The shrinking good quality lands and environmental degradation due to mismanagement and over exploitation of natural resources is a major challenge facing the world.

In developing countries, not only good quality lands are degraded by wind and water erosion, water-logging and salinity, loss of organic matter and biodiversity etc., but also are contaminated with heavy metals. With the expansion of industries on good quality rural lands, the farmers are irrigating their lands with effluents.

Various physical, chemical, and hydrological approaches are being developed and used to control soil erosion, soil salinity, and land degradation. These practices, however, happen to be very expensive and beyond the reach of the rural communities. In the situation, the emergence of alternative technologies such as the Vetiver system (VS), which involves the use of Vetiver grass, Chrysopogon zizinoides (old nomenclature Vetiveria zizaniodes), is being explored to restore the degraded lands and it seems very feasible, economical and environment-friendly.

This plant is both economically and ecologically important. It is able to act as a natural barrier against erosion and pollution and produces massive odorous root system which can be used for the extraction of an essential oil of great economic importance. The Vetiver has been named as the plant of the millennium based on its innumerable novel and marvelous qualities.

China, Australia, Vietnam, Thailand, Bangladesh, etc. are using the Vetiver system for river bank and dyke/stream bank stabilisation, mitigation of soil and water pollution. The use of VS on agricultural lands is not being utilised at its fullest extent in the world in general and in Pakistan in particular. It is anticipated that the Vetiver technology will make a significant difference in ameliorating the environment, conserving natural resources, and enhancing rural economies.

In this country this grass, commonly known as ‘khas’ or khas khas’, is extensively used for its scented roots in air coolers in summer, resulting in its depletion from its original habitats.

Most of the agricultural extension staff, rural developing agencies and farmers have little or no knowledge of the Vetiver system as little or no scientific work has been carried out by the scientific community.

The VS technology can play an important role in conserving and protecting all arable and grazing lands from any form of soil degradation and reclaiming degraded lands. By incorporating Vetiver grass, the farmers can increase the production .

Vetiver needs to be incorporated in the farming menu, and rural development initiatives while involving all the stakeholders including government organisations, extension service agents, researchers, NGOs and educational institutions.

Heavy metals being added to our soils through industrial, agricultural and domestic effluents, persist in soils and can either be adsorbed in soil particles or leached into ground water. Human exposure to these metals through ingestion of contaminated food or uptake of drinking water can lead to their accumulation in humans, plants and animals.

With the increasing use of agrochemicals to maintain and improve soil fertility, unwanted elements such as cadmium enter the soils due to contaminated sources of fertilisers and are introduced into agricultural soils, which, poses a potential threat to the food chain.

Non-biological remediation techniques: Various physical and chemical techniques to de-contaminated soils have been undertaken during the last 25 years. However, all of them are labour intensive and costly, and cannot be applied to million of hectares of land contaminated with inorganic heavy metals. These technologies result in rendering the soil biologically dead and useless for plant growth as they remove all flora, fauna and microbes including useful nitrogen fixing bacteria and P-enhancing mycorrhizal fungi.

Biological remediation techniques: Microbial bioremediation technology, well known for decontamination of organics, is not available for large-scale biodegradation of inorganic heavy metals. The health hazards caused by the accumulation of toxic metals in the environment together with the high cost of removal and replacement of metal-polluted soil have prompted efforts to develop alternative and cheaper techniques to recover the degraded land. Restoration of derelict land by establishing a plant cover is important before it poses serious health hazard by transferring the trace metals into the surroundings.

Current research in this area now includes utilisation of plants to remediate polluted soils and to facilitate improvement of soils structure in cases of severe erosion, the innovative technique being known as phyto-remediation. No botanical or biogeochemical exploration of trace metal tolerant and/or accumulating plant species has yet taken place in many parts of the world, including Pakistan. Many plant species, which can accumulate high concentrations of trace elements, have been known for over a century. Renewed interest in the role of these hyperaccumulating plants in phyto-remediation has stimulated research in this area and several plant species or ecotypes, associated with heavy metal enriched soils, accumulate metals in the shoots.

These plants can be used to clean up heavy metal contaminated sites by extracting metals from soils and accumulating them in above ground biomass. The metal enriched biomass can be harvested and smelted to recover the metal (phytomining).

Plants for phytoremediation: Plants that are used to extract heavy metals from contaminated soils have to be the most suitable for the purpose, i.e. tolerant to specific heavy metal, adapted to soil and climate, capable of high uptake of heavy metal(s), etc. Plants either take up one or two specific metals in high concentrations into their tissues (hyperaccumulators) with low biomass (Chaudhry et al., 1998)), or extract low to average heavy metal (not metal specific) concentrations in their shoots with high biomass.

Low biomass hyperaccumulators, generally, have a restricted root system. In contrast, non-accumulators, high biomass producing and tolerant plants have physiological adaptation mechanisms, which allow them to grow in contaminated soils better than others. The tolerance and specific behaviour at the root level must be taken into consideration while selecting plants for phytoremediation. Root system morphology allows some plants to be more efficient than others in nutrient uptake in infertile soil or stressed soil conditions.

Vetiver grass as phytoremediation: The Vetiver grass (Chrysopogon zizanioides) has been known to be a useful plant for thousands of years and has been cultivated for the production of scented oil produced by its roots as well as for its ability to retain soil and prevent erosion. It is a perennial grass belonging to the family Poaceae (Gramineae), originally from India, growing wild or cultivated. Since late last century, it is being used by the sugar industry in West Indies, Fiji, and eastern African islands like Mauritius for its soil conservation properties.

Recently the grass, due to its eco-friendly nature, found a new use for phytoremediation of contaminated sites. The Vetiver grass is both a xerophyte and a hydrophyte and, is not affected by droughts or floods. It is highly tolerant to droughts and water logging, frost, heat, extreme soil pH, sodicity, salinity, Al and Mn toxicity.

It is also highly tolerant to a range of trace elements such as As, Cd, Cu, Cr, and Ni. It is suitable for the stabilisation and rehabilitation and reclaiming of acid sulfate and trace metals contaminated soils, i.e. phytoremediation. This grass has been extensively used for land protection by mitigating soil erosion and water conservation, especially on very steep slopes, due to its faster root growth, i.e. root length may reach up to 3 m just in one year. Vetiver grass is regarded as a tool for environmental engineering and as one of the most versatile crops of the third millennium.

The Vetiver system (VS) is an effective, low-cost, and environmentally friendly technology to clean HM contaminated soils. The VS is emerging as an alternative technology for rehabilitation of degraded, saline, or trace metal contaminated soils, and for purification of water polluted with trace elements, agrochemicals, and industrial- effluent disposals. The success of phytoremedial efforts is not only dependant upon the choice of plant species but also their method of establishment.

Among the plants involved in phytoremedial measures, the Vetiver grass should receive special attention. It is a densely tufted, awnless, wiry and glabrous plant occurring in large clumps as hydrophyte or xerophyte on vertisols through to red alfisols. It can grow on both acidic (pH3) and alkaline (pH11) soils, and is tolerant to high levels of various trace metals such as arsenic, cadmium, copper, chromium and nickel (Truong, 1999). It produces up to two m high plant with a strong dense and mainly vertical root system often measuring three meters, useful in soil erosion control. It is propagated vegetatively and is non-invasive. It is extremely resistant to insect pests and diseases and is widely used worldwide for soil and moisture conservation and soil restoration. It is immune to flooding, grazing, fires, and other hazards.