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Cassava production and utilization in Liberia


Production and processing
Research
Cassava as animal feed
References

S. Ravindran and D. Kenkpen

Liberia is situated between latitudes 4-9°N and longitudes 7- 12°W with a total land area of 111 400 km². The country has a humid tropical climate with a rainy season extending from April to November. The average annual rainfall varies from 1800 mm in the north to 5000 mm at the coast. The dry season extends from December to March and the highest air temperature recorded has not exceeded 34°C. The 1985 census recorded a national population of 2.1 million; 80-85 percent of the working population was engaged in agriculture and forestry with over 90 percent of these earning a living from traditional agriculture.

Agriculture in Liberia was previously dominated by export crops which included rubber, oil palm, coffee, cocoa and citrus. Although these export crops still account for a substantial portion of Liberia's foreign exchange earnings, an increase in food crop production is now very evident. Food crops grown include rice (both upland and swamp), cassava and other root crops, banana, pulses and vegetables. The most prevalent methods of cropping are "slash and burn" and shifting cultivation. At present, food crops are produced mainly by subsistence farmers.

Production and processing

Cassava is now the second most important food crop in Liberia. It is grown throughout the country, although the area covered may vary considerably for different counties. A survey conducted by the Liberian Ministry of Agriculture in 1978 indicated that the total area covered by the crop in 1977 was only 86 000 ha with an average yield of 1800 kg/ha, and that 39 400 or 26 percent of all agricultural households in the country were involved in the production of cassava. However, cassava cultivation in the country increased substantially early in the 1980s. Total production for 1985 was estimated at 283 million kg which represents a significant increase of 23 percent compared to the 1984 production figures of 218 million kg. The same increase was also noted for area harvested (113 100 ha) and yield per ha (2500 kg). The number of households growing the crop in 1986 amounted to 95 400 or 62 percent of all agricultural households (FAO 1980).

Almost all the cassava harvested in Liberia is processed into various forms for human consumption. Cassava is normally left in the ground until it is required for sale, consumption by the farmer, or processing into a more durable form. Besides the tubers, the leaves are consumed extensively as vegetable. Cassava is traditionally boiled soon after harvest or processed into farina (gari), starch, fufu, or dumboy.

Farina or gari is the dry finely granulated product prepared from partially fermented cassava. If prepared correctly, well dried farina may be stored for many months without deterioration. The basic procedure for farina production is simple: the cassava is peeled, grated, and allowed to ferment for about 1-2 days when water is extracted by compression of the mash, then roasted. Farina is produced throughout the country, especially in Bassa, Bomi and Nimba counties.

For preparing fufu, cassava is fermented under water in used oil-drums and then hand-pounded in a large wooden mortar prior to moisture extraction; the fufu thus produced is sold in the local market. Under rural preparation methods the fresh peeled roots are placed under water for about 3 days and allowed to absorb water and ferment until soft. After fermentation, the water is drained off, most of the fiber removed and the roots pounded in large wooden mortars until a soft mash is formed. Excess water is extracted from the mash by placing heavy objects such as rocks on top of sacks containing the fufu. The consumer who buys fufu in the market normally adds water to the mash and sieves the mixture to remove the remaining fiber.

Cassava chips are prepared by peeling, washing and slicing tubers into suitable sizes followed by drying. Sun drying is the simplest, most economical method but has the disadvantage of taking up a large area of ground. The partially dried chips are loaded onto fine mesh grids within the house and allowed to dry for 2-3 days.

Cassava flour is obtained from dried cassava chips by grinding in hammer mills, cylindrical mills or by hand-pounding in a mortar.

Dumboy is prepared by boiling fresh cassava so that the roots become soft and split. The boiled roots are placed in a wooden mortar and hand-pounded with or without plantains.

