JOINT FAO/IAEA DIVISION

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1 JOINT FAO/IAEA DIVISION OF NUCLEAR TECHNIQUES IN FOOD AND AGRICULTURE INTERNATIONAL ATOMIC ENERGY AGENCY FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS WAGRAMER STRASSE 5, P.O. BOX 100, A-1400 VIENNA, AUSTRIA TELEPHONE: (+43 1) 2600, FACSIMILE: (+43 1) 26007, INTERNET: IAEA-311-D1-RC Co-ordinated Research Project on Development of Management Practices for Sustainable Crop Production Systems on Tropical Acid Soils through the Use of Nuclear and Related Techniques CRP D FINAL REPORT 15 to 19 November 2004 Vienna International Centre Vienna-Austria

2 EDITORIAL NOTE In preparing this publication for press, staff of the IAEA have made up the pages from the original manuscripts as submitted by the authors. The views expressed do not necessarily reflect those of the governments of the nominating Members States or of the nominating organizations. Throughout the text names of Member States are retained as they were when the text was compiled. The use of particular designations of countries or territories does not imply any judgment by the publisher, the IAEA, as to the legal status of such countries or territories, of their authorities and institutions or of the delimitation of their boundaries. The mention of names of specific companies or products (whether or not indicated as registered) does not imply any intention to infringe proprietary rights, nor should it be construed as an endorsement or recommendation on the part of the IAEA. The authors are responsible for having obtained the necessary permission for the IAEA to reproduce, translate or use materials from sources already protected by copyrights.

3 Participants of the Final RCM of the Tropical Acid Soils CRP, November 2004 Vienna-Austria Back row (From left to right): T. Muraoka, G.Hardarson, Minh-Long Nguyen, V.Bado, Jan Diels, J. L. Arrillaga, B. Vanlauwe, Ian Ferris, R. Giaccio Front row: Lee Heng (Ms), Marisol Lopez (Ms), A. García Altunaga, S. H. Chien, F. Zapata, W. Horst, J. J. Peña Cabriales, Upendra Singh, S. Urquiaga

4 TABLE OF CONTENTS 1. INTRODUCTION THE CO-ORDINATED RESEARCH PROJECT Title of the CRP: Project duration: Justification Overall Objective: Specific Research Objective: Expected Outputs from the CRP include: OVERALL IMPLEMENTATION THE FOURTH AND FINAL RESEARCH CO-ORDINATION MEETING (RCM) Objectives The Meeting CONCLUSIONS AND RECOMMENDATIONS Crop genotypes adapted to acid soils Soil/water management of tropical acid soils Ameliorating soil acidity and nitrogen infertility of tropical acid soils Ameliorating Low P Status of Tropical Acid Soils ACKNOWLEDGEMENTS...19 Annex A Programme of the meeting...20 Annex B List of Participants...23 Annex C Executive Summaries...26 Annex D List of publications

5 1. INTRODUCTION Against the background of the projected increases in world population there is a need to increase food production through intensification of agricultural production in the already cultivated land or expansion of the land into cultivation. Land for potential expansion of the agricultural frontier lies in the tropical rainforest and savannas regions dominated by acid infertile soils. The tropical rainforest ecosystem should be preserved to conserve biodiversity and protection against climate change. Thus, the most favoured lands are concentrated in the savanna agro-ecosystems, which are located in the sub-humid tropical region, and comprise a sizeable amount of the agricultural land in many countries of Africa and Latin America. In terms of agro-climatic conditions, the savannas present suitable conditions for rainfed agriculture. The soils, predominantly Ultisols and Oxisols, are typically acidic and infertile. In other soils, the problems of acidity are likely to increase due to increasing CO 2 levels in the atmosphere, the use of ammonium-based N fertilisers and other processes. Several international programmes of CGIAR institutes (CIAT, IITA, IFDC, CYMMIT, ICRISAT, WARDA and others) have concentrated their activities on developing technologies suitable for sustainable increases of agricultural production in the savannas. Currently there is a fast intensification through the development of intensive cropping and cultivation systems dictated by the regional and world markets. This intensification, however, must be accomplished without degrading the resource base. There are several examples of accelerated rate of resource base degradation due to cultivation of marginal lands, and lack of adequate soil management and conservation practices. Therefore, the overall goal of this project is to develop integrated soil, water and nutrient management practices to increase and sustain productivity of tropical acid soils. This can result in a major contribution to food security in the Sub-Saharan Africa and Latin America. Nuclear techniques will be employed to gather precise and quantitative information on the dynamics of water and nutrients in cropping systems and to monitor the value of the interventions designed to alleviate soil constraints to agricultural production and to conserve the resource base. Recognizing the strategic importance of the sustainable agricultural production in the savannas, the Joint FAO/IAEA Division convened a Consultants Meeting in Vienna (March 1-3, 1999) to review advances in the approaches for sustainable intensification of agricultural productivity of the savannas and to elaborate a detailed work plan of a new Co-ordinated Research Project (CRP). Based on the recommendations of the Consultants Meeting, the Joint FAO/IAEA Division through the Soil and Water Management & Crop Nutrition Section started implementation of a CRP with 7 research contract holders from developing countries (Africa and Latin America) and 5 agreement holders from advanced research institutes with the following specific objective: Improve agricultural production of tropical acid soils through the use of adapted plants, the amelioration of soil acidity and infertility, and better soil, water, nutrient and crop management. The First Research Co-ordination Meeting (RCM) was held in the IAEA Headquarters, Vienna, Austria from 5-9 June Mr. F. Zapata was the Scientific Secretary of the meeting (Refer to Report IAEA-311-D1-RC.810.1) The Second RCM was held in Brasilia, Brazil, from 11 to 15 March Dr. Segundo Urquiaga, from the Brazilian Agricultural Research Corporation (EMBRAPA)-National Centre for Agrobiology was the local organizer and Mr. F. Zapata was the Scientific Secretary of the meeting (Refer to Report IAEA-311-D1-RC.810.2). The Third RCM was convened in Ouagadougou, Burkina Faso, from August Dr. Vincent Bado from the Institut Nationale de l Environment et de Recherche Agricole (INERA) - 1 -

