Application of nitrogen-fixing systems in soil management [antikvár]

PREFACE In view of the continuing increase in cost and scarcity of mineral fertilizers resulting from the use of high-cost fossil energy, there is renewed interest in organic recycling and biological nitrogen-fixation to improve soil fertility and productivity. FAO, in cooperation with the Swedish International Development Authority (SIDA) has assumed a leading role in this respect, including the sponsoring of a series of important international meetings to promote the use of organic materials and biofertilizers. Examples of these meetings include: the Expert Consultation on Organic Materials as Fertilizers held in Rome in 1974; the Workshop on Organic Recycling in Asia held in Bangkok in 1976 and the Workshop on Organic Materials and Soil Productivity in the Near East held in Alexandria in 1978. The workshop in Alexandria recommended the further promotion of research, development, application and dissemination of information available on various aspects of biological nitrogen-fixation, including symbiotic systems of rhizobia/legume and /I20Z.la/blue-green algae, and free-living nitrogen-fixing bacteria and blue-green algae. Dr Y.A. Hamdi, a delegate and invited speaker at the workshop was requested to prepare the present Bulletin, which reviews the literature and provides information on the characteristics, production and use of biofertilizers in agriculture. Although some of the methods described are being continually improved upon, it is hoped that the compilation of various aspects of nitrogen-fixation under one cover in this Bulletin will be of interest and assistance not only to research workers, but also to extension workers and planners concerned with the further development and refinement of these natural systems for soil improvement and management throughout the various agro-ecological zones of the world.