Cultivation and Care of Vetiver


	1. Vetiver grass




	Vetiver hedgerows



	Vetiver cultivation around a pond

Vetiver is considered to be a rapidly growing variety of grass. It grows vertically tall and in thick clumps. It has a long fibrous root system which is knitted strongly together like a net in the soil. The roots penetrate vertically 3.0 m. deep and horizontally 0.5 m. under the ground; it will not affect the root system of other plants. Serving as an underground barrier, the roots hold the soil together, retain water, as well as filter and absorb plant nutrients, and hazardous chemical substances which resultingly help to reduce pollution in the environment. Contour planting of vetiver across the slopes and along the road shoulders help trap silts and filter crop residues, while only letting parts of water to flow through. This effectively reduces soil erosion and prevents surface soil from being washed away. Vetiver is also planted around the base of fruit and perennial trees on the plains, and on dry, deteriorated area in order to preserve rainwater in the soil. Vetiver leaves are also used for mulching to maintain soil moisture. In other cases, vetiver is planted around the reservoirs and ponds, and along irrigation canals, and ditches, in order to prevent siltation of these water sources and equally important, to impede toxic chemicals present in the catchment areas from contaminating the water sources.
However, it is necessary to take proper care of the planted vetiver in order to successfully achieve the above-mentioned benefits. Summary of appropriate steps for planting and taking care of vetiver grass are described in this booklet.


	2. Vetiver Cultivation


	2.1 Vetiver cultivation areas

	As stated before, vetiver grass is grown because of its multi-purpose benefits, for example, to prevent soil erosion, to preserve soil moisture, to rehabilitate deteriorated land etc. However, if growing vetiver will be for propagation purposes, then it is necessary to select an area with high fertility and plenty of water and sunlight. Such conditions enhance vetiver growth performance and allow it to grow new clumps very quickly. Therefore, vetiver cultivation to achieve different purposes can be described according to selected areas for cultivation. 2.1.1 On steep slopes The area should be steep slopes that do not serve as a watershed and where farming or logging activities are being carried out, such as on highland or slash and burn farms. Under this type of topography, vetiver should be cultivated along contour lines across the slopes or in a semi-circle around each tree facing uphill like a "Huang Sui" (a Chinese grave, with a semi-circular tombstone in masonry or concrete), in order to reduce soil erosion. Vetiver will effectively perform its duty if the cultivation is carried out following a well-designed cultivation plan; that is they should be planted in a number of rows suitable to the steepness of the slopes and farming areas. Moreover, in a single row they should be planted closely together. 2.1.2 On flat land The purpose of vetiver cultivation on flat land is to use the leaves for mulching so as to preserve soil moisture and conserve rainwater in the soil. Another benefit from mulching is to restore deteriorated land by enriching the organic contents and allowing the translocation of minerals in the lower layers to the upper layers of the soil. Vetiver is also cultivated on flat land for propagation purposes. For this topographical condition, vetiver grass can be cultivated in any single or integrated patterns such as in rows, semi-circle, circle etc.




	Vetiver cultivation on critically deteriorated land



	Vetiver cultivation in a semi-circle pattern




	Vetiver cultivation around a new pond



	Vetiver cultivation in deep gully eroded area

2.1.3 With critical conditions
Areas that are susceptible to being easily eroded are the edges of existing or new ponds, road shoulders, around the dams or reservoirs, and along gullies, hills, roadsides etc. Due to the extent of damage to the areas, vetiver cultivation should be carried out in dense clumps. The soil should be fertilized to enhance growth performance while the clumps should be trimmed to allow side growth and tillering. The thicker the clump, the more effective it will be in trapping silts from runoff and in preventing erosion of road shoulders and pond edges after a heavy rain. For a deep eroded gully, vetiver should be planted in an inverted "V" shape and extend along the length at different altitude levels in a fishbone pattern, with 1.0 m. vertical interval in order to retard gully erosion and allow water to penetrate into the soil. Another pattern is to plant vetiver horizontally across the gully to trap silts which eventually fill up the gully. On critically deteriorated land, it is vital to shape vetiver clumps and strengthen them by planting more rows and accelerating growth performance using fertilizer, which thus effectively retards heavy runoff. The vetiver species which is suitable for gully area cultivation is Vetiveria zizanioides with ecotypes like Sri Lanka, Songkhla 3, Kamphaeng Phet 2, Surat Thani etc. These ecotypes have strong stems which easily grow new budding and rooting at the internode that can resist gushing flow of water.


