CASSAVA DEVELOPMENT IN NIGERIA

A Country Case Study towards a Global Strategy for Cassava Development

Prepared by

Department of Agriculture
Federal Ministry of Agriculture and Natural Resources
Nigeria

1 ACKNOWLEDGEMENTS

Sincere gratitude is expressed to the Honourable Minister for Agriculture, the Director-General, Federal Ministry of Agriculture and Natural Resources and the Federal Director of Agriculture, Mr O.A. Edache, for their encouragement and support to undertake this case study. The financial support provided by the Federal Government for this study and the development of cassava in Nigeria, particularly the Cassava Multiplication Project (CMP) is acknowledged.

Thanks are also expressed to Mr Felix I. Nweke, Messrs O.M. Jimoh and Goke Oladapo, the staff of CMP and participants of the workshop at CMP, Ijebu Ife, for discussing this report and their invaluable contributions.

Report compiled by:

2 EXECUTIVE SUMMARY

As part of the IFAD global strategy, Nigeria was selected to conduct a country case study along with other nations to analyse the past and present situation of cassava in Nigeria, with a view to describing the lessons learned from past development interventions and their implications for a strategy for future investment in cassava research and development.

The study was carried out using a combination of approaches, intensive use of literature review and quantitative secondary data and Rapid Rural Appraisal methodology.

The study revealed that cassava is one of the most important crops in Nigeria, playing a dominant role in the rural economy in the southern agro-ecological zones and is increasingly gaining importance in other parts of Nigeria.

Nigeria is currently the largest producer of cassava in the world with an annual output of over 34 million tonnes of tuberous roots. Cassava production has been increasing for the past 20 or more years in area cultivated and in yield per hectare. On average, the harvested land area was over 80 percent higher during 1990–1993 than during 1974–1977.

The growth in cassava production has been primarily due to rapid population growth, large internal market demand, complemented by the availability of high yielding improved varieties of cassava, a relatively well developed market access infrastructure, the existence of improved processing technology and a well-organized internal market structure.

Cassava is produced largely by small-scale farmers using rudimentary implements. The average land-holding is less than two hectares and for most farmers, land and family labour remain the essential inputs. Land is held on a communal basis, inherited or rented; cases of outright purchase of land are rare. Capital is a major limitation in agriculture; only few farmers have access to rural credit.

Almost all farmers in the main cassava belts of the southeastern, southwestern and central zones grow cassava, which is typically intercropped as a main or minor crop. Rotation and fallow systems are the traditional systems used by the farmers to maintain soil fertility but population pressure has resulted in reduced fallow, continuous cropping and reduced soil fertility. Farmers are generally aware of the benefit of inorganic fertilizer, but the commodity is scarce and a major constraint in cultivating improved varieties.

Almost all the cassava produced is used for human consumption and less than 5 percent is used in industries. As a food crop, cassava fits well into the farming systems of the smallholder farmers in Nigeria because it is available all year round, thus providing household food security. Compared to grains, cassava is more tolerant to low soil fertility and more resistant to drought, pests and diseases. Furthermore, its roots store well in the ground for months after maturity.

Cassava is important, not just as a food crop but even more so as a major source of cash income for producing households. As a cash crop, cassava generates cash income for the largest number of households, in comparison with other staples, contributing positively to poverty alleviation.

Cassava is usually consumed in processed forms. Cassava processing by traditional methods is labour-intensive but the application of improved processing technology has reduced processing time and labour and encouraged further production. Industrial utilization of cassava products is increasing but this accounts for less than 5 percent of the total production.

Women play a central role in cassava production, processing and marketing, contributing about 58 percent of the total agricultural labour in the southwest, 67 percent in the southeast and 58 percent in the central zones. They are almost entirely responsible for processing cassava which provides them with additional income-earning opportunity and enhances their ability to contribute to household food security.

Government intervention and the efforts of non-governmental organizations in the cassava subsector have led to a number of measures that support the production, processing and marketing of cassava, dating back to the 1970s. These include government programmes such as the National Accelerated Food Production Programme (NAFPP), Operation Feed the Nation (OFN), the Agricultural Development Projects (ADPs), the development of the National Agricultural Research Systems and their close collaboration with the International Institute of Tropical Agriculture (IITA) and other international agricultural research centres and large-scale planting material multiplication and distribution facilitated by the IFAD-assisted Cassava Multiplication Programme (CMP) and activities of oil companies and church organizations.

