In 1893, a far-sighted German agronomist smuggled 66 samples of the succulent plant Agave sisalana (sisal) out their native Yucatan peninsula in Mexico and took them to Germany's East African colony of Tanganyika. The hardy agave, which produces some of nature's longest and strongest plant fibres, thrived in the country's hot tropical climate and by the early 20th century was producing the ropes of the German naval fleet.

Under German, then British, administrators, sisal fibre became the colony's main export commodity, highly prized for use in cordage and carpets worldwide. When the United Republic of Tanzania was born in 1961, it was the world's biggest sisal grower, with fibre production of 200 000 tonnes a year. Sisal was the country's main foreign exchange earner and its cultivation and processing employed more than one million people.

Output shrinks. Then, in 1967, most of the sisal industry was nationalized, leading to severe disruption of its efficiency and output. Around the same time, sisal fibre was targeted by the manufacturers of synthetic substitutes, who were often supported by restrictive trade policies and subsidies. In less than 15 years, polypropylene textiles and twine claimed more than half of sisal's market, dealing a heavy blow to production in Tanzania, China and Mexico. By 1998, Tanzania's sisal output had shrunk to 19 000 tonnes, less than 10 percent of its peak in 1964, and Brazil had emerged as the world's leading sisal supplier.

That same year, sisal began to make its comeback in Tanzania. The sisal industry was re-privatized, mainly into the hands of Tanzanian businessmen, and investors and development agencies joined efforts to revitalize sisal production. "Sisal has huge potential," says Salum Shamte, managing director of Katani Ltd., one of the country's leading sisal producers. "It can be grown throughout the year, even on marginal land and in semi-arid areas, and inputs such as mineral fertilizers and pesticides are not a pre-requisite. Those are serious advantages for an agricultural product, especially in poor areas where agriculture is the mainstay of the economy."

Renewing Tanzania's sisal industry requires diversification from traditional products to newer applications where strong, plastic non-synthetic materials are needed. "Traditional products such as twines, ropes and bags must be improved to combat competition," says Shamte.

But we must also intensify efforts to produce and market those products where sisal has technological, environmental, geographical and cost advantages - in specialty paper, padding for cars, insulation material, roofing tiles and fibreboard, and in environmentally friendly composite materials.

Cash crop. Tanzania's small-scale farmers will play an important part in sisal's future. Katani Ltd has launched a sisal outgrower scheme on five of its estates in Tanzania's Tanga Region, allocating more than 12 000 hectares to 2 500 farm families. The company provides loans, extension advice and technical services that have allowed the farmers to grow sisal as a cash crop along with traditional food crops such as maize and beans. According to Katani, sisal farmers' income has increased to an average of US$320 a month, earned throughout the year, compared to less than US$40 a month among subsistence maize farmers.

Agave sisalana offers a range of other uses. The biomass left after fibres have been removed represents as much as 98 percent of the plant, and most is now flushed away as waste. To exploit the economic value of this material – amounting to some 15 million tonnes annually - the Common Fund for Commodities, UNIDO and the Tanzanian sisal industry have funded the first commercial plant to use sisal residues to produce biogas, electricity process heat and fertilizer. Ongoing evaluation of the plant indicates that 75% of the energy produced could be distributed to rural homes and 25 percent used in sisal processing.