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Roots, tubers and plantains: recent trends in production, trade and use
by C. Calpe1


Following the world food crisis in the early seventies, many countries invested in irrigation, agricultural research and fertilizer subsidies, which resulted in a strong growth in world cereal production. These factors, however, had few, if any, positive effects on the production of other staples such as roots, tuber and plantains (RTPs), which often continued to be considered as “inferior foods”, being displaced from their more fertile lands by cereals. Furthermore, the expansion of the livestock and poultry sector indeveloping countries over the last two decades relied mainly on feed grain imports rather than on the exploitation of the potential of domestically produced RTPs for feed use. Section II of this paper reviews the changes in production, utilization and trade of RTPs over the last decade or so, and, because the scope of this Workshop is mainly to assess the potential for these products as feeds, special attention is placed on this aspects. Section III focuses on cassava, which unlike other RTPs, developed as an important feed ingredient traded internationally. The special conditions which made this development possible are examined.


Changes in production, trade and consumption patterns, 1976–78 to 1986–88

Statistics on production, trade and utilization on RTPs are generally poor. Except for potatoes, which are mostly cultivated as a cash crop, estimates for the other RTPs are often difficult to obtain as they are mostly “subsistence crops” and are little marketed outside their immediate areas of cultivation. This section relies on FAO Food Balance Sheets, which despite some shortcomings (particularly regarding trade statistics), are the only source providing complete country coverage on supply/ utilization for these products. Because the information on “minor” roots such as taro and yam is even more limited and as they are important only in particular regions, this paper mainly deals with potatoes, sweet potatoes, cassava and plantains.

1 Presented by S. Nyvold.

World production of roots and tubers stagnated over the last decade reaching 580 million tons in 1986–88 compared with 571 million tons a decade earlier (Table 1). Similarly the production of plantains remained virtually unchanged around 24 million tons. These poor production performances contrasted with a relatively high growth in cereal production estimated at close to 2 percent per annum over the same period. International trade in fresh RTPs is small mainly because of their bulkiness and perishability, but in the processed form it has developed, with the opening of new markets for feed especially for cassava products. In addition, border trade in RTPs may be important in regions such as Africa and Latin America but is often not officially recorded. International trade statistics are thus likely to underestimate the actual volume of trade in those products.

Among roots and tubers, the largest at the global level is potatoes. World potato output was stable between 1976–78 and 1986–88 at around 282 million tons: there was a significant expansion in developing countries and a decline in the developed countries, which still produced about three-quarters of the total in 1986–88. Potato production in developing countries rose by some 26 percent over the period, or by an average rate of over 2 percent per annum, from 56 million tons in 1976– 78 to close to 71 million tons in 1986–88. About 65 percent of the developing countries production was concentrated in the Far East (China alone accounting for 40 percent) where a 2 percent annual growth was recorded. Output grew fastest in the Near East (6 percent per annum) and Africa (3 percent per annum), albeit from very small production bases.

TABLE 1.Production of cereals, roots and tubers and plantains
  Cereals Roots & tubers Potato Sweet potato Cassava Plantains
1976–78 1986–88 1976–78 1986–88 1976–78 1986–88 1976–78 1986–88 1976–78 1986–88 1976–78 1986–88
Millions MT
WORLD 1433.3 1688.9 571.2 579.6 281.9 281.3 163.3 151.9 117.5 137.4 24.1 24.3
Developed countries 797.9 839.9 228.7 213.4 225.9 210.6 2.3 2.3 - - - -
North America 308.9 314.5 19.4 20.0 18.8 19.4 0.6 0.6 - - - -
Western Europe 154.1 190.6 51.1 48.2 50.9 48.1 0.1 0.1 - - - -
Eastern Europe 290.3 288.3 150.7 136.6 150.8 136.7 0.1 - - - - -
Oceania 19.8 23.2 1.0 1.3 - - - - - -    
Other developed countries 24.8 23.3 6.5 7.3 4.4 5.1 1.5 1.6 - - - -
Developing countries 635.4 849.0 342.6 366.2 56.0 70.8 161.0 149.6 117.5 137.4 24.1 24.3
Africa 44.9 59.6 80.2 97.8 2.9 4.0 26.0 29.5 46.4 59.2 17.7 17.5
Latin America 82.7 104.5 45.9 46.4 10.3 12.2 3.3 3.0 31.6 30.5 5.4 5.9
Near East 52.9 66.4 5.6 9.6 5.2 9.2 0.2 0.2 - - - -
Far East 454.8 618.5 209.5 210.9 37.6 45.4 130.8 116.1 39.3 47.4 1.0 0.8
Other developing countries - - 1.4 1.6 - - 0.7 0.8 0.1 0.2 - -