Through these efforts, appreciable progress has been made in genetic improvement, agronomic practices, root storage and in the development of processing technology and rural infrastructure. Concerted efforts have also been made to introduce improved practices to farmers. Thus, improved varieties now occupy approximately 0.75 percent of cassava land area and several labour-intensive operations in processing, notably grating, dewatering and milling, have been mechanized. This has had a great effect on cassava land area expansion and production growth. Despite the rapid growth in cassava production, the cassava subsector in Nigeria is still constrained by a number of factors, namely pests and diseases, agronomic problems, shortage of planting materials, inconsistent policy measures, poor market access, limited diversification of processing options, inefficient extension delivery system and inadequate access to improved processing technology.

Consequently, future intervention strategies should include the following:

• development, rapid multiplication and dissemination of improved varieties to enhance the availability and diversity of improved planting materials;

• development and extension of improved agronomic practices for cassava production;

• deliberate efforts to support the development of cassava processing protoypes and identification of applicable and useful technologies and incentives for local entrepreneurs to fabricate them. This will save labour and improve the efficiency of processing, raise the quality and enhance marketability of products. The design of such machines should be gender-sensitive, bearing in mind the cardinal role of women in processing;

• strengthening of extension-farmer linkage with research to facilitate the ongoing spread of cultivars, management practice and processing techniques. This should lead to the mobilization of farmers through emphasis on a participatory development approach, family- or group-based extension and seed multiplication activities involving due recognition of the role of women in production, processing and marketing and assistance that would enable all farmers to take advantage of development programmes as far as possible; adequate and sustained research funding which must be timely released;

• development of new cassava products and packaging techniques for existing and new products;

• promotion of industrial uses of cassava and diversification of processing options to encourage increased cassava production and enhance rural household income;

• establishment of a sound macroeconomic policy that would promote sustained cassava development;

• investment in rural infrastructure (especially feeder roads and water supply) to promote cassava production, processing and marketing; and

• greater involvement of the private sector and non-governmental organizations in the use of research and technology in cassava production, processing and marketing and in the development of infrastructural facilities.

3 INTRODUCTION

3.1 NIGERIA: GENERAL COUNTRY BACKGROUND

Nigeria covers 924 000 km² on the west coast of Africa; vegetation ranges from tropical forest in the south to the sahel savannah in the north. The country comprises the Federal Capital Territory and thirty-six (36) states. The Federal Government is responsible for economic development policy while the states have jurisdiction over activities confined within their boundaries, including implementation of development projects.

Nigeria has a population of about 120 million people, of which 65 percent is rural-based and is growing at a rate of 2.83 percent per annum. Average population density is about 100 persons/km² , ranging from 40/km² in the middle belt and northern states to over 400/km² in some southern states.

Prior to the discovery of oil in the 1970s, agriculture was the mainstay of the Nigerian economy, accounting for about two-thirds of the Gross Domestic Product (GDP). With the oil boom, agriculture's contribution to GDP declined to 25 percent by 1980 and Nigeria moved from being a large exporter to a major importer of agricultural products. Since the mid-1980s, as a result of a decline in oil revenue and policy measures implemented under a Structural Adjustment Programme (SAP), agriculture's contribution to GDP has risen to about 40 percent.

Nigeria's land stretches from latitude 4°N to 14°N and from longitude 3°E to 14°E. Of this area, 71 million ha (77 percent) are considered cultivable; about 32 million ha (45 percent of the total cultivable land area) are cultivated. Annual rainfall ranges from 2 500 mm in the coastal areas to about 500 mm in the far north.

A wide range of agro-ecological conditions allows for very diverse crop production. The northern part of the country is suitable for sorghum, millet, maize, cowpea, groundnut and cotton. The main food crops in the middle belt and the south are cassava, yam, plantain and maize. Low-lying and seasonally flooded areas are increasingly being used for rice production.

