Application of nitrogen-fixing systems in soil improvement and management

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. 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 Azolla/blue-green algae, and free-living nitrogen-fixing bacteria and blue-green algae. It is hoped that the compilation of various aspects of nitrogen-fixation under one cover in this Bulletin will be of interest and assistance to research workers and extension planners concerned with the further development and refinement of these natural systems for soil improvement and management.