Cassava is a tropical root crop, originally from Amazonia, that provides the staple food of an estimated 800 million people worldwide. Grown almost exclusively by low-income, smallholder farmers, it is one of the few staple crops that can be produced efficiently on a small scale, without the need for mechanization or purchased inputs, and in marginal areas with poor soils and unpredictable rainfall. Since 2000, the world’s annual cassava production has increased by an estimated 100 million tonnes, driven in Asia by demand for dried cassava and starch for use in livestock feed and industrial applications, and in Africa by expanding urban markets for cassava food products.
There is great potential for further production increases – under optimal conditions, cassava yields can reach 80 tonnes per hectare, compared to the current world average yield of just 12.8 tonnes. Booming demand offers millions of cassava growers in tropical countries the opportunity to intensify production, earn higher incomes and boost the food supply where it is most needed. But how smallholder cassava growers choose to improve productivity should be of major concern to policymakers. The Green Revolution in cereal production, based on genetically uniform varieties and intensive use of irrigation and agrochemicals, has taken a heavy toll on agriculture’s natural resource base, jeopardizing future productivity. In moving from traditional, low-input to more intensive cultivation, small-scale cassava growers should not make the same mistakes.
Importance of Cassava
- Rural development
Policymakers in tropical countries are recognizing the huge potential of cassava to spur rural industrial development and raise rural incomes. They look to Thailand, where increases in yields over the past two decades have boosted smallholder earnings by an estimated US$650 million and lifted many cassava growers out of poverty. In southern Brazil, cassava is a multi-million dollar industrial crop, processed in factories that employ thousands of rural people. It has been estimated that investments in cassava research and development in Africa could generate some of the highest gains in agricultural GDP26.
- Urban food security
A major driver of production increases will be high prices of cereals on world markets, which sparked global food price inflation in 2008. In Africa, persistent urban poverty has boosted the consumption of cassava food products as consumers seek cheaper sources of calories. Cassava could also help improve the nutrition of low-income populations – new biofortified varieties produce roots that are rich in vitamin A, iron and zinc.
- Import substitution
Many governments have, or are considering, mandatory blending of mostly imported wheat flour with domestically produced cassava flour in bread making. Nigeria recently raised its levy on wheat flour to 100 percent, and will use revenue for a cassava bread development fund11. It has also announced plans to substitute 10 percent of the maize in poultry feed with cassava grits, which will increase annual demand for cassava roots by 480 000 tonnes. In East Africa, the animal feed industry is turning to cassava, as maize and wheat become increasingly unaffordable.
- Renewable energy
Global output of bio-ethanol could reach 155 billion litres by 2020, up from around 100 billion litres in 2010. Cassava currently contributes to only a small part of production, but demand from China is growing rapidly following its decision to no longer use cereals to produce biofuel. Currently, 50 percent of China’s ethanol is derived from cassava roots and sweet potatoes, and in 2012 it was expected to produce 780 million litres of ethanol from 6 million tonnes of dried cassava13. China plans to develop cassava varieties suitable for biomass energy production in colder and drier regions of the country’s north.
Worldwide, cassava is the second biggest source of starch, after maize, with production estimated at 8 million tonnes a year. However, tropical countries import each year some US$80 million worth of maize starch that could be replaced by starch from locally grown cassava. In Thailand, which has earned some US$4 billion from starch exports since 2000, scientists are developing a variety with root starch that rivals premium “waxy” maize starc. A recent cassava mutation offers smaller root starch granules that reduce considerably the time and energy required for ethanol production.
- New industrial uses
Worldwide, cassava is the second biggest source of starch, after maize, with production estimated at 8 million tonnes a year. However, tropical countries import each year some US$80 million worth of maize starch that could be replaced by starch from locally grown cassava. In Thailand, which has earned some US$4 billion from starch exports since 2000, scientists are developing a variety with root starch that rivals premium “waxy” maize starc. A recent cassava mutation offers smaller root starch granules that reduce considerably the time and energy required for ethanol production.
Preparing healthy cassava stems for planting
Obtain stems for planting from mature plants 10–12 months old. Stems should be stored vertically on the soil under a shade. The distal end of the stems should touch the soil, which is moistened regularly, with the surroundings kept free from weeds.
Handle the stems with care not to destroy the nodes that may result in losses. Do not make jagged cut surfaces or keep stems in the open (leading to drying). Cut stems, with sharp tools, preferably secateurs or cutlasses, into 25-cm cuttings with 5–7 nodes
Handle the stems with care not to destroy the nodes that may result in losses. Do not make jagged cut surfaces or keep stems in the open (leading to drying). Cut stems, with sharp tools, preferably secateurs or cutlasses, into 25-cm cuttings with 5–7 nodes