Research

The Central Agricultural Research Institute (CARI), Suakoko in Bong County of Liberia has a Root and Tuber Research Program which places particular emphasis on cassava. The program is partially financed by the International Development Research Centre (IDRC) of Canada. Cassava research at CARI is focussed on developing cassava varieties for high yields, disease resistance and root quality. Three high yielding varieties, CARICASS I, CARICASS II, and CARICASS III have already been released and are under multilocational and on-farm trials. The yields of these varieties have been proven to be superior to the local variety both at on-station and on-farm trials (table 1).

The Animal Nutrition Project at CARI has been conducting feeding trials on livestock and poultry using both cassava tuberous roots and leaves. The main objective of this research program is to formulate balanced feed rations for pigs and poultry using cassava as major energy source to reduce competition of animals for imported cereal grains.

Table 1. Comparative yields of CARI improved cassava varieties and the local type! without fertilizer application; Liberia, 1983-84

Cassava variety

On-station yields (CARI)

Off-station yields (Liberia)

Cape Mount County

Nimba County

Bassa County

 

t/ha

CARICASS I

32.8

31.8

20.5

26.6

CARICASS II

58.4

58.4

16.4

39.6

CARICASS III

29.0

29.0

9.8

31.5

Local

nd

7.8

4.3

nd

Source: IDRC Year 2 Annual Progress Report (1983-84): Root Crops Project, Liberia
Note: nd = not determined

Cassava leaves for animal feeding are processed by spreading and shade-drying. When dried the leaves are milled and preserved in polythene bags. Cassava tuberous roots for animal feeding are washed and sliced into thin slices (2-3 cm) without peeling. They are dried on a wire mesh over a low fire. The dried cassava chips with approximately 8- 10% moisture are either stored in jute bags or milled and stored in polythene bags for future use. Shelf-life under room temperature for cassava flour is 4 to 5 months whereas the chips can be stored without deterioration for over 8 months.

When cassava flour was incorporated into the diets of Hampshire and Segher breeds of pigs to constitute 40% of their rations, their performance in terms of growth, productivity and carcass quality was not adversely affected. On the other hand, the final weight of Segher breeds in the treatment group was 5% more than the control group fed on corn-based rations (CARI 198586). However, such compounded pig feeds containing cassava as basal diet were always balanced for protein using ground soybean ( 15%) and blood meal (5%). Broiler rations containing 10% cassava flour and 12% cassava leaf meal are reported satisfactory for obtaining 1.5 kg live weight per bird at 42 days (CARI 1979-80). At CARI, prolonged use of cassava tuberous roots as pig feed has so far not caused diseases like goitre, sterility, or neurological disorders. This may probably be due to the addition of protein diets like vegetable oil meal, legume leaf meal, or blood meal into such mixtures. However, vomiting was observed in weaner piglets when fed with raw cassava.

Cassava as animal feed

Large scale utilization of cassava as animal feed is only practiced by CARI and a few commercial pig farmers in the country. However, feeding of cassava leaves, cassava peels and unwanted (thin) tubers to pigs and small ruminants is commonly practiced in the rural areas. The quantity used for feeding livestock in the country may not exceed 1 percent of the total production. This may be due to insufficient production and current high price ($5 to $8 for 45.4 kg bag of fresh tubers).

The acceptance and cultivation of high yielding cassava varieties like CARICASS I, CARICASS II and CARICASS III by farmers is naturally expected to increase national production levels of cassava. Higher production of cassava may lead to its increased utilization as animal feed. In this vein, CARI has already released into the market some animal feed formulations based on the cassava tuberous root as a major energy source. However, better cassava processing and storage techniques appropriate to the country will have to be developed if full benefits are to be obtained.

References

1. CARI (Central Agricultural Research Institute). 1980. Annual report 1979-80 of the Central Agricultural Research Institute, Suakoko, Liberia.

2. CARI (Central Agricultural Research Institute). 1986. Annual report 1985-86 of the Central Agricultural Research Institute, Suakoko, Liberia.

3. FAO (Food and agriculture Organization). 1980. Production yearbook 1980. Food and Agriculture Organization, Rome.


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