The development of biofuels over the last decade has been highly controversial, with negative media attention focusing on the impacts of subsidized biofuel production on food prices, the destruction of the rainforest to make way for new plantations or farms, and the trampling of local land rights. This criticism has led to the quest for more sustainable biofuels, with efforts to develop best practice and certification schemes, and to identify new “candidate crops” for sustainable biofuel production. Jatropha curcas rose to prominence among these candidates.

Jatropha is indigenous to Mexico, but has spread across the tropics as an ornamental plant—an inedible perennial that could, optimists hoped, be grown by poor, small-scale farmers on degraded and semi-arid land, thus helping sustain rural livelihoods through biofuel production without infringing on food production. But others feared that jatropha was a veiled excuse for land grabs, a harmful invasive species, and detrimental to soil quality.

While these controversies played in the background, biofuel companies arrived in African villages looking for seed to start nurseries. Initially they paid high prices for seeds, which had never been of any commercial use to the villagers. This quickly raised interest in local communities, facilitating subsequent recruitment efforts by these companies to grow jatropha as a crop in the field rather than on marginal lands.

As it turned out, this “miracle crop,” like most crops, only flourishes with fertilizer, weeding, pest control, and other general labors and expenses. Most farmers gave up on growing this perennial in the field, but they continued to harvest and sell the seeds of existing trees. Investors, disappointed by low yields and production volumes, pulled out.

Thousands of Zambian farmers were left with unsold seed after the hype, but this is the story of a village that embraced the opportunity to produce a local commodity with higher economic and social value: soap.

The Village Ecology of Jatropha

In the eastern province of Zambia, where farming is the economic mainstay, maize is not only the staple crop but also the main cash crop, thanks in part to a long tradition of government subsidy and purchase. The second most common cash crop is cotton, produced for the multinationals Dunavant and Cargill. Other crops grown largely for subsistence include groundnuts, cowpeas, sunflower, and pumpkin. Most farmers have some livestock, and ox-drawn ploughs are widely used.

In the villages, each household has its own yard, which contains a variety of small wooden structures, from sleeping huts and storage sheds to kitchens and bathrooms. At the yard’s edge, using species not browsed by livestock, people plant trees or bushes as windbreaks or property borders. Jatropha is one of these species.

The villages are not dense or homogeneous. If their parents are alive, young villagers who start their own family must build their abode at the edge of the village. Housing slowly expands into surrounding common land, reducing over time the area available for cattle grazing and fuel wood collection. The agricultural fields tend to be farther out, and so are unaffected by this expansion. When all the children have already built their own houses and started their own families, then the parents’ place will be abandoned upon their death. Within a few years, all that remain of the old homesteads are the (now) big bushes around the old properties, which accounts for the abundance of mature jatropha trees in original village centers.

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Dan van der Horst
Jatropha seeds once held great promise as feedstock for biofuels. As it turns out, their use for local soap production can be both much more economical and environmentally sound.

The Economics of Jatropha Soap Production

A former employee of a now defunct Australian biofuel company introduced us to Sikwenda village. It was one of the places where he had tried to recruit farmers to grow jatropha as a field crop. None of these field trials succeeded, but the tree persisted and remains the single most abundant species in the village. Some farmers have also started planting new jatropha hedges around their vegetable gardens in order to keep out goats.

We interviewed villagers in Sikwenda and asked what potential uses of jatropha seed they knew. They had heard of soap making, but never tried it. Soon after our visit they had formed a group, named it Kasike (a religious reference meaning “from above”), and asked if we could find them someone to teach them to make jatropha soap. Deviating from our original research plan, which was to study how farmers combine traditional knowledge with outside expertise when adopting new cash crops,1 we decided on an action research experiment. We connected Kasike with an experienced soap maker and bought some caustic soda from the capital Lusaka.

They have been making soap on their own ever since. The quantitative data below are based on Kasike’s experience, unless stated otherwise.

Members of the Kasike group collect seed inside the village and rent a ‘yenga’ press to extract oil from the seed. This oil is mixed with water and caustic soda at a ratio of 8:8:1, by volume. The soap must then dry for two weeks, with one kilogram of soap containing roughly one liter of jatropha oil, and offering a far more lucrative product than the straightforward sale of seed.

Seed is valued at US$0.10–0.16 per kilogram (kg), diesel at $1.5/liter (pump price), and soap at $2.5–5/kg. A farmer therefore gets two to three times more value from the oil than from the seed, and two to three times more value from the soap than from the oil.

In short, it makes no economic sense to sell the oil as a diesel substitute. And with the price of oil pegged to diesel prices at the pump, soap has the additional benefit of offering opportunities for higher value niche markets, including sale to tourists and export to the global north as a fair-trade, herbal, and organic product.

Jatropha Soap by Numbers

Twenty kilograms of seed yields four liters of oil, which is processed into four kilograms of soap. The production costs of this batch of soap are:

  • Seed: 20kg * $0.10 = $2 (price previously paid by biofuel company)
  • Caustic soda: 0.5kg = $1.2 (shop price; wholesale price is 50 percent lower)
  • Labor to press oil (eight hours) and make soap (two hours) = $5 (the official minimum wage in Zambia is $4/day)
  • Rental of press: $2 (based on press rental for sunflower)

Total cost = $2.55/kg soap. Sale yields $2.5–5/kg, so net profit is $0–2.45/kg soap. Even if profit is zero, the farmer earns a worthwhile wage of $1.75/kg soap. Wage labor at $4/day is difficult to find in rural areas, so this is an attractive prospect. Kasike members have been selling their soap at the lower end of this range, but jatropha soap makers in other parts of Zambia, who have received training in marketing, are easily selling their soap at the higher end of this range.