Although trade in potato products rose considerably between the tworeference periods (from 5–6 million tons to 9–10 million tons) it continued to account in 1986–88 for only three percent of world production (compared with around 13 percent for cereals). Furthermore, it was heavily concentrated in Western Europe, which accounted for 70 percent and 74 percent of world imports and exports respectively.

As regards potato utilization, about half of the world total is estimated to be consumed as food, one quarter is fed to animals and the rest is used as planting material, processed or wasted. Feed use of potatoes is very high in China, where it was estimated to exceed 35 percent of total utilization in 1986–88. The relatively large use as feed is probably because of difficulties with inland transportation in this country which encourages considerable local and on farm use of roots and tubers. Elsewhere the quantity of potatoes fed to animals only represented a small share of supply. Thus, while potatoes are mainly used for human consumption, in certain circumstances, such as where there is low tuber quality, feedstuffs shortages or poor marketing structures, they are used as feed.

Sweet potatoes are mostly grown in developing countries which accounted for over 98 percent of world output, China alone producing about three quarters of the total. Between 1976–78 and 1986–88, world sweet potato production fell from 163 million tons to 158 million tons as a result of low output in China where land was increasingly diverted to cereal cultivation. By contrast, production rose by an overall 13 percent in Africa to some 30 million tons in 1986–88. Production in the other regions was basically unchanged over the period. The constraints to the expansion of sweet potato production vary from country to country. In many producing areas, yields have failed to improve due to varietal degeneration as some varieties are often grown for many years and even decades. In addition, there appear to be few incentives to use agricultural chemicals on sweet potatoes. Producer prices do not make their application economical, and a lack of markets has hindered the expansion of production.

International trade in sweet potatoes was practically non-existent in 1976–78, although unrecorded transactions are likely to have taken place. In the second half of the eighties, sweet potato trade was boosted by EEC import demand for feed. Since 1987 exports from China to the European Community have been regulated through a bilateral agreement which set an annual ceiling of 600 000 tons of dry sweet potato chips (about 1.5 million tons of roots), which could enter EEC member countries free of duty. This development resulted in a sharp increase in sweet potato trade which averaged about 1.4 million tons in root equivalent in 1986–88. In recent years, however, trade in sweet potatoes has fallen, mainly reflecting China's inability to fulfil its quota to the EEC. This was probably due to domestic transportation problems as well as increasing requirements in China itself. Elsewhere, the sweet potato trade has remained extremely limited.

On the utilization side, world food consumption of sweet potatoes is estimated to account for over 50% of supply while 30% is estimated to be feed and the remainder used as planting material, processed or wasted. Feed use in China is thought to be of the order of 20 percent of availability, a proportion that falls to 16 percent for developing countries as a whole. In Africa, however, only 3 percent of supply is estimated to be feed and over 20 percent wasted. This could indicate the existence of some potential in this region for larger on-farm use as feed if waste could be cut.

Cassava, which is almost exclusively grown in developing countries, is the only root for which global production rose to a significant extent over the decade under review. Between 1976–78 and 1986–88 world output expanded by 17 percent from 117 million tons to 137 million tons (or 1.6 percent per annum) as a result of significant growth in Africa, where cassava is often a staple food. This reflected, to some extent, the recognition by farmers and Governments, particularly after the 1984 drought, of the role that cassava plays in food security, since it is much less sensitive to climatic conditions than most cereals and other RTPs. The adoption by certain countries (e.g. Nigeria), of policies intent on reducing cereal imports also acted as an incentive to increase cassava plantings in recent years.

