Biological nitrogen fixation in nutrient management

Abstract

The use of costly chemical nitrogen fertilizers for increased food production is a global concern due to their economic and environmental effects. It is the dire need of the day to find out some alternative to the nitrogen fertilizers which is economical and environmentally safe. Biological fixation of atmospheric diatomic nitrogen into a form useable by the plant is a possible alternative to the chemical nitrogen fertilizer which is economically viable, ecologically desirable, and environmentally safe with reduced external inputs. In most of the symbiotic systems, Rhizobium-legume association contributes its major part in providing the N to most of the cropping system, whereas Anabaena and Azolla can be important in reduced conditions such as flooded rice. Despite the importance of nitrogen fixation, there are a number of sociocultural and scientific constraints that limit the adoption of BNF system in agriculture. The major limitation is the hindrance in the management of nutrients in the soil using the BNF as sustainable system. However, if these limitations are handled carefully on scientific basis, then BFN can be a potential source for the management of soil nutrients. Crop residues from nodulated crops also provide nutrients especially nitrogen to the subsequent crops. By adopting the BFN as cropping system, it can cut the heavy use of nitrogen fertilizer which is not only costly but also polluting the environment especially the groundwater. However, optimization of nitrogen fixation can balance the use of fertilizer and thus can help to manage the nutrients for the crops in a sustainable manner. In the present chapter, it is discussed how BNF can be crucial in managing the nutrients.