bushes; (3) A cluster of tillers developed originally from a mother plant of the vetiver in all directions. In vetiver, a clump is formed when a plant has been grown for a certain period and produces numerous tillers in all directions.

Of all these parts, only the first and the last (tiller and clump) are used extensively in most vetiver growing countries to propagate the vetiver grass, simply because they are the convenient parts to be used in propagation. Besides, the cost of their production is relatively lower than that of the other parts while the success is higher. Of the remaining structures, culm and clump are also used in propagation to some extent.

While preparing the planting material the tillers are usually separated from the main clump. Dig out the clumps of Vetiver cutting the roots off about 20 cm below surface.Cut off the leaves about 25-30 cm. above the root and break the clumps into planting pieces or tillers taking care to discard dead tillers. Prepare the multiplication plot well by cultivating and getting rid of weeds. The area need not be leveled as Vetiver tillers are extremely hardy. There should be moisture in the soil while planting the tillers.The tillers 3/pit are spaced at 40 cm apart. This wide spacing in multiplication plot/nursery gives each plant ample room to tiller or produce more planting material. In the first two months when the plants are getting established weed the area to keep the weeds under control. Once the plants started to grow vigorously, cut the leaf to about 50cm. Cutting encourages "tillering"and produces more planting material in a short period. Plants grow faster and produce more tillers if fertilizer is applied. A mixture of 1:1 NP may be used to give 40 kg NP/ha. Always plant Vetiver in the wet season to ensure that they get full benefit of rain. A spacing of 15-20 cm may be given in order to form a hedge in areas where it is desired. (Fig.3). Only a single row of tillers,3/pit, need to be planted. Once the hedges are established the only care needed is trimming to a height of about 30 cm.

Like its relatives maize and sugar cane Vetiver is among the group of plants that use a specialized photosynthesis. Plants employing this so called C₄ pathway use carbondioxide more efficiently than those with the normal (C₃ or carbon cycle) photosynthesis. For one thing, most C₄ plants convert carbon dioxide to sugars using less water, which helps them to thrive under dry conditions. The plant is insensitive to photo period and grows year round where temperatures permit. It is best suited to open sunlight and will not establish easily under shady conditions. However once established plants can survive in shade for decades.

All these may seem strange but there is more! Vetiver grass grows so densely that it can block the spread of other grasses including some of the world’s worst creeping grasses. In Zimbabwe tobacco farmers reportedly plant vetiver around their fields to prevent invasion of other tough grasses. In Mauritius sugar cane growers rely on Vetiver to prevent Bermuda grass from penetrating their fields from adjacent road sides. In High Range, for example, a Vetiver plot established at Kundaly in early 1990s kept Kikyu grass (Pennisetum clandestinum) from creeping in. Obviously establishing Vetiver hedge along the periphery of tea fields could prevent invasion of deep rooted tough grass weeds. This aspect will be of particular interest in the context of Kikyu grass control in organic tea cultivation.

Indeed the excitement surrounding Vetiver grew so much and the implications of using it seemed so astounding that people queried the sincerity of those who were discussing it with such zeal !

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