6 was the local organizer and Mr. F. Zapata was the Scientific Secretary of the meeting (Refer to Report IAEA-311-D1-RC.810.3). This Final report (IAEA-311-D1-RC.810.4) describes the Forth and Final RCM of the CRP, which was held in Vienna from November It contains a full description and the main conclusions and recommendations of the project. The programme of the meeting, list of participants, executive summaries submitted by the participants and list of publications are included as annexes. 2. THE CO-ORDINATED RESEARCH PROJECT 2.1. Title of the CRP: FAO/IAEA CRP on Development of management practices for sustainable crop production systems on tropical acid soils through the use of nuclear and related techniques. (D ) 2.2. Project duration: 5 years ( ) 2.3. Justification As a result of the increasing world population, there is a need to increase food production. This can be achieved through intensification, diversification and specialisation of agricultural production systems in existing cultivated land or by expansion of the land under cultivation. Currently, about 40% of the potentially arable land resources are cultivated worldwide. The greatest potential for expanding agricultural land lies in the tropical rainforest and savannah regions dominated by acid, infertile soils. It should be noted however, that the cultivation of marginal lands and the lack of appropriate soil management and conservation practices on the better lands, have resulted in an accelerated rate of degradation of the natural resource base. Therefore, the required increased food production must be achieved without further degrading the resource base. Much of the required production will have to come from agro-ecologies that are capable of supporting more intensified production systems. Acid soils, mostly Oxisols and Ultisols, cover 1.7 billion ha, approximately, 43% of the world s tropical land area; with 64% of tropical South America, 38% of tropical Asia and 27% of tropical Africa. The problems of acidic soils are likely to increase, with increasing CO 2 levels in the atmosphere. In addition, more land in developing countries is becoming acidic due to the use of ammonium-based nitrogenous fertilisers, removal of farm products and nitrate leaching. The most favoured lands are concentrated in the savannah agroecosystem. The savannah area is located in the sub-humid tropical zone, and comprises a sizeable amount of the agricultural land in many countries of Africa and Latin America. In terms of agro-climatic conditions, the savannahs represent the most suited conditions for rainfed conditions. In Africa the savannahs have historically produced all of the sorghum, millet, cowpea, much of the maize, yams and groundnuts and more recently large amounts of cassava, soybean, cotton and upland rice. In view of the above, several international agricultural research organisations have focused their activities on identifying technologies suitable for the savannah regions. IFDC has carried out extensive research on fertiliser management on the acid savannah soils of Africa and Latin America. IITA, CIMMYT and CIAT have given special attention to the improvement of maize for savannah conditions and followed more recently by an EU-funded project to study mechanisms for tolerance of maize to Al and develop user-friendly sustainable technologies to mitigate soil acidity. CIAT has also developed new agropastoral systems for the savannahs that can improve soil fertility and quality. ICRISAT has major programs on sorghum, millet and groundnuts. IITA has also active - 2 -

7 programs on soybean and cowpea. ICRAF has also studied the potential for agroforestry. WARDA is working extensively on rice production in inland valleys located through the savannahs. In addition, networks have been created to integrate national efforts into regional programmes and improve the flow of technology from the IARCs into the regions. As a result of all these efforts, many technologies are available for the savannahs. However, there are significant gaps in the development and transfer of the technologies to the farmers. Consequently, agricultural production in the savannahs remains far below its potential. There are several examples (maize, cassava, and soybean) that illustrate the potential technological improvements that are available to stimulate food production within the moist savannahs on a sustainable basis. Similarly, there are improved technologies for other crops such as yams, cowpea, etc., albeit not of the magnitude of maize, upland rice, cassava and soybean. A key issue that has not been sufficiently addressed and that is lacking for the majority of the farmers in the savannahs is the improvement of resource management/conservation technologies that are vital for sustainable agricultural production. In summary, bridging the gap between the potential and actual production of the savannahs is possible using improved technologies to intensify crop production while conserving the resource base. This can result in a major contribution to food security in Sub- Saharan Africa and Latin America. In line with the strategic objective of the sub-programme D1 of the Joint FAO/IAEA Division an integrated approach to soil, water and nutrient management for sustainable crop production in the savannah ecosystem is proposed. For more information, please refer to the document Strategy Plan of the sub-programme D1. The proposed project will focus on three main lines of investigation: 1. Utilising acid-tolerant and P efficient genotypes. 2. Addressing issues of acid soil infertility. 3. Developing good management and conservation practices for acid savannah soils. This division is arbitrary because these areas of research are closely inter-related. In most cases, combined approaches will be required. It is envisaged that the work will be implemented via an eco-regional approach, identifying specific benchmark areas as focal points for strategic research and development activities. Natural resource conservation will be enhanced by promoting production intensification on the better lands combined with the use of biological approaches for nutrient management and soil conservation. Several nuclear techniques have potential to study the topics to be addressed in this project. These include, the soil moisture neutron probe for soil water studies and root activity, N-15 techniques for measuring N cycling (N recovery from organic residues and chemical fertilisers, biological nitrogen fixation, etc.) in soils, crops and water; P-32 techniques for evaluating soil P dynamics and the agronomic effectiveness of P fertilisers, in particular phosphate rock-derived products; C-13 for measuring decomposition rates of organic residues and identification of sources of organic matter in soil organic C pools, Cs-137 for measuring soil erosion at the landscape level, etc. The proposed CRP will be conducted through the creation of a network of National Agricultural Research Systems (NARS) and International Agricultural Research Centres (IARCs). Synergies will be enhanced through appropriate linkage to existing networks on acid savannah soils. Close collaboration will be established with the AGL and AGP Divisions of FAO in Rome. The improved technologies developed under this project should be transferred to the farmers, who are the beneficiaries of the project. To ensure direct transfer of the results and the expected impact from the outputs, several activities will be implemented to disseminate the information generated through the project: the results should be published in local and international journals. Whenever - 3 -

