I. Cassava Production: An overview
According to FAO estimates (2006), world production of cassava roots is approximately 226
million tonnes, of which 54% (122 million tons) are produced in Africa. Most of the
production is in West Africa, which produces some 63 million tonnes, equivalent to 52% of
the production. Eastern Africa, with a production of approximately 31 million tonnes,
accounts for some 25% of total global cassava production. As indicated in the Table below,
Ghana is the third African producer, after Nigeria and the Democratic Republic of Congo,
with a yearly production of approximately 9.5 tonnes, equal to 8% of total cassava production
in the continent.
Source: Fao, 2006
Cassava is one of the world’s most important crops. Throughout the tropics, the plant’s root
and leaves serve as an essential source of calories and income. About 600 million people in
Africa, Asia and Latin America depend on the cassava crop for their food and incomes. In
Africa cassava production has more than quadrupled since 1961, from 33 million tonnes per
year to 122 million tonnes in 2006.
In countries like Nigeria and Ghana, wide adoption of high-yielding varieties and better pest
management has resulted in a sharp rise in production. Cassava is a year-round crop, with
production levels that are steady but small. It is also a perishable and bulky product, which
makes it very costly to transport without some initial processing. Poor subsistence farmers are
the main growers of cassava, and women are largely responsible for the work of processing it
to make gari, fufu, tapioca and other products. The uses of cassava are expanding, as further
processing can produce chips, pellets, flour, alcohol and starch. A wide range of industries
use cassava in the production of livestock feed, textiles, confections, plywood and soft drinks.
Cassava is a typical tropical plant. The approximate boundaries for its cultivation may be
accepted as from 30 (degree sign)N to 30 (degree S latitudes); however, most cassava is
located between 20?N and 20?S. In general, the crop requires a warm, humid climate.
Temperature is important, as all growth stops at about 10?C. Typically, the crop is grown in
areas that are frost-free year-round. The highest root production can be expected in the
tropical lowlands, below 150m altitude, where temperatures average 25-27?C, but some
varieties grow at altitudes of up to 1500m
The plant grows best when rainfall is fairly abundant, but it can be grown where annual
rainfall is as low as 500mm, or where it is as high as 5,000mm. The plant can stand prolonged
periods of drought in which most other food crops would perish. This makes it valuable in
regions where annual rainfall is low or where seasonal distribution is irregular. In tropical
climates, the dry season has roughly the same effect on Cassava as low temperature has on
deciduous perennials in other parts of the world: a period of dormancy lasts two to three
months, and growth resumes when the rains begin again.
Cassava grows best on light, sandy loams, or on loamy sands which are moist, fertile and
deep, but it also does well on soils ranging in texture from sands to clays and on soils of
relatively low fertility. In practice, it is grown on a wide range of soils, provided the soil
texture is friable enough to allow the development of the tubers.
Cassava can be produced economically in soils so depleted by repeated cultivation that they
have become unsuitable for other crops. In very rich soils the plant may produce stems and
leaves at the expense of roots. In some parts of Africa, freshly cleared forest soils are
regarded as highly suitable after they have borne a cereal crop.
On average, cassava yields are about 20 percent of those obtained under optimum conditions
and even when interventions are designed to increase productivity, the response is limited,
mainly because the market is small. Despite its multiple uses, cassava is a product in search of
II. Products obtained from cassava processing
Some of the uses are:
a) Cassava Chips: which are used in various industries as follows:
• Animal Feeds.
• Alcohol for producing alcohol for liquor manufacture and disinfectants;
• Gasohol for producing bio- ethanol.
b) Cassava Starch : used in various industries, for instance:
• Food and Beverage: The cassava starch is used in both its original form and in
modified forms in products such as instant noodles, sago and seasoning sauces.
• Paper Industry, where it is mixed with the paper pulp to strengthen and thicken it.
• Glue Industry for producing glue for plywood industry.
• Medicine Industry as the diluent of capsule medicine and pill.
• Monosodium Glutamate: for producing the MFG for seasoning food;
• Bio-Degradable plastics.
c) Cassava Leaf mainly as raw material of animal feeds in order to increase protein/colour
substance especially in egg and also for food.
d) Cassava Root, burnt and used as charcoal generating high heat but without smoke.
However, as noted in the Table below, the scale of operations for the different uses is
Scale of operation Main products Residues
Small scalel Gari, chips, starch, Cassava peels, starch
(less than 10 tonnes per day flour bagasse, gari sieviate, fufu
fresh tuber) sieviate, waste water,
discarded roots, foliage,
sieviate, cassava stumps
Medium Scale Chips, flour, gari, Cassava peels, starch
(less than 50 tonnes per day ethanol, starch bagasse, waste water, foliage,
fresh tuber) cassava
Large scale Chips, starch, gari, Cassava peels, starch
(more than 50 tonnes per day ethanol bagasse, cassava ethanol
fresh tuber) pulp, cassava
stumps, waste water, foliage
III. Cassava as feedstock for bio-fuel production
The development of cassava as feedstock for bio-fuel production is constrained due to a
number of factors, not least the comparative disadvantage of cassava versus other bio-ethanol
feedstocks with higher sugar content. Being starchy, there is a need to first convert the starch
into sugar and the sugar into ethanol making bio-ethanol production from cassava relatively
more expensive than bio-fuels from plants with a high sugar content such as sweet sorghum,
tropical sugar beet and sugar cane. There are indications that high sugar varieties are being
developed, but the characteristics of these plants are still under study. However, while high
sugar varieties can be developed to produce bio-ethanol competitively, dried cassava chips
can be used to make bio-ethanol using enzymes to produce bio-ethanol from cassava
exclusively or in combination with other feedstocks. This versatility makes cassava a unique