The hardy jatropha tree as a biofuel source may not be the panacea for smallholders that some have claimed, say Miyuki Iiyama and James Onchieku.
It sounds too good to be true: a biofuel crop that grows on semi-arid lands and degraded soils, replaces fossil fuels in developing countries and brings huge injections of cash to poor smallholders.
That is what some are claiming for Jatropha curcas, the 'miracle' biofuel crop. But studies on the ground suggest a lot more research and development (RD) is needed before farmers can come close to seeing any of the promised benefits.
So what exactly is jatropha, and what has a 'reality check' on its potential revealed?
Jatropha is a small tree that grows to 35 metres in height and a member of the Euphorbiaceae family. It is native to Central America but is now grown in many parts of the tropics and subtropics. The seeds, which contain up to 35 per cent oil, can be processed into biodiesel for transport and biofuel for lighting and cooking.
It is poisonous and cannot be used for food. In many places, it is also grown as a fence to exclude livestock, and is also used for traditional medicine. The seed cake, a by-product from biofuel production, can be used for fertiliser and animal feed, provided it is detoxified. The roots, which are able to reach water and nutrients deep in the soil, can cut soil erosion.
A report by the UN Food and Agricultural Organization (FAO) and International Fund for Agricultural Development (IFAD) found that in 2008 jatropha was planted on about 900,000 hectares globally, the bulk - 760,000 hectares - in Asia, along with 120,000 hectares in Africa and 20,000 in Latin America.
But by 2015 jatropha planting will have risen more than ten times to 12.8 million hectares worldwide, the report estimates
It has only been in the past few years that interest in jatropha as a biofuel crop has mounted, particularly because of its purported ability to thrive on marginal land and in drought conditions.
As for claims about the tree's fast-growing nature, early fruiting, pest and disease resistance due to its toxicity, and its potential to not only produce biodiesel, but also as fuel for light and heat for cooking.
The media has chimed in too, with articles about the potential for jatropha to stop deforestation and provide greatly-increased incomes as international investments promise to convert wasteland into plantations that create thousands of jobs. Typical statements have been: 'Jatropha doesn't have to compete with food crops for arable land', and 'even in the worst of soils, it grows like weeds.'
In an attempt to test the claims, Endelevu Energy, the World Agroforestry Centre and the Kenya Forestry Research Institute embarked on the Reality Check study supported by the German government, which we published last December.
The main finding of the Reality Check is that jatropha is not economically viable when grown by smallholders in Kenya, either in a monoculture or intercrop plantation model. This is due to low yields and high production costs, and a lack of guidelines for applying agronomic and silvicultural best practices.
Hundreds of farmers we interviewed for the study spoke of extremely low yields and uneconomical production costs. Many had paid as much as US$1220 per kilogram for seeds, but received little or no advice on crop management, and were unable to access markets for the small number of seeds harvested. They chose to abandon the jatropha they had planted.
The only case where we would recommend jatropha cultivation and where it makes economic sense is as a natural fence, as this needs few inputs. This is the way jatropha has been grown in East Africa since it was introduced centuries ago.
As for the claim that jatropha can grow almost anywhere, our research found that while this may be the case, high yields are not guaranteed. Even in ideal conditions, the tree requires management to become productive, including pruning to increase the number of flowering branches, and adequate fertiliser and water.
In addition, more than 75 per cent of farmers we spoke to reported at least one pest or disease in the course of a year, including golden beetle, leaf spotting, mildew and fungus.
Meeting of minds
While we were analysing the situation in Kenya, the FAO and IFAD were conducting their review into the anti-poverty potential of jatropha at a global level.
Our report shares many of their conclusions, in particular that yields are marginal, at best, and many of the investments and policy decisions on developing jatropha as an oil crop have been made without sufficient scientific evidence.
Realising the true potential of jatropha requires separating facts from the claims and half truths, the FAO/IFAD report says.
It does recognise that if well exploited, jatropha could provide opportunities for good returns and rural development, but expecting jatropha to substitute significantly for oil imports in developing countries is unrealistic.
Too soon for promises
So, while it is possible that jatropha could eventually evolve into a higher yielding oil crop that is productive on marginal lands, and markets could be established for its oil and other useful by-products, it is far too soon to make such promises.
The reality is that jatropha is still essentially a semi-wild plant and as such its seed yields, oil quality and oil content are all highly variable. Considerable research is needed into the agronomy of jatropha and crop improvement.
The FAO/IFAD report recommends short-term research focused on producing superior clonal plants, with longer-term work on developing improved varieties with reliable trait expression and a seed production system that ensures farmer have access to productive and reliable planting materials.
For now, the main potential of jatropha is as part of a strategy to reclaim degraded land, provide a source of locally processed and used oil, and as a hedgerow to control grazing. Until further RD is conducted by establishing jatropha trials in various agro-ecological zones, with farmers informed of best practices significant plantations remain risky and uneconomical. Only 'business as usual' should continue.
Miyuki Iiyama is a fellow at the World Agroforestry Centre; James Onchieku is principal research officer at the Kenya Forestry Research Institute.