8 possible field trials should be done in farmers fields and close links should be established with extension services. Also, data base formation and validation of models should be considered. The Agency s involvement is justified in that: * isotopes (stable and radioactive) and radiation techniques are essential to obtain a quantitative estimate and subsequent evaluation of soil, water and nutrient management practices as well as to monitor the value of the interventions. * the objectives of the proposed project are in line with project D1.02 (IAEA PWB ), with the overall strategy set in the medium term plan of the sub-programme D1, and with the strategic objectives of the FAO s Department of Agriculture. * the research approaches envisaged are highly relevant to a number of Member States with high potential agricultural land in the savannah ecosystem. * the proposed CRP will entail the formation of a network of international and national research institutes working on tropical acid soils. Experimental guidelines will be developed to address the main priority areas in an integrated manner using nuclear techniques. Promising results will be disseminated to end-users through appropriate links to extension networks and by conducting on-farm trials Overall Objective: To develop integrated soil, water and nutrient management (SWNM) practices to increase and sustain productivity of tropical acid soils Specific Research Objective: Improve agricultural production of tropical acid soils through the use of adapted plants, the amelioration of soil acidity and infertility and better soil, water, nutrient and crop management. 2.6 Expected Outputs from the CRP include: i. Acid-tolerant and P-efficient genotypes that have been screened and validated ii. Data on carbon, nutrient and water dynamics that have been obtained using nuclearbased techniques iii. Improved SWNM practices, with appropriate guidelines iv. A database of results from on-station and on-farm experiments v. Enhanced human skills and institutional capacities for on-farm and on-station research on integrated SWNM practices vi. Satisfactory communication of results 3. OVERALL IMPLEMENTATION The Consultants Meeting held in 1999 outlined the logframe of the project and provided guidelines on the target topics, site/partner selection, and use of isotopic techniques to be used in conducting research. The project proposal was approved by the NA subcommittee on August The initial research network comprised seven research contract holders: Brazil (2), Burkina Faso (1), Cuba (1), Mexico (1), Nigeria (1), Venezuela (1) and five research agreement holders namely representatives from (CIAT-Colombia), WARDA (Cote d Ivoire), Germany, IITA-Nigeria, and IFDC-USA). During the first RCM the main soil constraints to agricultural production in tropical savannahs of Latin America and Africa were critically analysed, the work plan of the project was reviewed and research protocols/guidelines were developed

9 During the second RCM, research results were reviewed and progress made evaluated in accordance to the work plan. The research protocols were revised and modified, as needed. Six contractors, four agreement holders (TSBF/CIAT-Kenya; IITA-Nigeria, Germany and IFDC-USA) and one technical contractor from Australia (identification of Al;-resistant and P-efficient plant genotypes adapted to tropical acid soils) attended. During the third RCM, research results were reviewed, progress made in the implementation of the project was evaluated and plans were made for completion of the project. Six contractors, four agreement holders (TSBF/CIAT-Kenya; IITA-Nigeria, Germany and IFDC-USA) and one technical contractor from CSIRO, Australia attended. During the final phase of implementation, three technical contracts were awarded to support the following research areas and achieve expected outputs from the project: (i) to create an agronomic phosphate rock (PR) database, (ii) to develop a decision support system for direct application of phosphate rock (PR-DSS) and (iii) to conduct research to identify nitrogen use efficiency indicators for maize genotypes grown in acid soils. The final RCM of the CRP was held from November 2004 at the IAEA Headquarters in Vienna, Austria. 4. THE FOURTH AND FINAL RESEARCH CO-ORDINATION MEETING (RCM) 4.1. Objectives The objectives of the Final RCM were: a) To review all the research results obtained during the duration of the project, including the last reporting period ( ); and b) to evaluate the overall implementation of the CRP in accordance with the log-frame and work plan of the project The Meeting The meeting was formally opened by Dr. Long Nguyen, Head of the Soil and Water Management & Crop Nutrition Section of the Joint FAO/IAEA Division. He welcomed the participants on behalf of the FAO/IAEA Division and made remarks regarding sustainable agricultural production in tropical acid soils, the next steps to ensure technology transfer to end-users and the need to maximize outcomes through co-ordinated efforts and standardization of datasets. Dr. F. Zapata, the scientific secretary made an overview of the main objectives, strategies, past activities of the CRP, and presented the objectives and the programme of this meeting (Annex A). Six research contract holders (Brazil (2), Burkina Faso, Cuba, Mexico, Venezuela), three technical contractors (IFDC-USA (2) and Germany) and two research agreement holders attended the meeting. In addition staff of the Section and the Science Unit, IAEA Seibersdorf Laboratories participated. The full list of participants is shown in Annex B. Presentations The first two days consisted of technical sessions, with presentations by the participants grouped by savannas of Latin America and Africa and supportive research. The participants presented their final research reports highlighting their main areas of research. The results obtained were thoroughly discussed. It was noted that the results from the savannas of Latin America and Africa are site-specific due to particular environmental (soil and climate) and socio-economic conditions. Summaries from the final reports are given in Annex C. Formulation of Conclusions and Recommendations On Wednesday 17 November 2004, participants divided in four working groups formulated and prepared written reports on conclusions and recommendations of the project, i.e. a) identification of adapted (Al-tolerant, P-efficient and N-efficient) genotypes to acid soils, b) correction of soil acidity and N infertility (liming, fertilizer N, biological nitrogen fixation in grain legumes, organic residues, - 5 -

10 cover crops/green manures, etc.), c) correction of P infertility (P fertilizer, phosphate rock agronomic database and decision support system for direct application), and d) improved soil (no tillage, soil organic carbon and nitrogen accumulation) management practices. The production of publications was also discussed in a general session. Most participants have prepared several manuscripts but need to further edited and submitted for publication in scientific journals. It was agreed to go ahead with the IAEA TECDOC as final publication of the CRP. Final review of project documents and visit to the IAEA Seibersdorf Laboratories. The following day participants together with the scientific secretary reviewed final reports and executive summaries. Contents of the manuscripts to be submitted for the final IAEA publication of the project were also discussed and agreed. The visit to selected areas of the IAEA Laboratories at Seibersdorf provided an insight on the techniques to be utilised in forthcoming projects of the subprogramme. Final session At the end of the meeting, the group leaders presented the conclusions and recommendations for consideration and approval of the participants. Mr. Zapata revised the outputs of the project and assessed the criteria for the project evaluation, i.e. efficiency, and effectiveness. A task lied ahead to communicate the results and transfer these to the end-users to achieve the desired impact and relevance of the project. The project has generated a wealth of information on all these topics that needs to be properly interpreted and synthesised. Activities and deadlines to ensure completion of this work were defined. Mr. Long Nguyen officially closed the final RCM. In the afternoon, individual discussions were held with some participants. In a special session Drs. S.H. Chien and U. Singh, IFDC presented the phosphate rock decision support system to the staff of the Joint FAO/IAEA Division. Overall, significant progress in the development of sustainable agricultural production practices for predominant cropping systems in the tropical savannas of Latin America and Africa has been achieved. 5. CONCLUSIONS AND RECOMMENDATIONS During the final session of the meeting, the participants organized in working groups formulated the following conclusions and recommendations: 5.1 Crop genotypes adapted to acid soils Keywords: Al-tolerant, P-efficient and N efficient crop genotypes General conclusions In most tropical acid soils aluminium (Al) toxicity and phosphorus (P) deficiency in addition to nitrogen (N) deficiency are the most important factors limiting plant growth and crop yields. One of the key elements of sustainable cropping systems on these soils is the integration of crops and/or crop cultivars with high Al resistance, P, and N use efficiencies. General recommendations Efforts have to be made to integrate the 3 plant characteristics Al resistance, P use and N use efficiencies by plant breeders. This is a prerequisite for the adoption of such genotypes by small farmers into cropping systems on tropical acid soils of the savannah areas Aluminium resistance and soil-acidity tolerance Conclusions - 6 -

