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close this bookSPORE Bulletin of the CTA No. 14 (CTA Spore, 1988, 16 p.)
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Bi-monthly bulletin of the Technical Centre for Agricultural and Rural Cooperation


Until recently, most market gardens were located on the outskirts of cities and, in a few cases, even within. They have now spread to rural areas but their viability there is threatened if transportation and marketing systems are not improved. If rural producers are to succeed, both agronomic and economic solutions to their problems need to be found.

The success of market gardens depends primarily on the initiative of these new entrepreneurs, whose numbers have increased dramatically over the last few years. Different production systems and objectives, as well as varying results, combine to make generalizations difficult in this field. It can be said, however, that if vegetable production in cities is designed to satisfy the large demand of consumers, in rural areas it reflects primarily the objectives of the producers themselves.

Market gardeners have flourished in African cities because their crops can produce large quantities from small areas. Using sewage sludge to enrich their compost and grey or used water for watering, such gardeners often exploit any available land, even in the centre of urban areas. Increasing construction in urban areas, however, is slowly pushing them out to suburban plots or land even further away from the city. Even so, many market gardeners are still producing on small plots ranging in size from less than ten to up to 100 square metres which are intensively cultivated by hand. In Kinshasa, more than 6000 urban farmers were identified in the business of supplying both the city and surrounding towns.

Such producers are very diverse: they include women seeking financial independence; civil servants who want to supplement their incomes; young people who are attracted by such "modern" agriculture; and the unemployed.

Increasingly, however, it is men who make their full-time living out of market gardening because it can be very lucrative. They specialize in European type vegetables (potatoes, cabbage, tomatoes, carrots, squash, and so on) leaving their wives the responsibility of growing African vegetables. But despite the spectacular growth of market gardening in urban and suburban areas the supply of cities generally remains inadequate. In Brazzaville, of the 18,000 t of vegetables consumed annually, only 3000 t are produced locally. Projects like Agricongo are attempting to modernize and increase production around urban centres.

Families in rural areas have always grown their own "sauce ingredients". These consist of various local crops (okra, pimento, tomato, leafy vegetables) produced in small backyard plots, or in association with other food crops in more humid areas. What is new is the appearance in the countryside of market gardens whose produce is destined to be sold elsewhere. The revenue from such sales is generally used to buy cereals thereby ensuring local food security. By improving living conditions in rural areas, NGOs and some governments also hope to limit emigration towards the cities (see SPORE No. 2). Market gardening is also well received by local farmers because it does not compete with their cereal crops, which remain the first priority. Produced during the off-season, vegetable crops can be used to exploit both idle hands and abandoned lands. Furthermore, although they require intensive care, there is no need for expensive equipment or specialized techniques to succeed.

Such initiatives have been rapidly developed not only in the droughtstricken Sahel but also in more humid regions where they can generate considerable revenues. One indication of this is the considerable amount of land now dedicated to market gardening. Collective gardens have sprung up around wells and vegetables now occupy increasing space in irrigated fields. Lands that were abandoned, such as easily-irrigated lowlands or sandy soils unsuitable for cereals, have now been brought back into production. Growing methods have also changed: cultivation is now more intensive, green manure is being used, and improved seeds are being introduced.

Enthusiasm but little experience

For the first few years, the enthusiasm of farmers and some NGOs disguised the problems inherent to this kind of production. The multiplication of these projects throughout sub-Saharan Africa also tended to ignore the fact that to succeed, crops must not only grow well but sell well. Unfortunately, very little was done in the beginning to ensure production and commercialization of such cross.

One of the main difficulties is that there is no regular supply of inputs. From time to time it is difficult to get the right seeds as improved varieties for foreign vegetables are rarely produced locally. Imports are either insufficient or arrive too late, especially in remote areas. Furthermore, there is the problem of hybrid seeds that cannot be reproduced at all and must be bought every year.

This is particularly crucial for potatoes, an up-and-coming new crop. Local production of seed potatoes is often impossible because the tubers are difficult to store under tropical conditions. They are supplied from Europe but often arrive too late. The organization of seed production is one of the main priorities in order to increase the output of market gardens. Furthermore, the plants themselves are not always adapted to the local climate or cultivation techniques. Improved varieties are more sensitive to drought and pests. Finally, it is unfortunate that so little work has been done on local vegetables that are more resistant and which can be grown during the hot and humid season.

Such crops require more stringent protection measures, all the more important because they grow during the dry season and thus are a prime target for insects that have nothing else to eat at that time. That explains why cotton pests such as Heliothis become major problems for out-ofseason tomatoes, why thrips attack onions, or diamond-back moths threaten cabbages. To limit such damage, growers treat their beds with insecticides which they find on the local market, often designed to be used on cotton crops. Unfortunately, they are poorly trained in the use of pesticides and have little choice other than, as one of them explained, the "white powder bought in bulk at the market". Excessive treatments are common especially in suburban areas. This leaves toxic residues on the produce and builds up resistance in the pest themselves.

The growers also have to deal with other, more dreaded problems such as nematodes or Pseudomonas solanacearum, a bacterium that infects the soil and makes it unfit for growing tomato crops. Researchers are now working on improved varieties to help overcome such difficulties.

Plant problems are particularly serious in humid, tropical zones with relatively little direct sunlight. On the other hand, tropical uplands which have lower temperatures are much more suited to producing a large variety of vegetables. If such regions are well exploited, it seems that they could supply large areas. Generally speaking, research on market garden crops remains inadequate. Current work deals with the selection of new varieties and crop protection. In view of the increasing importance of such crops, however, national and foreign research organizations are renewing their interest in these long-forgotten crone.

Commercialization is lacking

The sale of market garden produce essentially takes place through the traditional systems which usually rely on women. These networks involve numerous intermediaries, except for the very small producers who sell directly on the local markets. Transportation systems that are often inadequate or poorly adapted, and poor packaging and storage methods, result in heavy losses. Furthermore, those producers who are far removed from markets depend entirely on local merchants for information about current prices and supply conditions on the market. Those who are not near major transportation routes or urban areas are faced with considerable problems in selling their produce. Sacks of onions and crates of tomatoes often rot by the roadside because of poor collection and transportation systems.

Another problem is that many of these vegetables mature at the same time. In the Sahel, they all arrive at the same time on both rural and urban markets, usually between January and March. Sales during such periods of glut are often impossible and the bottom can fall out of the market. This has happened much more frequently during the last few years with the increase in the area cultivated. Villagers outside Matam in the Senegal River valley, for example, are no longer able to sell their produce on the saturated local markets

For farmers, sales are often the only reason for growing such crops. If they cannot make sufficient profit this way, they prefer to find a more lucrative activity that requires less effort. With the good results of the past few years, their financial needs are less pressing. In some areas there has already been a movement away from market gardening towards other activities that are considered to be more profitable such as gold panning or jobs in the city.

