Adding Value to Invasive Weed to Improve Cambodian Livelihoods

For millennia, the animals and plants found abundantly in the water bodies and wetlands of Cambodia have been a primary source of food for people, at least as important as rice. The country's main freshwater body, the Tonle Sap Lake, was until recently a core element of food security. But climate change and industrial land use have seriously reduced these benefits, and stakeholders are now seeking to mitigate these changes and find alternative livelihoods in the basin of Southeast Asia's largest lake. Water hyacinth (Eichhornia crassipes) - an introduced weed native to South America known as 'kamplauch' in Khmer - is widely seen as an environmental disaster, choking water bodies and decimating fish recruitment. The fast-growing weed damages fish populations by covering the water surface and reducing oxygen levels. In Cambodia, the flowers are eaten raw, typically with the fermented fish paste known as 'prahok', a staple food in Khmer cuisine. They are also consumed with "teak kroeung" (prahok mixed with fish) and noodles. But the biomass of water hyacinth is also a natural resource which can provide even greater support to livelihoods for people living around water bodies and wetland areas. ADDING VALUE Many technologies exist for adding value to water hyacinth. The three most successful are floating gardens, woven fabric handicrafts and animal feed (including poultry and fish feed). Other possibilities include bio-fertilizer (as compost or for cultivating worms) and biogas. Floating gardens adapt to the fluctuating aquatic environment of floating and inundated communities around the Tonle Sap. Commercially viable water hyacinth products include handicrafts and industrial fabrics woven from the stems, and protein for animal feed extracted from the leaves. These technologies are used elsewhere in the world and are well understood. Research into community-based value chains and adaptation is required to reach economically viable thresholds in Cambodia. Water-hyacinth handicraft enterprises have already b een established by international non-governmental organisations and the private sector in Cambodia. And successful pilot work on floating gardens has already been carried out in three provinces around the Tonle Sap Lake. Different enterprises use different parts of the plant. FLOATING GARDENS In Bangladesh and Myanmar, water hyacinths and other aquatic weeds are built up to become a floating bed used to support various crops. Vegetables and spices are the main crops of such floating-garden systems. In one study, Bangladeshi villagers grew 23 different types of vegetables and five types of spices. In seasonally flooded areas, the beds are spread over the soil as the water recedes. Dry-season crops can then be grown on this soil without further tillage or fertiliser. Economic analysis of the system shows very high returns because the plants have their roots immersed in the water within the floating bed, therefore getting high rates of nutrient and oxygen transfer. This is in fact an ancient hydroponic sy stem. WOVEN FIBRE AND HANDICRAFTS Dried and woven water hyacinth stem is used extensively as a material for the upholstery of furniture, and other handicrafts such as handbags. The industry is well developed in Vietnam, China and Indonesia, with some development also in Thailand. There are already some very sophisticated product designs on the market, which are sold in the region or to Western buyers. Stems can be harvested at the same time as preparing floating beds (the flotation comes from the special structures around the roots and culm). Stems are sun-dried, bundled and sold to factories for weaving. Some enterprises support weaving operations at the household level, with skills training and designs provided. LEAF PROTEIN Research shows that up to 22 percent of the dry weight of water-hyacinth leaves contain crude protein, with a good amino acid profile (high leucine and phenylalanine and significant levels of most other biologically important amino acids). Digestibility is suitable for fish and livestock diets. Production technology for leaf protein concentrate (LPC) is simple grinding and aqueous extraction followed by thermal/lowered pH precipitation. Equipment is simple - grinding machinery, boiling vessels, a heat source, plastic drums for precipitation and gravity-filtration systems. POSSIBLE RESEARCH FOCUS The Inland Fisheries Research and Development Institute of the Fisheries Administration - part of the Ministry of Agriculture, Forestry and Fisheries - is considering research into adding value to water hyacinth. Improving livelihoods - especially for people living around the lake but also other waterways and wetlands - would be the goal of such research. The focus would be community fisheries which are legally mandated to include community- based aquatic resource management. The Fisheries Administration oversees community fisheries through its Department of Community Fisheries Development and institute for research purposes. Source: Agence Kampuchea Presse