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Dan van der Horst
Young women in Zambia mix jatropha oil with water and caustic soda, a simple recipe for making soap.

Jatropha Soap as a Consumer Product

Locally, jatropha soap has proven very popular, with villagers excited to make it and keen to use it. They have complimented its good lather, softness on hands, and catalyzing properties in healing cuts and infections—more so than the industrially produced soaps they normally use. We’ve also observed the soap’s use in washing clothes, thus reducing local reliance on detergents. This particular substitution is very interesting from a carbon perspective: The life-cycle carbon footprint of detergents is very high. One liter of jatropha oil can reduce more carbon emissions by displacing detergents than it can by displacing diesel fuel.

Homemade jatropha soap, of course, has disadvantages in the eyes of some consumers. Commercially produced soaps are better packaged, contain perfume, and don’t get soft as quickly. The first two disadvantages could be addressed in the future through further product development. Kasike members are currently experimenting with molded shapes using plastic bottles, as well as with ways to combine natural herbs and perfumes in their soap.

The Health Economics of Jatropha Soap

A soap-use survey conducted among Kasike members in March 2012 showed that four out of five households, having run out of soap and money, experienced more than one soap-free day per month. This was particularly likely to happen during the lean months: Farmers sell their maize and cotton crops in June and July, often resulting in cash scarcity during the middle of the rainy season, from January to March, when the new crops are not yet ripe and there is nothing to sell. Being without soap caused significant personal discomfort, and people felt deprived without clean clothes to wear or soap with which to wash after a day of hard, sweaty work in the field. People also recognize that being without soap increases the risk of infection and disease, especially in the case of skin diseases—more common in the wet season—and dirty hands after visiting the toilet. Diarrhea infections are a leading cause of childhood illness and death,2 but research shows that nearly 50 percent of gastroenteritis cases can be prevented by good hand washing practices using soap.3 It could thus be argued that domestic soap making can help to avoid soap-free days, and that improved access to soap (i.e. more “soap security”) will result in fewer cases of skin disease and gastroenteritis. These benefits can be augmented by, for example, integrating soap making into the school curriculum in combination with hygiene promotion. Women are traditionally tasked with cooking and looking after young children, so they are the key stakeholder and beneficiary of greater local soap production and access.

Scaling and Replicating Soap Production

Jatropha is common and widespread across rural Africa, and soap is a popular and important item in the household budget. Yet, since the biofuel boom collapsed, most jatropha seeds are left to rot under trees. This opens tremendous opportunity to expand the skills and practice of soap making. Given seeds and the knowledge, all that’s missing are caustic soda and an oil press. The former is easily obtainable in urban stores, and it should not be difficult to persuade rural shops, consumer co-ops (commonly organized among Zambian farmers for the purchase of fertilizer), or other rural institutions to buy a bulk quantity of caustic soda and resell it in smaller amounts.

The central barrier to soap production is, then, access to an oil press. Although soap production at scale would easily recuperate the investment, up-front costs are high (a manual press costs $300 in Zambia) and manual presses are labor-intensive devices. Investment in a new press would most likely come from a wealthier individual who can afford to buy the press and rent it out, or from a cooperative enterprise. A third option is for locally embedded nongovernmental organizations to buy a press and offer it on rotation in the villages where they work. Interviews with several individual yenga press owners, who generally use the press to produce cooking oil, revealed a reluctance to allow their press to be used for jatropha oil pressing, for fear of the poisonous properties of jatropha. This important issue can be overcome by washing the press with hot water and soap after use—a practice already in place among members of Kasike.

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Dan van der Horst
Children display locally produced jatropha soap in Zambia. Kasike, the manufacturing union, is now working on molded shapes and herbal perfume for its jatropha soaps.

Despite these stumbling blocks, there is enough interest in soap making that the Kasike farmers are setting up a peer-training program to expand soap making outside of Sikwenda. It is important to note that cooperative modes of production, as opposed to purchase, are institutionally novel in this farming landscape. The very poor road network means that few farmers have independent access to a market. By and large, farmers are “price takers” with limited entrepreneurial skills. The members from Kasike have been very successful in collecting seed, making soap, and distributing it, but we observed a paucity of skills in accounting, financial planning, marketing, and broader organizational skills—all essential for the long-term success of a growth-oriented business. But how growth-oriented should Kasike be?

Sikwenda village sold 2,000 kilograms of seed to the biofuel company D1 in 2011. If all of these sales were converted to soap for use within the village, this would likely make Kasike the largest rural soap producer in Zambia—but the amount produced would only roughly satisfy total soap demand within the village. In short, even where mature jatropha bushes are already abundant, the total yield is sufficient for little beyond local soap consumption. For-profit businesses that aim to develop this market are thus likely to be hampered by lack of seed. One potentially promising option is to plant jatropha along roads in the countryside, and as hedges surrounding cropland, thus avoiding competition with food production. But the first priority must lie in improving local livelihoods through health benefits and cash-saving and income-generating opportunities for small-scale farmers whose yards and villages are already playing host to under-utilized plant species like Jatropha curcas.

Acknowledgements

We gratefully acknowledge funding by the UK Natural Environment Research Council (NERC), the Economic and Social Science Research Council (ESRC) and the Department for International Development (DfID) for project funding (ref: NE/I003819/1) as part of a larger programme on ‘Ecosystem Services for Poverty Alleviation’. We are equally indebted to the members of Kasike, the inhabitants of Sikwenda, and many other Zambians who shared their experiences and knowledge with us.

Dan van der Horst

Dan van der Horst lectures in environmental policy and management at the School of Geography, Earth, and Environmental Sciences, University of Birmingham, UK. His main area of research is in natural resource...

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