The question that remains is how to increase sales. Several answers are possible but there are no easy solutions. An increase in the consumption of vegetables in rural areas is encouraged, primarily to improve the local diet, which is often inadequate. The consumption of fresh vegetables in rural areas is far behind that in urban areas and European vegetables are eaten only as a last resort. In Mauritania, for example, the average annual consumption of vegetables is about 24 kg but villagers eat only 6 kg. Modification of traditional eating habits is necessary.

Spreading out the production period is another way of ensuring better sales. This could involve the development of tomato varieties that grow during the winter and others that can be planted early. African vegetables that can be grown throughout the year also enable farmers to spread out their production

In order to ensure more regular supply for markets, attention must also be given to better storage methods. In this respect, onions and potatoes are receiving research attention designed to find varieties that keep better. For highly perishable produce, such as tomatoes, processing techniques are recommended. Solar drying is a simple solution available to all but it alone cannot handle large excesses. The development of small industrial units to process tomatoes into concentrate seems promising but, in order to make such investments cost-effective, there needs to be good organization of production and collection systems.

At one point, export crops were hailed as the way of the future and this resulted in the development of numerous plantations outside urban areas. Markets for such products however, became more and more difficult to find and maintain. Today only green wax beans still find sufficient buyers. Produced in Senegal and Burkina Faso, they demand careful cultivation and harvesting, thus farmers have little room for error. Furthermore, shipping methods often require production dates that simply cannot be respected.

At the moment, the absence of guaranteed markets is the biggest obstacle to the success of market gardening. Efforts must therefore be made to give these crops the place they deserve in the local diet and economy of rural regions. It would be unfortunate if the enthusiasm of the farmers is not matched by equally energetic efforts of others to ensure that such hopes for the future are realized


3rd Seminar of CIRAD/DSA on ~Amenagements hydro-agricoles et systemes de production'. Montpellier. December 1986

Dupriez H and P. de Leener 1987 African Gardens and Orchards. Terres et Vie Wade, I., 1986 City Food: Crop Selection in Third World Cities. 54 pp

Available at USD 5 from: Urban Resource Systems 783 Buena Vista West San Francisco, CA 941 17


Agroforestry farming with trees

Agroforestry is a term which has only recently come into general use. It is used - and practised - most widely in tropical countries because of its advantages in optimizing production while reducing soil erosion. While the name may be new, the technique has long been practised in some countries.

A groforestry covers all systems where trees are deliberately left or planted on land where crops are grown or animals grazed, and so includes pratices as diverse as shifting cultivation, taungya, the growing of shade trees in cash crops such as coffee, and the use of living fences to contain or exclude animals.

The upsurge of interest in these practices over the last ten years stems from the increasing population pressures and shortages of food and fuel among poor people in many developing countries. To meet their needs, those living in the more marginal areas have been forced to shorten the time the land is left fallow, to encroach further into forested land, and to overgraze pasture. As a result, the natural soil cover has been removed and the recycling of nutrients prevented leading to soil erosion and rapid decline in crop yields.

Agroforestry is seen as one way of solving these problems, since by including trees in their farming systems, farmers not only benefit from a supply of wood and other tree products but help ensure their land remains fertile and productive as well

Leaf litter from the trees adds organic matter to the soil and acts as a mulch to retain soil moisture and prevent soil erosion. Deep-rooted trees may tap sources of nutrients which are out of the reach of annual crops, making them available once the leaves fall. Leguminous trees such as leucaena can also improve soil fertility more directly by nitrogen fixation. Tree roots can help bind the soil and also create channels which improve its aeration and permeability to water.

A mixture of tree and annual crops of different heights provides a more complete ground cover which again helps protect the soil from erosion and makes maximum use of available sunlight. The tree cover helps moderate extremes of temperature preventing rapid heat loss from the soil at night and protecting crops from excessive heat during the day.

While these environmental benefits are of great importance to the conservation of fragile ecosystems in the long term, farmers are more likely to appreciate the value of trees in their farming system if they can see more immediate rewards. Multi-purpose trees which provide fodder for stock and edible fruits or nuts, as well as fuel, timber and support for climbing vegetables are those most likely to be used.

Traditional systems

Traditional agroforestry systems differ in the extent of the association between tree and crop or livestock components. Amongst the most closely integrated agroforestry systems are home gardens such as those commonly found in West Java and the more humid parts of West Africa. These gardens contain an intensive mix of crops of all types so that their structure resembles the natural forest. Annuals such as rice, maize and sweet potato are among perennials such as fruit, nuts and fibres and forest trees retained to provide fuel, timber, tannins, gums and medicinal products. Fodder for small stock comes from tree leaves and the grasses which grow under the trees.

In the agroforestry system known as taungya, crops are grown among young trees only until the tree canopy closes over (one to three years), so that in this case the tree-crop association is temporary. The system was developed in Burma in the 1 850s, when foresters needed labour to help establish new plantations as teak was felled. By allowing farmers to grow crops among the trees, weed growth was controlled among crop plants and trees.

This system has since spread through Asia to Africa and Latin America. In West Africa it has been used to help establish plantations of Gmelina arborea. But although the system benefits poorer farmers as well as the forester, farmers sometimes resent the restrictions imposed and the constant need to move on. As a result they have been known to damage the trees deliberately and so postpone the time when they shade out the crone.

In the case of shifting cultivation, or bush fallow, trees and crops occupy the same ground in turn. Although the more valued trees may be retained during the years when crops are being grown, and the trees are never completely cleared, the association between trees and annual crops is less close than it is in other agroforestry systems. Even so in the past it shared many of the advantages of more closely integrated systems.

It is only now, when increasing demands o the land have led to shorter and shorter fallow periods, and in some cases eliminated them altogether, that soil erosion and reduced fertility have become a serious problem. Because bush fallow is the dominant form of farming in Africa as well as parts of the Pacific, it is this more than anything else which has promoted the search for alternative and more sustainable agroforestry systems.

For those involved in improving and developing existing systems, agroforestry demands an all-round approach very different from that found among conventionally-trained agriculturalists and foresters, so justifying the need for a new discipline with a new name. Researchers, extension workers, and policy makers concerned with agroforestry have to consider not only how these improvements will affect the sustainability of the system: they also have to take account of local laws and customs concerning the ownership of trees and land, since, for example, farmers may be reluctant to plant trees if this calls into question their rights to crop a particular area.

Although agriculturists can provide information about many of the crops found in agroforestry systems, little is known about most of the trees, with the exception of those such as leucaena, some acacias, glyricidia and calliandra. Even less is know about interaction between the trees and the crop. The research possibilities seem limitless.

Diagnosis and design

The International Centre for Research in Agroforestry (ICRAF) has played a key role in developing new research approaches to cope with the complexity of the subject. Established as recently as 1978, and based in Nairobi, its main aims are to initiate, promote and support research, and to increase awareness of the benefits which agroforestry brings. With only a limited number of staff, it is fulfilling these aims admirably, acting as a catalyst for agroforestry research worldwide.

