Monto Vetiver Grass
Vetiver grass - Chrysopogon zizanioides – commonly known as Monto grass, also call khus khus, is a tropical clumping grass with its origin in south India, where it has been used for centuries to mark boundary lines. It has the ability, when planted close together in a line, to create a near perfect barrier that filters out sediment, spreads rainwater, improves the shear strength of soil, and recycles soil nutrients.
Vetiver grass has been successfully used for environmental protection purposes in Australia, Asia, Africa, Europe and Latin America. The QDPI has selected Vetiver grass for soil and water conservation purposes.
Vetiver grass has been used world-wide for;
- soil erosion control
- stabilisation of slopes and banks
- wastewater and sewage treatment
- treatment of contaminated water and land
- agriculture improvement
The fragrant, insect-repelling roots yield an oil which is valuable in the perfume industry. Traditionally the roots were woven into mats, fans and fragrant screens. The tops of the grass were used for thatch, mulch, handicraft, fodder and animal bedding.
Vetiver grass is a clumping grass, with erect and stiff stems that grow to as much as 2m high. The roots can grow very long (3-5 m) and in the main do not spread much beyond the footprint of the crown of the plant.
When planted in single lines along contours, hedges of vetiver are found to be very effective in soil and moisture conservation. A well-established vetiver grass hedge will slow down rainfall runoff, spreading it out evenly, and will trap runoff sediments to create natural terraces. This allows more water to be absorbed into the soil, thus reducing run-off and erosion and also improving crop yields.
Stabilisation of slopes and banks
The Vetiver System can effectively and at low cost, protect slopes, stop or significantly reduce the risk of slippage, and prevent down-stream water contamination. This is because vetiver grass has vigorous, massive, dense, deep and penetrating root networks, reaching vertically 2-5m depths. These roots bind the soil and reinforce the soil structure against erosion. The roots have a high tensile strength - average 75 MPa that can increase shear strength of soil by a factor of 40, and because when planted on slopes vetiver will reduce slope hydraulic pressures through the removal of water. The combination of slippage prevention (mass wastage of soil) and its sediment filtering ability results in very clean water moving down the catchment.
Wastewater and sewage treatment
Vetiver grass is also widely used in Australia, China, Thailand and other countries for industrial and domestic wastewater treatment and recycling. Research has shown that vetiver grass has a fast and very high capacity for absorption of nutrients, particularly nitrogen and phosphorus in wastewater. Vetiver Grass takes up the water and in particular the grass will remove the nutrients from the water that passes through it.
Contaminated water and land
The Vetiver grass will tolerate high levels of nitrates, phosphates, heavy metals, and agricultural chemicals. Monto vetiver is tolerant to the most adverse conditions such as high acidity and alkalinity, high levels of salinity, pesticides and herbicides and also tolerates a wide range of heavy metal toxicities. The Vetiver System takes up the toxic materials and confines the contaminants to the affected area. In addition Monto Vetiver has a very high capacity to uptake N and P in soil and polluted water or wastewater. It also sequesters significant quantities of atmospheric carbon. The Vetiver System can be used for treating wastewater, recycling sewage effluent, rehabilitating mine tailings, stabilizing landfills and general rubbish dumps and controlling leachate.Vetiver tolerates very high levels of aluminium, manganese and a range of heavy metals in the soil.
The Vetiver System has many agricultural uses for: soil and water conservation, soil moisture improvement, groundwater recharge, recycling soil nutrients, pest control, mulch, forage, clean up of agricultural contaminated waste water, protection of farm infrastructure (canals, drains, roads, and building sites). The Vetiver System will reduce soil loss from farm land by as much as 90% and will reduce rainfall runoff by as much as 70%, thus significantly increasing the effective rainfall available to crops. The impact goes further - groundwater is recharged to the extent that ephemeral streams flow longer and stronger, wetlands are rejuvenated, wild life habitat is improved and soil fertility improves - resulting in increased crop yields that have been measured as much as 40%.
Vetiver can withstand burning, slashing and moderate tractor traffic. It is quite resistant to fire when green and resists infestation from most pests, diseases and nematodes.
Vetiver is non-invasive, has no runners or rhizomes and only spreads by division.
Vetiver is adaptable to a wide range of soil and climatic conditions. It can be established on very acid, sodic, alkaline or saline soils.
Vetiver grows in areas with an annual rainfall greater than 450 to 500mm. Due to its extensive and deep root system, it is very tolerant to drought. Established plants can stand extreme heat (50˚C), and frost (-10˚C) although plants are susceptible to frost during the establishment phase.
Vetiver is sensitive to full shade as this retards growth, especially in young plants.