	Vetiver cultivation also helps prevent siltation of water sources and chemical substances from flowing into the water sources, thus controlling water quality to be acceptable for daily consumption and for raising aquatic animals. The methods of cultivation vary according to the types of water sources as follows:

	- Around reservoirs : Three rows of vetiver should be planted around reservoirs. One row should be grown around the edges at the water detention level. Another row is then planted 20 cm. vertically above the first and the third row 20 cm. vertically below the first one (normally the water will not reach the detention level). - Around ponds : Two rows of vetiver should be planted 50 cm. away from the pond edges and from the water entrance passage. - Irrigation and drainage canals : Vetiver is planted in rows along the irrigation or drainage canals with a 50 cm. space away from the canals. - Road shoulders : Vetiver cultivation helps to prevent the damage of road shoulders and erosion caused by rain. The rows should be lined parallel to the road shoulders at a distance of 30-50 cm. to prevent car accidents due to poor visibility.




	Sri Lanka ecotype



	Vetiver hedgerows to trap silts


	2.2 Cultivation area preparation and contour line design

Preparation depends upon the local characteristics of the area. For instance when planning to grow vetiver along contours across the slopes, it is necessary to use proper instruments or hand-made tools to determine the contour levels. Hand-made tool will be effective as well as cheap, and in some cases, when materials are available, it will not cost anything. This tool is made by forming wood into a triangular shape (A frame), one which is commonly used in the southern region of Thailand to determine the contour lines across slopes for growing para rubber. Another tool easy to use is a rubber hose with a diameter of 1/4 of an inch and the length of 13 m., together with 2 laths at a length of 2.50 m. Mark the laths in centimeter in order to read the water level height. Then fasten the hose along the laths with its ends parallel to the ends of the laths. After that, place the two laths on flat surface land and fill water into the hose until both levels on the laths read 100 cm. This simple tool can be used to determine the distance between the vetiver rows and also the contour lines across the slope.

       When establishing the inter-row spacing for contour cultivation across the slopes, the distance is set at 1.50 m. vertically. This can be done by using the rubber hose to locate the highest or lowest point first. With one of the laths, one must mark from the highest point 1 and then move downwards until the other lath, placed in the ground, reads a water level at 150 cm., marking point 2, which is 50 cm. below point 1. Then move the initial pointer stick from 1 to be at 2 and descend the other stick until it reads a water level of 200 cm., marking point 3 which is 100 cm. below point 2. Therefore adding up the distance from points 1 to 3, it amounts to 150 cm. or 1.50 m. as set. This is the location of the first vetiver contour, and so repeat the same steps to derive the other contour lines.
       After the inter-row distance has been determined, the next step is to shape the contour by using the same tool. But for a better reading, it is recommended to add water until the levels at both ends of the laths read 150 cm. (close to human eyes' level). The steps begin with placing one stick at the first point (point 1) of the contour determined earlier. Then move the second stick by stretching the hose to full length (13 m.) across the slope and place on the ground where the water level reads 150 cm. Repeat the steps by moving the first stick to where the second stick (point 2) is marked and stretch the hose across the slope to another point which also reads 150 cm. Continue until the whole slope is marked and a contour is determined. The next contour lines can be done by following these same steps.
       Then in the final step, the contour lines should be slightly adjusted by moving the various fixed points to form a smooth curve which makes ploughing and crop cultivation easier. Not only that, it also enhances the capacity to retard heavy runoff and prevent erosion at reflexed points. However, the beginning and last points should remain where they were determined initially.


	2.3 Soil preparation around vetiver hedgerows

After the contour lines have been adjusted, use a ploughing machine or a cattle to plough the soil thoroughly at a depth of about 10 cm. and crush the soil particles to make them smaller. Although vetiver can grow in deteriorated or low fertility areas, it would be more productive and achieve quicker growth if the soil is enriched with fertilizer or compost of 15-15-15 formula at the rate of 25 kilograms per rai (or use 1 kilogram of fertilizer for a contour of 4-6 m.).


	2.4 Tiller preparation

The tillers which are prepared for transplanting are developed in small plastic bags (5x15 cm.) and are about 45 days old. These tillers are removed from the bags, planted closely together in the hole, and then carefully covered the roots with soil. In some cases, the tillers from the planted vetiver is used for further multiplication. Preparation of vetiver for cultivation to prevent soil erosion involves digging up the whole clump and then cutting off the roots and culms to about 10 and 20 cm. in length, respectively. The shoots are separated and bound together in bunches and the roots are soaked in water for about 5-7 days. The vetiver can be replanted once the new roots start to grow.