To help researchers investigate existing systems, see how they can be improved, and set priorities for research, ICRAF has developed an approach it calls D & D - diagnosis and design. In the diagnosis stage researchers discuss with farmers their basic needs, such as those for food, fuel, shelter and a cash income. They examine the existing system in terms of both its productivity and sustainability. In the design stage they use their knowledge of agroforestry systems elsewhere to suggest improvements which the farmers might adopt straight away.

At the same time they identify more serious problems which might be resolved by research and the development of new technology.

ICRAF has also proposed that an agroforestry research network for Africa (AFRENA) be set up, linking researchers in five widely occurring agro-ecological zones, so that those with common problems can share information. Two such networks have so far been established. One links Malawi, Tanzania, Zambia and Zimbabwe which all have highland areas characterised by a hot or warm climate and a single rainy season, where the natural vegetation is miombo or savanna woodland. The second is in the hot humid lowlands of West Africa and initially involves only Cameroon.

ICRAF is supporting the programme by first promoting the network approach among government departments and research institutions in the countries concerned and then offering training in appropriate research methods. The networks should help researchers establish which problems are best solved on a regional basis and which should be tackled at the local level.

However ICRAF is by no means the only international centre concerned with agroforestry. The International Institute of Tropical Agriculture (IITA) based in Nigeria and the International Livestock Centre for Africa (ILCA) based in Ethiopia, and with an outstation in Nigeria, have for some years been testing and developing the agroforestry system known as alley cropping.

Alley cropping

Originally from Asia, this is one of the innovative approaches adopted to tackle the problems caused by reduced bush fallows. Food crops are grown in the alleys between the lines of trees or shrubs. The trees are cut back like a hedge while the crop is grown, but allowed to grow out and cover the soil once it is harvested. The benefits are similar to those in a traditional bush fallow, but in this case cropping and fallowing occur side by side, so allowing continuous use of the same piece of land.

The researchers have confirmed that alley cropping can be adapted to Nigerian conditions, and have tested several tree species, examining how they can be established, at what height they should be pruned, and the best distance between rows. The system has now been adopted by several villages in southwest Nigeria, although researchers were horrified to discover farmers growing highly competitive crops such as yam, melon and cassava between the young trees instead of the recommended maize. However, the trees survived and the researchers realised that what mattered was that the trees could be adapted to suit the farmers' existing system, not whether they took six months or two years to establish.

This example highlights the importance of considering the farmers' needs in order to simplify the research that needs to be done. Once it is established that a system works, and has advantages over the existing one, it is more appropriate to consider the range of conditions which component species can tolerate rather than under what conditions they grow best. For farmers with limited resources farming under highly variable conditions, it is the flexibility and diversity of traditional agroforestry systems which give them their strength.


Steppler, H A and P K R NAIR 1987 Agroforestry a Decade of Development ICRAF. Nairobi

Beets W. 1986 The Potential Pole of Agroforestry in ACP States. A State-of-the-Art Study. CTA. Wageningen

ICRAF Newsletter Subscription free, contributions and letters welcome

ICRAF PO Box 30677 Nairobi KENYA

The language of the land

Pierre Rabbi

An author and educator, Pierre Rabhi was born in the Sahara and has been farming in the Ardeche region of France since 1960.

The desert survival skills of Pierre Rabhi led him to apply organic farming methods based on compost to regenerate the poor soils of his farm in France. But above and beyond such techniques, it is the renewal of ancient relationships between farmers and the land that he proposes as the best tool for good husbandry. It is also another way for extension workers to get their messages across to farmers.

All farmers throughout the world speak the same "language of the land", even if they often need interpreters to speak to one another.

Whether they are farming the high lands of Latin America, the rice paddies of Asia, the African plains, the Scandinavian taiga or the bad lands of France herself, they all share the same experience of direct communication with the land. Given this common base, farmers cannot help but understand each other.

So it is not as an "expert" but as a farmer that I speak to my counterparts. I talk only about things that I have experienced myself during almost 20 years of organic farming. This kind of agriculture represents not only a technique but an approach to the land that other farmers can adopt. My predecessors and I in this movement have shown that even the most exhausted soil can be rehabilitated with organic farming techniques.

When I started farming in the Ardeche -- known as the "Third World of France" -- my soil was shallow, hard to work and had very low fertility levels. Without using any chemical fertilizer or pesticide, it was regenerated solely by the use of high quality compost.

Produced by aerobic decomposition, compost is a living product. It enables the liberation and uptake of fertilizing elements in the soil and facilitates the infiltration of air and water by improving the soil structure. Farmers who use compost are part of a vast movement dedicated to the restoration and conservation of productive land: each generation tries to leave the next with soil in better shape than when it was inherited. This is hardly the case of those who practise "scorched earth" techniques. From the Ardeche to the Sahel, the task is the same: degraded soils must be restored if these areas are to prosper. This has been obvious to me ever since my first visit to Burkina Faso.

Organic farming, which implies working in harmony not only with nature but with people, can ensure the regeneration of both soil and environment as well as the improvement of local living conditions. This is because organic farming contributes to local and national autonomy by reducing the dependence of farmers on outside supplies. This, in turn, helps relieve the balance of payments deficit by reducing fertilizer imports.

Farmers in Africa still have deep bonds with the land and living things, both plants and animals. To have a meaningful discussion with such people, one must adapt to their way of seeing things. It would be a mistake to use language that is purely technical or scientific. To get technical messages across, one must use a symbolic language because many farmers in Africa and elsewhere also associate the visible with the invisible. For them, the invisible has almost the same reality as the visible.

If, for example, I want to explain aerobic fermentation to farmers in the Sahel, I would not talk about oxidation or reduction. I would talk instead about two different forms of energy: a living energy, which breathes life into the soil through compost and a dead energy, which suffocates and makes things rot. To get the point across that the soil, plants, animals and people are all necessary for the transformation of wastes into fertile compost, I explain that these elements all depend on one another in the same way as the beams of a hut. To build a solid, round roof, each rafter is indispenable. Such symbolic language, based on everyday things, is the only way to have a real discussion with such farmers.

The technical approach adopted by most development officials too often neglects this universal mentality of "people of the land". It is well known, however, that farmers tend to listen and to trust only people who also know the land and speak its language.

Following the advice of Pierre Rabhi, Burkina Faso has officially adopted organic agriculture as part of its action programme for agricultural development. A centre on ecological agriculture has been established in Gorom Gorom in order to train farmers in such techniques, notably composting. Pierre Rabhi has also created a similar centre on his farm to train people in organic farming and has written Du Sahara aux Cevennes published by Candide (ISBN 2 904877 01 0) and available in French only at 70 FFR from:

Candide Lavilledieu 07170 Bayssac France

For further details, contact:
Pierre Rabhi Montchamp 07230 Lablachere France

This article is based on an interview conducted by Radio France International and does not necessarily reflect the viewpoint of CTA.

The promising future of Sesbania rostrata Reducing the need for commercial fertilizer

A seminar in Dakar, Senegal, in January 1988 broke new ground by bringing together two types of researchers who do not often meet: those doing fundamental scientific research and those working on the practical application of such results. The occasion was an international seminar on Sesbania rostrata which was organised by the CTA in collaboration with ORSTOM (the French development research agency) ISRA (Senegal's national agricultural research institute), and the genetics laboratory of the University of Ghent in Belgium.

