Role of Algae as a Biofertilizer

Sustainable agriculture is advantageous over conventional agriculture for its capacity to accomplish food demand by utilizing environmental resources without negatively affecting it. The beneficiary role of blue-green algae (BGA) by way of supporting the nitrogen economy of paddy fields and enhancing rice productivity is well documented. The simple presence of BGA in soil results in formation of soil aggregates, which reduces soil loss during rainy season and regulates aeration, soil temperature, hence, improving physical and chemical properties of soil vis-a-vis physical environment of the crop. BGA are helpful in restoring soil nutrients by secreting exopolysaccharides and bioactive substances. They have the potential to mobilize insoluble forms of inorganic phosphates. Algalization has been employed for reducing the amount of exchangeable sodium, which results in altered soil pH and leads to reclamation of sodic soils. Some red algae used as biofertilizers have been found to augment growth nutritional value and yield of crop plants. This chapter provides an overview of the role of algae as biofertilizers.