Tho's hypothesis is that Vetiver 'wicks' moisture up to the accompanying plant's roots....even when both plants are planted in the same hole.
In Thailand, as elsewhere (like my own garden) , vegetable beds are laid out with similar attributes in mind by bordering them with Vetiver hedges.
As you can see (click on image to enlarge), the Vetiver is also cut for mulch.
Vetiver roots -- which can go down 2 metres -- are also sponsoring of rich microbial activity and carbon sequestration. As well the stems and scented leaves offer various means of protecting companion-ed plants from bugs.
For those interested an updated users manual for Vetiver is freely available online.HERE.
Full of DIY approaches and tips for applying Vetiver to your land.
It begins with a discussion about sheet erosion and explores the many uses and properties of the grass..
When planted correctly (i.e. close together), it will quickly form a dense, permanent hedge.
•Has a strong fibrous root system that penetrates the soil verti-cally and binds the soil to a depth of up to 3 meters and can withstand the effects of tunneling and cracking.
•Is perennial and requires minimal maintenance.
• Is practically sterile - it produces no stolons or rhizomes, it seeds are sterile . It will not become a weed.
• Has a crown that is below the surface, which protects the plant against fire and overgrazing.
•Has sharp leaves and aromatic roots that repel rodents, snakes, and similar pests.
• Has leaves and roots that have demonstrated a resistance to most diseases.
• If managed correctly it makes an excellent fodder....
• Is both a xerophyte and a hydrophyte, and once established, vetiver grass can withstand drought, flood, and long periods of waterlogging.
• Will not compete with the crop plants it is used to protect, and in fact, vetiver grass hedges have been shown to have no negative effect on - and may often boost - the yield of neighboring food crops.
• It has associated nitrogen processing mycorrhiza, that explains its green growth throughout the year.
• Is cheap and easy to establish as a hedge and to maintain—as well as to remove if it is no longer wanted.
• Will grow in all types of soil, regardless of fertility, pH, or salinity, including sands, shales, gravels, and even soils with aluminum toxicity.
• Will grow in a wide range of climates and is known to grow in areas with average annual rainfall between 200 and 6,000 millimeters and with temperatures ranging from a ‘flash frost” of -14º to +55º Centigrade.
• Is a climax plant; therefore, even when drought, flood, pests, disease, fire, or other adversity destroy all surrounding plants, the vetiver will remain to protect the ground from the onslaught of the next rains.
Thanks! I'll also send Paul a copy.
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