The participants from more than 30 countries, discussed the results of their work and identified the problems posed by the integration of S. rostrata (and other plants with nitrogen-fixing nodules on . their stems) in the cultivation practices of African and Asian farmers. S. rostrata is an adventitious nitrogenfixing plant that is frequently found in the Senegal River valley as well as throughout the Sahel.

Although well known for many years, this plant was not studied in any depth until 1979 when ORSTOM researcher, Dr B. Dreyfus, discovered nitrogen-fixing nodules on its stems. This discovery hailed the beginning of basic research which rapidly developed throughout the world in 20 or so laboratories which analysed the physiology and genetics of the micro-organism responsible for the stem nodules. It is a new type that combines the properties of free nitrogen-fixing bacteria (like Klebsiella) and symbiotic bacteria (like Rhizobium). In fact, it was during this very seminar that this new bacterium was officially baptized as Azorhizobium caulinodans. At the same time as this basic research was started, agronomic researchers from 20 or so African and Asian countries began to examine the possibility of exploiting this new system capable of fixing high levels of nitrogen whether for irrigated crops (particularly with rice) or for rain-fed crops (notably with row crops).

The seminar gave a platform for the results of the latest research on the symbiosis of S. rostrata and A. caulinodans which appears more and more often as a priority subject for experimental trials. Such discoveries dealt first of all with the genetics of Azorhizabium. The substances that initiate and regulate nodulation have now been identified as well as the new genes that fix the nitrogen. The study of the interaction of Sesbania-Azorhizabium at the cellular level has, for the first time, enabled the in vitro development of nodules based on the infection of S. rostrata protoplasm by Azorhizabium. Such nodules will no doubt enable future research in this area to advance current knowledge of the cellular interaction between these two organisms.

The recent result of a plant/host mutant that does not have nodule sites opens the way to the identification of genes coded for this remarkable characteristic of nitrogenfixing stem nodules. The seminar also provided the opportunity for an update on the most recent molecular biology techniques capable of producing transgenic plants which have resistance to viruses, insects or herbicides.

Researchers at the seminar also confirmed preliminary observations which suggested that S. rostrata has considerable nitrogen-fixing potential. This exceptional symbiosis between S. rostrata and Azorhizabium explains the success of the use of S. rostrata as a green manure which, in almost all cases, enables the yield of irrigated rice to be doubled.

As for row crops, the contribution of S. rostrata to nitrogen supplies of associated plants is less signficant but still substantial. New uses of S. rostrata were also presented, including its ability to provide forage, fuelwood and pulp. In Senegal, it has even been shown that its leaves can be used for human consumption. The comprehensive study of the integration of S. rostrata in agriculture has already identified certain limits to its use, notably its sensitivity to a short photoperiodicity and to certain nematodes in areas that were flooded.

At the end of the seminar, numerous recommendations were made primarily to co-ordinate both field and laboratory research. They will be included in the proceedings which will be jointly published by CTA and ORSTOM.

New crops for food and industry

If it is agreed that the world has the potential resources to support its future population, it must also be acknowledged that - if governments should concentrate on the more equitable distribution of those resources - scientists and agriculturalists must direct their efforts towards new means of utilizing them.

This will entail producing new forms of old crops by breeding and selection, domesticating and managing wild species, and using biotechnology to create new plants.

It was to discuss future needs and developments in this field, and to put members of different disciplines in touch, that 130 participants from 33 developed and developing countries from all five continents gathered at the University of Southampton, U K from September 22-25 1987. The occasion was a Symposium on New Crops for Food and Industry, sponsored among others by CTA.

This symposium was a response to the global interest in increasing and sustaining agricultural productivity without contributing more to the surplus of the well-established staple crops of North America and Europe. But perhaps the most positive result of the gathering was the establishment at Southampton of a centre to develop and exploit under-utilized crops for food, energy and industrial raw materials in the tropics, sub-tropics, arid and semiarid and temperate regions.

CTA supported the attendance of two experts from ACP countries and delegates heard 41 papers on topics ranging from less-known oil-bearing plants to Indonesian seaweeds; development for industry, from biomass production in the desert using algae to the potential of herbal drugs; and to argue vigorously on behalf of their own individual crop specialities.

Despite such individual enthusiasm it was established that the needs of developing countries must come first, and to meet these, various criteria for crop priority emerged from both papers and discussions. They included the market potential and utility of the crops, the socioeconomic and the agricultural-environmental benefits, the degree to which systems can be developed to sustain production, the degree to which a new crop will help stabilize a shifting cultivation system or enable a fragile drought-prone environment to be stably productive; whether it is both independent of major agrochemical inputs and pest and disease-resistant, and the management of the genotype and environment interaction during development.

Other important priorities followed: that funding should not be wasted on new crops whose viability was open to serious doubt and that the conservation of genetic resources was vital. There was universal acknowledgement of women's role in agriculture, and of the social and agricultural importance of smallholdings in tropical countries.

It was further agreed that international agencies such as FAO, IBPGR, CGIAR, etc, should allocate funding to new crops, that these bodies should commit funds on a long-term basis rather than on shorter "seed" programmes.

The most concrete result of the symposium arose from a forum on the final day, chaired by Professor P Day from the Center for Agricultural Molecular Biology, Cook College, Rutgers University, New Brunswick. The symposium adopted the University of Southampton's proposal for a Centre for Under-Utilized Crops (International Co-ordinating Centre).

This establishment, which came into being on January 1 1988, will assist in and co-ordinate research and development in the field and laboratory, offer training courses on topics related to new crop development, start a newsletter and set up a database that will interact with others at Kew near London and elsewhere

Women in development

CTA is to fund a bibliographic project on the role of women in agriculture in southern Africa. The need for such a project was identified during a CTA-sponsored workshop on Agricultural Information Sources in Lilongwe, Malawi between June 15 and 261987 where 25 participants were trained in the use and production of bibliographic tools. This project, like the workshop, is expected to bring benefits in both the short and long term.

Women have always played a vital part in Third World agriculture, and in Africa they produce 90% of all domestically consumed food. But the raised feminist consciousness and educational standards of the 1980s, and the expectations arising from these, have only recently brought an awareness of the need to collate the increasing amount of written material on this subject.

The bibliography will list all published material on women in development in the four southern African nations of Botswana, Lesotho, Malawi and Zambia (chosen because they share a common experience of women's work). It will also attempt to collate information which originates from the Commonwealth, the Third World, ACP countries, and non-aligned countries, analysing by subject and identifying areas not covered.

The researchers, three women and one man from the four countries involved, aim to recognize and evaluate the quality, quantity, nature and subject scope of material available in their own countries. By providing potential users with a guide to existing data they hope to reduce unnecessary duplication of research and development schemes. They also seek to assist local libraries and documentation centres in amassing the identified literature, and to establish active cooperation from its producers.

