Vetiver Grass Technology - some random observations

Without soil and water there will be no photosynthesis and no life on this planet. Both are becoming degraded and in short supply globally -- Vetiver Grass Technology (VGT) can improve both and deserves government focus and support."

 

Arbuscular mycorrhizal fungi: AMF have an important role in the growth of vetiver and we are seeing increased use of vetiver by permaculturists for all sorts of purposes including its planting within stands of other crops and sometimes very close to young plant seedlings such as papaya, mango, dragon fruit. etc with what appears to be positive growth benefits (linked possibly to moisture and AMF). This begs the question as to differentiating between vetiver cultivars on the basis of root architecture for this purpose and are some cultivars better at hosting AMF.

Leaf and stem density: Although the roots are important, particularly as a stand alone plant, the leaf and stem density as well as the total mass, play an important role when vetiver is used as a conservation barrier to trap sediment flow  to disperse concentrated water flows across and behind the vetiver barrier, and reduce flooding ... These same barriers have a use as a source of forage, thatch, mulch etc. High leaf density and mass in vetiver  generally is reflected in its tillering capacity and root mass. Deeper rooted plants also are better at recycling soil nutrients and better growth under dry conditions. We have noticed that once users understand the multiple benefits of vetiver they are more receptive to using the plant for soil conservation. Also deeper rooted plants can punch through soil pans and the impediments thus enabling ground water recharge (by as much as 4 times) from the spread out rainfall runoff temporarily trapped behind the barriers — reflecting a secondary but important benefit of vetiver barriers.

Root digging: We have in the past been concerned about the potential of vetiver hedgerows being dug for the oil.  In reality it is rarely a problem and we virtually never receive feedback that it occurs. Most vetiver that is planted for oil (VPO) is planted on lighter sandier deep soils that are easy to dig (often on flat land) - on the other hand most vetiver grown for soil conservation or slope stabilization is grown under conditions and soil types that make digging difficult and uneconomic. Where VPO is planted on sloping land and where the digging process can result in erosion, farmers need to incorporate permanent vetiver contour barriers to protect the VPO crop. This message needs to be passed on to these farmers (as is being done now in Haiti).  

Vetiver type for oil: My impression (and I stand to being corrected) is that from what I have seen in the field and from many photographs that have been posted on line is that the VPO types appear to be sturdier, bulkier, taller and more dense than some of the other types, and that the triploid/polyploids used for oil originating from south India would appear the sturdiest. Thus, as long as the plant is sterile why not use the VPO for environmental purposes. One big advantage of this would be that VPO producers  could become integrated with the "not for oil" vetiver users thus providing a secondary income for oil producers (very useful when there is an oversupply of oil and oil prices are low) and what should be a very low cost source of plant material for other users. (planting slips would be low cost as they would be a byproduct of VPO harvesting and the potential supply is very high).  Assuming we can discount the “digging” aspects as a problem then can we narrow the vetiver types to a few that are multipurpose includes quality oil, deep roots, good host to AMF, and sturdy and dense stems and leaves. 

Vetiver types generally:  Other aspects that are becoming important include (a) salt tolerance - especially for coastal stabilization (b) insect habitat and pest control - Chinese are now using vetiver as a dead end trap crop for rice stem borer control and as a habitat for beneficial insects such as parasitic wasps -- I wonder if there are any differences between vetiver types as to their attractiveness and “killing” of insects such as stem borers -- (c) fire tolerance - with increase in wild fires are there types of vetiver that are more resistant to fire, (d) decontamination of polluted soil and water, and (e) cold tolerance - increasing demand to use vetiver under very cold winter hot summer climatic regimes. The Chinese claim that have identified types that perform better and survive cold (freezing) conditions.

 

Barriers deterring the use of Vetiver Grass. (1) Some research shows that farmers need to be financially supported to undertake soil conservation works. - seems to work in the US in various forms but not in poor countries. Poor country conservation has generally come through World Food Program “food for work” programs and bilateral and multilateral aid agencies, or heavily subsidized  programs where there is no incentive for farmers to maintain their works and where there are huge opportunities for corruption by officials at all levels (2) engineered design based systems are generally preferred by “officials” - a bigger  budget line -  more room for corrupt practices and more control by involved officials. (3) biological systems are generally not preferred by engineers as most have not been trained in such aspects. They are also much lower costs and less opportunity for corrupt practices. (4) In most developing countries soil conservation is the responsibility of a “Soil Conservation Department” most of these are focused entirely on soil conservation and rarely consider the wider and secondary aspects that are derived from the primary work. Thus when introducing (perhaps reluctantly) a technology like Vetiver Grass the conservation agents  are either generally unaware of the many secondary benefits or do not tell the end user what those benefits may be. This all adds up to low adoption rates (5) In this age of "global environmental threat" primary and secondary schools should have a curricula that includes a compulsory class on basic environmental principles. — in other words some serious thought needs to be given to environmental education.

