- Email: [email protected]
Cassava in shifting cultivation: A system approach to agricultural technology development in Africa
Agriculture, Ecosystemsand Environment,20 (1988) 221-227
221
ElsevierSciencePublishersB.V., Amsterdam-- Printed in The Netherlands Book Reviews CASSAVA IN SHIFTING CULTIVATION
Cassava in Shifting Cultivation: A System Approach to Agricultural Technology Development in Africa, by Louise O. Fresco. The Royal Tropical Institute, Amsterdam, The Netherlands, 1986, 240 pp., softcover, Dfl. 39.00, ISBN 906832-013-0. Cassava is the most important staple food crop in Zaire, where both tubers and leaves are used, the former being the major source of energy and the latter a major source of protein, vitamins and minerals. Cassava plays an important role in the agricultural systems in Zaire. Very little socio-economic research on the crop has been carried out in Africa and this study is a welcome addition at this time. The book is a very comprehensive account of agricultural experience and development with special reference to cassava in one region of the humid tropics of Africa. Without doubt, if all projects in Africa were as thoroughly reported and analyzed as this one, we would all know much more about farming, in terms of crop suitability and performance and the effect of various systems, on the most basic and important resources of all--the soil. The book aims to do two things: look at the application of farming systems to shifting cultivation in a way that concentrates on the development of agricultural technology and, secondly, to report a specific case study of cassava in shifting cultivation in Kwango-Kwilu in Central Zaire a region that is typical of humid tropical Africa. The author's background research for this book is systematic and comprehensive; she cites relevant references in appropriate and meaningful contexts and has genuinely tried to optimize the data on which she has based conclusions and recommendations. Francophone and Anglophone methods of farming systems research are compared and contrasted both historically and contemporarily. The essential difference, according to the author, is that the French approach is more longterm and addresses the needs of all farmers in a given region, whereas the Anglophone approach is more short-term and limited usually to specific categories of farmers or selected technologies. This may well be a good and plausible explanation of the traditional differences in approach between the two systems, but it does not necessarily confine or limit the potential progress with either system; in many instances short-term interventions (e.g. improved crop varieties) are essential to increase output, especially of staple crops such as cassava. There is no substantive evidence yet that, in the case of cassava, this causes major disruption to the stability of the existing system of shifting cultivation in Africa.
222 Technologies in areas such as disease- and pest-resistant varieties are scalen e u t r a l - - t h e y can be appropriate to and benefit all categories of farmers. So a short-term research focus can bring results that have wide applicability and potential for adoption. The IITA successes in combating cassava mosaic virus (CMV), bacterial blight disease (CBB), cassava mealybug and cassava green spider mite are pure examples of this--technologies were developed to protect and nurture the existing productive potential of the cassava crop. The effects of new technologies on soil and general environmental degradation are now of major concern, and most agricultural researchers are concerned to identify and assess these effects. Shifting cultivation, or the new sustainable systems such as alley cropping t h a t are now being tested in Africa, are ways to maintain soil fertility and prevent erosion, while still allowing incremental increases in crop production. The focus of recent years on sustainable agriculture in Africa acknowledges t h a t farming systems must be in h a r m o n y with the natural fallow or tree-based ecologies of the humid tropics. W h a t matters most is not whether research is crop-based or ecology-foc u s e d - t h e overriding concern is to ensure that the effects of new technologies or systems are rigorously and extensively assessed to see if they add to the productivity, stability and sustainability of local crop production systems. Two approaches are increasingly recognized as very important in this regard: firstly, the extensive testing of improved crop materials throughout m a n y ecologies and socio-economic conditions and, secondly, the exploration and selection of local germplasm for use in national or regional breeding programs. These are the essential components of adaptive research for cassava in Africa today. Cassava, as a very suitable and sustainable crop for Africa's fragile soils, has not got the same potential as other food crops for soil and environmental degr a d a t i o n - i n fact it stabilizes most farming systems. The author is correct in stating t h a t more research is needed on a regional basis to assess the effects of the crop on soil fertility under more intensive systems of shifting cultivation and the sustainable alternatives that are currently emerging. In relation to research needs and approaches, the author tends to underestimate the importance and significance of b e n c h m a r k advances in research t h a t served to retain cassava as a major staple food crop in the tropics. The development of disease resistance to CMV and CBB were absolutely essential for progress to be possible in other areas, such as yield potential and stability, early maturity and tuber quality. These advances ensured t h a t cassava survived as a central crop in tropical farming systems. There is certainly a need for greater research in areas such as postharvest handling and processing of cassava in order to find better ways of utilizing the crop at village and farm levels. This is an area t h a t IITA will concentrate on in future as part of a strengthened c o m m i t m e n t to cassava research in the humid tropics.
