NEWSLETTER (NL2026-10): A Historic El Niño; King of Thailand Vetiver Awards; Understanding VS Limits; A Philippine Riverbank Protection Attempt; News from Latin America; GVF’s First Sites; Plant Suppliers List; Practitioner Evidence Compendium; Vetiver Research News; Earthshot Close-out

 

A Historic El Niño: What Vetiver Users Should Consider

El Niño is back, and this one is shaping up to be among the strongest on record. On October 8, NOAA’s Climate Prediction Center reported that El Niño “continues to strengthen,” with a strong-to-very strong event likely through January–March 2027. The World Meteorological Organization (WMO) goes further. It forecasts record sea-surface temperatures in the central and eastern tropical Pacific this October–December, with the key Niño 3.4 index running about 6.7°F (3.7°C) above normal at a December peak. That is well past the previous record of 4.7°F (2.6°C), set in 2015–16. WMO puts the odds that El Niño lasts through February 2027 at close to 100%.

El Niño doesn’t do the same thing everywhere. It shifts rainfall, making some regions wetter and others drier, and the right response for vetiver users depends on which side of that line you are on. Here is what the regional forecasting centers are saying for places where vetiver practitioners are active:

Region Outlook Source
Greater Horn of Africa (Kenya, Ethiopia, Somalia, Uganda, Tanzania, Rwanda, Burundi) Wetter than normal, October–December. A 90% chance of enhanced rain over southern Ethiopia, central and southern Somalia and northeastern Kenya. Seasonal totals above 16 in (400 mm) are likely in parts of central Kenya, the Lake Victoria Basin and western Tanzania. ICPAC, Aug 18
Peru, north and central coast An “extraordinary” coastal El Niño through January 2027, then strong into autumn 2027. Above-normal rain on the north and central coast and northwestern highlands. The Tumbes, Chira, Piura, La Leche and Jequetepeque rivers are expected to run high from November. ENFEN (via Infobae), Oct 17
Central America and the Caribbean Drier than normal in southern Central America and parts of the Caribbean. The Dry Corridor is already in crisis: failed maize crops and livestock deaths in Honduras, Guatemala and El Salvador, and national emergency declarations. WMO, Oct 8; AFP, Sep 16
Southern Africa Drier October–December across Angola, Namibia, Botswana, Zimbabwe, southern Zambia, Mozambique, most of South Africa, Eswatini and Lesotho. The dry signal persists into January–March over the central and southern parts of the region. Wetter over most of Tanzania, eastern DRC and the far north of Malawi and Zambia. SADC SARCOF-33, Aug 27
South America, other areas Drier over much of northwestern South America; wetter in the southeast. WMO, Oct 8
Western Pacific A broad dry signal. WMO does not name countries, so check with your national meteorological service. WMO, Oct 8

 

Where it is going to be wetter

  • Plant now, early in the rains. In East Africa the October–December rains are the planting window, and vetiver establishes most easily in moist soil. Put new hedges where young plants won’t be washed out: upper slopes, field boundaries, the heads of small gullies and the shoulders of drainage lines.
  • Don’t plant into the line of fire. Slips set on riverbanks or in active waterways just ahead of peak flows will probably be lost. Hold those plantings until flows recede.
  • Protect your nursery. Raise or move beds off flood-prone ground. Nursery stock is what you will need for repairs.
  • Plan for repairs. Heavy El Niño rains leave behind landslips, gully heads and damaged embankment faces. Stock planting material now. TVNI’s Standards and Guides include a module on landslip repair.

Where it is going to be drier

  • Don’t plant into dry soil without water. Slips need moisture to root. If you can’t water them in and mulch them, wait for the rains – in southern Africa, that may mean next season.
  • Keep the nursery alive. It is your savings account for the recovery: shade it, mulch it, and give it whatever water you can spare.
  • Use the hedges you already have. When hedges are cut, spread the prunings between crop rows. Vetiver mulch cuts evaporation and keeps the root zone cooler (see The Hedge That Pays Twice).
  • Make every rain count. In a drought year a hedge’s most important job is to slow runoff and let it soak in where the crop can use it (see Water First – Think Water, Then Erosion).

Also note that a season like this one is a natural experiment. Hedges that hold soil and moisture through a historic El Niño produce exactly the kind of evidence that persuades governments and donors. See the GVF item below, and the ICV-8 awards.

A caveat: seasonal outlooks are probabilities, not promises, and local conditions can buck the regional pattern. Check with your national meteorological service, and treat the advice above as general guidance drawn from TVNI’s guides, not a prescription for your site.

