Abstract:
The economic and environmental costs of heavy use of chemical fertilizers in agriculture are a global concern. Sustainability considerations mandate that alternatives to Nitrogen fertilizers must be urgently sought. Biological nitrogen fixation (BNF), a microbiological process which converts atmospheric nitrogen in to a plant usable from, offers this alternative. Nitrogen fixing systems offer an economically attractive and ecological sound means of reducing external inputs and improving internal resources. Symbiotic systems such that of Anabaena – Azolla system can be used as a source of nitrogen in cropping systems.