Thus they intend to bring into being the basis of an ongoing bibliographic source on women in development and on other related topics which may eventually be expanded to cover Africa as a whole

The researchers hope, by extension, that through the increased awareness engendered by such a bibliography, women can be encouraged to participate actively in national, regional, and even continental economic life and, as one contributor put it, "to spearhead the integration of women in development in southern Africa

New control for Panama disease

Scientists in India believe that a new control technique may prove cost-effective in controlling Panama disease the widespread fusarial wilt that inflicts serious damage on bananas.

The new technique involves injecting a solution of 2% carbendazim directly into the corm, and the researchers from Tamil Nadu Agricultural University have compared this treatment to soil drenching with Methoxy ethyl mercuric chloride - the common treatment at present and to using a combination of the two methods. Results show that the new technique is extremely effective, indicating the curative action and stimulation of plant growth by carbendazim. The best control of all was given by the combined treatment, though the optimum cost-benefit came from the corm injection on its own. Similar effects from the application of carbendazim have been reported in other crops.

For more details, contact:
Department of Plant Pathology Tamil Nadu Agricultural University Coimbatore 641 003 INDIA

Fellowships for African researchers

The Project on African Agriculture: Crisis and Transformation is offering fellowships to African researchers or to research teams working alongside them for innovative projects that combine both training and research activities.

Interdisciplinary approaches that analyse the agricultural crisis in Africa are particularly favoured. These fellowships are designed for recent graduates working in research institutes or universities as well as government agencies.

For more details, contact:
Fellowship Program Project on African Agriculture Social Science Research Council 605 Third Avenue New York, N Y 10158 USA

PESTNET Now for Rwanda - The African Regional Pest

Management R&D Network, better known as PESTNET, has recently finalized the programme and budget for its proposed activities in Rwanda. From the start Rwanda was identified as one of four countries where PESTNET hopes to place emphasis on the generation of desired pest management production technology and to test methodologies, technologies and information for validity.

In particular the programme and budget now approved will cover proposed collaborative research on the assessment of the stemborer problem in Rwanda on sorghum and maize - the two important staple food crops in the country's economy.

For more details, contact:
PESTNET Coordinator International Centre of Insect Physiology and Ecology P O Box 30772 Nairobi KENYA

Microcatchments increase yields

Farmers in Somalia's northwest region have recently completed trials which show that a new water retention system increases their yields for less work.

Farmers had been using standard bunds to conserve soil and use available rainfall more efficiently. Last year, a field engineer, Kenneth Proud, tried another method. He got farmers to plant only a small area above existing bunds. Then the remainder of the land was smoothed and used as a microcatchment which supplied water to the cultivated area. The ratio of cultivated land to catchment area is crucial. Soil type, degree of slope, and rainfall must also be taken into consideration.

With sorghum requiring between 450 and 650 mm of rainfall to produce a good yield, the catchment area had to be three times the size of the planted field. Each field has above it a catchment area that feeds water solely to that field.

In the trials the smaller, but better-watered fields yielded the equivalent of 1,869 kg per hectare. Yields on 100 traditional farms were about 230 kg per hectare. Not only were yields better but inputs were greatly reduced. Farmers have now asked the World Bank for help in extending the system.

New Scientist February 4 1988 New Science Publications Commonwealth House 1-19 New Oxford Street London WC1A ING U K

Bollworm control with pheromones

Work at the Central Cotton Research Institute in Pakistan has shown that using sex pheromones to disrupt cotton bollworm mating may offer a non-toxic alternative to chemical control.

Three bollworm species, Pectinophora gossypiella, Earias vittella and E insulana, cause serious losses in cotton crops, and chemical control has proved problematic, particularly because of the adverse effects on beneficial insects and the difficulty in timing applications accurately. Sex pheromones - the chemicals released by insects in minute amounts to attract a mate offer easier control of the pest and the preservation of beneficial insects as well as avoiding the possibility of pesticide resistance building up.

The major pheromones of each of the three species are formulated together and applied by hand at the pin square stage by means of rope or twist ties. The level of disruption achieved can be measured by reductions in pheromone trap catches. In the experiments so far, the new control technique has proved so effective that researchers also report an almost complete lack of moth flying activity following one simple application. Results suggest that more than 99% disruption can be achieved for P. gossypiella and E. vittella, with 89.5% for E. insulana. This is taken as evidence that a significant lowering of reproductive rates should be attainable in the not too distant future.

For more details, contact:
Central Cotton Research Institute Old Shujabad Road Multan PAKISTAN

Traditional livestock treatment

A databank on traditional ways of treating livestock illnesses in tropical regions is currently being established.

The group of veterinarians involved in this project hopes to collect specific information such as: animals treated and their age, their illnesses, the techniques and substances used to cure them, the effects as well as the region or country involved.

For more details, contact
Heifer Project Exchange Dean Roedke RDLO P O Box 57 Mbeya TANZANIA

Communication consultants

A multi-media group of experienced consultants has been formed by the Danish Broadcasting Corporation. Called DaniCom/Danish Development Communication Consultants, the group is a not-forprofit consulting service specializing in communication and media in Third World countries.

Media and communication often come into project formulation at too late a stage, with the result that promotion of the project idea and local support never get a chance to develop fully. DaniCom sees communication as a system for promoting local initiative through information, feedback and dialogue, and offers expertise in radio, audio cassettes, TV, video, cine film, still photography and printing.

For more details, contact:
DaniComm Danish Broadcasting Corporation Radiohuset DK-1999 Fredericksberg C DENMARK

Living beehive legs

Living beehive supports are being used by traditional beekeepers in Uganda in order to support both traditional and topbar type hives.

In the tropics hive supports can be easily damaged by termites or rot. If hives are kept in trees they are usually not easily accessible for frequent inspection. So Ugandan beekeepers have developed live supports. They cut two large stakes, with a suitable "Y" shape, from either the bark cloth tree, Ficus natalensi, or a species of coral tree, Erythrina abyssinica. The stakes are placed in the ground at a distance apart to suit the hives. Hives can be placed firmly in the Y or they can be suspended by wires strung from the posts.

In time the posts will sprout and the branches and leaves will shade the hives from the sun. It is also possible to use the leaves as a fodder for livestock, or as a mulch.

The living hive supports are a good example of agroforestry and apiculture coming together.

November 1987 newsletter International Bee Research Association 18 North Road Cardiff CF1 3DY U K

Documenting mycotoxins

A reference library is currently being established by UNEP in Nairobi to help African countries control mycotoxins and to take preventative measures for the future. It will bring together all the literature that has been published on this subject. The authors of articles, brochures or publications on mycotoxins are invited to ensure that their work is included in this collection.

For more details, contact:
Mycotoxins Reference Library UNEP P O Box 30552 Nairobi KENYA

Funds available for research

The Directorate General for Science, Research and Development of the Commission of the European Communities (CEC) has announced a second research and development programme "Science and Technology for Development".