Sources

ICV-8: The King of Thailand Vetiver Awards – Deadline extended to 31 January 2027

Deadline for submissions for the King of Thailand Awards has been extended to January 31, 2027

In August we announced the dates for the Eighth International Conference on Vetiver (ICV-8, Chennai, India, 12–14 May 2027) and the awards TVNI will present there. The conference’s most prestigious awards are now also open, and their deadline comes much sooner.

Her Royal Highness Princess Maha Chakri Sirindhorn, Chairperson of the Chaipattana Foundation and Patron of The Vetiver Network International, will present the King of Thailand Vetiver Awards at the ICV-8 opening ceremony. There are six awards of US$2,500 each:

  • Outstanding Vetiver Research: (1.1) agricultural application; (1.2) non-agricultural application.
  • Outstanding Dissemination and Application of the Vetiver System: (2.1) dissemination and technology transfer; (2.2) application of the Vetiver System.
  • Outstanding People Participation (two awards funded by PTT Public Company Limited): (3.1) on-farm applications and socio-economic impacts; (3.2) disaster mitigation or environmental protection.

Winners will have the opportunity to present their papers at ICV-8. Their costs of participation, international travel and accommodation during the conference are covered. New in the updated announcement: the first and second runners-up in each category – eight awards in all – will also receive Certificates of Excellence.

How to apply. Send the application form, a one-page abstract of 400–500 words, and the full paper (no more than 6,000 words or 15 pages, as a Word file) to [email protected] by 31 January 2027. The required format is written for research papers, but the announcement says it “may be amended for submissions that are not research based.” Practitioners and community groups should not be put off.

Nor should the date. Much of what an entry needs is a careful write-up of work you have already done. If you are preparing one and are worried about the timing, let us know at [email protected] – we will do what we can to help you get it in.

Two points are worth noting. First, the People Participation awards are for work carried out by groups of people participating voluntarily – farmer groups, community organizations, village programs – the very users this network was built to reach. Second, one of the dissemination criteria rewards “successful integration of VGTs and VS into larger scale government and/or private sector initiatives,” such as policies and mainstreaming into programs. With Bangladesh, India’s railways and Kenya’s Kakamega County watershed program all moving in that direction this year, we hope to see entries from the people who made it happen.

A reminder: TVNI’s own ICV-8 Awards (the Case Study Awards, the GVF Field Evidence Award and the certificates of recognition) close on 1 April 2027 – details in NL2026-08. Work done now to document a strong application will not be wasted.

Full criteria, paper format and the application form may be found at the following link. Please note that the form at this link does not yet have the updated deadline date, and shows the original 15 December 2026 date, ,which is now changed to 31 January 2027: The King of Thailand Vetiver Awards – entry instructions

The Critical Importance of Understanding VS Limits and Good Design as Governments Scale Up

Last month we reported on Bangladesh’s move toward national adoption of vetiver. Since then, the government’s 34-member technical committee, chaired by the Prime Minister’s Finance and Planning Adviser, Rashed Al Mahmud Titumir, has been given its terms of reference. Among other things, it must estimate a realistic per-kilometer planting cost and decide how much space to leave along roads and embankments. Those are the right questions. There is a third that matters just as much: where vetiver should not be asked to do the job on its own.

Bangladeshi commentators are already asking it. A broadly supportive op-ed on Independent Television Bangladesh (ITV BD) noted that most of vetiver’s international successes are on hillslopes and on road and embankment slopes, and that there are fewer examples of vetiver alone holding back a large river in flood. It also cites a study of coastal embankments at Kuakata, where sandy silts were easily moved by surges. Its conclusion is that vetiver should be used on embankment slopes, the upper parts of canal banks, ground eroded by runoff, and haor areas, and not relied on alone in the direct path of a river’s strongest currents. These conclusions are correct and consistent with what TVNI and experienced practitioners have long advised: vetiver protects the bank face and the slope above it, and where a strong current is undercutting the toe, it is paired with toe protection rather than used in its place – as in the Vietnamese river schemes documented on vetiver.org.

The op-ed describes correctly how the Vetiver System is meant to be used, and what goes wrong when programs skip that design discipline as they scale up. In practical terms:

  • Surface and shallow, yes. Vetiver controls surface erosion and reinforces the upper 6–10 feet (2–3 m) of soil. Deep-seated failures, and failures controlled by rock structure, need geotechnical solutions, which vetiver can complement.
  • Scour at the toe needs toe protection. Where a riverbank fails because the current undercuts it, the toe has to be protected. Vetiver protects the slope above and stops rain and overland flow from gullying it.
  • Water first. On slopes, the aim is to get water out of the ground faster than it comes in. Hedges help, but where seepage drives failure, drainage must be designed in (see Water First).
  • Use the right plant. The op-ed also raised concerns about biodiversity. National programs should specify the sterile, non-seeding cultivars used in Vetiver Grass Technology, not fertile wild material (see Vetiver Genotypes by Region, Fertility and Weed Status).

