The International Workshop on Biological Nitrogen Fixation for Increased Crop Productivity, Enhanced Human Health and Sustained Soil Fertility was held in June 2002 at ENSAM-INRA, Montpellier, France. The main goal of the workshop was to define research strategies for a Challenge Program initiative on Biological Nitrogen Fixation, and develop a pre-proposal based on the concept note submitted and approved by the CGIAR iSC. More than 35 participants from various scientific disciplines, research institutions and from four different continents (Africa, Asia, Americas and Europe) attended the workshop. This book, based on the proceedings of the workshop, takes a holistic approach to harnessing legume BNF technologies, starting from a socioeconomic perspective, and progressing to agronomic and genetic options, and bringing together innovative aspects and participatory research strategies.

Biological nitrogen fixation in tropical agrosystems: twenty years of biological nitrogen fixation research in Africa; Sustainable agriculture: definition and measurement; Biological nitrogen fixation systems in tropical ecosystems: an overview; A protocol for screening legumes as soil-improving crops; The sustenance of tropical agriculture with multipurpose azolla; Facteurs pedoclimatiques limitant la lixation biologique l'azole; Response of some tropical nitrogen-fixing woody legumes to drought and inoculation with mycorrhiza; Improvement to the Phaseolus/Rhizobium symbiosis, with particular reference to the Caribbean region; Effect of pest management systems on biological nitrogen fixation; Agronomic evaluation of a rock phosphate as a phosphorus source for Leucaena leucocephala grown on an utisol; Nodulation of soybean grown under field conditions and inoculated with Bradyrhizobium japonicum strains; Effect of fertilization and Rhizobium inoculation on the growth of Leucaena and Gliricidia on an alfisol in south-western Nigeria; Early growth and nodulation in Leucaena and Gliricidia and the effects or pruning on biomass productivity; Comparative stude on the growth and productivity of Sesbania and Leucaena in the Central Plateau region, Rwanda; Supernoculation and non-nodulation mutants of soybean; Genetically improved rhizobia and their use in agriculture; Sustainability of nitrogen-fixing cropping systems: Nodulation and nitrogen fixation and transfer in a cowpea/rice cropping system; The role of legumes in sustaiing soil productivity and controlling soil erosion; Fitting soil-improving legumes into inland valley rice-baes cropping systems in West Africa; Herbage yield and soil fertility restoration potential of some tropical forage legumes.

Keynote addresses. Plant factors affecting N2 fixation. Technology for inoculant production. Environmental factors affecting symbiotic n2 fixation. Inoculation trials. N2 fixation in grain legumes. N2 fixation in pasture legume. N2 fixation in trees. Associative n2 fixation. The azolla/ananaena association. Critique of methodologies. The nitrogen relationships of maize/bean associations. Assessing the nitrogen contribuktion of cowpea (Vigna unguiculata) in monoculture and intercroped. Nitrogen fixation by groundnut (Arachis hypogeae) in intercropped and rotational systems. Effect of cowpeas in cereal rotations in conditions in Upper volta. Residual effects of pigeopea (Cajanus cajan). Atechology assessment of biological nitrogen fixation. Economic analysis of biological nitrogen fixation. Research and development for biological nitrogen fixation in India. The brazilian program in biological nitrogen fixation. Internationally sponsored development of biological nitrogen fixation technology. Research on biological nitrogen fixation in the international agricultural research centers.

Plant factors affecting N2 fixation; Technology for inocullation production; Environmental factors affecting symbiotic N2 fixation; Inocullation trials; N2 fixation in grain legumes; N2 fixation in pasture legumes; N2 fixation in trees; Associative N2 fixation; The azola/anabaena association; Critique of methodologies; General considerations.

Nitrogen fixation by leguminous plants is especially important when farmers are trying to minimise fertilizer use for cost or environmental reasons. This second edition of the highly successful book, first published in 1991, contains thoroughly updated and revised material on the theory and practice of nitrogen fixation in tropical cropping systems.