John Greenfield's World

WATER - CLIMATE CHANGE - FLOODS

noreply@blogger.com (greenfield) — Fri, 28 May 2010 04:12:00 +0000

WATER - CLIMATE CHANGE - FLOODS

In the United States, withdrawals from the Ogallala Aquifer for irrigation amounted to 26 cubic km (21 million acre feet) in 2000, which is slightly greater than the historical discharge rate of the Colorado River. As of 2005, the total depletion since pre-development amounted to 253 million acre-feet (312 cubic km, or billions of tonnes). With this amount of water/weight being withdrawn from its position under ground, surely the earth's gravitational field could be affected which in turn could have an effect on the climate??

As we have learned, in the "Economist's" special report on water, the amount of water is 'finite'. Let's just take the US alone. It has added 253 million acre feet to the Earth's existing surface water. As a fossil aquifer, water from the Ogallalah could have been safely buried under ground in its aquifer for centuries, it is now being exposed to the elements for evapotranspiration adding to the water vapour in the atmosphere, which comes back as rain - another 312 cubic km of it. No wonder the world is experiencing some massive flooding, and this is only one aquifer.

Scores of countries are overpumping aquifers as they struggle to satisfy their growing water needs, including each of the big three grain producers—China, India, and the United States. All this water is being added to the atmosphere to be returned as heavy rain, causing floods.

For fossil aquifers—such as the vast U.S. Ogallala aquifer; the deep aquifer under the North China Plain, or the Saudi aquifer—depletion adds water vapour to the atmosphere and brings pumping to an end. Farmers who lose their irrigation water have the option of returning to lower-yield dryland farming if rainfall permits. In the more arid tropical regions, however, such as in the southwestern United States or the Middle East, the loss of irrigation water does not necessarily mean the end of agriculture, if they use the vetiver system to their advantage.

Just a thought.

John
May 28th 2010

WATER

noreply@blogger.com (greenfield) — Thu, 27 May 2010 02:48:00 +0000

WATER

In the Introduction to the first edition of my “Little Green Book” (Vetiver Grass - A Method of Vegetative Soil and moisture Conservation) 27 years ago, I wrote a paragraph on the importance of Water and how the groundwater reserves were being pumped dry, how the vetiver hedges held the runoff giving it a chance to soak in to the soil, find and recharge those aquifers, where as the constructed system of conservation was designed to divert the runoff to the drainage network thus wasting it. In later editions of the green book, for some obscure reason, that paragraph was edited out. Let me repeat here, the importance of water in view of the present paralysing world population explosion.

The “Economist” Magazine’s issue May 22nd 2010 has an excellent hard hitting special report on “Water”. Nature has decreed that the supply of water is fixed; meaning that while the demand for water rises inexorably as the world’s population is exploding, a point will ultimately be reached where there will not be enough water to go round.

The article states that “Meeting the demand for water is a different task from meeting the demand for almost any other commodity”. One reason is that the supply of water is finite , however the law of conservation of mass states that however you use water, it cannot be destroyed, neither can it be readily made.

Throughout the ‘special report’ there is no recommended solution to this problem of water shortage, while it goes on to discuss the inexact terminology used in the media and elsewhere , concepts like efficiency, productivity and saving, attract woolly thinking. Efficient irrigation; describing systems that result in 85% of the water disappearing as vapour, half the world’s wetlands have disappeared over the past hundred years. How Dams are silting up etc. most of the problems outlined in the report can be addressed by the use of strategically placed vetiver hedges controlling runoff. No other system of conservation that I know of comes anywhere near the efficiency of the vetiver system for conserving our precious water.

This fact was brought home to me with our project in Andhra Pradesh, India, in the 1980s, hectares of farmland were abandoned to forestry projects, where Eucalyptus trees were being planted on the bare soil rolling hills as the only trees that could withstand the dry conditions. I asked the project staff why they had abandoned this land for agriculture and was told that the rainfall had diminished to such a point that Eucalyptus was the only plant that would now survive. Nonsense!