TVNI’s revised VGT Guides and Design Standards already draw these lines. Guides give best estimates from field practice. Design Standards apply only where measured results allow firm design parameters. Specifications, the contract documents, are issued only for Design Standard modules; they exist today for water margins and watercourse banks (A1) and engineered slopes (B1), among others. And the Hedge or Stand-alone? sheet flags dams and levees as an area where “engineering practice and field experience currently disagree.”

Overpromising is the fastest way to lose a national program. One high-profile failure on the wrong site can undo a hundred quiet successes on the right ones. As Bangladesh’s committee writes its specifications, we trust they will draw upon the deep knowledge and experience of Dr. Mohammad Shariful Islam, who in 2025 published a “Standard Specification for Slope Stabilization Using Vetiver Grass,” and on TVNI’s published resources (guidelines, standards technical manuals) for developing a clear map of where vetiver works on its own, where it works as part of a combined design, and where it doesn’t belong.

Sources

Philippines: Strong on Community, Questionable on Design

The following is based on a news release only, as TVNI could not find any technical design documents, which may show more. We include it here because much too often we are learning about projects and initiatives that quite simply misapply VS and, in doing so, both waste the time and lose the trust of the communities and individuals with which they work and undermine the reputation of VS through poor quality design and application. We feel it is important to point out these instances, in hopes of getting the message out that VS only works when it is properly applied.

A newspaper article came to TVNI’s attention, which related that the Philippine environment department (DENR) was reporting that it and the Ata-Manobo community, with GIZ support, had restored a 1.3-mile (2.1 km) stretch of eroding riverbank at Sitio Patil, Kapalong, Davao del Norte. The aim of the project was to protect 1,017 residents from flooding and bank collapse at the Kapalong–Maguimon confluence, where strong currents threaten homes. The article reports that to accomplish this aim, across 20 acres (8 ha), 1,350 clumps of malibago (Hibiscus tiliaceus), 729 of bamboo, 797 of vetiver and 715 of Trichanthera gigantea were planted and more than 80% have survived.

The community side is impressive: training for the Indigenous People’s Organization, honoraria for planting and upkeep, residents reporting attempts to cut the plantings, municipal funding and a Payment for Ecosystem Services framework.

However, taking the article at face value, the design raises four concerns.

  • Not laid out in hedgerows, just few, thinly spread plants. About 3,600 clumps over 20 acres is roughly one per 15-ft (4.7 m) grid. A documented village scheme in Viet Nam planted its bank face on a 3.3-ft (1 m) grid. At TVNI’s spacing of 4–6 in (10–15 cm), one continuous vetiver row along 2.1 km needs 14,000–21,000 slips; 797 clumps would plant perhaps 4–16% of a single row. Simply planting scattered clumps will not work “where strong currents threaten homes.”
  • No armoring reported at the toe. At a confluence, the current undercuts the base of the bank. Without toe protection (e.g., riprap, gabions, or other suitable armoring technique) and a gentler bank slope (Paul Truong recommends no steeper than about 2.5 horizontal to 1 vertical), the bank will continue to be undermined and collapse, taking the plants on the bank face down with it.
  • Woody plants at the edge. Heavy bamboo and tree clumps on an undercut bank can topple and pull the bank with them. In Truong’s review, bamboo repeatedly failed on Vietnamese riverbanks.
  • Survival is not performance. The report gives no figures on whether the bank has stopped retreating.

If the report is accurate, the likely result is a greener riparian buffer with useful fodder, poles and shade, and less surface erosion on the upper bank – but little protection where the river is cutting into it. DENR concedes the vegetation “cannot prevent all floods.” It is also unlikely to stop the bank collapse it was meant to prevent. TVNI’s own Practitioner Evidence Compendium (see below) records the same failure modes: a healthy riverbank planting lost to an undercut outside bend (VE-0330) and clumping bamboo that pulled banks into the river (VE-0325).

That is why the strong community work cuts both ways. People who were told the planting would protect their homes, and then watch the bank keep falling, will reasonably conclude that it didn’t work. The next agency or NGO to offer help – especially one proposing vetiver – will meet that skepticism, and vetiver will carry the blame for a design problem.