11 A simplified screening technique for Al resistance in maize based on Al-induced callose formation in root apices after short-term Al treatment has been developed and validated. A 15x15 maize open pollinated maize cultivars diallel (parents from breeding programmes in Brazil, Cameroon, Guadeloupe, Colombia) was evaluated under field conditions in 5 environments and in hydroponics using grain yield reduction by soil acidity and Al-induced callose formation as a parameter, respectively. The statistical analysis clearly showed that the General Combining Ability (GCA) rather than the Specific Combining Ability (SCA) was of major importance for Al resistance. Al-induced callose formation was negatively correlated to yields on acid soils. This screening technique proved to be a powerful tool in the identification of germplasm with high combining ability for adaptation to acid Al-toxic soils. The same methodology failed for common bean. 32 common bean cultivars were thus screened for Al resistance using the traditional technique using Al-induced inhibition of root elongation in hydroponics as parameter. In a parallel experimental approach 11 common bean genotypes were tested for soil-acidity tolerance in Cuba. 4 cultivars with improved adaptation were identified and could be recommended for use by farmers. The physiological studies have added additional evidence of the root-apoplast involvement in Al toxicity and resistance in addition to the release of organic acid anions. Also, the results confirm the possible involvement of plasma-membrane properties in Al sensitivity and resistance. Recommendations The developed screening technique for Al resistance should be extensively used in maize breeding programs aiming at breeding for acid soils tolerance. The prospects and limitations of this technique should be evaluated for other crops. The identified (bred) Al-resistant cultivars should be made available to small farmers. This will reduce the lime requirements of his fields and thus the production costs. The plant physiological studies to get a more in-depth understanding of Al resistance and Al toxicity should be advanced in order to facilitate and accelerate the breeding of Al-resistant crops Phosphorus use-efficiency Conclusions Testing of 5 sorghum cultivars, 5 rice cultivars in low-p, high-al acid soils of Venezuela, and 13 soybean and 7 cowpea cultivars in field experiments in low-p soils of West Africa revealed important genotypic differences in P use efficiency. The determination of the L-value using the 32 P dilution technique allowed assessing genotypic differences in the mobilization of sparingly soluble soil-p fractions. Efforts have been devoted to the adaptation of the technique to acid, low P, strongly P-fixing soils. Substantial differences existed between 22 plant species, including green manure species. Among the most efficient species were pigeon pea, cotton, eucalyptus, rice and white lupin, whereas maize and soybean belonged to the less efficient species although genotypic differences existed also between 30 maize and 32 soybean cultivars. Transgenic sorghum lines expressing a bacterial citrate synthase and thus an enhanced excretion of citrate from roots did not show enhanced P use efficiency in greenhouse conditions. A relationship between P mobilisation capacity and exudation of organic acid anions and P use efficiency under field conditions could not be established yet

12 Field experiments conducted on 2 sites in the Northern Guinea Savannah of Nigeria and accompanying green-house pot-experiments revealed a positive rotational effect of P- efficient cover crops with enhanced P mobilisation capacity on maize growth and grain yields particularly with return of crop residues. This could be attributed to a better P supply to maize especially on the strongly P-fixing soil. Recommendations The efforts towards a better understanding of P use efficiency and the development of quick screening techniques for P use efficiency needs to be intensified. The L-value methods should be adapted to specific soil conditions, evaluated and validated more intensively for the screening of crop cultivars. The incorporation of P-efficient crop species and cultivars into cropping systems on acid soils should be put into practise particularly by small farmers in order to reduce the necessary P fertilizer input and thus production cost Nitrogen use-efficiency Conclusions Biological N 2 fixation (BNF) capacity of the legumes cowpea, common bean and soybean in the savanna acid soils of West Africa is much lower than for soybean in the savanna soils of Brazil. Therefore, there is much scope to enhance the N derived from N 2 fixation in these legumes under such conditions. Important genotypic differences in N 2 fixation capacity has been found by comparing 7 and 28 common bean cultivars in Cuba and Mexico, respectively; 24 cowpea cultivars in Burkina Faso, and 20 soybean cultivars in Benin in both pot and field experiments using the 15 N dilution technique. Fertilizer N use-efficiency has been assessed for 5 sorghum and maize cultivars, each, in Mexico indicating genotypic differences in N use efficiency among these cereals. 16 maize cultivars have been characterized for N use efficiency in field experiments in Zimbabwe and Kenya. N uptake and N utilization efficiency appeared to be equally important. There were major differences in leaf senescence (stay green) between the cultivars, however, the relationship to N use efficiency was not unequivocal. In experiments with young maize plants grown in nutrient solution, N deficiency induced senescence of older leaves with clearly different rates between cultivars. The experiments do not yet allow clarifying the causal relationships between stay green, assimilation rate of the lower leaves, root growth, N uptake and finally N use efficiency. A compartment technique has been developed and validated, which allows the determination of root growth and N uptake activity of roots in the field at specific plant stages of development. Recommendations Efforts to increase the contribution of the legumes cowpea, common bean and soybean in West Africa to the N budget of the cropping systems through BNF particularly on acid soils need to be intensified. Optimization of the soil/plant conditions for the establishment of the symbiosis, selection of effective rhizobial strains, and particularly the breeding of cultivars with most effective symbiotic N 2 fixation are necessary. The improvement of the genotypic N use efficiency of non leguminous crops needs to be addressed much more aggressively in spite of the complexity of the physiological and molecular processes involved. Investigations for enhancing N use efficiency is urgently - 8 -