This consists of two sub-programmes for which research proposals are requested. Of particular interest to SPORE readers will be the sub-programme "Tropical and Subtropical Agriculture" whose expenditure commitments are estimated at approximately 55 million ECU. This programme comprises four broad sectors covering the improvement of agricultural products, conservation and better use of the environment, agricultural engineering and post harvest technology, and production systems. Detailed aspects of each of these sectors and the particular objectives of the Commission in funding suitable research projects are set out in the application documents which can be obtained from the address below.

Proposals will be selected on the basis of a number of factors one of which is the possibility of collaboration between research bodies in the members states and in developing countries.

The call for proposals is open for two years from mid-December 1987 and the Commission wishes to receive proposals for participation in this sub-programme according to the following schedule of dealines:
Phase 1 February 291988 Phase 2 June 30 1988
Phase 3 December 31 1988 Phase 4 June 30 1989
Phase 5 December 31 1989

The phasing of the call for proposals and the selection of projects for funding are necessary for technical and financial reasons, and the date of reception will have no adverse effect on selected proposals.

For more details, contact:
Mr C Uzereau Tropical and Subtropical Agriculture DG Xll, CEC rue de la Loi 200 B-1049 Brussels

Sweet potato for food and industry

Sweet potato cultivation provides both employment and food for Nigeria and many other countries where the crop is grown. It is the sixth most important food crop in the world and has several advantages over other staples. It has, for instance, a tremendous capacity for producino drv matter per unit area of land in a short time and it requires fewer production inputs than yam, cassava or other staple crops. It is also less vulnerable to drought and heavy storms.

S C O Narinyi of Nigeria's National Root Crops Research Institute highlights sweetness, strong taste and aroma, and the colour of the cooked product, as the most important areas requiring attention if the acceptability of sweet potatoes is to be enhanced. Deep orange and violet (or purple) flesh colours are disliked and white or yellow fleshed cultivars are generally preferred. Also, while other staple crops such as rice, cassava, potato, yam and cocoyam have little taste and need flavouring to increase palatability, many consumers object to the taste and smell of sweet potato. Nevertheless, others consume sweet potato because of its sweetness and flavour so there is opportunity for selection to modify these characteristics to suit a greater proportion of the population.

Industrial processing is another option for modifying appearance and taste: tubers are now peeled, sliced, dried and milled into flour, which can be used in various food preparations. With maize and soya bean flours, good infant foods have been produced and sweet potato flour blends well with wheat flour for making bread, biscuits and cakes.

High yielding cultivars from the International Institute of Tropical Agriculture (IITA) in Ibadan, Nigeria are in demand From farmers and further cultivars are on trial. With yields of 25-40 t per hectare, a growing period of three to four months, wide ecological adaptation, easy preparation and low input requirements, the sweet potato obviously has considerably unexploited potential as a major crop.

For more details, contact:
S C O Narinyi National Root Crops Research I nstitute Umudike PMB 7006 Umuahia NIGERIA

Electrostatic spraying

An air-assisted electrostatic sprayer has been used successfully in glasshouse trials to apply less than 1 litre/ha of pesticides to control whitefly in tomatoes. The technique has been tested at the AFRC Institute of Horticultural Research, Littlehampton, U K. High volumes (1,000 litres/ha) of insecticide sprays are wasteful because the majority of the chemical is deposited on upper leaf surfaces, or 'runs off' to the ground, whilst the pests feed on the undersides of the leaves.

The air-assisted electrostatic sprayer produces tiny charged droplets of chemical and achieves good penetration of the crop canopy. The electric charge attracts the droplets equally to both sides of the leaves. As a result, much more of the chemical reaches the parts of the crop where it could be effective against the pest.

Glasshouse trials have also shown that insecticides may be applied selectively to the apical foliage of tomatoes to control adults, eggs and young larvae of whitefly. This minimizes contamination of fruit and reduces harmful effects on the whitefly parasite Encarsia.

For more details, contact:
Peter Grimbly AFRC Institute of Horticultural Research Littlehampton Sussex U K

New bulletin on bananas

"Musarama" is the title of a new bulletin published by the International Network for the Improvement of Banana and Plantain (INIBAP) with the support of CTA and the International Development Research Centre (IDRC). This quarterly, whose first issue has just appeared, is designed to inform and put in contact all those who work on bananas and plantains.

Contributions are actively encouraged.

For more details, contact:
Musarama INIBAP B P 5035 34032 Montpellier Cedex FRANCE

Horticultural databank

Fieldworkers, researchers and documentation centres can now make requests to the databank of the Horticultural Crops Group of the FAO for information on high yielding varieties of fruits, vegetables, root crops or tubers. Such information can be provided according to geographical zones, the species or the crop

For more details, contact:
Horticultural Crops Group FAO Via delle Terme di Caracalla 00100 Rome ITALY

Recent publications

Wesselow, M R, 1986. Donkeys - their care and management Third edition, 144 pp ISBN 090000 126 7 Available from: Centaur Press Fontwell Sussex BN18 OTA U K

Pandey, R K, 1987. A farmer's primer on growing soybean on riceland. IRRI/IITA ISBN 971
104 168 5 Available from: IRRI P O Box 933 Manila PHILIPPINES

Ruttan, V W, 1987. Agricultural research policy and development ISBN 92 5 102580 0 Available from: FAO Via delle Terme di Caracalla 00100 Rome ITALY

Pieterse, M T A and H J Silvis 1988. The world coffee market and the international coffee agreement Wageningen Agricultural University ISBN 90 6754 118 4 Available at USD 19 or FFR 27.50 from: PUDOC P O Box 4 6700 AA Wageningen THE NETHERLANDS

Smith O B and H G Bosman (eds.) 1988. Goat production m the humid tropics. Proceedings of a workshop at the University of Ife, Nigeria ISBN 90 220 0935 1 Available at FFR 79.50 from: PUDOC PO Box 4 6700 AA Wageningen THE NETHERLANDS

Wuest, P J, D J Royse and R B Beelman (eds.), 1987. Cultivating edible fungi. Proceedings of the International Symposium on Scientific and Technical Aspects of Cultivating Edible Fungi ISBN 0 444 42743 3 Available from: Elsevier Scientific Publishers PO Box 211 1000 AE Amsterdam THE NETHERLANDS

AGRHYMET from the satellite to the hoe

AGRHYMET's regional centre in Niamey co-ordinates the programme, by centralizing and processing the data from nine national meteorological services. Field observers provide daily readings of agroclimatological and meteorological conditions to the national centres which forward summaries to Niamey. This information is then processed and enriched with regional data provided by weather satellites and then sent back to the national services to pass on to interested users. The programme also incorporates observations made by certain public or private services as well as those of the Agency for the Security of Aerial Navigation in Africa and Madagascar (ASENCA).

Having such information readily available enables better planning of agricultural activities, such as seeding times, predicting harvesting conditions or implementing emergency programmes to deal with insect invasions or disease outbreaks. It also improves the ability to evaluate future harvests by taking into consideration the meteorological conditions that prevail during the growing season. In the long term, the analysis of data collected over several years facilitates the task of national planning services when they need, for example, to introduce a new crop that will suffer minimum losses under rare but possible climatic conditions.