On the project area they had a D6 Caterpillar Bulldozer equipped with a three tined ripper and were using the blade to ‘shave’ all the other growth off the area to "conserve moisture" for the trees. They were making no attempt to conserve runoff. I took the Bulldozer, angled and tilted its blade, ripped a line across the slope and on the return trip created a “V” ditch with the tilted blade, along the ripping. These “V” ditches paralleled each other eight meters apart down the slope; they were planted with Eucalypts and I planted vetiver hedges along their base to take over from the “V” ditch bunds once they had ‘melted’ with age. At the time the Project Staff could see no use for this operation.

When I returned to the area six months later after the monsoon, we were all amazed to see the results. Young Teak trees (Tectona grandis) had appeared from nowhere like mushrooms, the Project’s forester did not know that Teak had grown in the area maybe 100 years ago, the survival of the Eucalypts had increased from the usual 8% to over 96%; the local villagers were amazed to see their little streams had started to flow again for the first time in living memory. All this, from the simple conservation of runoff.

It is essential that reports like this one in the Economist, on water, are written to alert the public to a major future problem that we must face, it is a pity that they do not have a solution to the problem of how to feed and water this massive future population, it is an even greater pity that they have totally ignored the potential of the Vetiver System, where their billons of dollars of aid could be efficiently used to address the problem.

John
May 27, 2010.

noreply@blogger.com (greenfield) — Tue, 11 May 2010 00:10:00 +0000

Soil Conservation Measures

Comparing the old with the New

The standard system of soil conservation measures, originally devised in the US, functional there and in the low rainfall areas of Europe and other temperate zone countries, in my opinion is not appropriate for the high intensity rainfall areas of the tropics, which of course it was not designed for, but is being recommended for.

This blog will argue that too much time is spent noting the causes and measuring the effects of erosion in the tropics without actually developing sustainable techniques for preventing or controlling it. Too much time is spent and money wasted on conferences debating the causes of erosion without ever reaching a conclusion on which is the most effective way of controlling it; that temperate climate methods of controlling erosion have been continually and inappropriately applied to the tropics often with disastrous results and further; that the Vetiver System of erosion control in the tropics is not only ‘eco-friendly’; is cheap to apply and if correctly installed, virtually 100% effective making it the only system sought after by the subsistence farmers themsleves. Vetiver hedges last longer, (200years and still growing in India,) than any man made conservation measures but the system, as a sustainable means of stabilising tropical soils, is still ignored by academia and Governments. Why? it is not a weed, the clone of Chrysopogon zizanioides is totally sterile.

Much of the research being carried out on the causes of and remedies for erosion throughout the World is based on static measures of conservation such as terracing; retainer walls; rock rip-rap; masonry walls; gabions; contour banks; diversion banks, waterways; gully plugs; silt traps; tree planting, etc all technologies developed for and used to some effect in temperate climate low intensity rainfall areas. For example, the tropics can experience London’s 650mm annual rainfall in one day, so measures designed for that rainfall, can hardly be expected to work in areas receiving five times that amount.

In a report published by the East-West Center “Soil Conservation Strategies for Upland Areas of Indonesia”,1989. Paper No. 9. Brian Carson conducted a major study of erosion problems and measures for controlling them in Indonesia (in the wet tropics) in the 1980s and made recommendations for strategies to address those problems. Although the Vetiver System had been in practice for many years when the study was undertaken, it might have been unknown to Carson or considered a strategy not worth including in the study, which, for some obscure reason, is a problem we have with the East West Center in Hawaii, their refusal to credit the Vetiver System.

An example of an “appropriate” sub-package that swept Indonesia for conservation at the time of the study was the use of grasses, such as Setaria sphacelata for strengthening terrace risers and for livestock fodder. Setaria on terraces proved to be totally useless, but was the basis of FAO’s (the UN Food and Agricultural Organisation) “Solo Conservation Project” that failed miserably and was abandoned as the terraces eroded.

