N-biofertilizer
Nitrogen (N) is one of the most essential nutrients
for plant growth as it has a fundamental role in energy metabolism and protein
synthesis. Ammonium and nitrate are two available forms of N for plants.
However, chemically produced ammonium (urea as amide form) is a much expensive
and energy-intensive process and also poses various threats to the environment,
human, and soil health. N-biofertilizer (a formulation of N-fixing microbes) is
one of the better options to supplement the chemically produced N-fertilizer.
Some microbes have the ability to fix atmospheric N into ammonium and these
microbes are called N-fixing microbes. Example: Blue-green algae (BGA,
cyanobacteria), BGA associated with Azolla, Azotobacter,
Azospirillum, Pseudomonas, Rhizobium, Actinobacteria, etc.
Rhizobium is the major
N-biofertilizer used in black gram crops mainly in the form of soil and seed treatments.