The need for low cost rural roads that require minimal maintenance is critical for rural people. USA rural road program in the 1930s helped lift rural areas out of depression and spurred on agricultural growth. Today's developing countries need to develop rural road infrastructure as one of the critical investments to reduce poverty. Recently I was in correspondence with an acquaintance of mine in Kenya on this topic, and thought I would share my letter on this blog as it has important implications:
"There is overwhelming evidence from around the world that the Vetiver System (VS) is an effective and low cost solution for cut and fill, and raised road bed stabilization. Highway examples include China, Italy, Thailand, Malaysia, Vietnam, Congo (DR), Madagascar, El Salvador, Honduras and Venezuela; and for Railways - Australia, China, South Africa, Madagascar, and India are using VS, the latter includes VS in its standard design manuals. Vetiver has also been used in these and other countries for bridge abutment and culvert stabilization (where it always works well). Research has been carried out on the plant's engineering properties - (more than most other grasses?)
Most government agencies and their engineering staff have shown little interest or understanding how VS functions. As an example very few engineers understand that vetiver hedgerows apart from nailing a slope in place also spreads out down slope water flow which reduces the concentration of potential damaging water load, thus spreading out the potential risk of high pore pressure spots, and as a result reduces the chance of slope slippage and slope erosion.
Sometimes engineers turn to their agricultural colleagues for advice - sadly the latter have little to offer, and often through ignorance give the wrong advice. On other occasions those responsible for construction think they know better, apply the technology incorrectly (some times deliberately) and then report failure! It is interesting that where ever the Vetiver System has been correctly applied it has been nearly 100% successful.
The main constraints to using VS on roads have in my experience been: inadequate funding for road slope stabilization, lack of knowledge, lack of supervision, ignorance (planting a grass other than vetiver) , and corrupt practices.
I grew up in Kenya and have worked there. During my recent visit I saw many cases where VS could be used for long term road stabilization. In many instances I saw attempts to stabilize road slopes with other grasses that had failed because of their inappropriateness, over grazing, drought, lack of community involvement, and general misapplication. VS cannot be used everywhere but it could be used on many troublesome sites in Kenya (and all other countries in the tropics and semi tropics).
I understand that one of your reservations is the lack of planting material. This is a Catch 22 issue, and can be easily rectified by advanced planning. There is good quality vetiver planting material in Kenya (I don't know of a tropical country that does not have vetiver), and additional plant material can be very quickly acquired using local farmers to multiply and sell vetiver. I don't know how much you know about the Kenya smallholder tea industry, but I recall that it was initially thought that only commercial and centralized nurseries managed by professionally trained staff could produce good quality tea seedlings for small holders. Not so, within a very short time there were thousands of farmers propagating quality tea seedlings. The same would be true for Vetiver plant material.
In Ethiopia the current accelerating on farm adoption of vetiver for soil and water conservation is farmer driven - neighbors providing the plant material and advice - no conservation engineers or other stumbling bureaucrats needed!! In Madagascar a major slope stabilization of a road approach through a very large "moving" sanddune was successfully fixed using VS. The 30 odd local small farmers who supplied millions of vetiver plants to the road contractors made a lot of money that changed their lives.
Interestingly in Haiti, after many successful attempts by the engineers to block (despite on ground evidence in Haiti to the contrary) VS use on all sorts of spurious grounds, the government, including the Prime Minister, has now accepted that VS should be used for soil and water conservation and road stabilization, because most other approaches have either failed or are too expensive.
Likewise at last years workshop in Ethiopia the overwhelming majority of the 200 attendees from all the major agencies, NGOs, farmers and others supported the use of VS for soil and water conservation and thoroughly rejected the "engineered" fanya ju and other constructed terraces on the grounds of cost, maintenance and lack of discernible farm benefits.
Climate change appears to be effecting Kenya and other East African countries already - more devastating extreme floods and droughts. The beauty of vetiver is that it helps to protect from the damage of extreme rainfall events, and survives drought, and it can be put into place and become effective much quicker than other technologies. My first job b ack in the 1960s was as a conservation officer in Zambia. We used to build small dams and rural roads. I wish that I had known about vetiver in those days. It would have been by far the best technology for stabilizing rural roads, drains, miter drains, culverts and bridges, and for small dam and spillway stabilization.
I have included two photos from a highway trial in Indonesia comparing Vetiver with other grasses, including the fabled Bahia grass. I need not comment on the differences between technologies, they are quite obvious.
One last point, in general, with few exceptions including China and Vietnam, the private sector has made better and more effective use of vetiver than the public (government sector). I have to assume that the two sectors are motivated differently. The private sector is looking to improve its "bottom line" by doing an effective and efficient job that will attract additional contracts, where as government agencies are looking for big budget line items that attract in the short term bigger and more costly contracts, with little attention to long term sustainability and effectiveness.
If nothing else, I would strongly urge that your roads agency sets up some similar trials (under proper design and supervision) to those in Indonesia to prove for itself the value of the technology. Better still go and visit some of the places where VS has been successfully used for slope stabilization".
Dick Grimshaw
The Vetiver System has been instrumental in developing rural roads in various Asian countries. Since soil settlement is a problem that affects rural roads, soil stabilizing is highly recommended. The Vetiver System is one way of keeping the soil intact and maximize road use. Other soil stabilization methods must be applied depending on the technology available for each country, the kind of soil, and as well as the willingness of the government and the private sector to maximize the usability of the soil.
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