Weather bulletins, maps or reports produced by AGRHYMET are not only destined for government agencies or international and national research organizations. The objective of AGRHYMET is to make such information available to end users, notably farmers, through extension services and the media. That is why after an initial phase dedicated to establishing its data collection and analysis system, this programme is now entering a new phase designed to ensure that its services can become a valuable working tool for farmers.

If countries in the Sahel have been pioneers in this field more humid regions of Africa are now beginning to pay similar attention to better exploitation of agrometeorological information. It was in this context that a seminar on this subject was recently held in Benin

For more details, contact:

IFIS - International Food Information Service

In 1968 food science and technology lacked a voice to acquaint a world just coming to the realization that food supply was unlikely to meet the demand of a global population which would double by the year 2000 with this emerging and vital discipline.

The International Food Information Service (IFIS) was created to fill that gap. It aims to provide a comprehensive, high-quality international database in food science and technology, in both printed and machine-readable form. IFIS was formed at a time when developing countries were reaching out for a level of food research and development that would allow them not only to sustain their population but to export food to other countries.

IFIS works with four partners: CAB International (CABI); the Institut fur Dokumentationswesen, Germany, the Institute of Food Technologists USA; and the Agricultural Information Centre of the Netherlands (PUDOC). Its purpose is to fulfil the needs of both developed and developing countries through its databases - Food Science and Technology Abstracts (FSTA) based at the U K editorial office at Shinfield, and its subsidiaries PTSA for packaging and VITIS for wine.

Inclusion of material already covered by other databases in related subjects is avoided. The general philosophy of IFIS is to treat food science and technology only where it affects the journey between producer. and consumer, though there will inevitably be some overlap.

FSTA can rival almost any scientific database in its depth and breadth of coverage: between 1969 and 1986 FSTA's first 18 volumes contained 313,000 abstracts of world food science and technology output, culled from 1,562 journals from 83 countries contributing regularly and from 312 journals from 57 others. Other sources include patents, which represent 12.5% of the database; standards (3.5%), books (2%) and reviews (2.5%), with special efforts being made to include relevant contributions from both developed and developing countries. India, for example, is one of the leading sources

Although most FSTA monitoring and abstracting is carried out in the U K, 12 worldwide links have been established with national organizations to monitor and abstract local literature.

These include the Central Food Technology Research Institute, India, the University of the Philippines and the Technical Information Center for the Food Industry in Czechoslovakia. These links mean that language is no barrier to IFIS staff, who themselves cope with more than 40 languages.

There are 20 major abstracts subject headings within the database, the majority of which are commodity headings and the most important of which are milk and dairy products; alcoholic and nonalcoholic beverages; meat, poultry and game; and cereals and bakery products. Al1 these are broken down into sub-headings. Patents have only recently been categorised under their own section heading.

Other information products from IFIS include "Packaging Science and Technology Abstract's (PSTA), published bi-monthly, the quarterly nviticulture and Enology Abstracts (VITIS-VEA), "Food Annotated Bibliographies. (FABs), produced on a monthly as well as a cumulative basis, photocopy, and IFIS on-line services (details from the German office).

These publications spring from the IFIS German office at Frankfurt/Main, a not-forprofit company, as does the policy of closer cooperation with the developing world. This is achieved through such formal agreements as the one with the Central Food Technology Research Institute in Mysore, India, and by using modern information transfer media for countries with limited telecommunications facilities. Meanwhile, IFIS is actively exploring every possible means of improving this.

For more details, contact:
U. Schutzsach Managing Director IFIS Gmbh Herriotstrasse 5 6000 Frankfurt 71 WEST GERMANY
H Brookes A/Joint Managing Director I FIS Lane End House Shinfield RG2 9BB UK

Agroforestry for development

1987 saw the tenth anniversary of the establishment of the International Centre for Research in Agroforestry (ICRAF) which is based in Nairobi. "Agroforestry a Decade of Development" was written and published as part of the celebrations of this anniversary, and has been edited by two of the organization's leading figures, Professor Howard Steppler and Dr P K Nair.

It draws together contributions from some 18 authors each of whom is a leader in his field and active in the promotion of agroforestry. Such a range of contributors has inevitably also led to a range of definitions for agroforestry itself: a clear sign that the discipline is still young!

Much of the text deals with the work of ICRAF and this is particularly evident in the early chapters that centre on ICRAF's history and prospects for the future. Nevertheless, the breadth of experience of all the authors is reflected in later chapters which deal in detail with the ecological, institutional and developmental aspects of agroforestry and the results of research in this area.

Throughout the book the interdisciplinary nature of agroforestry is highlighted in all areas, from research to evolution and ultimately transfer. Differences in approach are also evident and nowhere is this more so than in the sections that describe the prominent agroforestry systems in a range of regions as seen by residents or those who have some years of experience in these areas.

Research findings are given regarding alley cropping, the role of nitrogen fixation, the potential of multipurpose trees and shrubs, and on Leucaena, the multipurpose tree genus that has proved so suitable for tropical agroforestry. Specific proposals are also made for future research activities concentrated into four main areas: systems, nutrient enrichment, germplasm evolution and tree component improvement. All of these combine to form management approaches to take agroforestry and indeed agroforestry research into the next decade.

For those interested in futher information on ICRAF's work a special issue of Agroforestry Systems (Vol 5 No. 3) was issued to coincide with the publication of the book. It contains 12 articles written by ICRAF staff and summarizes a decade of ICRAF's achievements.

Steppler, H A and P K R Nair (eds). 1987. Agroforestrya Decade of Development ICRAF. Nairobi. 335 pp. ISBN 92-9059-036X

Available from:
ICRAF House P O Box 30677 Nairobi KENYA

Tropical fruits

Tropical Fruits is a book aimed at those with an interest in tropical fruit, whether at college or in the field. This is the second edition of the book which was originally published in 1980 and widely regarded as the first detailed text on the subject for many years. This new edition has been extensively re-written and expanded throughout, and also includes sections on "new" crops such as pineapple-guava, passion fruit, Iychee and kiwi.

The book concerns itself both with fruits themselves and the techniques needed to cultivate them. Thus early sections are taken up with a detailed study of fruit growing in the tropics, and an explanation of the latest advances in crop protection. Cultivation pratices, both old and new, are also set out with a wide range of references listed.

Minor tropical fruits are also covered such as the sapodillas of Tobago, the cherries of Suriname and Iychee trees in Mauritius. Finally, appendices set out common names and their botanical equivalents, and list families and genera of fruit crops.

The book is written by Jules Samson, who grew up among the fruits in Suriname. He went on to become Director of the Agricultural Experiment Station there before becoming a lecturer in tropical crop husbandry at the Wageningen Agricultural University in the Netherlands, a post from which he has recently retired.

Tropical Fruits provides a comprehensive range of information for anyone concerned with the subject. The revision of the text has been so thorough that this second edition provides a valuable update for anyone who has come to rely on its predecessor.