The underlying factors behind cassava growth in the Far East were of a different nature, and basically related to the development of export markets by Thailand and to a lesser extent Indonesia. In Latin America, by contrast, production stagnated or fell due to lack of production incentives and competition in demand from cereals, which was only partially compensated for by the development of new markets for feed, particularly in Colombia and Brazil.

World trade in cassava products also experienced a significant increase over the period, rising from 15–17 million tons in 1976–78 to some 27–32 million tons a decade later. This sharp increase was stimulated by the growth of the EEC markets for cassava, albeit for restricted quantities. EEC cassava imports have been regulated since the early 80s through bilateral trade agreements with major exporters. In addition, new markets have developed since the mid-eighties and particularly in the far East (see next section).

World cassava production is mainly for food consumption, which accounted for 58 percent of supply in 1984–86. About 28 percent was estimated to be fed to animals, 3 percent was processed into industrial products and 11 percent wasted. However, wide differences existed among regions. In Africa, cassava continued to be predominantly a food crop with 80 percent of supply consumed as food and only 2 percent destined for feed use. Given the relatively poor distribution and marketing conditions in the region, about 16 percent were thought to consist of post-harvest losses, a share that may be underestimated. Feed use of cassava in Latin America was much higher - 37 percent - compared with 42 percent for direct human consumption. In the Far East, the major exporting region, food consumption accounted for 80 percent of available production. Feed was estimated to account for only 6 percent and waste for 10 percent. However, the development of cassava trade within the region is leading to a greater use of cassava in feed by non-producing countries such as Japan and the Republic of Korea, while feed use in China is increasing, absorbing around 40 percent of supply in 1986–88.

Cassava has also become an important feed ingredient in the EEC, as its use in feeds rose from 15 million tons (in root equivalent) in 1976–78 to 24 million tons in 1986–88. This has been made possible by high domestic cereal prices, which have allowed cassava to compete successfully with grains in those markets (see also Section III below).

World production of plantains remained at around 24 million tons between the late seventies and eighties with most regions maintaining their share of the total. World trade expanded in the late eighties, owing to larger imports by El Salvador and the USA, but still accounted for less than one percent of global output.

According to FAO Food Balance Sheets some 62 percent of world supply was destined for human consumption in 1986–88, 14 percent processed, 21 percent wasted and only 2 percent used as feed. This represented a shift in utilization patterns since 1976–78. In this period feed use accounted for 9 percent of overall supply, while availability for food (55 percent) was lower. These changes were probably induced by the adverse production trends in Uganda - the world's largest producer - which resulted in lower feed use in Africa. Post-harvest losses, although somewhat reduced over the period (from 24 percent to 21 percent of supply), remained high relative to roots.

Feed use of roots and tubers

World feed use of roots and tubers (Table 2) rose by 12 percent to 153 million tons between 1976–78 and 1986–88, compared with 19 percent for cereals. Growth was particularly pronounced in developing countries where it rose by 35 percent over the decade to reach 68 million tons (in fresh root equivalents). However, their expanding animal product sector continued to rely predominantly on cereals, often imported, the use of which in feeds grew by 55 percent to 133 million tons in 1986–88. Most of the expansion in the use of roots and tubers (as well as cereals) in animal feeding was concentrated in the Far East, and more specifically in China, where a high growth of per capita income, continued to be recorded in the 80s. The greater feed use of roots and tubers in this region was not associated with increased production but rather with a shift in utilization patterns away from food. In the other developing regions, the feed use of roots and tubers fell, mainly as a result of poor production performance and continued substitution by feed grains. Similarly the utilization of plantains in feeds over the same decade declined, since larger requirements for food reduced the availability for feed, in the absence of significant increases in production.