Sources

News from Latin America and the Caribbean

Last month’s newsletter noted that the regional press had been quiet on vetiver and promised a report from our Latin American coordinators. Here it is.

Dominican Republic – the 1st International Vetiver Forum. Congratulations to Dr. Erickson Taveras Castro, president of the Red Dominicana de Vetiver (Dominican Vetiver Network), on the 1st International Vetiver Forum, held on October 29 in Santo Domingo.

The forum was hosted at the headquarters of the Junta Agroempresarial Dominicana (JAD), whose executive president, Osmar Benítez, opened the day by offering JAD’s institutional support for initiatives that benefit agriculture and industry. Backing of that kind gives vetiver a seat at the table where farm and land-use decisions are made.

The program brought together national and international speakers. Dr. Taveras set out the forum’s purpose: linking technical knowledge with institutional cooperation and community participation. Max Puig, Executive Vice President of the National Council for Climate Change and responsible for climate change policy, spoke on vetiver as a climate solution for adaptation, mitigation, soil protection and restoration – a sign of how seriously the forum was taken. Rafael Luque, Coordinator of the Latin American Vetiver Network, reviewed the region’s experience, including cases from Puerto Rico, Guatemala and Mexico, and the role of national and regional networks. TVNI’s presentations covered the history, evolution and applications of the Vetiver System, how a vetiver hedge works, TVNI’s Global Vetiver Farmer (GVF) Program, and vetiver as a business opportunity.

Oswaldo Luque, Venezuela Country Coordinator, walks along the hundreds of meters of vetiver hedgerow that have been established as part of the Parque Lineal de Santiago de los Caballeros in the Dominican Republic. Source: Mundo Vetiver WhatsApp Group

Most encouraging is what came out of it. Participants adopted a final declaration calling for a national agenda for the responsible promotion and use of the Vetiver System, including:

  • pilot projects in priority zones, backed by technical assessment and monitoring;
  • training and guidelines adapted to local climate and soils;
  • enterprises in planting material, installation and maintenance services, and crafts, where viable;
  • attention to women, youth and vulnerable rural communities; and
  • a place for vetiver in public environmental policy.

The declaration is also clear-eyed. On infrastructure and slopes with structural risks, vetiver solutions are to be designed with specialists, not substituted for necessary engineering – the same point made in “The Critical Importance of Understanding VS Limits and Good Design as Governments Scale Up” above. A coordination table will now identify priority projects and see them through, alongside environmental education in schools and communities.

The network calls the declaration a starting point. It is a strong one, and it gives the Dominican Republic a real chance to become one of the region’s reference countries for the Vetiver System. Well done, Erickson, and thanks to everyone who made it happen.

Mexico – floating wetlands on an urban river in Veracruz. Mexican researchers have published an account of three floating vetiver wetland modules installed in September 2025 on the Paseo de Los Ahuehuetes river in Nogales, Veracruz. Each module carried nine plants on a 3.9 × 3.3 ft (1.20 × 1.00 m) platform. All 27 plants established, reaching an average height of about 34 in (85.5 cm) with roots of about 22 in (55 cm), and the modules came through a rise in river level from about 3.3 to 7.2 ft (1 to 2.2 m) without damage. The authors report that, as no baseline sampling was done, the water-quality changes they saw can’t yet be attributed to the vetiver. That is a lesson for every floating-wetland project – design the monitoring before you launch the rafts.

Ecuador – tannery effluent. Researchers in Ecuador tested vetiver and water hyacinth, alone and together, on secondary effluent from a tannery in Tungurahua. After 45 days the combined system had cut BOD₅ by 83.6%, hexavalent chromium by 75.0%, turbidity by 99.2% and total nitrogen by 71.1%. But COD, conductivity, ammonium and total solids stayed above discharge limits. The authors concluded that this is a promising polishing stage, not a stand-alone treatment – just as TVNI’s Module C: Vetiver for Wastewater, Effluent, and Pollution Control recommends.

El Niño at both ends of the region. This season brings drought to the Dry Corridor and flooding to Peru’s north coast (see the lead item). ATTENTION network members in those areas: before-and-after photographs and simple notes on how hedges held up this season are some of the most persuasive evidence there is. Please share them with TVNI or the Mundo Vetiver group, and consider them for the ICV-8 awards.

Colombia and Venezuela. Colombia and Venezuela now have the first two registered GVF sites in Latin America (see below).