For 'controlling erosion', measuring everything seems to be the order of the day, even repeating measurements that have already been made for ‘Erosion control factors’ – ‘Field Observations on Erosion’ – always measuring, measuring, measuring but fixing nothing is what FAO; the Government Conservation Departments and the Aid agencies are good at. Why spend years measuring erosion to develop some hokey meaningless erosion formulae? For example; Soil Erosion Assessment: The ‘Useless’ Soil Loss Equation (USLE) where A = RKLSCP* and you can feed that twaddle in to your computer and you never need to get your feet muddy again. USLE was developed for gently sloping agricultural land in the United States and in my estimation is meaningless, even in the States. It is armchair mathematicians trying to put formulae to natural processes as unstable as soil erosion and climate in the tropics – forget it, there are too many banana skins in that equation, its utter rubbish. Visual observations leading to control measures leaves the Formula findings for dead. In the tropics especially, erosion is a dynamic process that cannot be ‘fixed’ with static systems of control, or analysed by formulae.

(*The USLE is composed of six factors to predict the long-term average annual soil loss (A). The equation includes the rainfall erosivity factor (R), the soil erodibility factor (K), the topographic factors (L and S) and the cropping management factors (C and P). The equation takes the simple product form - A = RKLSCP )

What are they Measuring?

The strategies Carson described, were typical then and are typical now of the thinking today. Soil characteristics including texture, percentage of organic matter; structure and porosity can markedly affect the erodibility of soil and consequently affect the design of static conservation measures.

Rainfall erosivity; soil erodibility; slope length and steepness; cropping factor; .

As the Text Books say: “One way to determine the rate of erosion is to try to measure the amount of soil being moved” – why not put that effort in to stopping the soil from moving in the first place. Major errors are made in estimating soil erosion for the hilly regions of any tropical country prior to designing control measures, but that doesn’t stop the practice.

River Problems:

High sediment loads of rivers quickly reduce the useful storage capacity of man-made essential reservoirs and silt up irrigation canals. Sedimentation within river channels results in reduced discharge capacity exacerbating annual floods that cause great hardship for farmers or townships on the alluvial plains. It is stated in Carson’s report that “The lack of good sediment data in tropical rivers is a major problem for the researcher, why??.

If the river has got obvious silt in it, find out why and reduce the source with strategically placed vetiver hedges in the catchment area, what’s the point of measuring it? it is already history when its in the river. Towns and farmland are often protected from flooding by Levees or Stop-Banks, but Rivers that move through a meander plain are difficult to control by these measures, and Levees have a habit of ‘bursting’ in floods because they are unprotected from over topping. Planting vetiver hedges along levee banks, even with only one hedge along the top, one along the middle of the levee, and one along the base, does a great job of protecting these Levees from braking down. There is no other system in the tropics that can protect Levees so well.

When the river in a meander plain bursts ‘free’ of its Levees to find another natural course, the expensive Levees are left in the field high-and-dry as a monument to man’s stupidity. When a river leaves its old course to meander in a new area, the vetiver hedges that protected its banks can be dug up and planted along its new banks, so little is lost.

Mass Wasting

Research has been carried out on the causes of “mass wasting”, Landslides/ mud-slides; processes of erosion with engineers stressing soil mechanics; geologists stressing rock type; hydrologists pointing to prolonged precipitation; and foresters emphasising deforestation. Mass wasting processes of erosion are a complex result of a number of interdependent factors. Thus, not surprisingly diverse opinions appear in literature and the academics need the “USELESS” formula to design their controls. Simple, strategically placed Vetiver hedges can handle all these problem areas.

Increasing population pressures are resulting in accelerated surface erosion through the opening of vegetation protected soils to annual cropping. The major problem facing the World today is over population. Over the past century, increasing proportion of soil loss has been attributable to accelerated erosion induced by increased population on a limited land resource, resulting in ‘mudslides’ causing massive waste of land and life.

This brings to question the issue of static control measures which require access to large sections of the farmers land if these measures are to function correctly. Diversion banks must be channeled at the correct fall to a safe outlet which could be kilometres away. As agricultural productivity declines and the returns decrease, the famer loses interest in terrace, contour bank or waterway maintenance, so slope degradation occurs at a greatly accelerated rate.