Broadly speaking, the cassava-growing belt falls within three agro-ecological zones of the southeast, southwest and the central areas. The first two zones fall within the humid tropics. The predominant soil types are the ferralitic soils which are rich in free iron but low in mineral reserves and are consequently low in fertility. The central zone lies between the southern and the drier northern agro-ecological zones. The soils are poor, due to leaching from heavy and intense rainfall and so limited fertility is a constraint to agricultural production.

3.2 RATIONALE AND JUSTIFICATION FOR THE STUDY IN NIGERIA

As part of the IF AD global strategy for cassava development, Nigeria has been selected to conduct a country case study among other nations. The selection of Nigeria is largely based on the considerable level of experience in the development, multiplication and processing of cassava into various food, feed and raw material forms and the continued dominance in cassava production. These gains would need to be sustained, especially through a diversification of usage of cassava for industrial purposes, hence this case study would help in formulating a future strategy for the realization of this important goal. The report of this country case study which was carried out across the major cassava-producing states, would provide an easy reference for the various countries to share experiences which may be useful for future project interventions and development strategy in the cassava subsector.

3.3 TERMS OF REFERENCE

The purpose of this study was to analyse the past and present situation of cassava in Nigeria with a view to describing the lessons learned from past development interventions and their implications for a strategy for future investment in cassava research and development.

Specifically, the study investigated the following:

1.   A description of the evolution of cassava development in Nigeria, which includes the identification of significant interventions that have influenced evolution. This includes:

1. trends in cassava production and utilization between 1987 and 1997 at the national level and by major cassava-producing states within the country;

2. major interventions, both at the national and state levels, that have influenced the evolution of the cassava sector, including:

   • changes in the development model adopted by the country (e.g. from a model of import substitution to a model of trade liberalization);

   • changes in import, pricing, of credit policies for cassava or competing commodities;

   • investment in cassava research or development, including production, processing and marketing of the crop;

   • investment in infrastructure and services to promote rural development and/or the development of the crop both in service infrastructure (roads, storage facilities, etc.) and processing infrastructure.

2.   An analysis of the successes and failures (or limitations) of the interventions identified above in removing the constraints to and/or realizing the opportunities for the development crop. Criteria used for analysing the relative success of each intervention include:

• total economic benefit;

• return on investment;

• impact on equity, including gender;

• adoption or non-adoption of technology;

• impact on the environment;

• impact on the development of institutions and organizations associated with the cassava sector.

3.   An enumeration of the lessons learned from past experiences.

4.   A synthesis of the implications for a future strategy for cassava development in Nigeria.

3.4 METHODOLOGY

The case study was carried out using a combination of approaches. First, a comprehensive review of existing literature on the organization and management of cassava crop economy in Nigeria was undertaken. Secondly, quantitative information on the area, production, marketing, etc., of cassava was collected from the libraries of major institutions that are active in the cassava subsector as well as through visits and contacts.

To supplement these two approaches, the Rapid Rural Appraisal (RRA) methodology was adopted to provide information that the literature and personal interviews could not supply. This involved collecting information from selected key farmers and some major processors/marketers of cassava.

4 CASSAVA PRODUCTION IN NIGERIA

Cassava is one of the most important crops in Nigeria. It is the most widely cultivated crop in the southern part of the country in terms of area devoted to it and number of farmers growing it. Indeed, it is grown by almost every household. Cassava has also increased in importance in the Middle Belt in recent years. In all places, cassava has become very popular as a food and cash crop and is fast replacing yam and other traditional staples of the area. In all, over four-fifths of the cultivable land area is suitable for cassava growing (Figure 1).

Figure 1. Agro-ecological suitability zones for the cultivation of cassava, based on combined data for soils, mean rainfall, mean temperature, temperature range and the length of growing season in Nigeria

4.1 INTRODUCTION, SPREAD AND ECONOMIC IMPORTANCE

Cassava (Manihot esculenta Crantz) was introduced into central Africa from south America in the sixteenth century by the early Portuguese explorers (Jones, 1959). It was probably the emancipated slaves who introduced the cassava crop into southern Nigeria, as they returned to the country from South America via the islands of Sao Tome and Fernando Po. At that time there were Portuguese colonies off Nigeria's shores (Ekandem, 1962). Cassava, however, did not become important in the country until the end of the nineteenth century when processing techniques were introduced, as many more slaves returned home.

