Question

Azolla is used as a biofertilizer, because it

• A. Has association of nitrogen-fixing Rhizobium
• B. Multiplies very fast to produce massive biomass
• C. Has association of nitrogen-fixing Cyanobacteria
• D. Has association of Mycorrhiza

Answer 1

Answer: (C)

Azolla can be used as a biofertilizer as cyanobacteria. Cyanobacteria live in symbiotic association with the roots. As a result, Azolla-Anabaena can fix almost three times more atmospheric nitrogen than legumes. Typical rates for legumes are 400 kg of nitrogen per hectare per year those for Azolla-Anabaena are 1100 kg of nitrogen per hectare per year.

So, the correct answer is option C.