World cassava trade expanded considerably in the seventies and eighties from less than 1.5 million tons in 1970 to a record of 12 million tons (in pellets equivalent) in 1989. This remarkable increase was largely the result of the workings of the EEC's Common Agricultural Policy (CAP). In 1967 the EEC introduced a common variable import levy on cassava chips and pellets, at 18 percent of the barley levy. In 1968, this levy was bound to a maximum 6 percent ad valorem duty under the Kennedy Round of the GATT negotiations. At the same time, the application of the CAP resulted in high domestic prices of cereals in member countries which exceeded, in most years, world levels and stimulated import demand for alternative feeds. Cassava pellets which, when supplemented with protein meals, can substitute for grains in animal rations, could accordingly fetch much higher prices in the Community than those which would have resulted otherwise. Considerable increase in compound feed production in the EEC in the seventies and eighties gave an additional boost to the demand for cassava pellets (Table 3) which became the major cassava product in international trade.

TABLE 2.Feed Use of cereals, roots and tubers and plantains
  Cereals Roots & tubers Potato Sweet potato Cassava Plantains
1976–78 1986–88 1976–78 1986–88 1976–78 1986–88 1976–78 1986–88 1976–78 1986–88 1976–78 1986–88
Millions MT
WORLD 520.0 617.8 135.8 152.8 80.2 68.5 26.2 44.0 29.2 40.0 2.1 0.7
Developed countries 434.1 484.4 85.3 84.6 70.1 57.9 0.4 1.5 14.8 26.0 - -
North America 141.8 164.0 0.9 1.0 0.9 0.9 - - - - - -
Western Europe 103.7 105.0 23.8 29.8 9.0 5.3 0.1 1.4 14.7 24.1 - -
Eastern Europe 167.2 187.3 60.1 53.0 60.0 51.7 - - - 1.4 - -
Oceania 2.7 4.0 - - - - - - - - - -
Other developed countries 18.7 23.9 0.5 0.8 0.2 - 0.3 0.1 - 0.5 - -
Developing countries 86.0 133.4 50.6 68.2 10.1 10.6 25.6 42.5 14.4 14.0 2.1 0.7
Africa 2.9 4.5 2.5 1.5 - - 0.7 0.3 1.7 1.1 1.7 0.2
Latin America 30.5 42.9 12.1 11.9 0.5 0.3 0.5 0.4 11.1 11.2 0.5 0.5
Near East 13.6 24.6 - 0.2 - 0.2 - - - - - -
Far East 39.0 61.4 35.9 54.5 9.6 10.0 24.6 41.8 1.7 1.7 - -
Other developing countries - 0.5 - - - - - - - - - -

The resulting high prices (Table 4), however prevented cassava feed products from successfully competing with grains in non-EEC markets except in 1973–74, when prices of grains reached record levels. In an attempt to stimulate non-EEC markets, some major exporters changed their policies in 1984. Since then a dual price system developed under which prices remained high in the EEC market but were considerably lower in non-EEC countries thus stimulating a sizeable expansion of cassava imports into these markets (see below).

High export prices to the EEC in the seventies and eighties encouraged a large expansion of cassava production in Thailand, the response being much weaker in other major producing countries (Table 5). Output in Thailand, which originally produced only small quantities of cassava for its starch industry, was subject to an exceptional boost. Production in this country rose from 3.4 million tons of roots in 1970 to 24.3 million tons in 1989. The existence of virgin land in the Northeast and the development during the Vietnam war of a major road network connecting that region with southern ports led to an increased cultivation of cassava without curtailing the production of other crops. Owing to high export prices, farmers' profit margins for cassava were also high relative to other products. Furthermore, considerable private investment in processing and port-handling facilities led to reduced marketing costs, which improved the advantages of Thailand relative to other potential exporters, particularly Indonesia.