223 Overall this is a good and valuable book which relates a farming-systems perspective of the development and application of improved technology for cassava production in a specific project in Zaire. The results, coupled with the frank and extensive discussion by Ms. Fresco, give the findings a reality that is often absent in some of the more general and abstract deliberations on farming systems in Africa. Towards the end of the book there is, however, a tendency to overgeneralize and extrapolate on the basis of findings in one small region of Africa. Here the author can be reminded of her own counsel in relation to farming syst e m s - w i t h o u t testing and evidence, these findings may not have the same implications or relevance in another region. The book confirms the success of cassava farmers in Kwango-Kwilu, Zaire in expanding production sufficiently to meet the food needs of an ever-increasing population in the region. It is the type of success that countless other regions of Africa will need to emulate over the next decade and beyond if millions of people are to have sufficient basic food for survival. S.K. HAHN AND M. CONNOLLY International Institute of TropicalAgriculture PMB 5320Ibadan Nigeria CROPPROTECTION Advisory Work in Crop Pest and Disease Management, edited by J. Palti and R. Ausher. Crop Protection Monographs, Springer Verlag, Berlin, 1986, 305 pp., hardcover, DM 198.-, ISBN: 3-540-16242-9. For many crop pest management problems the role of the advisory or extension agent is critical. His role is to appreciate fully the specific problems that farmers face, to be aware of relevant scientific and technical knowledge and to pull all this together to come up with an appropriate solution. He then has to convey this information to the farmer. Undoubtedly, this difficult and demanding task has not been adequately recognised, at least in terms of the status and reward given to advisers as well as in the scientific support that is directed towards helping t h e m in their task. A book devoted to this subject, therefore, is to be particularly welcomed. Unfortunately, this particular book is a disappointment. The main problem is that 'Advisory Work in Crop Pest and Disease Management' attempts too much. The editors have included sections covering economic aspects, legal aspects, diagnosis, sampling, monitoring, the use of remote sensing, computerised systems for pest management, pesticide application, public and private pest control services, and so on. The result is that the dif-
221
ElsevierSciencePublishersB.V., Amsterdam-- Printed in The Netherlands Book Reviews CASSAVA IN SHIFTING CULTIVATION
Cassava in Shifting Cultivation: A System Approach to Agricultural Technology Development in Africa, by Louise O. Fresco. The Royal Tropical Institute, Amsterdam, The Netherlands, 1986, 240 pp., softcover, Dfl. 39.00, ISBN 906832-013-0. Cassava is the most important staple food crop in Zaire, where both tubers and leaves are used, the former being the major source of energy and the latter a major source of protein, vitamins and minerals. Cassava plays an important role in the agricultural systems in Zaire. Very little socio-economic research on the crop has been carried out in Africa and this study is a welcome addition at this time. The book is a very comprehensive account of agricultural experience and development with special reference to cassava in one region of the humid tropics of Africa. Without doubt, if all projects in Africa were as thoroughly reported and analyzed as this one, we would all know much more about farming, in terms of crop suitability and performance and the effect of various systems, on the most basic and important resources of all--the soil. The book aims to do two things: look at the application of farming systems to shifting cultivation in a way that concentrates on the development of agricultural technology and, secondly, to report a specific case study of cassava in shifting cultivation in Kwango-Kwilu in Central Zaire a region that is typical of humid tropical Africa. The author's background research for this book is systematic and comprehensive; she cites relevant references in appropriate and meaningful contexts and has genuinely tried to optimize the data on which she has based conclusions and recommendations. Francophone and Anglophone methods of farming systems research are compared and contrasted both historically and contemporarily. The essential difference, according to the author, is that the French approach is more longterm and addresses the needs of all farmers in a given region, whereas the Anglophone approach is more short-term and limited usually to specific categories of farmers or selected technologies. This may well be a good and plausible explanation of the traditional differences in approach between the two systems, but it does not necessarily confine or limit the potential progress with either system; in many instances short-term interventions (e.g. improved crop varieties) are essential to increase output, especially of staple crops such as cassava. There is no substantive evidence yet that, in the case of cassava, this causes major disruption to the stability of the existing system of shifting cultivation in Africa.