The Role of Forests/Jungles

The role of forests and tree planting in soil conservation management is often misunderstood. Although well-managed forests provide for optimum conservation, badly managed forests with no undergrowth, and the indiscriminate planting of pine trees or poplar ‘poles’ to control erosion can be much worse than many existing agricultural uses. Trees themselves do not control erosion, their undergrowth and leaf litter does.

The most successful soil conservation strategies observed by Carson were developed with little thought to soil conservation, but emphasized increasing agricultural profitability. The Vetiver System is in this category, get the farmers interested in a way of increasing their production at little cost.

Carson found that the government of Indonesia has been strongly committed to controlling erosion through the conventional static soil conservation programs. However high Indonesian officials and villagers alike generally agree that these conservation programs have fallen short of expectations. With that result it is no wonder Indonesian farmers are not really interested in “soil conservation”.

Finally some facts to consider:

A study, conducted by Dr.David Pimentel, Professor of ecology at Cornel University. pulls together statistics on soil erosion from more than 125 sources, and he reports:

• The United States is losing soil 10 times faster -- and China and India are losing soil 30 to 40 times faster -- than the natural replenishment rate.

• The economic impact of soil erosion in the United States costs the nation about $37.6 billion each year in productivity losses. Damage from soil erosion worldwide is estimated to be $400 billion per year.

• As a result of erosion over the past 40 years, 30 percent of the world's arable land has become unproductive.

• About 60 percent of soil that is washed away ends up in rivers, streams and lakes, making waterways more prone to flooding and to contamination from soil's fertilizers and pesticides.

• Soil erosion also reduces the ability of soil to store water and support plant growth, thereby reducing its ability to support biodiversity.

• Erosion promotes critical losses of water, nutrients, soil organic matter and soil biota, harming forests, rangeland and natural ecosystems.

• Erosion increases the amount of dust carried by wind, which not only acts as an abrasive and air pollutant but also carries about 20 human infectious disease organisms, including anthrax and tuberculosis.

The above facts show it is time we stopped talking about erosion control, measuring its effects in the tropics and invested in the natural vetiver system. Over the last fifty years it has proven itself without a reported failure.

On the average, vetiver costs only 30% of the simplest static systems to install; once established there are no maintenance costs, and it lasts decades if not centuries.

RULE of THUMB:

1 To control erosion, you must control runoff!

2 Don't tell farmers that you have come to show them how to conserve their soil, tell them that a simple way to increase their yields by 30 - 50% by planting vetiver hedges that will store the rainfall as moisture in their fields and this can even help in drought prooing their crops.

John Greenfield

May 10 2010

misguided aid to the third world

noreply@blogger.com (greenfield) — Sat, 20 Mar 2010 02:02:00 +0000

Misguided Aid to the Third World.
The ‘Poverty’ gap

“The road to hell is paved with good intentions.” It most certainly is.

80% of Third World poverty occurs among the rainfed farmers and their extended families in the tropics. Over forty years spent on the ground in these countries has exposed me to a huge range of well-intentioned aid agencies, donor countries and myriad alphabet agencies from the UN. University researchers, engineers and theoretical economists from all the above have been battling for decades to come up with a workable solution to the poverty and hunger in these areas, and are still battling. I have met many outstanding individuals of every creed and hue over the years, but these brilliant minds are no match for the lack of coordination and different demands and agendas of the many and various donor agencies involved in every developing country.

Donor countries with no experience in the tropics send their ‘experts’ into the field and make multi-million dollar investment in schemes that are not sustainable and therefore doomed to fail right from the start. Heads of government and UN departments listen to economists who have no field experience and allocate aid according to their assumptions. “History repeats itself”. It has to, because we never seem to listen. Look at the massive Groundnut Scheme dreamed up by the British Government after the Second World War. The remnants of that disaster can still be found in Tanzania today. That was in 1946-48, almost 60 years ago and still these organisations haven’t learned from these failures.