Sources

GVF: The First Sites Are In – and Why an El Niño Year Is Worth Recording

The Global Vetiver Farmer (GVF) Demonstration Program launched on October 23. By October 31, 14 sites had registered in nine countries – Australia, Colombia, Kenya, Mauritius, Papua New Guinea, the Philippines, the United States, Venezuela and Viet Nam. Half were registered by farmers themselves, and two research partners have already signed up. The sites range from basic contour hedges and block plantings to kitchen gardens, a food forest and a plantation grid: very different farms, all recorded with the same distances and codes.

An El Niño year is a good year to start. GVF asks one question at harvest: how does the crop change with distance from the hedge? In a normal year that measures the hedge’s everyday effect. In a drought or a deluge, it measures what farmers and funders most want to know – whether hedges protect yields when the weather turns. Records from East Africa, Peru, Central America and southern Africa this season will be especially valuable. A poor harvest is still a good record, and in a dry year a lower crop right at the hedge edge can be normal, often offset farther out. Please record it anyway, and note the season’s conditions in the comments.

To take part: register your site (two minutes, once per farm) on the GVF page, join the #GVF WhatsApp group, and see the open results and map, updated every hour. Questions: [email protected].

Vetiver Plant Suppliers List Updated

We have updated TVNI’s Global Vetiver Grass Plant Suppliers page and removed entries that no longer appear to be operating, mostly those with no working email address or website.

If your nursery or company is listed, please check that your details are current and let us know of any changes. If you supply vetiver planting material and are not yet listed, we would be glad to add you. Send the following to [email protected]:

  • your name and organization;
  • location and contact details;
  • website; and
  • the vetiver cultivar you supply (if known).

Why the cultivar? Because what buyers need is good-quality, sterile planting material. Invasiveness in vetiver is a property of the genotype, not the species. The cultivars used in Vetiver Grass Technology set no viable seed, while some wild, fertile types do (see Vetiver Genotypes by Region, Fertility and Weed Status). If you are buying, ask your supplier which cultivar you are getting. An accurate, up-to-date list helps people everywhere find the right plant.

TVNI’s Practitioner Evidence Compendium, Version 2.0

Readers of these newsletters know how much practical knowledge flows through the vetiver WhatsApp groups – India’s AW#Vetiver and Latin America’s Mundo Vetiver among them (see NL 2025-10), and through the TVNI Facebook group. The problem has always been that it scrolls away. A farmer’s careful observation on hedge spacing, or a contractor’s account of a slope that failed, is read by a few hundred people and then lost.

TVNI’s Practitioner Evidence Compendium is our answer. It turns field posts into numbered, citable evidence records, each graded for the strength of the evidence behind it. Version 2.0, released on October 31, brings together four WhatsApp groups (AW#Vetiver, Mundo Vetiver, #GVF and VS Ethiopia – some 29,400 messages screened) and 361 posts from the TVNI Facebook group. Where both channels recorded the same observation, the records were merged, leaving 162 records from 39 countries and territories. Each record is graded M (Measured), D (Demonstrated), I (Inferred), R (Reported) or X (Contested).

Why grade? Practitioner evidence ranges from measured results to a single photograph and a hunch, and readers deserve to know which is which. Grading lets the strong records be cited with confidence and flags the promising ones that need checking. Many of those are natural candidates for GVF sites or for the ICV-8 case study awards. As we noted in August, on many questions practitioner records are better evidence than the journals – the research lags the practice.

What’s in it. Of the 162 records, 23 are Measured, 63 Demonstrated and 47 Reported, and 13 are Contested. The WhatsApp groups hold 22 of the 23 Measured records; the Facebook group adds breadth – 20 countries not previously represented – but little measurement, since most posts are photographs with captions.

How to use it. The Compendium is a single Excel workbook. Start with the Record index, where filters let you combine, for example, Class = Failure and Region = Latin America, or Grade = M. The full record, with its caveats and follow-up, is on the Records sheet. Before citing a figure externally, filter to Measured records and cite the record number, the observer, the grade and the source. And remember what it is: a record of what practitioners report, not a technical standard. For design and specification, use TVNI’s Design Standards.

How to help. The records that grade highest share a few features: a location, a date, photographs, and numbers – with a note on how they were measured, or a plain statement that they are estimates. If you post in the groups, a few extra lines like that make your experience count.

Download the Practitioner Evidence Compendium, Version 2.0 (Excel workbook).

Coming soon. In the next few days we will post an overview of the Compendium’s contents and a summary of its most interesting and important findings to date.

