Vetiver: The potential Hill protector in Uganda

The use of vegetation in soil and water conservation has been with us for over 5000 years when a Sumerian king issued a decree to use grass for the protection of irrigation and water supply channels and storage dams.

In Uganda tie bands were introduce by the Colonial government which required that tie bands be planted along contours to control erosion and conserve soil against erosion and preserve soil moisture.

Passpalam Nototam was the grass of choice in the East and North of the country. Elephant grass was used only on contours for erosion control, to aid water sink into the soil and reduce surface run off and as mulch. Mulch helps preserve soil moisture, aids water sinking into the soil, minimize weed growth and adds organic matter to the soil. This was popular in the central region where mulching banana plantations helped reduce weeding times.

Of recent elephant grass has been adopted as a fodder of choice among zero grazing farmers. It grows rapidly and responds well to soil water moisture. It also is of good nutritional value for cattle.

Unfortunately, with independence, we thought everything introduced by the colonial government was evil, oppressive and needed to be eliminated.Communities dug up the tie bands making way for soil erosion, soil fertility degradation and waster loss.

In greater Kigezi terraces were removed because they were more fertile than the main gardens. This is detrimental to household food security and sustainable livelihoods.

Government has of recent implemented a soil fertility and soil moisture conservation program in several districts across the country sponsored by DANIDA. In some places contour bands were resurrected in combination with water basins in an effort to help trap any surface run off and to conserve soil fertility.

Population growth, land fragmentation, declining soil fertility, climate change, the destruction of the environment and the evasive Witch weed have combined to exert pressure on the land for human settlement and farming. These have resulted in unprecedented land clearance for farming and settlement. High risk areas have not been spared which have worsened land degradation through erosion, deforestation, absence of fallow periods and in some hilly areas pre-positioning of the land to landslides. The landslides in the Elgon region is a case in point.

One of the worst affected areas of Uganda by absence of vegetation and contour bands are the hilly areas of the country like South Western Uganda, the Elgon area and Ruwenzori region with erosion during the rains degrading once fertile soils.

Problems faced by Uganda in the area of soil and water conservation exist in other countries from which we can learn valuable lessons.

Thailand has taken soil and water conservation to heart through the promotion and use of Vetiver grass as hedge rows to protect soil moisture and minimize water erosion.

Vetiver is the choice grass.

Several factors make Vetiver grass a first choice for water and soil fertility management.

·        It is a densely tufted perennial clump of grass with relatively stiff leaves and you do not have to plant it every season.

·        The leaves are at the base of the plant with leaf sheaths closely overlapping creating a physical barrier at the ground surface.

·        Vetiver is best suited to controlling water during heavy down pours as its tufted sheaths are close to the ground and if well planted will block surface run off reducing its erosive power..

·        It is very well suited to not only a variety of soils but also climatic conditions making it to be widely distributed internationally.

·        It is relatively easy to propagate and establish as it is done vegetatively.

·        It is a low maintenance plant, that requires little space and attention.

·        Is resistant to burning and grazing hence you do not have to fence it off if it is used within paddocks.

·        Has shown little competition with associated plants as is not tall (as Gliricidia sepium or Leuceana Lucocephala) it does not shade any plants in its vicinity but can instead tolerate some partial shading.

·        It can with stand drought, withstand heavy down pours and recover when covered with soil.

·        The straight, deep and none tillering roots require no maintenance and enables the grass take root where there has been little land preparation compared to other tie band vegetation types.

Nutritional Value

Vetiver does not have very high nutritional value as it falls between that of Pennisetum purpureum and fresh maize Stover.

The effectiveness of hedge rows.

Most favorable is the species, density and vigor of growth, and the absence of gapsin spacing. If the vegetation is going to be used in moisture and soil conservation, stabilization of stream banks and gullies, the protection is required at the ground level where the action by water is. A quick establishing, deep rooted grass is preferred that must not cause turbulence that otherwise increases the erosive capacity of the water. In this category Vetiver grass is the best choice plant.

Benefits of Vetiver

Vetiver is widely used in soil and water conservation in India, China, Thailand and in many African countries like Kenya, Zimbabwe and South Africa. It has wide application in tea and fruit plantations, and as contour bands along cultivated slopes.

It has also been used to stabilize rice paddy bands and irrigation channels.

The grass is good for thatch, fodder for livestock, hand crafts from the leaves and brooms from the flowers. Roots are used to make combs.

Some farmers in Ethiopia have used it in the control of invasive grasses like Digitaria Scalarum and Cynadon dactylis.

In Nigeria it is used as land boundary marks while in Ghana it is used as silt traps at dam entrances.

In Mali it is used in helping households have sustainable livelihoods while in the Himalayas it is used to stabilize road sides.

Other uses include dam reservoir stabilization, hedge terraces, pollution control when it holds water back thus curbing the spread of the pollutant as well as land slide control.

In countries like Thailand, China and Nepal; where it is used it has proven cheap for farmers, easy to establish, quick to grow and has some economic benefits like job creation through handcrafts production, thatch material and for mulching and adding organic matter to the soils and thus increasing soil fertility.

Crop propagation and husbandry

In selection of the planting material, plants that have not flowered are used as they grow vigorously.

When establishing a nursery bed soil is prepared carefully to eliminate weeds. Locations with termites, rats or moles are avoided as they could destroy the seedlings.

Material that has 2-3 tillers per slip are and planted fifteen to twenty centimeters deep spaced at forty by forty centimeters between and within rows. Sometimes a spacing of fifteen by forty centimeters is used between rows.

Keep moist to ensure the young plants are not exposed to water shortage. Watering every 3-5 days may be good depending on the weather in the seedling area.

Transplanting is after thirty-five to forty-five days done best at the beginning of the rain season which minimizes losses due to drying out and reduces need for watering.

Before transplanting the shoots are pruned to between ten to thirty centimeters to reduce water loss and twenty centimeters of roots to eliminate planting with roots pointing up.

Planting is in fifteen to thirty-centimeter-deep furrows and soil is well compacted around roots to increase soil contact which aids plant growth take off.

The distance between rows will depend upon the steepness of the slope.

Vetiver pests and diseases

Vetiver has natural enemies like all living things.

Termites are a major problem when there are dry leaves on the plant. Control by removing dry matter. This problem is present in semi-arid areas.

The White grub (Eupledia spp) problem has been identified in Zimbabwe. Stem borers may need some chemical applications. The problem is present in South China, and in Terai in Nepal. Planting none infected materials is a good beginning point.

Holotrichia Serrata has been found to invade the roots as insect herbivores and will later nibble at the leaves.

Rats can be a nuisance where old plants exist or where there are other rat harboring environments.

Two brown sports (Curvularia trifolii) and Gloecercospora Sorghi)have been identified to affect Vetiver in India.

Fusarium spp wilt during the wet season and two hosts specific to Vetiver smuts can be bothersome to the plants.

Writer Abraham Hadoto (hadoto@yahoo.com, Tel 0712814814), @AHadoto