In my experience, a major reason for this failure is the myth perpetrated by successions of aid experts from the developed countries that the poverty of subsistence farmers is the result of a complex historical process that does not lend itself to simple or quick solutions. Economists are introduced to explain the situation, and anthropologists to analyse farmers’ needs, and then engineers to construct interventions developed for temperate climes, without ever seeming to reach an understanding of the basic problem.

It is an interesting fact of history that very advanced agricultural civilisations developed and flourished in some of the most arid zones of the world – in the Near East, North Africa and Central America – and then disappeared. Either because they failed to conserve precious soil and water, or because they used irrigation schemes that lacked a drainage component, which resulted in the salinisation of the most fertile alluvial areas.

Generally speaking, there are two methods of farming – ‘irrigated’ and ‘rainfed’. The world’s population is growing at a rate of around 1.7% annually and by as much as 4% in parts of Africa. Irrigated land accounts for around 20% of worldwide cultivation and 40% of global crop production. However, the cost of irrigation and drainage in the 1990s averaged around $US 10,000 per hectare but could be as high as $US 25,000 per hectare in the drier parts of Africa. Can developing countries really be expected afford to establish and maintain irrigated agriculture?

It is quite obvious that the additional food production needed in future years must come from the 80% of cultivated land that is rainfed and that the only way to address the hunger and poverty situation on a sustainable basis for subsistence farmers in the tropics is through moisture conservation. Making the best use of the rain that falls in the area. The average subsistence rainfed farmer today, because of increased pressure on the land, can lose up to 60% of his rainfall as runoff to the drainage network, which results in major flooding in the delta areas (Bangladesh for instance). This runoff also carries off his soil and what little nutrients are left. An annual rainfall of 1000mm is thus reduced to an effective rainfall of only 400mm, which, if poorly distributed (arriving at sporadic intervals) is incapable of sustaining a good crop and another “drought” is declared.

Over the years, many organisations have recognised the need to control runoff and consequent soil erosion and loss and have invested much effort and money in rainfed regions to address the problem mechanically, employing a battery of engineering solutions that have included contour banks, diversion banks, absorption banks, waterways, low dams and water harvesting schemes. All these have proved to be unsustainable in the long term. The subsistence farmer has neither the equipment nor the labour at his disposal to maintain such schemes and further, has issues with the amount of productive land such schemes take out of production.

The upshot of all this aid into rainfed areas has been increased erosion, lack of production leading to lack of food, increased poverty and because of increased runoff virtually no recharging of the underground aquifers that supplied fresh water to village wells or sustained perennial streams. The resulting floods from the runoff are getting horrendous.

The little country of Lesotho, in Southern Africa is a classic example of a well-intentioned constructed soil and water conservation system that has virtually destroyed the country. Diversion banks and waterways have eroded into gullies and canyons, making it impossible for farmers to cross from one side of their fields to the other. Erosion is out of control. Lesotho has been abandoned by the aid agencies that have left the country to its fate, never admitting their mistake.

Man’s efforts to intervene in nature have failed miserably. We are too impatient. We want an immediate ‘quick fix’, to bring in the bulldozers, get paid and get out. The results are engineering disasters worldwide. Stop banks that are expected to control rivers in a meander plain, ending with the river ten metres above the town. Diversion systems that deprive an area of its natural runoff, concentrating the runoff in drainage networks that were never meant to handle it. All of these systems requiring massive construction and maintenance costs before ultimately failing completely and disastrously.

What subsistent rainfed farmers need throughout the tropical world is ‘in-situ’ moisture conservation to produce their crops on a sustainable basis; in situ moisture conservation to produce their fuel wood; in situ moisture conservation to replenish their aquifers.

A natural system of moisture conservation that is simple; cheap to install; costs nothing to maintain; will last for decades at no cost; does not require any cooperation from their neighbours, or their government and does not interfere with their neighbours’ agricultural practices. Decades of field trials and research by dedicated scientists, extension workers and organisations across the globe have proved there is an alternative, cheaper, biological solution to the complexity of high-cost engineering and structural designs that require drawn-out bureaucratic accounting and bidding procedures to resolve our erosion and pollution problems. It is a grass – a quite remarkable and astonishing plant known as vetiver grass (Vetiveria zizanioides).

