Grass Grows 13-Foot Roots of "Steel"

John Roach
for National Geographic News

August 31, 2004

Watching grass grow is never boring for the staff of the Bethesda, Maryland-
based Vetiver Network—assuming the grass is vetiver.

Native to India, vetiver is taking root in a growing number of tropical countries, where it is used as an engineering tool to solve problems from soil erosion to pollution cleanup.

Key to the plant's performance: It grows a thick and seemingly impenetrable tangle of roots that plunge 13 feet (4 meters) straight into the ground. The roots essentially form a wall of steel that prevents erosion-prone slopes from slipping away.

Vetiver is not only cheap to grow but resistant to pests and disease. The grass soaks up pollutants and improves crop yields. What's more, it can grow in any kind of soil on any kind of slope in just about any tropical region that is free of freezing temperatures.

"There's just no negative aspect to [vetiver], and the positives we are learning more and more each time we turn around," said Dale Rachmeler, president of the Vetiver Network.

The network was formed in 1986 to promote the grass as a low-cost and efficient engineering tool, especially for development projects in cash-strapped countries.

Richard Grimshaw is the enterprise's founder and chairman. He says mainstream recognition of the technology has been slow, but notes that in the past 15 years vetiver use has spread to more than 100 countries, about 40 of which now have active projects.

The more people become aware of vetiver's many uses, Grimshaw said, the more people begin to use the grass.

Recently the grass received kudos for its role for stabilizing the slopes along a 101-mile (163-kilometer) railroad track that winds steeply through a dense forest on the African island nation of Madagascar.

Madagascan Railroad

The Fianarantsoa Côte Est (FCE) Railroad serves as the only means of transportation for the more than a hundred thousand rural Madagascan farmers who live between the highland city of Fianarantsoa and the eastern port of Manakara. The farmers grow and export mostly tree crops, such as bananas and coffee.

A study funded by the U.S. Agency for International Development (USAID) found that the railroad also benefits wildlife: The rail line helps preserve a corridor of intact forest that allows animals to migrate between national parks north and south of the track.

In past years erosion has devastated the rail line, however. Four years ago back-to-back cyclones whiplashed Madagascar over a two-month span. The storms sent over 5.3 million cubic feet (150,000 cubic meters) of debris sliding onto the tracks of the FCE railroad, putting the rail line out of service.

Karen Freudenberger conducted the initial USAID-funded study of the Madagascan railroad. She is now leading a 13-million-dollar (U.S.) FCE Rehabilitation Project to restore the rail line. The project will keep the forest corridor between the national parks intact.

Working with local leaders, Freudenberger developed a program to enlist farmers who live and work along the track to grow vetiver hedges to stabilize surrounding slopes.

The program emphasized the farmers' dependence on the railroad and demonstrated the connection between agricultural practices and landslides.

"Once a few farmers began using vetiver, the word got out quickly and the demand for vetiver systems increased significantly," Rachmeler, the Vetiver Network president, said.

Today more than 600 farmers have planted an estimated three million vetiver plants in hedges along the tracks of the FCE railroad. Between rows of vetiver, farmers are growing crops ranging from rice and cereals to fruit trees.

"This year we had one cyclone that did a U-turn and came back again, very similar to [cyclones] Eline and Gloria [in 2000]," Freudenberger said. "Instead of 150,000 cubic meters of debris, we had 300 cubic meters. So our strategy is working."

Stabile Plant

Because vetiver seeds are sterile and the plant's roots grow straight down, the grass stays wherever planted, Rachmeler said.

Vetiver is an exotic grass everywhere except India. But since the plant's seeds are sterile, the grass does not spread like an invasive species. (The plant can be raised from cuttings.)

When vetiver is planted in hedges—as it is in slope-stabilization projects—only water, not soil, can pass through. Over time, natural terraces are formed that are permanently stabilized.

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