ABSTRACT
Agriculture faces two major challenges in terms of sustainability: firstly, supplying nutrition to the world’s population and secondly, advancing ecosystem services to preserve clean air and water and other benefits for mankind. Currently, the global population is growing at an alarming rate, which poses a big threat to food security as the land for agriculture is limited and reducing more with time. To achieve the expected production of 321 million tons of food grain by 2020, the nutrient demand is estimated to be 28.8 million tons, while their supply will be just 21.6 million tons, a deficit of about 7.2 million tons. To bridge the gap between production and consumption, chemical fertilizers are used to further crop growth but may eventually cause significant harm to both the environment and human health. In this context, the use of biofertilizers in the agricultural sector is considered an alternative to chemical fertilizers because of their substantial capacity to increase crop quality and food safety. Biofertilizer contains microorganisms that promote the adequate supply of nutrients to the host plants and ensure their proper growth and physiological regulation. Most biofertilizers belong to nitrogen-fixing, phosphate-solubilizing, and cellulolytic microorganisms. Nitrogen biofertilizers fix the available forms of atmospheric nitrogen into the soil that are readily usable by the plants. These include Rhizobium, Azotobacter, Azospirillum, blue-green algae (BGA), and Azolla. In this chapter, we will discuss the main issues related to the promotion of nitrogen biofertilizers, and the potential of these biofertilizers as tools for small- and large-scale sustainable crop production.