Cassava is important, not only as a food crop but even more so as a major source of income for rural households. Nigeria is currently the largest producer of cassava in the world with an annual production of over 34 million tonnes of tuberous roots. Cassava is largely consumed in many processed forms in Nigeria. Its use in the industry and livestock feed, is well known, but is gradually increasing, especially as import substitution becomes prominent in the industrial sector of the economy. As a cash crop, cassava generates cash income for the largest number of households in comparison with other staples (Table 1). It is produced with relevant purchased inputs as frequently as and in some cases more frequently than other staples. A large proportion of total production, probably larger than that of most staples, is planted annually for sale.

As a food crop, cassava has some inherent characteristics which make it attractive, especially to the smallholder farmers in Nigeria. First, it is rich in carbohydrates especially starch and consequently has a multiplicity of end uses. Secondly, it is available all year round, making it preferable to other, more seasonal crops such as grains, peas and beans and other crops for food security. Compared to grains, cassava is more tolerant of low soil fertility and more resistant to drought, pests and diseases. Furthermore, its roots are storable in the ground for months after they mature. These attributes combined with other socioeconomic considerations are therefore what IFAD has recognized in the crop as lending itself to a commodity-based approach to poverty alleviation (FAO/IC, 1995).

Table 1. Percentage distribution of food crop cash income of households producing major crops

Source: Nweke et al., 1997
N —Number of producers
Others include millts, sorghum, beans and peas

The socioeconomic importance of cassava and the accidental introduction of cassava mealybug which ravaged most cassava fields in the major producing areas led to the Government's direct intervention in the subsector, in the implementation of the IFAD-assisted Cassava Multiplication Project (CMP) between 1987 and 1996.

In the early 1980s, Nigerian cassava production fell drastically due to the combined effects of pests (mealybug and green spider mite) and diseases (mosaic virus and cassava bacterial blight), thereby posing a threat to national food security. In response, IFAD initiated the CMP as a parallel-financed part of the World Bank-assisted MSADP-L The overall objective of the CMP was to multiply, promote and distribute improved varieties to farmers so as to improve productivity and income.

4.2 TRENDS IN CASSAVA PRODUCTION

Cassava production in the country has been increasing for the past 20 or more years. A recent survey of the cassava-growing areas shows that in more than 90 percent of the 65 representative villages, the farmer group respondents reported an increasing trend in cassava production over the 20 years prior to the interview in 1989 (Nweke et al., 1997; Ugwu, 1996). Further analysis of the available production data shows that, on the average annual basis, the harvested land area was over 80 percent higher in 1990–1993 than in 1974–1977. Both the yield and of course, the overall production showed a similar trend. Total production at present is estimated at over 34 million tonnes (Table 2). With this production level, Nigeria is the largest producer of cassava in the world.

Cassava production was reported to be increasing among villages where cassava, yam, rice, beans or peas, were the most important crops (based on farmers' ranking) in the cropping system (Ugwu, 1996). This implies that cassava was replacing these major crops, including fallow and pasture land in those villages.

Cassava production was reported to be declining in less than 10 percent of the representative villages for reasons connected with losses from livestock (mainly from cattle), pests and diseases and/or declining soil fertility. Unless fenced round, which is prohibitive considering the relatively low value of the crop, cassava fields could be destroyed by cattle, especially during the dry season when pasture is scarce. The villages with declining production trend were mostly located in the non-humid climate zone. Where soil fertility is low in this zone with short rainfall duration, farmers with a limited supply of fertilizer would prefer to grow short duration crops such as millet or sorghum.

Reasons adduced for the increasing trend by the farmer group respondents were rapid population growth and market demand. These two factors are related, since rapid population growth tends to increase market demand. The proportion of villages where cassava was increasing was significantly higher in the high population density zone (95 percent) than in the low population density zone (65 percent) (Ugwu, 1996). This agrees with the “contention that comparison between cassava growing environments and actual cassava distribution in Ghana and Nigeria demonstrates that the distribution of cassava could be primarily a function of population density rather than of agro-ecological considerations” (Stoorvogel and Fresco, 1991).

