Madagascar's extension service now recommends vetiver for on-farm soil and water conservation in combination with other measures such as contour cultivation, dead furrows, continuous vegetative cover, and crop rotations. On slopes under 5 percent, where burning is not practiced, a grass called "kisosi" (a species of Panicum, see Appendix B) is also recommended.
In these combinations, vetiver is employed as a first line of protection, not only against erosion but also against ground fires. It complements agriculture, horticulture, and reforestation. With well-established vetiver lines, for example, many other kinds of land uses that lead to soil conservation are being developed: annual crops, perennial crops (notably fruits and fodders), and reforestation, for example.
Although at first skeptical, the forestry research department10 is now supportive. It changed its position when tests on its own sites showed that vetiver by itself slows runoff as well as a dense forest cover could.
In a number of Madagascar's rural areas, farmers have discovered for themselves vetiver's effectiveness for stabilizing dams, rice-field bunds, and irrigation works, as well as for protecting roads that can flood and wash out.
Bredero's next major challenge is to prove vetiver's usefulness in preventing the devastating gullies and ravines (known as lavaka in the Malgache language) from chewing up more land. They are so big and there are so many of them that the sandstone formations north of the capital and around Lac Alaotra constitute an alarming sight.
Bredero is now tackling the problem from two sides. First, vetiver is planted on contour lines around the upper edges as well as down the sides of the ravines to slow down and disperse runoff coming from the top of the mountains. Second, wooden poles are driven into the sand at the bottom of the ravines. The soil retained by these wooden palisades is planted with vetiver, bamboo, and fast-growing and fire-resistant trees and shrubs.11 The result is a dense vegetative cover. About 10 of these pilot-sized watershed-protection projects are now established, and early experiences seem encouraging.
The final verdict on vetiver is not yet in, but this grass just might be the answer to Madagascar's raging erosion—one of the worst local environmental problems on the planet.