The response of Indonesia to favourable cassava export opportunities, was much weaker than in Thailand (Table 5). Although production expanded, particularly in Lampung, the development of the pelleting industry, and shipping facilities to handle big vessels did not take place until recent years. In addition, unlike in Thailand where little cassava was consumed domestically, exporters in Indonesia had to compete for supplies with demand for food consumption, particularly in years of poor rice harvests. As a result, exports from this country, while rising, were not subject to the spectacular increase experienced by Thailand.

TABLE 3. EEC imports of cassava chips and pellets
Total Thailand Indonesia China
  ('000 Tons)
1970 1352 926 296 15
1975 2222 1873 314 4
1980 4866 4116 372 336
1985 6336 5681 553 78
1986 5822 5098 352 270
1987 6982 5671 756 340
1988 7024 5805 834 311
1989* 6982 5224 825 170
1990* 6200 4800 825 175

* Preliminary

TABLE 4. Prices of cassava pellets, cassava/soybean meal mixture and barley in the EEC, and world maize prices
  Cassava pellets Cassava/soya -bean meal1 Barley2 Maize3
(US $/ton)
1985 104 120 136 112
1986 144 159 170 88
1987 119 167 202 76
1988 154 184 197 107
1989 144 172 175 111
1990 1614 171 1945 1124

1 80 percent cassava, 20 percent soybean meal (includes a 6% ad-valorem duty on cassava pellets).

2 Selling price in Germany

3 No. 2 yellow FOB US ports

4 Jan-Sept average

5 Jan-April average

TABLE 5. Cassava root production and cassava chips and pellets exports in major exporting countries
  Production1 Exports2
Thailand Indonesia China Thailand Indonesia China3
(000 tons)
1970 3431 10569 1600 1172 334 15
1975 7094 12649 2100 2239 303 4
1980 16540 13574 3300 4970 386 336
1985 19263 13851 3600 6598 543 78
1986 15255 13312 3500 5878 425 270
1987 19554 14356 3300 5850 783 340
1988 22307 15471 3250 7663 1086 311
1989 24264 17091 3160 9316 1200 170
1990 22780 17064 3200 79004 10004 1804

1 Root equivalent

2 Product weight

3 Based on EEC import statistics

4 Preliminary

Shipments from other producing countries such as Tanzania and Nigeria in Africa and Brazil in Latin America were small and erratic. In these countries, the use of cassava as food as well as overvalued exchange rates pushed domestic prices too high to make exports profitable.

The large increase in shipments of non-grain feed ingredients (NGFI)2 into the EEC during the seventies generated a wave of protests from European cereal producers particularly since large grain surpluses developed. In response, a series of negotiations were held in the late seventies with Thailand and subsequently with Indonesia and the other exporters, and a series of trade restraint agreements signed, which put a ceiling on the volume of cassava which could enter the Community at the level of 6 percent ad-valorem duty. Since the early 80s3, imports of cassava chips and pellets into the Community have been restricted under three different types of quota, the first of which was allocated to Thailand (which was recognized as the major EEC cassava supplier), the second to other GATT countries, 85 percent of which was assigned to Indonesia, and the last to Non-GATT countries, mainly China. Cassava feed imports exceeding the pre-established ceilings were subject to much higher import duties.

The volume of EEC cassava pellets imports from Thailand for the period 1987–1990 was fixed at 21 million tons with a maximum of 5.5 million tons in any one year. For 1991–94 the same overall quantity was fixed despite requests from the Thai Government for an increase. However, the new agreement provides greater flexibility as it allows Thailand to export up to 5.75 million tons a year, with the possibility of ‘borrowing’ up to 650 000 tons during the last six months of 1994 from the next four-years quota, as a means of ensuring continuity of supplies4. The bilateral agreement with Indonesia for both 1987–90 and 1994–94 provide for a maximum of 825 000 tons a year. The maximum amount allowed from other GATT countries was established at 145 590 tons. For China the volume was fixed at an annual 350 000 tons over both 1987–90 and 1991–94. Another 30 000 tons a year is reserved for other non-GATT countries (mainly Vietnam). As a result, the maximum amount of cassava pellets allowed to be imported into the EEC has been set at 6.9 million tons since 1987 (7.1 million tons in 1990), although this has not always been achieved5. The annual ceiling in 1991–94 has been raised to 7.1 million tons. EEC restrictions on cassava imports acted as a brake to the expansion of cassava trade. The adoption first by Thailand in 1984 and more recently by Indonesia of special policies to allocate the EEC quota among their exporters, contributed to a new expansion of trade and increased feed use by non-EEC countries.