Table 2. Estimates of annual area cultivated, root yields and total output for cassava in Nigeria during 1986–1996

Source: FMANR (1997)

Other factors which were not quite evident to the group respondents but which could explain the increasing trend may include: (i) the availability of improved varieties of cassava; (ii) relatively well-developed market access infrastructure; (iii) existence of improved processing technology; (iv) participation of middleperson in cassava marketing; and (v) other market-related factors.

The positive relationship between the above-mentioned factors and the expansion in cassava production may be explained as follows:

• improved cassava varieties were bred for high yield (high dry matter content), pest disease resistance, good product quality and early maturity, among other desired qualities. Cassava root yield is significantly higher for improved than for local varieties (Nweke et al., 1997). Higher root yield will result in larger total production per unit area;

• cassava processing by traditional methods is labour-intensive. Under this system, the relatively low field labour requirement contrasts with the high processing labour demand (Fresco, 1993). This implies that any cost-saving advantage of yield-increasing technology may not fully translate into expanded production if there is no matching cost-saving technology at the processing stage, since cost constraint is merely shifted to the processing stage (Nweke et al., 1997). On the other hand, the application of improved processing technology results in reduced processing time and labour, which, in turn, encourages further production. Nweke (1994) observed that the relationship between the cassava production trend and whether cassava grating or mash pressing machines were available in the village was such that the relative frequency of villages which reported an increasing cassava production trend was high among villages where mash pressing and milling steps were mechanized and 100 percent among villages where mechanized grating had been adopted;

• well-developed market access infrastructure is crucial for cassava marketing. Cassava roots are bulky and with about 70 percent moisture content, are very perishable. It is therefore, expensive to transport cassava especially along poor access roads. Market access is said to be good among villages where farmers go to markets by motor vehicle or where they do so on foot for distances of 10 km or less and poor where they have to travel on foot over 10 km (Nweke, 1994). About 85 percent of the representative villages had good market access Ugwu, 1996.

  Good market access also encourages the participation of middleperson in cassava marketing. By so doing, middlepersons relieve farmers of the marketing task, which gives them more time to grow more cassava. Cassava land area and root yield were found to be significantly higher among villages with good market access, but only the cassava land area showed a significant positive relationship with the participation of middlepersons (Ugwu, 1996). These observations imply that improvement in market access infrastructure and the participation of middlepersons in marketing cassava resulted in cassava production growth.

4.3 RESOURCE BASE OF THE FARMERS

4.3.1 Land

Under the Land Use Act of 1978, land is owned by the Government on behalf of the community. However, cultivated land is occupied by individuals and households under customary tenure where land is regarded as the property of the community or extended family, the head of the community acting as the primary trustee or custodian of the farming land. Under the communal system of land ownership, families and individuals acquired right of usage on a first come-first serve basis and such individual usage rights are heritable.

The basic qualification for land ownership is membership of a lineage. Any farmer who wants to farm outside his family land may get land on lease or rent. Payments for rented land range from token amounts to economic rates.

Outright sale of farm land is rare. For most households, ownership of farm land has been acquired through inheritance which is paternal, from father to son(s) or the nearest male relatives. This inheritance procedure and the customary concept of land ownership passes control over land to the household heads. However, in households where Muslim law is practiced, the son, daughter and wives are to share land in the ratio of 4:2:1. In most cases, women have access to land by virtue of their membership in the household as wives, daughters, or sisters. Their commonest access to land is through their husbands, fathers and brothers.

Less than half of available arable land in each agro-ecological zone of the cassava-growing area is put to use at any one time. Even though the area of land under fallow has been on the decreasing side, access to land per se is generally not seen as a serious constraint by the farmers. On average, the extent of land under fallow is greater than that under cultivation.

Generally, most of the farmers are smallholders with production primarily oriented towards meeting subsistence needs. They hold about 90 percent of the land and produce more than 90 percent of the agricultural commodities; large-scale farmers account for less than 10 percent of agricultural production. Average cultivated area per farming household ranges from 0.5 ha in the south to 2.5 ha in the central zone (Middle Belt). Traditionally, each farm had double or more of the cultivated area as fallow. However, increasing population pressure is reducing the fallow area and fallow period.