13 required for resource-poor farmers in developing countries for more cost effective production of food crops. Moreover, it can also contribute to reduce environmental hazards caused by high N-fertilizer application-rates aiming at increasing yields. A joint effort between soil scientists, plant physiologists, plant molecular biologists and plant breeders is necessary to achieve the required progress in this rather unexploited area of the breeding of more N use-efficient crop varieties. 5.2 Soil/water management of tropical acid soils Keywords: zero tillage, C/N cycling, soil water storage General conclusions 15 N and 13 C techniques were proven essential tools in collecting quantitative information related to N cycling and C dynamics in improved cropping systems on acid savanna soils. Integration of herbaceous or grain legumes (and their nitrogen inputs through BNF) in cropping systems enhances their overall productivity with positive impacts on soil fertility status and recovery of applied N fertilizer. Inclusion of legumes in cropping systems may have either positive (e.g., earthworms) or negative (e.g., nematodes) impact on the diversity and function of soil biota. Losses of N as ammonium and N 2 O are low and have little impact on the system N balance. Certain tree species are able to capture nutrients from the subsoil if there are adequate nutrient stocks in the subsoil with consequent positive recycling effects on the topsoil ph and other topsoil properties. Zero or minimum tillage in the savannas of Brazil does maintain crop yield, enhance the N balance (less N losses, higher BNF, higher fertilizer N recoveries), and improve soil C stocks with time. Conclusions derived from on-station trials at a single site are in principle only valid for that site. Consequently, general conclusions related to improved management of acid savanna soils are often contradictory Zero tillage investigations Conclusions per country and cropping system Brazil Legume-cereal rotations (Soybean wheat or soybean/maize rotations with inclusion of green manure legumes)(zero and conventional tillage) on Ferralsols/Acrisols. There were no marked differences between tillage systems (ZT and CT) in grain yields or N accumulation by the crops, but BNF was higher in the soybean crop under ZT. The higher values of soil N availability under CT in comparison to the ZT could explain the rapid and significant decrease of the total N content in the upper layer of the soil profile under the traditional soybean/wheat crop sequence. The highest values of N-NH 3 lost from the soil occurred under ZT. At the end of 13 years under a continuous sequence of wheat/soybean (R1) there was no significant difference in soil C stocks between ZT and CT. However, in the rotations where the N 2 -fixing legume vetch was planted as a winter green manure crop (soybean-wheat-vetch-maize (R2) and soybean-wheat-vetch-oat-maize (R3)), soil C stocks under ZT were increased by approximately 10 Mgha -1. Furthermore, the soil C stocks (to 100 cm depth) in R2 and R3 were 17 Mg ha -1 higher under ZT than under CT. Where soil C stocks under ZT were higher than CT, much of the N gain was at depths below the plough layer, suggesting that most of the accumulated soil C is derived from root residues. The 13 C abundance data suggested that in comparison to CT, the ZT system favored the preservation the native soil organic C

14 It was estimated that less than 900 g N-N 2 O ha -1 yr -1 were lost from the soil surface, where the highest values were found under CT. Venezuela Legume (crotalaria, indigophera, cajanus, soybean) sorghum rotations (conservation tillage) on Ferralsols. Favorable changes in the chemical, biological and biochemical variables were attributed to the conservation practices (minimum tillage, cultivars adapted to acid soils, crop rotations, combined use of organic and mineral inputs). Recommendations Recommendations from research results Under Ferralsol/Acrisol conditions in Latin America, zero tillage should be practiced as it is superior to conventional tillage in terms of soil conservation and soil fertility enhancement. Because of the above, N fertilizer application should be reduced for maintaining crop yield at current levels. Zero tillage with inclusion of green manures in the rotations should be practiced if the aim is to enhance soil C stocks with time and overall sustainability of the agricultural production systems. Recommendations for future activities Potential benefits of zero or minimum tillage should be investigated in the African savannas. Issues to consider are the need for regular deep tillage and the use of herbicides. Efforts should be directed towards a better understanding of importance of root (below-ground) biomass and turnover as the driving forces behind C accumulation/sequestration under zero tillage systems. Also, investigations should be made to assess the effects of zero or minimum tillage on soil water storage and field water balance and its influence on crop biomass production, including C accumulation/sequestration. Efforts should be made to initiate new long-term trials in the African and Latin-American savannas to properly study the impact of new soil management practices (e.g. minimum tillage in Africa) in the long run under the Conservation Agriculture initiative. Future field work should include multi-locational on-farm approaches in order to enhance the validity and applicability of the recommendations and conduct socio-economic studies to enable policy and decision-makers to formulate appropriate policies to promote the adoption of the best management practices in their countries. This can be best done under IAEA technical co-operation and other projects. Economic evaluation of zero tillage vs conventional tillage should be conducted, with special attention given to labour, energy and environmental issues, including above and below-ground biodiversity as well C/N cycling studies in cropping systems Conclusions per country and cropping system Brazil Legume-cereal rotations (Soybean wheat or soybean/maize rotations with inclusion of green manure legumes)(zero and conventional tillage) on Ferralsols/Acrisols. The BNF system in soybean is so efficient that attempts to increase grain yields by addition of N fertilizer are hardly ever successful if the plants have been effectively inoculated with the recommended Bradyrhizobium strains. The large contribution of BNF to the lupin and vetch crops

15 used as green manures of around kg N ha -1 is enough to balance, or even to increase significantly the soil N content, with good results reducing the N-fertiliser needs in agriculture without yield reduction. Since the N balance of new soybean varieties is almost nil or negative, it could be deduced that the rapid mineralization of the soybean residues favoured the grain yield of succeeding cereal crops by increasing soil N availability. This stimulation of mineralization of SOM induced by soybean crop residues could gradually reduce soil N stocks or SOM. N fertilizer use efficiency varied from 40 to 60% for a maize crop fertilised with 80 to 90 kg N ha -1, resulting in a grain yield of about 7 Mg ha -1. Major N losses via ammonia volatilization occurred when N fertilizer was applied spread in the soil surface. When the N-fertilizer was buried in the soil surface layer the N losses were insignificant. A maximum of 10% of the N-urea applied to a maize crop (40 kg N ha -1 ) spread in the soil surface was lost as ammonia volatilization under ZT. It was estimated that less than 900 g N-N 2 O ha -1 yr -1 was lost from the soil surface, where the highest values were found under CT. Brazil Maize - Brachiaria soybean rotations (zero tillage) on Ferralsols. Optimal application of N fertilizer was 30 kg N/ha at seeding and 90 kg N/ha at 30 days after planting. N fertilizer application did not affect P utilization by maize. Brachiaria produced over 8 t/ha following the maize crop. Soybean yield was not affected by the preceding crop. Brazil Crotalaria or millet maize rotation (zero tillage) on Ferralsols. The highest maize yield was obtained in the crotalaria-maize rotation, followed by fallow-maize and millet-maize. This was also true for the residual effects during the second year. Grain yield response to fertilizer N improved slightly in the crotalaria-maize system compared with the other two systems. The quantity of N derived from fertilizer increased with increasing N rate. Best values were obtained in the crotalaria-maize rotation. The maximum N use efficiency was obtained with 100 kg N/ha. Mexico Legume green manures (mucuna, canavalia, cajanus) maize associations (conventional tillage) on Acrisols. The application of earthworms and green manure was recognized and recommended as a promising agricultural practice to increase maize yield. For the population density of plants used in the study, the association of outstanding maize genotypes (N-efficiency) and highly N fixing legumes (%Ndfa) resulted in a higher fixation by legumes and a lower maize yield and fertilizer N use efficiency. Venezuela Legume green manures (crotalaria, indigophera, cajanus, soybean) sorghum rotations (conservation tillage) on Acrisols. Increased soil organic carbon and higher sorghum yields were obtained when legume green manures were included in the rotation and incorporated. Best fertilizer N use efficiency was obtained in upland rice when N fertilizer was split applied at 25, 45 and 60 days after planting with overall recovery of 66%. Single application at planting and split application at 25 and 60 days after planting resulted in overall recoveries of 38% and 56%, respectively