Research .  There are plenty of opportunities for vetiver research in many areas of application.  Vetiver research needs to be better coordinated. Such research should be multi-sector driven and not just the responsibility of the agricultural sector. Vetiver in its many applications could prove a very valuable a tool to mitigate many soil and water issues relating to climate change. A good case could be made to the World Bank and others to support such research

Policy: With 35 years of global research, development and experience to call on there is an opportunity for Government agencies to set out a clear policy directive on the use and development  of Vetiver Grass Technology (VGT) in all aspects. 

 

VGT is a proven success, is low cost, and applicable for a wide range of applications under a wide range of conditions. What more does one need!

VETIVER GRASS TECHNOLOGY (VGT) - OBSTACLES TO ITS APPLICATION

We have been promoting the modern concept of VGT since 1986, nearly 34 years, and even though most of the evidence from research trials and the field show that VGT in its many forms works well and is accepted by users, the rate of expansion in the use of the technology is not accelerating fast enough, particularly in the light of current global needs to mitigate climate change generated problems relating to land and water. I have recently been writing about the use of vetiver for river bank stabilization, a practice that is proven and being used  effectively in a number of countries. A yet to be published paper that reviews the West Bengal (India) river bank stabilization program reaches the following conclusions:

VGT did what it was supposed to do and applications resulted in stabilization of river banks and the local communities were generally happy with the technology that it is more effective (superior) and much less costly than engineered structures. Some of the more important conclusions of the review included: (a) the need to create appropriate policies that will encourage the use of vetiver (b) the need to develop effective technical specifications that can be incorporated into design manuals (c) the need for support to communities, both financially and technically to effectively use VGT (d) better involvement of local communities in the selection and design of riverbank stabilization sites (e) educating/informing communities in the many other applications and benefits of vetiver that would be of value to them (e) the need to develop appropriate mechanisms to allow smoother implementation of community based vetiver based schemes (f) the lack of interest and understanding by the engineers of the organizations responsible for drawing up design solutions for using biological solutions, particularly vetiver, and (g) the inability of community individuals (most of whom have daily income of less than $2) to fund river bank improvements or any other conservation activities without outside help.

These conclusions are not new and are not confined just to West Bengal, but rather are generally a global phenomena. Three key things have to be done: (1) creation of policies, including technical specifications and guidelines, at various levels of government that support biological solutions including vetiver (2) educate both professionals and communities in the technology and (3) find funding solutions that can be executed rapidly. 

 

Comments are welcome!!

The Role of Hedgerows in Agriculture

Woody hedgerows have played a vital role in English agriculture for centuries. Originally planted to primarily demarcate land holdings and to contain livestock movement  and side benefits not fully understood until recently following studies undertaken as a result of alarm for the rapid removal of hedgerows in the period since World War II. A paper "The role of hedgerows in soil functioning within agricultural land (2019)" by a team from Leeds University exposes some of the many soil related benefits linked to hedgerows.

The Abstract :

"Intensification of agriculture has led to major losses of hedgerows and field margins worldwide. Soil sample extraction, in situ time series of soil moisture, temperature and soil water quality analyses, annual earthworm
sampling and arbuscular mycorrhizal (AM) fungi sampling enabled comparison of soil functions between typical hedgerows, grass field margins, pasture and arable (mainly winter wheat) fields in a temperate, lowland setting. Mean bulk density (upper 50 cm), surface compaction and soil moisture content were significantly lower while organic matter content and pore water dissolved organic carbon concentrations were significantly greater in hedgerow soils, than margins or fields. Mean nitrate and phosphate concentrations were three and ten times larger, respectively, in soil solutions under hedgerows than arable fields while ammonium concentrations were least in arable fields. Saturated hydraulic conductivity was significantly greater under hedgerows (median=102mm hr−1) where it took an average of one hour longer for soils to reach maximum moisture content following rainfall, than adjacent arable (median=3mm hr−1) or pasture fields and margins (median=27mm hr−1). Hedgerow soils had a greater proportion of flow through micropores and less macropore flow than other soils. The pasture and margin soils had the largest proportion of macropore flow (> 85%) and more (and larger) anecic earthworm species, such as Lumbricus terrestris which produce vertical burrows. Earthworm density, biomass and diversity were greater in pasture and margin soils, followed by hedgerow soils, and tended to be lowest in arable soils. For both total and AM fungi, hedgerow soils hosted a distinct and heterogeneous soil community, margin and pasture communities were diverse but clustered together, and arable communities formed a distinct cluster, with low inter-sample variation and significantly lowest AM fungal richness. The findings demonstrate that soils under hedgerows, which should be conserved, can provide important functions on farmland including storing organic carbon, promoting infiltration and storing runoff, increasing earthworm diversity and hosting distinct AM communities."  Full paper at: https://www.vetiver.org/UK_HoldenSoilbiohedge2019.pdf

The paper concludes;

"Both hedgerows and grassy field margins can provide a wide range of enhancements to soil function that may provide wider ecosystem service benefits to accrue from agricultural systems. Given that global food security is a pressing issue and more intensive farm production may be required in some regions, it will be important to develop simple land management strategies that can enable food and fibre production to occur in a sustainable way. Enhancing the area of both field margin woody hedgerows and grass strips globally could be an important technique for reducing flood risk as well as for enhancing total soil C storage and the diversity of soil ecosystems across agricultural landscapes. One trade off that requires further research is the potential of hedges to capture pollution from the atmosphere which may result in reduced water quality in runoff and groundwater flow emerging from soils below hedges."
 