Samson. J A, 1986 Tropical Fruit. Tropical Agricultural Series, Longman. 336 pp ISBN 0 582 40409 6

Available from:
Longman Scientific and Technical Longman House Burnt Mill. Harlow Essex CM20 2JE U K

Weed Science in the Tropics

One of the reasons frequently given for large family size in traditional societies in developing countries is that it provices labour for crop production. In the tropics people spend more time removing weeds than in any other part of the world.

In these areas weed control is inextricably linked with the drudgery that characterises peasant agriculture, and it is argued that the task of removing weeds occupies a disproportionate percentage of the population, thereby preventing these countries from developing in other areas of their economies.

Against this background it is perhaps surprising that weeds are without doubt the most underrated of pests in the tropics and their control is often severely hampered by the lack of resources, appropriate expertise and, in many cases, determination.

Weed Science in the Tropics is a practical book aimed at anyone who is actually concerned with controlling these competitive plants on an everyday basis. It was written by Dr Okezie Akobundu of the International Institute of Tropical Agriculture in Ibadan, who believes that it will be of particular use to teachers, agricultural students and consultants as well as those who are involved directly.

The book seeks to introduce a new dimension into the teaching of the subject by placing weed science as an integral part of a crop protection programme - a point emphasised by the first chapter which is specifically devoted to this subject. Further into the book, six full chapters are devoted exclusively to herbicides, covering their chemistry, presence in the environment, their action in plants and the soil, and their safe and efficient use. This is justified, according to the author, by the fact that herbicides are relatively new to tropical agriculture and in general are poorly understood.

Despite the fact that the book offers a detailed guide to all aspects of weed biology and control, it has deliberately been written in such a way that those who require only a short introduction to the subject may focus on a restricted number of chapters, while more advanced students can find considerably more detail in other sections. The appendices list common and trade names of herbicides together with their manufacturers and information on mammalian toxicity and residue tolerance.

Akobundu. I O, 1987. Weed Science in the Tropics - Principles and Practices. Wiley-lnterscience. 522 pp ISBN 0-471-915440


Breeding plants for higher feed value

The importance of crop residues as livestock feed has largely been ignored in plant breeders' search for higher arain yields.

To many agriculturists the "ideal" plant is one that produces a large amount of grain or seed with as little residue as possible, indeed the dwarf high-yielding varieties of cereals have benefited from the plant's capacity to switch starch production from leaf and stem tissue to the seedhead. But for smallholder farmers, where crop residues provide up to 80% of the feed for ruminant livestock, the plant residue is an essential resource.

A workshop on "Plant Breeding and the Nutritive Value of Crop Residues" was jointly organised in December 1987 by the Overseas Development and Natural Resources Institute (ODNRI) of the U K and the International Livestock Centre for Africa (ILCA) and was held at ILCA headquarters near Addis Ababa, Ethiopia. It brought together for the first time plant breeders, economists and nutritionists to highlight the potential nutritive value of such residues and to map research plans for enhancing their palatability digestibility and nutrient content.

The point was made by Dr John Walsh, ILCA's Director-General when he said "In most African livestock systems crop residues are critical to animal production, and if the nutritive value of crop residues could be increased by breeding, the amount of feed available to animals would greatly increase".

Several speakers stressed the need to re-evaluate the concept of crop residues. Dr Tom Nordbloom, an agricultural economist at the International Centre for Agricultural Research in the Dry Areas (ICARDA), based in Syria said, "In much of North Africa and West Asia, when farmers sow their crops they expect to get feed for their livestock at harvest. This clearly influences their choice of crops and the way they manage them". He went on to say that the farmer's viewpoint needs to be recognized by agricultural scientists and development workers, to make them aware that straws and stovers are not just residues, but rather joint products.

According to Dr R E McDowell, former chairman of ILCA's board and visiting professor at North Carolina State University, up to two tonnes of dry matter as crop residue is available in developing countries to feed livestock for each 500 ka livestock unit Speaking as a plant breeder, Dr Gurdev Khush of the International Rice Research Institute (IRRI) in the Philippines commented: "Plant breeders are increasingly aware of the farmers's need to make use of as much of the plant as possible. And that means that we must consider the nutritional value of the straw in our selection programmes". A first step in this process is to define standardized techniques to screen breeding materials for straw nutritive value -ones that correlate with in vivo nutritive value.

Participants felt that elite materials and released varieties should be screened, but some plant breeders said that screening methods could also be applied to parental lines used in a breeding programme. In some crops characteristics such as plant height and leafiness could be used initially to screen large numbers of line.

The participants endorsed the need for collaboration between animal nutritionists and plant breeders and in addition the need to improve storage methods to preserve the nutritive value of crop residues. There was general agreement that research efforts should be concentrated on cereal crops, but that cowpea, groundnuts and pigeonpea should also be studied

There were more than 40 participants at the workshop among them four from ACi countries supported by CTA.

Forecasting the weather, pests and even harvests

Experience with the latest outbreak of locusts in the Sahel has shown that weather forecasting services -- if accurate and quickly available --can play an important role in not only predicting but even preventing the invasion of locusts. It is now possible for the optimum conditions for locust swarming to be identified and quantified with considerable accuracy.

Once a certain number of conditions are operative, the alert can be given

The same is true for other insects or diseases like the cassava whitefly, the sorghum gall midge, sweet potato weevil or tomato nematodes. Early and comprehensive analysis of weather data also enables the evaluation of such problems during the growing period of the plants. This means that accurate estimates of the harvests can be made in order to prepare for any food imports that may be needed in the case of deficits

Good knowledge of future weather conditions could also enable farmers to plan their activities accordingly and thus optimize their investments rather than lose considerable time not to mention harvests, because they could predict the weather. For typical climates, with well-defined seasons (particularly those that can involve sudden changes with disastrous results for local people, as in the Sahel), weather forecasting has begun to provide an extremely valuable service to farmers

Much remains to be done, however, particularly in other regions. That explains why the national meteorological service of Benin, the World Meteorological Service and the International Institute of Tropical Agriculture organized last July in Cotonou a series of workshops on agroclimatology and crop protection in humid and sub-humid tropical lowlands.

Jointly sponsored by the FAO, UNDP and CTA, this seminar was designed to promote the exploitation of agrometeorological knowledge and data to forecast and follow the development of crop pests, to provide such information to improve protection measures while reducing their cost, to establish a dialogue between crop protection and weather forecasting services in order to determine what kind of information is needed, and to identify the techniques that should be used for plant protection measures.

The seminar attracted 55 people from 17 countries who participated in six workshops that dealt with questions as diverse as access to information, improving everyday collaboration between governments, the impact of meteorology on the development and movement of major migrators, as well as weather and plant protection techniques for economically important crops such as groundnuts and cotton.

As far as information needs are concerned, the seminar underlined the importance of maintaining good communication with users and providing extension workers with good data.

Considerable progress has been made in the collection and processing of data, but the most important task that remains is to ensure that such information be made available in a way that local users can understand.

For further details. the proceedings of this seminar are available from CTA.