Runoff severe enough to cause erosion, landslides and mudslides is a dynamic system that cannot be controlled by static measures such as gabions and retainer walls. Use nature to control nature.

Vetiver is a unique grass that when planted as a single line can form a stiff dense hedge that prevents erosion; forms natural terraces; increases soil moisture; does not compete with companion crops; once established can withstand droughts, fire and floods and will grow on highly acid or alkaline soils; can reclaim mine dumps; stabilize road cuttings, embankments and river banks and is cheap to propagate and plant out, requiring only hand tools. A plant whose roots can absorb surplus nitrates and phosphates; can tolerate high levels of toxic elements such as arsenic, mercury, aluminium, and manganese; a plant that can protect dams and harbours from siltation: a plant proved to increase crop yields through moisture and nutrient conservation; a plant that only grows where Man plants it and will never become a weed. These hedges will grow anywhere on any soil in the tropics (and subtropics), and once established will last for more than 100 years.

Over the past twenty years, the Vetiver Network has had a major impact in the private sector and through NGOs (Non Government Organisations) worldwide promoting vetiver ‘contour’ hedges to subsistence farmers in rainfed areas. The Vetiver System is breathtaking in its simplicity and it works.

The Vetiver Network website (www.vetiver.org) provides a wealth of information, evidence, case studies and extensive references for all those willing to open their minds and tackle sustainable development in a truly sustainable manner.

John Greenfield

Director
Vetiver network
20 March 2010.

pacific islands at risk

noreply@blogger.com (greenfield) — Sat, 20 Mar 2010 01:53:00 +0000

Strategic Planning Essentials:- Water
Food
Fuel

The Sustainable Solution: Dense hedges of a grass that is non-invasive; non-competitive; lasts for centuries under the most extreme natural conditions and conserves the essential moisture for the sustainable production of crops – Vetiver Grass (Chrysopogon zizanioides )

The Protection of Tiny Ocean Islands Facing Future Climate change:

Ocean Islands, no matter whether they are in the Pacific, (the World’s largest area of scattered tiny Islands) or anywhere else in the world, as long as they are between the Latitudes of 30° North or South of the Equator, will depend on the Vetiver System for their future survival as viable habitats. Below is a copy of an unsolicited letter from Ethiopia, a country recognised world wide for its problems of famine that the UN and the world have battled to address. Ethiopia as a country has a landmass of over 1 million square kilometres, as opposed to the tiny area of Ocean Islands of maybe 2 – 300 square kilometres with no access to more land. Despite all the work of well intentioned Aid Agencies and the millions upon millions of dollars spent trying to find a solution to Ethiopia’s problems of famine, the farmers themselves recognised Vetiver hedges (The Vetiver System) as the best solution to their problems of susutainable subsistence.

Acceptance by farmers: (extracted from an unsolicited report on the Vetiver System) “Subject: Status report on the use of Vetiver Grass for soil and water conservation by GTZ IFSP South Gonder, Ethiopia 2004”.

“Vetiver has been planted alongside previously existing physical structures such as stone bunds, and also on untreated farmland, along the contour. In both instances, farmers were pleased with the performance of the vetiver, reasoning that it conserves soil and water, and provides practically immediate benefit by way of forage, thatching and mattress-stuffing material, green leaves for use in traditional coffee ceremonies, and as a potential source of further income. Farmers also appreciate the low labour requirements for hedge establishment, as well as the minimal maintenance needed in comparison to physical structures.

Farmers remove physical structures on their land after the vetiver hedges are sufficiently established, stating that these structures are obsolete due to the fact that the vetiver hedges efficiently trap soil and conserve moisture without occupying more land than is necessary, and that rodents thereby have no tendency to multiply after their breeding places (stone bunds) have been removed.

To enlarge on this last point, farmers insist that vetiver has a dramatic effect in reducing rodent numbers. This effect has been reported and observed in both the Ganwuha and Tach Gayint watersheds.