Vetiver mulching infographic, courtesy of Robinson Vanoh, Papua New Guinea, TVNI Director, owner of Eagle Vetiver Systems, and founder of the PNG Vetiver Network

Vetiver Research News

This is an ongoing feature of the Vetiver Newsletters, where we highlight recent research that adds something new and useful about the Vetiver System, not just what we already know. The items below were published, or came to our attention, since our August round-up.

A look into peer-reviewed, institutional, and practitioner literature and news turned up a number of interesting items from the last 10 months. On the research side, an Ecuador-based team has produced one of the more field-realistic root-reinforcement studies we’ve seen in a while, based on an 18-month-old vetiver installation. We also have new work from Ethiopia, Iran, India, Peru, Sri Lanka and South Africa; long-term phytoremediation results from Viet Nam; a sobering field test of vetiver oil as a mosquito repellent; a first Mediterranean forage trial; and a follow-up on India’s railways and a funding lead from the Asian Development Bank.

Engineering research: Ecuador’s field-grown root data

A research group working in southern Ecuador (Chavez Torres, Feng, Zhang and Kookalani, Applied Sciences, November 2025) did something most lab studies don’t: they took soil cores from vetiver that had actually been growing in the field for 18 months, on cultivated hillsides with slopes ranging from 30–60° (roughly 58–173% grade), across seven soil types spanning high-plasticity clay (CH), elastic silt (MH), organic silt (OH/OL), and low-plasticity/coarse silt (ML, CL-ML). Rooted soil was stronger at every depth tested, and modeled slope safety factors stayed above 1.10 in every scenario, with the biggest gains – up to 16% – in the high-plasticity soils (CH and MH).

That’s a more realistic test than most of what we are seeing, i.e., pot studies. A limit, pointed out by the authors, is that the modeling covered only dry conditions and shallow slip surfaces, down to about 6.5 ft (2 m); though this latter isn’t really a limit, as VGT applications for slope stabilization are effective for shallow, not deep, slips of this nature. Hopefully the authors will continue their study so that we get results on performance once the rains come, and at depths below 6.5 ft (2 m), to better understand soil reinforcement as a function of depth. For now, the headline from the study is “gains of up to 16% in high-plasticity soils, in the dry season, on slip surfaces 6.5 ft (2 m) deep or less.”

The same broader research cluster also published a companion study applying the same approach to filtered gold-mine tailings (clayey silt, CL) in Ecuador (Sustainability, June 2026), modeling slopes at 3H:1V, 2H:1V, and 1H:1V (roughly 18°, 27°, and 45°). Vetiver roots raised apparent cohesion by up to 34.6%, with little change in friction angle, and the authors are upfront that their results are preliminary and still a step away from field validation. A separate South African team is taking the mine-tailings angle further downstream: a May 2026 conference paper (CONECT, bench-scale only) reports that vetiver biomass harvested from gold-mine tailings can be anaerobically digested into biogas – a circular-economy signal worth watching, whose practical viability remains to be demonstrated.

Erosion control and carbon: Ethiopia, Iran, India, Peru, Sri Lanka

Ethiopia. A four-year field trial on a 13.2% slope in sandy clay loam soil in Ethiopia’s Jimma zone (Hailu et al., Frontiers in Sustainable Food Systems, January 2026) compared vetiver hedgerows against Desho grass (Pennisetum pedicellatum), Phalaris (Phalaris arundinacea L.), and a no-grass control on working farmland. Vetiver came out on top for soil carbon storage by a wide margin and had the highest soil moisture of the three grasses (though the moisture differences were not statistically significant), while its erosion-control performance wasn’t statistically distinguishable from Desho or Phalaris – only from the control. It’s a multi-year study with replicated field data, which is rarer than it should be in the literature. Hedgerows were planted at 8 × 8 in (20 × 20 cm) spacing at a site (Melko, Jimma Agricultural Research Center) with 67 in (1,702 mm) mean annual rainfall – dense spacing plus that much rainfall means the hedges should have closed well within the four-year trial window, so this is a solid piece of work. Soybean yield didn’t differ significantly between treatments; the authors attribute this to the younger age of the grass hedgerows delaying soil-fertility gains, a separate question from the erosion-control results above.

One caution: the paper’s figure of about 77 tons per acre (172 t/ha) is not a sequestration rate. It is the carbon the authors measured in vetiver shoots and roots (about 14 tons per acre, or 31 t/ha) plus the soil organic carbon stock to 3.3 ft (1 m) depth (about 7 tons per acre, or 16 t/ha), all converted to CO₂. None of it is sequestered in the sense that matters. The biomass carbon lasts only as long as the plants do, and soil organic carbon can be released back to the atmosphere as CO₂ if land use or management changes. Only the small, stable fraction that persists for decades counts as sequestration. See Vetiver and Carbon.