A common feature of the farming system is a subdivision of the farmers' holdings into a number of non-contiguous plots which they use interchangeably or simultaneously for the production of different crops. They usually grow their crops in varied mixtures because their aim is to produce all the crops required by the household and thereby spread the risk in doing so.

Land allocated to crops varies from zone to zone but the general pattern is that of allocating more land to crops of higher relative importance. Farm sizes are larger for cassava in the southern states while yam traditionally takes a larger share of farmland in the Middle Belt, even here, the land allocated to cassava has been on the increase as cassava has become more popular.

Declining productivity of land is a major source of worry for the farmers. The soils are generally of poor quality, lacking in important nutrients and easily prone to erosion. Farmers have, over the years, through experience and knowledge of the crops and the associated location-specific agro-ecological characteristics, adopted systems of crop rotation and fallow they consider appropriate for their needs. This practice which requires abundant land area is being constrained by land shortage in the face of increasing population pressure on land, especially as the use of available land requires labour or capital and technology which are out of reach to the average farmer.

Generally, a rapidly, growing population has made land-population ratio less favourable in some areas and has led to shortened fallow periods or semi-permanent cultivation. This has made the use of inorganic fertilizers necessary, but most of the farmers do not have access to fertilizers because of distribution problems and inadequate supply.

4.3.2 Labour

Agricultural labour is mainly organized around the families. There is a clearly defined division of labour along gender lines. Agricultural labour is essentially manual and labour-intensive, involving the use of rudimentary equipment - mainly simple tools and equipment such as hoes and cutlasses. Governments at the national state and LGA levels, have attempted to ease the labour constraint problem and stimulate expansion of farms through tractor-hiring services but the tractors are either inaccessible to the poor who need them most or in a state of disrepair. In view of the high cost of tractors and their likely decline in availability, their use by poor farmers is almost out of the question. Moreover, mechanization of farming activities such as land clearing and preparation will be difficult in most of the cassava-producing areas because of heavy rainfall and the dominance of trees and shrubs. Similarly, use of work oxen is difficult because of tsetse fly infestation and the nature of the soil. Thus, considerable efforts in terms of family and hired labour are needed to clear land and prepare it for planting.

Availability of labour within families or capital to hire labour, governs the area of land that can be cultivated and the types of crops that can be grown. While family labour predominates, hired labour is employed during peak periods. Farm labour demand is highest during the period before the onset of the rains and for weeding. Family labour is mostly used as hired labour is expensive because of migration of able-bodied young men and women to the cities in search of other higher paid and attractive jobs or education, leaving an aging farm labour force.

4.3.3 Capital

In addition to the use of rudimentary implements, lack of cash capital is a major factor influencing adoption of improved technology. A common feature in the country is the difficult access to capital from government lending or credit institutions. Only about 1 percent of the farmers are known to have benefited from formal credit schemes. Farmers mainly rely on income from the farm and traditional sources of credit (relatives, friends, money-lenders and cooperative groups). The funds available at this level are limited and cannot meet the credit requirements of the farmers. Also, interest charged on credit obtained from money-lenders can be quite high. The low level of income of poor farmers prevents them from meeting the capital requirements of improved technology. On the whole, the farmers are generally poorly organized and poorly educated and find it difficult to gain access to agricultural support services. Virtually all the farmers interviewed during Rapid Rural Appraisals in Benue, Imo and Ogun States in 1993 and 1995 mentioned capital as a major constraint in their agricultural enterprises.

4.3.4 Production practices

Almost all farmers in the cassava-growing areas grow cassava. It is grown mainly as an intercrop and sometimes as a sole crop. It can be a main crop as well as a minor intercrop (Table 3). The cassava-based cropping systems include cassava/cowpea/vegetables, cassava/bambara nut/vegetables, cassava/cereals/vegetables, etc.

Table 3. Percentage distribution of crop fields by cropping pattern

Source: Nweke et al. (1997)

Crop rotation and fallow systems are commonly used to maintain soil fertility. Wide variations exist between communities and households in the practice of these systems. However, cassava is usually the last crop in the rotation cycle.

Population pressure on land has reduced fallow periods, leading to greater intensive use of land and increasing problems of soil infertility. Meanwhile, fertilizer is scarce limiting the realization of the full potential of improved varieties. As capital utilization is low, land and labour remain the essential inputs for most farmers.

