ations of experience, careful observation and trial-and-error experiment. In many cases, traditional knowledge has been orally passed on for generations through stories, legends, folklore, rituals, songs and laws. In agriculture, these are built up through generations of farming and managing for­est and water ecosystems. While traditional knowledge is entrenched in these communities, it is also considered dy­namic because it adapts to and incorporates new knowledge from outside sources to suit gradually changing environ­ments (Grenier, 1998).
     Traditional knowledge has helped maintain and im­prove the livelihood of farming communities. In many rural communities, it governs local decisions in agriculture, health care, food preparation, education and natural resource man­agement (Warren, 1991). Traditional knowledge is being recognized as a base for many sustainable development ini­tiatives, such as sustainable agriculture and natural resource management, enriching global agricultural knowledge. It has produced lessons and insights in addressing rural hun­ger and poverty and accounted for on site crop genetic con­servation, crop diversification, regenerative soil and water management, organic agriculture and ecological pest man­agement. Much of sustainable agriculture has its roots in traditional and indigenous practices that are viable because of generations of innovation and improvement prompted by the sharing of knowledge and resources.
     In general, traditional systems are perceived to have great potential because (1) they are inexpensive and may be paid for in goods or services, (2) they are readily available and accessible even to those who do not have cash income, (3) people are more comfortable using them than western technology and (4) when combined with modern practices they provide more options for innovation in dealing with complex agricultural problems. However, traditional agri­culture is labor intensive. This may be viewed as either a disadvantage or an advantage, depending on the social cir­cumstances. For example, the additional labor might keep people from other economic activity. On the other hand, it could provide meaningful employment for rural people who would otherwise migrate to urban areas, thus creating adverse social effects such as leaving behind a household without its male head and potentially contributing to urban unemployment and poverty.
     In most cases, traditional knowledge is not only socially desirable but also economically affordable  and sustain­able and poses little risk to rural farmers. Since traditional knowledge evolved gradually within the community, it is appropriate to the needs of the local people (Rouse, 1999). Traditional systems are more directed toward self-reliance and self-sufficiency than some modern technology  (Fer­nandez,  1994). However, traditional agriculture has not been able keep pace with increased population pressure, evidenced by the great famines of the 1950s, 1960s and 1970s in Bangladesh, China and India. Traditional systems appear unable to provide sufficient food for current urban populations. What they can do, however, is provide prod­uct diversity equal to, if not greater than the total biomass production of conventional equivalents, while conserving scarce resources and providing food security for the pro­ducers (FAO, 2002). In general, the greater the biological diversity of the agricultural system, the greater is its ability

to withstand adverse climatic and pest events (FAO, 2002). In addition, there is historical evidence of wetland rice yields in India higher than present yields supported by chemical fertilizers and pesticides. In the 1700s, the yields in 800 vil­lages near Madras were reported to have averaged 3.6 t ha-1, surpassing 10 t ha-1 in some areas, whereas the current yield in that region averages 3.1 t ha-1. Genetic diversity was the main weapon against pests and diseases; but, from using about 30,000 traditional rice varieties, India now uses only a few, with 75% of rice produced coming from only 10 va­rieties (ESCAP, 2002).
     Today about 70% of the world's indigenous peoples live in Asia and the Pacific, where they are a major subgroup of the rural poor. Indigenous knowledge and traditional agricul­tural systems can provide answers to their food security needs. However, resource access is important. Marginalizing many indigenous communities could lead to the eventual loss of tra­ditional knowledge. Many of these communities are being de­prived of the ability to lead the lives they value (IFAD, 2002).
     Traditional knowledge  is  increasingly  becoming  ac­ceptable to the scientific community. In fact, "informal" research is being done in local communities by using tra­ditional knowledge (Stanley and Rice, 2003). In contrast, much past research failed from the lack of knowledge and understanding of local practices. Technology generated by formal research institutions can complement and improve indigenous methods.
     Before modern agricultural practices were developed, indigenous communities had already devised methods to en­sure the success of their agriculture. A common example of traditional knowledge emanating from communities is use of the neem tree (Azadirachta indica) in India as a natural fertilizer, pesticide and medicine. Knowledge of indigenous practices on crop protection and fertilization can be appre­ciated when developing appropriate programs for pest and soil management within the capability of farmers and that do not cause adverse effects on either the community or the environment (Varisco et al., 1992). It was estimated that in 1985, plant-based medicines, many first discovered by indigenous peoples, valued at US$43 billion were sold in industrial countries (Posey and Dutfield, 1996). As advances in biotechnology broaden the range of life forms contain­ing attributes with commercial applications, the full market value of traditional knowledge will definitely increase.
      Traditional knowledge is also important for food secu­rity and genetic conservation. In Nepal, a centuries-old seed management system allowed farmers to grow and protect their seeds (Timsina and Upreti, 2002). Modern plant breed­ing owes much to the landraces bred, conserved and devel­oped by traditional communities over the millennia. These local varieties have been the continuous source of genes used to develop and improve high-yielding varieties.
     In India, a study revealed that traditional health con­trol and treatment systems were effective in curing ailments in animals, including dysentery, arthritis, dog bites, coughs and colds, anestrus, wounds, bloat and diarrhea. Although modern veterinary medicines provide quicker cure, tradi­tional treatments are cheaper, locally available, and have fewer side effects (De Amitendu et al., 2004).
      Indigenous people have practiced sustainable forest use and management for centuries. Jackson and Moore (1998)