Biological Nitrogen Fixation in Legumes: An Overview

Nitrogen is an essential nutrient for plants and is often a limiting factor in crop growth. Large quantities of fertiliser are often applied to crops which is an energy-consuming, expensive and pollution producing procedure from production to application. Biological nitrogen fixation is a solution to reduce nitrogen-related problems in agriculture. Biological nitrogen fixation, the reduction of dinitrogen (N2) to ammonia, is an essential reaction in the global nitrogen cycle. Many legumes have evolved to establish a symbiosis with nitrogen-fixing soil-bacteria collectively known as Rhizobia. More than 98 species of symbiotic nitrogen-fixing rhizobia exist in 14 taxa in association with legumes.