Agricultural experts have confirmed that farmers are placing a high priority on vetiver in the field of soil and water conservation. Many farmers from outside project intervention areas have also proceeded to treat their own farmland with vetiver obtained from intervention areas.

According to project estimates, about 2,500 hectares have already been treated via vetiver hedge establishment with project assistance. This figure rises to more than 3,000ha when farmers introducing their own interventions without project assistance are taken into consideration”.

This is a unique case of the farmers themselves adopting a scheme that the farmers can see will work over all the other inputs of countless Aid Agencies, and these Ethiopian farmers are desperate to feed their families.

Think: Water – Topsoil – gardens - fuelwood – coconuts - fibre – thatching material – shell fish – fish and Turtles - barrier reefs; small ocean islands used to have all these essentials – now these commodities are threatened especially when you take climate change in to account. They are threatened by increasing soil loss and runoff and at present, no way to control it. This is exacerbated by over population.

I developed the Vetiver System (VS) 50 years ago for the Fiji Sugar Industry to stabilise farm land in the Fiji Islands, it was extremely successful and is still there today. This system is fully applicable to all other tropical developing countries in order to sustain agricultural production in every aspect. This system also sustains the production of fuel wood and the recharging of the essential natural aquifers, the protection of barrier reefs from excess runoff and soil loss and preventing navigable harbours from silting up.

The standard methods of constructed soil conservation still being taught at temperate climate Universities throughout the world, do not work in the tropics and especially in tiny ocean islands exposed to short duration, high intensity rain storms and hurricanes. The constructed system of ‘conservation’ is expensive to install, because of its design characteristics, takes up too much land to be properly installed, is short lived and is extremely expensive to maintain. The constructed system is designed to collect runoff, divert it to a safe outlet and dispose of it ‘safely’. This is the last thing a rainfed farmer on a small tropical island wants. The constructed system because it acts like a drain, is also the worst system for replenishing freshwater aquifers in these tiny Island atolls. Rainfall must be evenly distributed over the surface so that it can find access to the aquifers and replenish them before being lost to the sea as runoff.
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Recently, in the South Pacific, we have seen the devastation of the little Island Niue as a result of a 300+ kph hurricane. We have had storms of greater magnitude in Central America (Cyclone Mitch) where farms with vetiver hedges were protected and not devastated, those without vetiver protection ended up as mudslides (see below). Look at our website < www.vetiver.org >. (Please note, this is a philanthropic organisation, not a Company)

The Island of Niue is typical of so many of these little islands and atolls, it is 260 square kilometres in size has 4,108 ha of arable land of which 470 ha are, or were in permanent crops. For sustained viability, this land and the surrounding marginal land will need stabilising to prevent soil loss and runoff. This can only be done in the tropics using the vetiver system of hedges across the slope, around the island which, once established, are permanent and effective barriers to soil loss and runoff. Ocean Islands depend on rainfall to replenish their aquifers, usually on ‘perched-water tables’. In their natural state, these little Islands had some jungle cover which provided fuel wood and building material, but more importantly the jungle’s undergrowth and leaf-litter spread the rainfall run-off out, slowed it down, gave it a chance to seep in to and replenish the natural aquifers before it ran in to the sea.

With greater population pressure in recent years, tourist resorts, paved roads, airport runways etc. these jungles and especially the undergrowth have been destroyed. Gardens which used to produce sufficient food to mix with the fish and shell fish from the reef and lagoons are now producing little. Run-off is uncontrolled, top soil is disappearing fast and where it enters the sea, polluted, it kills the reef. Not only are food stocks going down but due to pollution, fish stocks are diminishing also. Where the barrier reef is damaged, there is no protection from the next hurricane, and the storm waves can now be devastating.

In their present state, these islands can be supplied with food, health needs and infrastructure by Aid Agencies and the ‘outside world’, but we cannot supply them with sufficient water (or soil), nor keep up the supply. Rainfall must be controlled so that it isn’t wasted as runoff; this is the only way to ensure water supplies to these little islands and keep them habitable. Very few of these little Islands have any rivers or streams, they depend on rainfall to replenish their ‘perched water-tables’, and the only way this can be done is by controlling the runoff and giving it a chance to soak in to the ground.