Iran. A field study on a vegetated highway embankment in Tehran Province, Iran (Haghighi and Sharifi, ECOPERSIA, winter 2026) found vetiver-rooted soil had substantially higher cohesion and shear strength than root-free soil, with the gain increasing on steeper slope sections (40–50%, 70–80%, and over 80% grade; soil texture isn’t reported). It’s a small, single-site study, but the general result, that field-grown vetiver roots measurably strengthen embankment soil, lines up with the broader literature and adds another global data point.

India. A laboratory physical-model study (Ashwini and Ramakrishnegowda, Soils and Rocks, 2026) tested vetiver, and vetiver combined with jute geotextile, on 45° slope models across four soil types – black cotton clay (Raichur district), red clay (Mandya district), sand (Mysore district), and laterite/silty sand (Dakshina Kannada) – under simulated rainfall. Vetiver alone cut soil loss by roughly 95–99%+ versus bare soil by the one-year mark, with runoff reductions in the 20–30% range depending on soil type, and adding jute geotextile gave a further boost, particularly before the hedge matured. Vetiver was planted at 6 in (15 cm) in-row spacing and monitored to 360 days. Each soil/treatment combination was a single, unreplicated model with no statistical testing, so these figures are indicative only, though consistent with other research findings on VGT impacts.

Peru. A small laboratory study from Peru (Villegas Llacua et al., 2026, International Journal of Civil Engineering, SSRG) tested vetiver planting density (4, 6 and 8 in, or 10, 15 and 20 cm, spacing) on scale slope models in silty-clayey sand (SC-SM) at slope angles from 20° to 35°, and found 6 in (15 cm) spacing gave the strongest early reinforcement among the densities tested.

Sri Lanka. A field trial in Sri Lanka’s mid-elevation tea plantations (Jayasinghe and Medina, Discover Soil, 2026) compared stone terraces, stone terraces combined with vetiver, terrace walls, and untreated controls on 60–72% slopes, with vetiver planted at 6 in (15 cm) spacing – a properly designed, replicated field test. The combined terrace-plus-vetiver treatment cut runoff by 80% versus untreated plots, with nitrogen and potassium losses also significantly reduced (phosphorus was not).

Other findings: Thailand, Türkiye, Viet Nam

Thailand. Vetiver essential oil is often marketed as a natural insect repellent. A Thai study put it to a real test against Anopheles dirus, a major malaria vector. In semi-field trials, DEET cut mosquito landings by 95.75% over six hours; vetiver oil cut them by 51.9%. Then came a nine-month community trial in Sisaket Province with 457 participants randomized to DEET, vetiver oil or a placebo. Participants rated vetiver oil about the same as the placebo, and DEET users stuck with their product much more consistently.

The takeaway for vetiver oil and product enterprises: vetiver oil has some repellent activity, but it should not be sold as protection against malaria mosquitoes. Caveats: one formulation and one vector species were tested, and most participants applied repellent to clothing rather than skin, which likely reduced protection for every product tested.

Source: Saeung, M. et al. (2026), “Protective efficacy and user acceptability of DEET and Vetiver essential oil repellents against Anopheles dirus (Diptera: Culicidae): semi-field and community-based evaluations,” Journal of Medical Entomology – https://doi.org/10.1093/jme/tjag148

Turkey. Our June newsletter looked at vetiver’s shifting climatic range. New data now come from Bornova, İzmir, on Turkey’s Aegean coast at about 38°N, where researchers grew vetiver as a forage crop from May 2025 to March 2026. Every plant survived (100%), reaching an average height of about 5 ft (155 cm) and yielding about 8.8 oz (250 g) of dry matter per plant, with 13.4% crude protein. The authors conclude that vetiver can be grown as an alternative roughage and silage crop under Mediterranean conditions.

Caveats: this is one season and one winter, and İzmir’s winters are mild. The plants were irrigated. A silage pH of 5.16 is on the high side for grass silage, which may point to limited fermentation; the authors do not discuss this. Still, it adds a well-documented Mediterranean site to a map where such data are scarce.