16 Burkina Faso Grain legumes (groundnut, cowpea) sorghum rotations (conventional tillage) on Lixisols. Compared to continuous cultivation of sorghum, cowpea and groundnut increased succeeding sorghum yields (2.9 and 3.1 times more grain yields). The nitrogen fertiliser equivalency (NFE) of groundnut (35 kg N ha -1 ) was higher than this of cowpea (25 kg N ha-1). A better fertilizer N use efficiency was observed in legume-sorghum rotations. In continuous sorghum, fertiliser N use efficiency (FNUE) was 20%, compared with 28 and 37% in cowpeasorghum and groundnut-sorghum rotations, respectively. In sorghum mono cropping, fertilizer N recommendations for succeeding sorghum was 40 kg N ha -1. Nitrogen fertiliser recommendations for succeeding sorghum were 51 and 58 kg N ha -1 when sorghum was rotated with groundnut or cowpea. Legume-sorghum rotations increased soil mineral nitrogen. The soils of legume-sorghum rotations provided more nitrogen to succeeding sorghum compared to mono cropping of sorghum. In cowpea-sorghum rotation soil and succeeding sorghum roots were most infected by nematodes while groundnut decreased nematode infections. Soil organic carbon was 0.36% in continuous sorghum and 0.39% and 0.54% in cotton-groundnutsorghum and fallow-sorghum rotations, respectively. Only fallow-sorghum rotation maintained soil organic carbon, exchange acidity and base saturation at same levels like those of original soil. Highest quantities of available P (P-Bray I) were observed in soils of mono cropping of sorghum and lowest quantities were observed in fallow-sorghum rotation. Manure applications increased soil organic carbon, total N and available P. Except for fallowsorghum rotation, all rotations increased aluminium saturation and decreased soil ph compared to original soil. Manure or dolomite applications decreased exchangeable acidity and maintained soil ph and base saturation at same levels as the original soil. Nigeria Maize tree (Leucaena, Senna, Gliricidia) intercropping (minimum tillage) on Lixisols. In a long term trial with inputs of tree-derived organic resources (Leucaena leucocephala, Senna siamea), and fertilizer, alone or in combination, the Senna-based system with fertilizers was the more resilient one, both in terms of crop yields and soil fertility status. In the above trial, trees had a positive impact on the maintenance of exchangeable cations in the top soil. Exchangeable Ca, Mg, and K and hence ECEC were only slightly reduced after 16 years of cropping in the tree-based systems, and even increased in the Senna treatment. In a set of medium to long term trials with various hedgerow trees, topsoil Ca content, ECEC, and ph were substantially higher under Senna than under Leucaena or Gliricidia to the no-tree control plots at sites with a Bt horizon, rich in exchangeable Ca, largely related to the recovery of Ca from the subsoil under Senna trees. Benin Soybean-maize rotation (minimum tillage) on Acrisols. Residual effects of previous soybean, amended with manure or N fertilizer resulted in significant improvements in maize grain yield although the actual values remained low (< 1 t/ha). Recommendations Recommendations from research results For sustainable crop production with efficient use of external inputs, green manure or grain legumes should be introduced in the cropping systems. Inclusion of such species also positively affects the soil fertility status. To access nutrients below the crop rooting zone, specific tree species should be introduced in association with the food crops provided there are adequate nutrient stocks in the subsoil

17 In the Brazilian savannah (Cerrado), the commonly used millet-maize rotation should be reevaluated as it resulted in lower yields compared to the fallow-maize and crotalaria-maize rotations. Alternatively, N fertilizer strategies should take this into account. Recommendations for future activities BNF should be assessed under field conditions as results from pot experiments only reveal relative potential of legumes to fix N. More investigations are needed to quantify below-ground contributions of BNF. Investigations are needed to identify deficiencies of secondary and micronutrients (e.g., K, S, Zn) as these may become limiting factors of crop production in the medium to long term. Efforts should be made to initiate long-term field trials to properly study the impact of new soil management practices (e.g. crop rotations with herbaceous legumes in Latin America). Investigations on the occurrence of deficiencies of secondary nutrients as constraints need to be covered in such efforts. Research activities are needed to understand and quantify the various dimensions of rotational benefits in legume-cereal rotations besides N. Special emphasis should be put on changes biological and physical properties following legumes crops. Future field work should be using multi-locational on-farm approaches in order to enhance the validity and applicability of the recommendations. Such approaches are essential to put various components together and evaluate the overall cropping systems in a farmer-participatory way Soil water investigations Conclusions Most participants assumed that water was not a limiting factor in the humid savanna areas, though there were major variations in total rainfall and its distribution during the growth season affecting crop yields. No data are reported except one nitrate leaching study performed in Brazil, where water monitoring in the soil profile was essential. Recommendations Recommendations for future activities It is very important to monitor soil water status and collect data on the water balance components to get detailed information on water dynamics as affected by soil, water and nutrient management practices (Conservation Agriculture CRP?). In above efforts, it is essential to look at interactions between soil water and nutrient use efficiency. 5.3 Ameliorating soil acidity and nitrogen infertility of tropical acid soils Keywords: liming, fertilizer N, BNF grain legumes, animal manures, green manures/cover crops, organic residues Conclusions In the course of this CRP, nuclear and related techniques provided reliable information to address limitations of soil acidity and nitrogen infertility in a range of cropping systems on acid tropical soils in Latin America and Africa. In Latin America, the studies were conducted on savannah soils that are strongly weathered and inherently acid, whereas in Africa the soils are weakly acidic but prone to acidification as cultivation intensifies. In Burkina Faso, satisfactory agreement between the isotopic dilution and the total N difference method was observed for BNF assessment in cowpea