Vetiver hedgerows can be very valuable in preventing erosion and water damage to tracks, wells and gardens within housing areas, and in protecting roads (even against Tsunamis which will go over the hedges and not under them). The hedgerows should be coupled with urban tree planting in housing areas, which could serve as shade as well as a source of timber; food; fuel or forage. When planted along embankments and in catchment areas, vetiver hedgerows can also reduce erosion of roadsides. If there are streams in the country, the hedgerows are also extremely important in permanently reducing stream bank erosion and sediment loads entering streams, reservoirs and harbors. The massive root system of the vetiver plant (measured down to six meters in Thailand) forms an extremely dense ‘underground bio-dam’ across the slope, and is capable of clarifying water and not only maintaining but increasing year around water flow of springs and streams by holding back runoff and giving it a chance to find an underground aquifer.

By periodic pruning of the hedgerows, vetiver can provide voluminous amounts of material for handicrafts, baskets, hats, mulch for composting to improve soil texture and carbon content in the natural terraces formed behind the hedgerows. Growth harvested from vetiver hedgerows makes excellent pest-free thatching, lasting three times longer than traditional thatch. It can be used for compost; however, young regrowth is tender and makes useful livestock feed even in times of drought.

Vetiver hedgerows are not invasive, and are propagated by cuttings only. Seed of V. zizanioides is not obtainable as this species is sterile. Planting material for propagation nurseries, if not locally available, can be imported. A single line of ‘slips’, planted like rice seedlings, across the slope is all that is needed. The plants do not produce viable seed. Planting hedgerows is initially labour intensive, but once established, these hedgerows require little maintenance and last for years. Because of their soil filtering function, natural terraces begin forming behind vetiver hedgerows soon after planting. Not only do hedgerows mitigate erosion, but empirical data indicate that the survival, growth and production of trees and annual crops planted behind the hedges can be increased by as much as 50% by conserving topsoil, increasing the availability of nutrients and moisture for these plants. For example in China, "Tea yields increased by 40% when grown in conjunction with vetiver grass hedges, and vetiver hedges are much cheaper and more effective than the traditional stone terraces." Vetiver hedgerows also benefit coffee, cocoa, breadfruit and mango production to name a few.

Vetiver grass hedges planted across the slope of steep hillsides establish extensive root systems and begin reducing erosion within the first year. A study by scientists from Texas A&M after Hurricane Mitch in Honduras, shows that erosion was reduced from "92 tons of soil/ha/yr to 0.9 tons/ha/yr on steep hillside farms that were protected by contour hedgerows of vetiver.” The only farms that weren’t destroyed during Hurricane Mitch, the most violent hurricane ever recorded, were those protected by vetiver hedges.

What is needed now, is to get a small Island as a demonstration area using the Vetiver system, to show the Aid Agencies the economic effectiveness of this system and be used as an example to the rest of the World’s ocean islands. We would need to get approval from the governing body of the Island or Island group to lay down such a demonstration covering the full benefits of the Vetiver system on one Island. We would need to get approval to import the planting material, the experts and labour to lay out the demonstration and the funds to cover this plus a maintenance period of at least three seasons. We would also need to budget for a high standard DVD documentary to be made of the demonstration for further publicity of what can be done in such threatened areas.

John Greenfield

January 3. 2008

Welcome to The World of Greenfield

noreply@blogger.com (The Vetiver Network (International)) — Fri, 19 Mar 2010 16:56:00 +0000

We are looking forward to John Greenfield's blog. I hope he will blog not only about vetiver, but about agricultural development, oysters, research, or what ever comes to mind. He is nearly 80 years old, has a mind of a young man, and has a very rich experience in agricultural development world wide. He is very practical, has a great sense of humor, and tons of wisdom. His blog should be full of insights and will keep you all laughing.

Go for it my old friend!

Dick