Source: Güzar, B. & Geren, H. (2026), “Vetiver (Vetiveria zizanioides (L.) Nash)’in Bornova Koşullarına Adaptasyonunun Araştırılması” [Adaptation of vetiver to Bornova conditions], Tekirdağ Ziraat Fakültesi Dergisi – https://doi.org/10.33462/jotaf.1952003

Viet Nam. Most vetiver phytoremediation studies run for weeks or months. This one, at the former Bien Hoa Airbase in Viet Nam, covers 55 months of vetiver on contaminated ground. It is exactly the kind of longer-duration field work we argued for in August, and it follows up the Bien Hoa endophyte study we reported in NL 2024-10. The researchers combined a surface survey (53 locations) with depth profiles to about 20 in (50 cm), comparing vetiver-treated and untreated plots.

  • Cadmium is the target. It was the dominant contaminant, mostly in mobile forms, and the only metal vetiver accumulated at higher concentrations than the soil (a bioaccumulation factor above 1). That factor rose 2.3-fold over a 40-month assessment period. Chromium and nickel were largely locked in residual forms, much less available to plants.
  • The roots survived a fire. A fire at month 52 burned off the canopy but spared the roots. Uptake was higher at month 55, possibly from regrowth, though the authors say this needs more monitoring.
  • Harvest to remove. The authors recommend managed harvest-and-regrowth cycles to keep extraction going, and judging cleanup by bioavailable rather than total metal.

A caveat: the design is observational, so it shows patterns, not proven mechanisms. Harvested biomass from contaminated sites must be handled and disposed of as contaminated material.

Source: Nguyen, T. et al. (2026), “Depth-dependent trace metal speciation, bioavailability and soil–plant transfer across 55 months of vetiver phytoremediation at Bien Hoa Airbase, Vietnam,” Environmental Geochemistry and Health – https://doi.org/10.1007/s10653-026-03499-9

Infrastructure and funding

India’s railways go bioengineering. As first reported in NL2026-09, after landslides disrupted service in July, Central Railway began planting vetiver hedgerows along contour lines on two monsoon-damaged slope sections, on the Mumbai–Pune and Thal Ghat lines, totaling roughly 57,000 sq ft (5,300 m²). Two independent news outlets have reported on this and identified it as a pilot. It is particularly welcome news, and we’ll continue to watch for results: if the pilot succeeds, Central Railway could roll it out as a national program for stabilizing the country’s rail lines.

A funding lead. The Asian Development Bank announced in May that Germany has joined its Nature Solutions Finance Hub with €5.5 million in grant co-financing, as part of a push to mobilize $5 billion in nature-positive investment across Asia and the Pacific by 2030. The announcement doesn’t mention vetiver specifically, but it’s a live, named funding channel that experienced VS practitioners, service companies and networks in South and Southeast Asia and the Pacific may want to approach directly for watershed or slope-stabilization proposals. We looked for a dedicated contact for the Nature Solutions Finance Hub itself and couldn’t find one; the best route right now is ADB’s general inquiries channel (adb.org/contacts) or your national ADB office, referencing the Hub by name.

A persistent gap – smallholder research

Wide searches continue to find little or nothing new and independently published in the last year on vetiver’s smallholder adoption economics, cost-effectiveness, or livelihood outcomes. Given how central that question is to scaling the Vetiver System, it’s a gap we are pointing out to researchers and practitioners in the broader, global VS community. This, among others, is precisely why TVNI recently launched its Global Vetiver Farmer initiative, which asks farmers to record their yield benefits and researchers to help quantify other, broader benefits.

Background on why this evidence gap matters can be found here. And if you’re working on vetiver adoption data, field trials, or livelihood outcomes – published or not yet written up – we’d love to hear about it for next month’s issue.

The Earthshot Prize 2026: A Close-out, and Thanks

In January we reported that the Vetiver System had received three independent nominations for the 2026 Earthshot Prize. On September 18, Earthshot announced its 15 finalists. The Vetiver System was not among them, and none of the finalists works with vetiver. The five winners, each receiving £1 million, will be announced at the Earthshot Prize Awards Night in Mumbai on November 17 – the first time the Prize has been held in India. We congratulate all the finalists.

TVNI sincerely thanks our three nominators – BVRio, EARTHDAY.ORG and McGill University – for their confidence in the Vetiver System and the effort behind their nominations. The nomination also brought TVNI into Earthshot’s nominee network, which has already shared funding opportunities with our members (see NL2026-02). And the evidence we asked members for at the time – quantified case studies, before-and-after photographs, cost data – is exactly what the ICV-8 award juries will be looking for.

Sources

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Jim Smyle
Labels: Agriculture and farming, Community and livelihoods, Disaster mitigation, Erosion and soil and water conservation, Guides, standards and publications, Network news and events, Policy, upscaling and dissemination, Pollution and wastewater, Slopes and infrastructureTagged , , , , , , , ,

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