4.4 CONSTRAINTS IN CASSAVA PRODUCTION

Constraints in cassava production include a wide range of technical, institutional and socioeconomic factors. These include pests and diseases, agronomic problems, land degradation, shortage of planting materials, food policy changes, access to markets, limited processing options and inefficient/ ineffective extension delivery systems.

4.4.1 Pests and diseases

Cassava is plagued by various diseases and insect pests. Pests and diseases including the ACMD, CBB, the mealybug (which has been greatly controlled), green spider mite (GSM) and the large grain borer which attacks dry chips of cassava in storage.

In the 1997 season, the various diseases and pest considered to be most important in seven cassava-producing states were: mosaic disease, bacterial blight, leaf rollers, termites, anthracnose, root rot, mealybugs, spider mites, white flies, rodents and stem girdlers. In different areas of the cassava production zone, one or more pests and/or diseases are important.

White ants (termites) destroy stems that are planted before they sprout. Some areas appear to be very prone to this problem. A higher plant population (12–13 000 plants/ha) is used to compensate for those that would be lost. Various chemical control measures are recommended, but the need for safe use and high costs restricts their use among many small farmers who grow cassava in mixtures. Also the menace of rodents is a regular occurrence in the field.

4.4.2 Agronomic problems

Biotic constraints

• Use of low yielding varieties. The varieties in use by farmers often yield less than 10 tonnes/ha when there are new varieties that can give root yields of over 30–35 tonnes/ha. The local varieties are very susceptible to diseases and pests of cassava although consumers and processors still prefer them for specific uses and characteristics.

• Livestock damage of cassava farms have been widely reported. Thus, the community arrangements to protect farms are made to include as many crops as possible.

Abiotic constraints

• Low soil fertility affects many cassava-growing areas because the fallow periods are shorter as the pressure on arable land near homesteads is increasing. At the fresh tuberous root yield of 30 tonnes/ha (which is feasible under good field practice), the amount of major nutrients removed from the soil at harvest amounts to 164 kg of nitrogen, 31 kg of phosphorus, 200 kg of potassium, 80 kg of calcium and 31 kg of magnesium. Also needed are about 7 kg of a combination of several important microelements, e.g. iron (3.6 kg), manganese (1.4 kg), boron (0.5 kg) and copper (0.2kg) (Asher et al., 1980).

• As the direct use of soil amendments in cassava cultivation is low, the yield potentials of the various varieties of the planted cassava crop are not often attained. The use of organic manure could improve soil properties, but this technical fact seems not to be economically feasible under the circumstances of most cassava farmers.

4.4.3 Land degradation

The principal causes of land degradation include soil erosion, deforestation and soil spillage. Erosion is a general problem all over the country, especially in the southeastern zone. Desertification resulting from deforestation is peculiar to central, northeastern and northwestern zones, while oil spillage occurs essentially in the oil-producing zones. Each of these processes tends to reduce the productive potential of land and to impair the sustainability of soil fertility.

4.4.4 Shortage of planting materials

The cultivars released for cultivation in Nigeria have not all been extended to farmers. Although 17 have been released (Table 4) only about five of them have been made available to farmers. Out of these five, two varieties; TMS 30572 and 4(2)1425, continue to dominate. This seems to be related to the higher availability of the stems from distribution agencies of government and other partners. Many released varieties are yet to be multiplied on a large-scale and made available. Shortage of planting materials is also compounded by farmers' inability to preserve planting materials.

4.4.5 Food policy changes

In terms of food security and food production incentives there has been no policy consistency. Initially, the availability of oil revenue made it possible for the Government to respond, to food shortages with large-scale importation. The petroleum income also raised a demand for food as well as encouraging rural-urban migration which resulted in farm labour shortage.

The dramatic increases in prices of most tradable agricultural exports that accompanied the devaluation of the naira and the liberalization of exports were not applicable to cassava and cassava products to any significant extent because as a non-tradable staple food product, prices were not directly influenced by world market developments.