	2.5 Vetiver hedgerow cultivation

Once the soil has been thoroughly mixed with compost or manure and chemical fertilizer, remove the 45-day old tillers from the bag and place them in the hole along the contours with about 5 cm. inter-plant spacing. However, if the plantlets with free roots are used, then only 2-3 tillers are planted at an interval spacing of 5 cm. for each hole. The plantlets prepared in the plastic bags have greater and faster growth potential than those with free roots because their root system has already been developed for a while within the bags. However, planting plastic bag tillers on very steep slopes is more difficult and unfavourable because it takes too long and requires extensive labor. Therefore, it is more common to grow plantlets with free roots on the slopes because it is more convenient to transport, light and cost effective.
The planting season regularly starts at the beginning of the rainy season when soil moisture is adequate. But for irrigated areas, the vetiver should be planted before the rainy season arrives because it will have more time to grow strongly and be capable of filtering silts and retarding runoff to prevent soil erosion. It takes at least three months for the vetiver to grow into big and dense clusters, thus creating a strong wall.




	Cultivation rows with an inter-plant spacing of 5 cm.


	3. Taking Care of Vetiver




	Leaves should be trimmed to obstruct the elongation of the internode



	Dead vetiver tillers should be timely replaced


	In order to realize the benefits from vetiver cultivation, it is necessary to take reasonable care of the grass once it is grown. This includes replacing the tillers which have died and trimming the leaves in order to obstruct the elongation of the internode. Such measures will stimulate the growth of vetiver into thick clumps and its leaves are used as mulch to preserve moisture.

	3.1 Replanting vetiver

	After one month of cultivation, it is important to check the condition of the living barrier. If vetiver tillers are found dead, then it is necessary to replant them at once in order to prevent gaps in the rows. Gaps will reduce the effectiveness of vetiver in trapping crop residues and silts, and its capacity to retard and absorb water during a heavy rain. Water will then overflow rapidly and erode the area thus creating a deep gully. Replanting vetiver timely helps to strengthen the living barrier and effectively filter the silts.

	3.2 Shaping vetiver hedgerows

	Once the vetiver is fully grown which is after approximately three months, its apex or leaves should be cut to a level of about 30 cm. above the ground so as to accelerate shooting and forming of new thicker clumps. As for the cut leaves, they can be used as mulch to help reduce evaporation, maintain soil moisture, and for other productive purposes. It is advised to trim the leaves every one to two months to obstruct the elongation of the internode and foster tiller growth in denser clumps.


	4. Summary


	The following are ten recommended guidelines to proper cultivation and care of vetiver. 1. Once vetiver tillers are discovered dead, it is vital to replace them at the earliest opportunity when the climatic and soil conditions allow, such as availability of water supply, rainfalls, or soil moisture. 2. During the rainy season, the leaves should be cut once every 60 days or before an elongation of the internode. For the dry season, cut the leaves when deemed necessary. 3. The leaves cut from vetiver which has been planted along contours across the steep slopes are to be placed above the contour lines. For vetiver which has been planted in rows or in a circle around the bases of the fruit and perennial trees on flat land, the leaves are to be placed in between the rows or at the tree bases respectively. 4. After having been grown for 3-4 years some vetiver tillers may die because they have been trimmed only a few times or the internodes are allowed to elongate and flower before trimming. It is then advised to cut the vetiver in the dry season to almost the ground level and they will emerge new shoots again when the next rainy season arrives. 5. For the purpose of soil and water conservation, vetiver should be planted tightly (for plantlets with free roots) or not more than 5 cm. apart (for plastic bag tillers). Again, the dead ones should be replaced at once for effective conservation results. 6. For vetiver cultivation on deteriorated land with low fertility, it is recommended to fill the bottom of the plant hole with manure or compost. Once the tillers start to sprout, 15-15-15 chemical fertilizer should be added to accelerate growth at a rate of 25 kilograms per rai (0.4 acre), along the contour or above each one for slopy areas. 7. Vetiver cultivation in rows, semi-circle, or circle, should be kept at a distance of at least 1.5-2.0 m. from fruit and perennial trees plantation. 8. It is not recommended to plant vetiver in a thick forested area or where fruit and perennial trees have grown maturely covering the area. 9. Climbing weeds grown around vetiver should be removed quickly because they will interfere with the growth performance and also block sunlight from reaching the vetiver. 10. For propagation purposes, vetiver should be planted in a fertile area or otherwise, 15-15-15 fertilizer should be added at a rate of 25 kilograms per rai (0.4 acre). In addition, the leaves should be trimmed regularly to prevent the roots from overgrowing which makes it difficult to dig up and remove the tillers for replanting elsewhere.

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