222 Technologies in areas such as disease- and pest-resistant varieties are scalen e u t r a l - - t h e y can be appropriate to and benefit all categories of farmers. So a short-term research focus can bring results that have wide applicability and potential for adoption. The IITA successes in combating cassava mosaic virus (CMV), bacterial blight disease (CBB), cassava mealybug and cassava green spider mite are pure examples of this--technologies were developed to protect and nurture the existing productive potential of the cassava crop. The effects of new technologies on soil and general environmental degradation are now of major concern, and most agricultural researchers are concerned to identify and assess these effects. Shifting cultivation, or the new sustainable systems such as alley cropping t h a t are now being tested in Africa, are ways to maintain soil fertility and prevent erosion, while still allowing incremental increases in crop production. The focus of recent years on sustainable agriculture in Africa acknowledges t h a t farming systems must be in h a r m o n y with the natural fallow or tree-based ecologies of the humid tropics. W h a t matters most is not whether research is crop-based or ecology-foc u s e d - t h e overriding concern is to ensure that the effects of new technologies or systems are rigorously and extensively assessed to see if they add to the productivity, stability and sustainability of local crop production systems. Two approaches are increasingly recognized as very important in this regard: firstly, the extensive testing of improved crop materials throughout m a n y ecologies and socio-economic conditions and, secondly, the exploration and selection of local germplasm for use in national or regional breeding programs. These are the essential components of adaptive research for cassava in Africa today. Cassava, as a very suitable and sustainable crop for Africa's fragile soils, has not got the same potential as other food crops for soil and environmental degr a d a t i o n - i n fact it stabilizes most farming systems. The author is correct in stating t h a t more research is needed on a regional basis to assess the effects of the crop on soil fertility under more intensive systems of shifting cultivation and the sustainable alternatives that are currently emerging. In relation to research needs and approaches, the author tends to underestimate the importance and significance of b e n c h m a r k advances in research t h a t served to retain cassava as a major staple food crop in the tropics. The development of disease resistance to CMV and CBB were absolutely essential for progress to be possible in other areas, such as yield potential and stability, early maturity and tuber quality. These advances ensured t h a t cassava survived as a central crop in tropical farming systems. There is certainly a need for greater research in areas such as postharvest handling and processing of cassava in order to find better ways of utilizing the crop at village and farm levels. This is an area t h a t IITA will concentrate on in future as part of a strengthened c o m m i t m e n t to cassava research in the humid tropics.
223 Overall this is a good and valuable book which relates a farming-systems perspective of the development and application of improved technology for cassava production in a specific project in Zaire. The results, coupled with the frank and extensive discussion by Ms. Fresco, give the findings a reality that is often absent in some of the more general and abstract deliberations on farming systems in Africa. Towards the end of the book there is, however, a tendency to overgeneralize and extrapolate on the basis of findings in one small region of Africa. Here the author can be reminded of her own counsel in relation to farming syst e m s - w i t h o u t testing and evidence, these findings may not have the same implications or relevance in another region. The book confirms the success of cassava farmers in Kwango-Kwilu, Zaire in expanding production sufficiently to meet the food needs of an ever-increasing population in the region. It is the type of success that countless other regions of Africa will need to emulate over the next decade and beyond if millions of people are to have sufficient basic food for survival. S.K. HAHN AND M. CONNOLLY International Institute of TropicalAgriculture PMB 5320Ibadan Nigeria CROPPROTECTION Advisory Work in Crop Pest and Disease Management, edited by J. Palti and R. Ausher. Crop Protection Monographs, Springer Verlag, Berlin, 1986, 305 pp., hardcover, DM 198.-, ISBN: 3-540-16242-9. For many crop pest management problems the role of the advisory or extension agent is critical. His role is to appreciate fully the specific problems that farmers face, to be aware of relevant scientific and technical knowledge and to pull all this together to come up with an appropriate solution. He then has to convey this information to the farmer. Undoubtedly, this difficult and demanding task has not been adequately recognised, at least in terms of the status and reward given to advisers as well as in the scientific support that is directed towards helping t h e m in their task. A book devoted to this subject, therefore, is to be particularly welcomed. Unfortunately, this particular book is a disappointment. The main problem is that 'Advisory Work in Crop Pest and Disease Management' attempts too much. The editors have included sections covering economic aspects, legal aspects, diagnosis, sampling, monitoring, the use of remote sensing, computerised systems for pest management, pesticide application, public and private pest control services, and so on. The result is that the dif-