The main source of price increases for cassava products on account of SAP and market liberalization policies was indirect, through increases in the prices of substitute products such as rice, wheat and maize. The ban placed on the importation of these tradable products raised the domestic prices, hence reducing their demand, with the result that consumers switched over to the consumption of cassava and cassava products. This culminated in price increases. However, the increases were short-lived because of inconsistent government policies.

There is, thus, evidence of a lack of synergy between macroeconomic and sectorial policies; the macroeconomic policies have not been able to secure macroeconomic stability, an external balance or a diversified economic base. Consequently, there is a serious inconsistency giving conflicting signals to the farmers.

Poor access also makes movement of goods and people difficult. This is more so during the rainy season when many parts of the rural area are inaccessible. The roads linking the major towns are usually quite good. Though the farmer market access food network is better in Nigeria than in other countries studied by COSCA (Nweke et al., 1992) the rural feeder road networks are poorly developed and absent in some places. This has significant implications for marketing, cost of inputs, access to health facilities and other social services and may therefore have adverse effects on production and rural standards of living.

Table 4. Attributes of the seventeen cassava varieties released for cultivation in Nigeria

The HCN content of the products was determined quantitatively by the enzymic method. Where this was not available, it was determined by the picrate leaf method and therefore reported as either high or low.

4.4.6 Access to markets

Marketing can be a problem for poor farmers who may not have resources to transport their commodities to the market, especially those living in villages with poor feeder roads. Typically farmers transport their farm produce to the market on heads as head loads, on bicycles or in lorries. With poor market access, marketing of cassava can be particularly problematic because of its bulky nature, especially if it is not processed.

4.4.7 Diversification of processing options

Compared with many countries of Africa, there is a wide range of cassava food products in Nigeria. However, industrial demand for cassava is relatively small, probably less than 5 percent of the total production. There is a potential market for cassava products in animal feed, flour and starch industries, but the size of the industrial, market is small because of an inadequate supply of cassava products, a weak link between industrial processors and producers of cassava products and a preference for imported starch.

4.4.8 Extension delivery system to farmers

Discernible progress has accrued from the national agricultural research and extension systems. This is reflected in the adoption of some improved varieties of cassava, development of technologies for various farm operations, improved management practices and improved linkage between research, extension and farmers. However, there are still some constraints with the extension delivery strategy. The Unified Agricultural Extension System (UAES) which ensures a single line of command in the dissemination of technologies to the farmer has not been fully implemented for logistic reasons, especially with the cessation of most of the donor funds that were used for the take-off of this policy instrument. The implication of this, therefore, is that limited impact has been made in the non-crop subsectors.

Closely following from this is the shortage of human resources necessary to implement the Training and Visit extension management system. For most ADPs, the target ratio of EAs 1:1 000 fanners could not be realized. This had a negative impact on the effectiveness of the coverage of the various cells/circles in a given locality.

The operation of Research-Extension-Farmers-Linkage-System (REFILS) has been inadequately supplied with inputs such as seeds, fertilizers, etc. Extension mobility is also insufficient to enhance the attainment of the goals of REFILS.

There is the defectiveness in the use of contact farmers as recommended by Benor and Baxter (1986). In principle, contact farmers were expected to have multiplier effects on the adjacent farmers. However, there is insufficient formal feedback to the ADPs and limited spread of extension messages outside the contact farmers.

However, the contact farmers selectively adopt recommended practices and are often unrepresentative of the general farming population. They are usually better off and more able to afford the inputs to implement the new technologies. Only a few contact farmers are able to pass on the information to other farmers on a regular basis, which means that only a few farmers are being exposed to new technologies from research. Besides the occasional field day, there is no systematic way that other farmers in the cell have access to this information.

Furthermore, recent economic changes have caused input prices to rise more rapidly than product prices, reducing profit margins for small-scale processors of cassava products. To ensure that increases in yields bring some benefit to the women who are primary processors of cassava, alternate product markets need to be developed. Products that have a potential for improved market outlets include flour, starch and cassava chips for industry.

Another fundamental problem with extension strategy is the irrelevant nature of some of the recommendations. Quite often, the technological options offered by extension do not fit into the farming system and the socioeconomic conditions under which the rural people are operating. For instance, a broader range of new varieties that match different ecologies and end-user requirements should be developed and released to farmers.