I find this paper interesting in that the positive benefits from woody hedgerows (as well as grassy field margins as grown in England) replicate many of the benefits shown in vetiver grass related research, particularly those aspects relating to the role of soil micropore, rainfall runoff reduction and the slow down of flooding, the high arbuscular mycorrhizal (AM) fungi, and enhanced soil carbon storage.  Although not specifically addressed in the paper, well managed English hedgerows when planted across the slope act as formidable soil retention barriers as any one can see when taking a walk along a hillside hedgerow where the difference between up slope and down slope can be as much as 3 or 4 feet -- just as we find with vetiver hedge barriers.

This paper reinforces the need to plant dense vegetative barriers (hedges) along farm field boundaries in our efforts to mitigate climate change and intensified agriculture. Under small farm agriculture in the tropics, where landholdings are extremely small, vetiver "hedgerows" make ideal boundary barriers, and when properly managed, take up minimum space, have an infinite lifespan, and provide many secondary benefits.

THE VETIVER LATRINE

THE VETIVER LATRINE from Roger Gietzen (see: http://www.healthy-mind-body.com/humanitarian/vetiver_latrine.html for details of vetiver latrine design and its construction)

"It's now been three years since I started installing vetiver latrines in Haiti.  For all those who helped me with that project, I want to thank you again.  You know who you are.  Here is an update on my progress: 

175 latrines have been installed in the two communities I serve.  They are providing sanitation where there was absolutely none.  The people are happy and likely healthier.  There was not a case of cholera this last year, whereas in the previous years there was always 1-2 during the rainy season. But these numbers are too small to draw conclusions from.

Black Vetiver - Chrysopogon nigritanus

C. nigritanus on a flood plain in northern Ghana

More on Chrysopogon nigritanus.  I have continued investigations into this species of vetiver - common name ”Black vetiver”. It is found in nearly all sub-saharan African countries generally in association with river flood plain and seasonally flooded areas. For example the peripheral  areas of the Kafue River flats in Zambia, and the flooded areas of the Niger and Senegal rivers of West Africa. Its main uses include medicinal, freshening drinking water, thatch, handicrafts, forage (when young after burning), and farm boundary marking.

It appears only to propagate naturally from seed in these permanent/semi-permanent waterlogged areas.  Outside of such areas seeds either do not germinate or die after germination, and if used domestically the plant is propagated through slips.

The species appears to be retreating. Tony Cisse who farms near Dakar, Senegal only grows C.zizanioides descended from Chris Juliard’s importation (ex South Africa) initiative (1990s). He writes "Traditionally the most common use for C.nigritanus in Senegal has been for the roots that are added to drinking water. This is the common way people recognize the plant and its name in local languages. Whereas it would seem logical that it should be grown locally, there is now very little evidence of this. Vetiver roots are imported from neighboring Mali, and sold in small bundles. I have heard it was used in the past (possibly over 60 years ago or more) to demarcate fields, but I have never seen nor heard of it growing naturally, at least in the western areas of Senegal.  Reasons for this are likely to be associated with climate change and the drop in annual rainfall. There are very few areas that can be designated as flood plains, and standing water and ponds are generally very rare if they exist for more than a few weeks at most during the rains, and so this could account for this absence, although still present in Mali. The water table in much of Senegal is below the reach of vetiver roots. It is possible that there are parts of Eastern or northern Senegal along the river where the right conditions for C. nigritanus exist, but I have not been there to observe".  In Nigeria and other African countries, where new dams have been constructed, the downstream flood plains are no longer flooded and wild vetiver seems to be a diminishing component of the ecosystem.

C. nigritanus hedgerow for erosion control - Mambila Plateau Nigeria

Sterile non invasive C.zizanioides remains the preferred choice for all Vetiver System applications. Even though Nigerian research does support C. nigritanus for erosion control and phytoremediation applications note C. nigritanus has NOT been tested for steep slope stabilization and virtually no work has been carried out to identify many of its characteristics - depth, tensile strength, shear strength of its roots; pest control properties, forage value, and others) I would recommend its use for erosion control and phytoremedial applications where it is a native plant, and then only after exhausting all efforts at locating and propagating C. zizanioides. In either case propagation has to be by clump division, so it would be best to use the superior and well tested C. zizanioides particularly where country wide programs are developed and where many nurseries will be required.

C. nigritanus grown on the campus of Abuja University, Nigeria.

Further research on C. nigritanus should be encouraged. Trials might well identify many more characteristics similar to those of C. zizanioides and may also better delimit areas where it is most suitable for application. Both species are very closely related and appear to behave rather similarly. Determining those differences would reinforce future recommendations.