18 BNF assessment in grain legumes (soybean, common bean, cowpea, and pigeon pea; see Table 1) using 15 N methodology indicated that there is a scope for increasing BNF especially for common bean and to some extent for cowpea and groundnut. This can be achieved through better agronomic management, rhizobial strain selection, and further plant genetic improvement. Liming with CaCO 3 increased % Ndfa of common bean from 28 to 38% on an Acrisol (initial ph-kcl of 3.8) in Cuba. Application of dolomite to cowpea doubled the amount of Ndfa on a sandy Ultisol (ph-h ) in Burkina Faso. Observed fertilizer N recoveries (FNR) varied widely across the different sites (Table 2). Both the inclusion of legumes in the cropping system and the shift from conventional to mimimum tillage increased the FNR (Table 2) but this improvement seemed to decrease with increased fertilizer N application rates (Fig. 1). Table 1: Biological Nitrogen Fixation in grain legumes Number of genotypes Inoculation Type of experiment %Ndfa Amount of nitrogen fixed Common bean Cuba 4 Yes Greenhouse % mgn plant -1 Cuba 7 Yes Field 26-37%??? kg N ha -1 Mexico 28 Yes Greenhouse 0-38 % 0-18 mgn plant -1 Soybean Brazil 21 Yes Field % kg N ha -1 Benin 22 Yes Greenhouse % mgn plant -1 Venezuela 1 Yes Field 68 % Burkina Faso 1 No Field 33 % 13 kg N ha -1 Cowpea Burkina Faso 24 No Field % kg N ha -1 Groundnut Burkina Faso 1 No Field 2-23 % kg N ha -1 Pigeon pea Venezuela 1? Greenhouse, 45days % mg plant -1 Venezuela 1? Field, Duration? 79% Mexico 1 No Field, 240 days 81% 495 kg N ha -1 Table 2: Effect of minimum tillage and rotation with legumes on the fertilizer N recovery (FNR) of the fertilizer applied to a cereal crop. Site, country, annual rainfall, FAO soil type N rate (kgn ha -1 ) Crop Baseline system FNR (%) baseline Improved system FNR (%) improved system Selviria-MS, Brazil, 1370 mm, Latosol system 30 (urea) Maize Maize after 41 Maize after millet 42 Crotalaria fallow

19 Farakoba, Burkina Faso, 900mm, Ultisol, FNUE in 7 th year of rotation trial Farakoba, Burkina Faso, 900mm, Ultisol, FNUE in 7 th year of rotation trial Kouare, Burkina Faso, 600mm, Alfisol, FNUE in 8 th year of rotation trial Farakoba, Burkina Faso, 900mm, Ultisol, FNUE in 8 th year of rotation trial Londrina, Brazil, 1800 mm, Typic Haplorthox Londrina, Brazil, 1800 mm, Typic Haplorthox Londrina, Brazil, 1800 mm, Typic Haplorthox Londrina, Brazil, 1800 mm, Typic Haplorthox Planaltina, Brazil,??? mm, Oxisol; 22 nd year of trial; which rotation? 37 (urea) Sorghum Continuous sorghum cropping 37 (urea) Sorghum Continuous sorghum cropping 37 (urea) Sorghum Continuous sorghum cropping 37 (urea) Sorghum Continuous sorghum cropping 40 (urea) Wheat CT soybeanwheat 40 (urea) Maize CT Maize after lupins 40 (urea) Maize CT Maize after lupins 80 (urea) Maize CT Maize after oats 20 Cotton- Groundnut - Sorghum 20 Groundnut- Sorghum Cowpea- Sorghum 17 Cowpea - Sorghum rotation 19 Cotongroundnut - Sorghum rotation 50 NT soybeanwheat 49 NT Maize after lupins 34 NT Maize after lupins 39 NT Maize after oats 90 (AS) Maize CT 46 NT

20 Difference in fertilizer N recovery between the improved and the baseline system (% of N added) Selviria, Brasil Farakoba, Burkina Faso Kouare, Burkina Faso Londrina, Brasil Planaltina, Brasil Amount of N fertilizer added (kg N ha -1 ) Fig. 1: Relationship between the changes in fertilizer N recovery (difference between the improved and the baseline system as % of N added) versus the amount of N fertilizer applied. Recommendations Assess if promiscuous soybean varieties truly realize their BNF potential in association with indigenous rhizobia (i.e., without inoculation) across the entire African savannah, and determine if there is a need for improving BNF through better agronomic management and further genetic improvement of soybean. It is advisable to assess BNF in acid tropical soils under field conditions to have reliable estimates on net N inputs in units of kg per hectare There is a need to confirm some of the conclusions of this CRP in multi-locational experiments, preferably in on-farm conditions. There is a need to identify and elucidate the key mechanisms responsible for the observed rotational effects (i.e., effects other than N effects) in legume-cereal systems. Better understanding of these is required to optimise cropping systems in tropical acid soils. 5.4 Ameliorating Low P Status of Tropical Acid Soils Key words: P sources, agronomic effectiveness of PR sources, PR database, PRDSS Conclusions Nuclear and related techniques used in the CRP on Development of Management Practices for Sustainable Crop Production Systems on Tropical Acid Soils through the Use of Nuclear and Related Techniques, provided reliable information to ameliorate low P status in a range of cropping systems on acid tropical soils in Latin America and Africa. In Latin America, the focus was on soils that are inherently acid with Al toxicity and high P fixation, whereas in Africa the studies were conducted on savannah soils that are weakly acidic but prone to acidification (low buffering capacity). In P-deficient soils excellent P crop response