2 Including dried cassava, molasses, milling by-products, maize gluten, dried beets, oil cakes and citrus pulp.

3 Thailand had agreed only ‘informally’ to limit its 1979 and 1980 cassava exports at the 1978 level.

4 In 1990 Thailand was allowed to borrow up to 750 000 tons from its 1991–94 allowance.

The allocation of the EEC quota by Thailand was originally on a ‘first come, first served basis’. Since 1984 an incentive or ‘bonus’ quota was introduced which reserved part of the quota for export to the EEC to exporters selling to non-EEC countries. In 1989, for example, about 50 percent of the overall quota was destined to the bonus programme, the other half being distributed in proportion to stocks. The distribution of the bonus quota, was made on the basis of a pre-established ‘bonus rate’. In 1989, 500 000 tons were allocated at a ratio of ‘1 to 1.3’ (for each ton sold to third countries, exporters received 1.3 tons of the EEC quota) and the remaining part at a ratio of ‘1 to 1’. In 1989 the Indonesian Government decided to distribute all its EEC quota under a similar bonus system, which was very attractive since it entitled exporters to receive 2 tons of the EEC quota for each ton sold to other markets.

These incentive export measures resulted in a dual international price system for cassava feed products. Export prices to the EEC, which continued to be linked to high domestic grain prices, were attractive to exporters, who were prepared to sell at a lower price to third countries in order to have access to part of the remunerative EEC market quota. Prices on non-EEC markets were linked to prices of world cereal and protein-rich meals and were, therefore, set at much lower levels. In 1989, for example, the prices (f.o.b.) to non-EEC countries were about one third of those obtained in the European Community. This resulted in expansion of demand for feed by non-EEC countries particularly the Republic of Korea and Japan as well as the USSR and Eastern European countries6. In total it rose from less than 0.5 million in 1984 to 4 million tons in 1989.

5 In some years it has been exceeded because of delays between the issuance of import certificates by the Commission and the actual arrival of supplies in European ports.


The production of RTPs in developing countries, with the exception of potatoes and cassava, has grown slowly over the decade 1976–78 to 1986– 88. Potato production rose, but from a relatively small basis, and was mostly destined for human consumption, particularly in urban areas. Cassava production also increased either for food consumption (in Africa) or for export (in the Far East).

Domestic demand of RTPs for feed did not appear to be a driving force for an expansion of production in any of the developing regions, even in the Far East, where increasing volumes of RTPs were fed. Post-harvest losses in most developing regions were estimated to account for 15 percent of supply; for plantains the waste was of the order of 20 percent. Although losses could be reduced through improved transportation and storage techniques as well as through the development of small animal production units close to the production areas, further analysis would be required to assess whether investment in related projects would be economically and financially justified. Indeed, a major constraint to investments in these crops in many developing countries continues to be the more favourable level of cereal prices.

The development of import markets for cassava feed products has been linked to the artificially high cassava prices in the EEC. Although nonEEC countries have learnt in recent years how to use cassava in feed rations, it would not pay them to continue to use it if the price of the cassava/protein rich meal were to exceed world price of feed grains. Production costs in Thailand and Indonesia still appear to be too high for an ‘autonomous’ expansion of these markets (i.e. without the prop of the dual-price system) particularly since world cereals prices are rather weak. The exceptional development of cassava feed use in the last decade is thus unlikely to be repeated for other RTPs. Although there is scope for major producing countries to replace feed grains with domestically produced RTPs, their prices relative to those of feed grains will continue to be the critical factor.

6 Demand in those countries has fallen considerably in 1990 reflecting reduced feed use and shortages of hard currency.

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