21 Results confirm P need for BNF and show effect of PR sources on BNF. Effects of P sources and soil properties (e.g., P fixation capacity, Al saturation) on crop yield (e.g., Latin America versus West Africa). Interaction with Ca were observed, e.g. sometimes better P (or PR) response due to liming 32 P isotopic techniques used for estimation of available P in the laboratory and greenhouse. They need adaptation for their application in very low P and high P sorption (fixation) acid soils. Crop genotype responses P rates, P sources including appropriate PR (Cuba example with common bean, Mexico no response from sorghum transgenic varieties with different citric acid (CA) release, may be associated with PR source with free CaCO3 reduced effectiveness of CA released. Inadequate standardized characterization site (soil, climate) and PR samples. e.g., P response limited by rainfall, no response to P (PR) limited by Al toxicity, over-liming, etc., makes difficult proper interpretation of results and drawing of conclusions. Powdered mixtures of PR and WSP without compaction or granulation proved to be ineffective for the starter effect of WSP on PR effectiveness as shown by the results from Brazil utilizing the low-reactive Patos PR and a high P-fixing soil. An agronomic PR database with standard characterization of PR solubility measurements has been created and a decision support system for direct application of PR sources (PR DSS) was developed under a joint FAO/IAEA and IFDC collaboration project. The PR database has been further expanded including entries from geological and agronomic key references. Some of these data have been made available as it was included in the DAPR (Direct Application of Phosphate Rock) website created jointly by FAO/IAEA and IFDC. Recommendations PRDSS Testing using CRP Results A. Input Data Needed PR Solubility Soil ph Crop rhizospheric effects Soil texture, OM, P-fixation Capacity, Al Saturation Rainfall (temperature, wet-days) Crop and genotypic effects duration, Al toxicity and P fixation Planting and harvest dates B. Data for Evaluation Yields/response with PR and WSP (TSP, DAP, SSP) Economic data CRP Paper Summarizing PR Responses Possible joint publication (with all contributors) Paper Content: 1. Brief description of PRDSS 2. Brief description of trials (Refer to individual papers) 3. Validation different trials Comparison 1:1 line (observed vs. simulated RAE) Example: data from PR trials in Cuba and at IFDC with common bean and upland rice were used for PRDSS testing showing five data points were close to 1:1 line whereas four data points deviated from the line

22 limitations, constraints 4. Conclusions/recommendations PRDSS TEST: Upland Rice (IFDC) and Bean Varieties (Cuba) 100 Predicted RAE Observed RAE Common Bean Upland Rice Standard site, soil, climate, crop, management characterization of field trials All field trials must have full and standard characterization of the PR sources, particularly the PR solubility as determined by the 2 nd extract of Neutral Ammonium Citrate of finely ground rock. These trials (i) should be conducted on soils that have been characterized, (ii) at least have rainfall record during the cropping season, (iii) crop duration and other variety characteristics (name of variety, etc) be known, and (iii) apart from agronomic data on yield the planting date and harvest date be provided. Modified PR Sources Under unfavourable conditions for PR use, e.g. low reactivity, high soil ph, etc., modifications of the phosphate rock by (i) partial acidulation of PR, (ii) dry compaction of PR with WSP, or (iii) wet granulation of PR with WSP are recommended to improve their agronomic and economic feasibility. Powdered mixtures of PR and WSP should not be recommended for high P-fixing soils because of possible poor starter effect of powdered WSP on PR effectiveness.. Additional Benefits of PR Sources Need for quantifying the additional beneficial effects of PR due to availability of exchangeable Ca and liming effect on Al toxicity in tropical acid soils. Network of PRDSS Field Validation Trials These field trials will be used to validate the PRDSS and also evaluate effect of one-time versus annual application over a two-year period to capture immediate and residual effects and effect of

23 PR as liming agent. The trials are in: Burkina Faso, Tanzania, Malaysia, Vietnam, Argentina, Brazil, Togo and sites in Mali and Thailand through University of Hawaii. The effects of lime (combined effects of ph and Ca) and gypsum (Ca effect) applications, e.g., Brazil, on P and particularly, PR availability, need to be quantified. Efficient Crops and Cultivars Identification and use of crops and cultivars with improved P use efficiency, particularly soil P and PR sources, in cropping systems. Since in acid tropical soils, Al toxicity, low P status, and N deficiency is common, it will be highly beneficial to identify/develop cultivars that integrate Al tolerance and P and N use efficiency. 32 P Isotopic Techniques use in acid high P-fixing soils Thorough evaluation of 32 P isotopic techniques is needed in high P-fixing acid tropical soils, soils with very low available P, and with range of soil P sources (WSP, PR) Website for Direct Application of PR The web-based PRDSS will result in greater accessibility of information and decision choices to a large audience comprising of researchers, extension workers, farm managers, progressive farmers, policymakers, and fertilizer companies. Based on relative agronomic and economic feasibility provided by the PRDSS they will be able to make informed decisions for use of PR for direct application as compared with WSP. This will avoid trial and error use of PR and thus save time and money. Alternatively if direct application of PR is not suitable modifications/suggestions will be given. At a final stage the PRDSS will be linked to DSSAT P modeling to predict crop yield to be obtained with WSP and PR sources and made economic assessment (cost/benefit ratio) to determine whether use of PR or WSP versus no P application would be most profitable to the farmers in the tropical regions of acid soils. The DAPR website will also contain other relevant information on P and PR. The agronomic PR database with standard characterization of PR solubility measurements available on this website will be updated regularly. 6. ACKNOWLEDGEMENTS On behalf of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, the Scientific Secretary would like to express his gratitude to the participants and their teams for their dedication and untiring efforts in implementing the work plan of the project. The 15 N analytical and other supportive services provided by the staff of the Soil Science Unit are duly acknowledged. Special thanks are given to Ms. Rosario Leon de Muellner for secretarial and administrative assistance during the implementation of the project

24 Food and Agriculture Organisation of the United Nations Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture Wagramer Strasse 5, P.O. Box 100, A-1400 Vienna, Austria Phone: (+43 1) 2600 Fax: (+43 1) Internet: In reply please refer to: 311.D1.RC Dial directly to extension: (+431) Annex A Programme of the meeting Final Research Co-ordination Meeting of the Co-ordinated Research Project on Development of Management Practices for Sustainable Crop Production Systems on Tropical Acid Soils through the Use of Nuclear and Related Techniques 15 to 19 November 2004 Vienna International Centre Room F0118 P R O G R A M M E Monday, 15 November Opening Session 09:15-09:30 Welcome address Minh-Long Nguyen, Section Head 09:30-10:00 Remarks by F. Zapata, Scientific Secretary 10:00-10:30 Coffee break SESSION I: Chairperson: Ming-Long Nguyen Savannas of Latin America Presentations from participants (45 minutes each + 15 minutes discussion) 10:30-11:30 Mr. Segundo Urquiaga (Brazil)) 11:30-12:30 Mr. Takashi Muraoka (Brazil) 12:30-14:00 LUNCH BREAK Session II: Chairperson: C. Bernard Savannas of Latin America Presentations from participants (Cont.) 14:00-15:00 Mr. Juan Jose Pena-Cabriales (Mexico) M-12/Rev. 2 (Jun 04) 15:00-16:00 Mr. Alvaro Garcia (Cuba) 16:00-16:30 Coffee Break 16:30-17:30 Ms. Marisol Lopez (Venezuela)